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Cornell University Library 
 TN 23.K32 1896 
 
 The ore deposits of the United States / 
 
 3 1924 004 476 887 
 
\^y 
 
 v. 
 
 Cornell University 
 Library 
 
 The original of this book is in 
 the Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924004476887 
 
THE 
 
 OKE DEPOSITS 
 
 OF THE 
 
 UNITED STATES 
 
 BY 
 
 JAMES F. KEMP, A.B., E.M. 
 
 PROFESSOR OF GEOLOGY IN THE SCHOOL OF MINES, COLUMBIA COLLEGE 
 
 REVISED AND ENLARGED. 
 
 NEW YORK AND LONDON 
 THE SCIENTIFIC PUBLISHING COMPANY 
 
 1896 
 
 & 
 
Copyrighted, 1893, 
 
 BY 
 
 Thk Scientific PuBLisHiNa Company. 
 
f n ittctnorB of 
 JOHN STRONG NEWBERRY* 
 
 FIRST PROFESSOR OP GKOLOGT IN THE SCHOOL OP MINES, COLUMBIA COLLEGE 
 
 This book is respectfully inscribed by 
 
 his old student and friend 
 
 THE AUTHOR 
 
 *Dr. Newberry died whUe the book wa3 In press. 
 
PREFACE. 
 
 The following pages presuppose for their comprehension som^ 
 acquaintance with geology and mineralogy. The materials for 
 them have been collected and arranged in connection with lectures 
 on economic geology, first at Cornell University and later at the 
 School of Mines, Columbia College. To the descriptions of others 
 the author has endeavored to add, as far as possible, observations 
 made by himself in travel during the last ten years. The purpose 
 of the book is twofold, and this fact has been conscientiously kept 
 in view. It is, on the one hand, intended to supply a condensed 
 account of the metalliferous resources of the country, which will 
 be readable and serviceable as a text-book and work of reference. 
 For this reason every effort has been put forth to make the bibliog- 
 raphy complete, so that, in cases where fuller accounts of a region 
 are desired, the original sources may be made available in any 
 good library. But, on the other hand, it has also been the 
 hope and ambition of the author to treat the subject in such a way 
 as to stimulate investigation and study of these interesting phe- 
 nomena. If, by giving an extended view over the field, ai^d by 
 making clear what our best workers have done in late years toward 
 explaining the puzzling yet vastly important questions of origin 
 and formation, some encouragement may be afforded those in a 
 position to observe and ponder, the second aim will be fulfilled. 
 In carrying out- this purpose, the best work of recent investigators 
 on the origin and changes of rocks, especially as brought out by 
 microscopic studv. has been keot constantly in mind, and likewise 
 in the artificial production of ttie ore ana gangue minerals. So 
 much unsound and fix^Usb theorizing has been uttered and believed 
 about ores, that too touch care cannot be exercised in basing ex- 
 planations on reasonable and right foundations. 
 
 Acknowledgments are due to many friends for encouragement, 
 suggestion, and criticism. To Prof. Henry S. Williams, now of 
 
VI PREFACE. 
 
 Yale, but late of Cornell, whose interest made the book possible, 
 these are especially to be_ made. On particular regions much ad- 
 vice has been obtained from Dr. W. P. Jenney, for which the 
 author is grateful. In the same way Prof. H. A. Wheeler of St. 
 Louis, Prof. R. A. F. Penrose of Chicago, and several other friends 
 have contributed. Dr. R. W. Raymond suggested the method of 
 enumerating the paragraphs. It has the advantages of being elas- 
 tic and of showing at once in what part of the book any paragraph 
 is situated. 
 
 The geologists of the United States Geological Survey, who 
 have been engaged in the study of our great mining regions, es- 
 pecially in the West, have laid the whole scientific world under 
 a debt of gratitude, and in this country have probably been the 
 most potent influences toward right geological conceptions regard- 
 ing ores. Of authors abroad. Von Groddeck has been a. means of 
 inspiration to all readers of German who have interested them- 
 selves in this branch of geology. The writer cannot well forbear 
 acknowledging their influence. 
 
 Should errors be noted by any reader, the writer will be very 
 appreciative of the kindness if his attention is called to them. 
 
 J. F, Kemp. 
 Columbia College, 
 IN THE City of New York. 
 
PREFACE TO THE SECOND EDITION. 
 
 In the second edition many pages have been rewritten and ex- 
 panded. The endeavor has been also made to introduce into the 
 body of the work the new materials that have become available in 
 the last year. This is especially true of iron ores, of the geology 
 of the Sierras, and of nickel and cobalt. In all some fifty pages 
 of new matter have been added, and fifteen cuts. Acknowledg- 
 ments are herewith made to Professors W. H. Pettee of Ann 
 Arbor, H. S. Munroe of New York, and C. H. Smyth, Jr., of 
 Hamilton College, and to Mr. H. L. Smyth of Cambridge, and Mr. 
 W. C. Knight of Laramie, for suggestions, as requested in the 
 preface to the first edition. 
 
 J. F. K. 
 
TABLE OF CONTENTS, 
 
 PAQE 
 
 Preface v 
 
 List of Illustrations xiii 
 
 List of Abbreviations xvii 
 
 PART L— INTRODUCTORY. 
 
 Chapter I. — General Geological Facts and Principles. 
 
 The two standpoints of geology, 3, 4; the scheme of classifica- 
 tion, 4, 5; classification of rocks, 6; brief topographical survey of the 
 United States, 6, 7; brief geological outline, 7-10; the forms as- 
 sumed by rock masses, 10, 11 1-11 
 
 Chapter II. — On the Formation of Cavities in Rocks. 
 
 By local contraction, 12, 13; by more extensive movements, 
 13-17; faults, 17-20; secondary modifications of cavities, 30-22 13-22 
 
 Chapter III. —The Minerals Important as Orbs ; the Gangue 
 Minerals, and the Sources whence both are Derived. 
 
 The minerals, 23; source of the metals, 23-27 23-27 
 
 Chapter IV. — On the Filling of Mineral Veins. 
 
 Resum6, 28; methods of filling, 28, 29; ascension by infiltration, 
 29-33; lateral secretion, 30, 31; replacement, 33, 34 28-34 
 
 Chapter V. — On Certain Structural Features of Mineral Veins. 
 
 Banded structure, 35-37; clay selvage, 87; pinches, swells, and 
 
 lateral enlargements, 37; changes in the character of the vein filling, 
 
 38; secondary alteration of the minerals in veins, 38-40; electrical 
 
 activity, 40, 41 35-41 
 
 Chapter VI. — The Classification of Ore Deposits, a Review and 
 A Scheme Based on Origin. 
 
 Statement of principles, 42-44; schemes involving only the 
 classification of veins by Von Weissenbach, 44; Von Cotta, 44, 45; 
 Le Conte, 45; general schemes based on form: Von Cotta and 
 Prime, 46, 47; Lottner-Serlo, 47; Koehler, 47; Callon, 47; schemes 
 partly based on form, partly on origin: J. D. Whitney, 48; J. S. 
 Newberry, 48; J. A. Phillips, 49; schemes largely based on origin: 
 J. Grimm, 50; A. von Groddeck, 51; R. Pumpelly, 51, 53; schemes 
 entirely based on origin: H. S. Munroe, 53, 53; J. F. Kemp, 53-55; 
 remarks on the above, and discussion of methods of formation, 56-63; 
 fahlbands, 63; additional and later schemes of classification: Wads- 
 worth, 64; Posepny, 64-66; Fuchs and De Launay, 66; F. D. Power, 
 66, 67; Crosby, 67; general bibliography of ore deposits, 68-71. , . .43-71 
 
X TABLE OF CONTENTS. 
 
 PART II.— THE ORE DEPOSITS. 
 
 Chapter I. — The Iron Series (in Part). — Introductory Remarks 
 ON Iron Orbs. — Limonite. — Sidbrite. 
 
 General literature, 75, 76; table of analyses, 76; general remarks, 
 76-79; limonite, Example- 1, bog-ora, 79-82; Example 3, brown 
 hematite not Siluro-Cambrian, 83-88; Example 3«s, SiluroCambrian 
 brown hematites, 88-93; origin of same, 93, 94; analyses of limon- 
 ites, 95; siderite or spathic ore, introductory, 95; Example 3, clay 
 ironstone, 95, 96; Example Za, black-band, 96-98; Example, 4, Bur- 
 den mines, 98-100; Example 5, Roxbury, Conn., 100; genetic discus- 
 sion of siderite, 101 75-101 
 
 Chapter II. — The Iron Series, Continued. — Hematite, Red and 
 Specular. 
 
 Introductory remarks, 103; Example 6, Clinton ore, 103-109; 
 Greenbrier Co., W. Va., 109; Mansfield ores, Penn., 109; Example 7, 
 Crawford Co., Mo., 110-113; Example 8, JeflEerson Co., N. T., 
 113-114; Example 9, Lake Superior hematites, 114r-131; introductory, 
 114-116; Marquette district, 116-130; Menominee, 131, 133; Penokee- 
 Gogebic, 133, 133; Vermilion Lake, 134, 135; Mesabi, 135-131; Ex- 
 ample 10, James River, Va., 131, 133; Example 11, Pilot Knob, Mo.> 
 133-134; Example 11a, Iron Mountain, Mo., 134-136; analyses of 
 hematites, 186, 137 103-137 
 
 Chapter III. — Magnetite and Pyrite. 
 
 Example 13, Magnetite beds, 138-145; Adirondack region, 
 138-140; New York and New Jersey Highlands, 141, 143; South 
 Mountain, Penn., 143; Western North Carolina and Virginia, 143; 
 Colorado, 144; California, 145, 146; Example 13, titaniferous magne- 
 tite, 145, 146; Example 14, Cornwall, Pa., 146-150; Example 14a, 
 Iron Co., Utah, 151; Example 15, magnetite sands, 151, 152; origin 
 of magnetite deposits, 153, 153; distribution of phosphorus, 154; 
 analyses of magnetites, 154; pyrite, 154^157; Example 16, pyrite 
 beds, 154-157; statistics, 157; remarks on Cuban and Mexican iron 
 ores, 157-159 .' 138-159 
 
 Chapter IV. — Copper. 
 
 Table of analyses of copper ores, 160; Example 16, continued, 
 pyrite beds, 160, 161; Ore Knob, N. C, 161; Spenceville, Calif., 163; 
 Example 17, Butte, Mont., 162-165; Gilpin Co., Colo., 165; Llano Co., 
 Texas, 166; Example 18, Keweenaw Point, Mich., 166-171; Example 
 19, St. Genevieve, Mo., 171, 173; Example 20, Arizona Copper, 173-180; 
 Morenci, 173; Bisbee, 176; Globe, 178; Santa Rita, N. M., 178; Black 
 Range, 179; Example 30^', Crismon-Mammoth, Utah, 180; Sunrise, 
 Wyo., 180; Example 31, copper ores in triassic or Peruvian sand- 
 stone, 180-182; Eastern States, 180, 181; Western States, 183; statis- 
 tics of copper, 183 160-183 
 
 Chapter V. — Lead Alone. 
 
 Introductory and analyses of lead ores, 184; Example 33, Atlan- 
 
TABLE OF OONTENTB. xi 
 
 tic border, St. Lawrence Co., N. Y., 184, 185; Mass., Conn, and East- 
 ern N. Y., 185; Southwestern Penn., 185; Davison Co., N. C, 185-186; 
 Sullivan and Ulster Counties, N. Y., 186; Example 23, Southeast- 
 ern Missouri, 186, 187; statistics of lead, 188 184-188 
 
 Chapter VI.— Lead and Zinc. 
 
 Example 24, the Upper Mississippi Valley, 189-198; Washington 
 Co., Mo., 194; Livingston Co., Ky., 194, 195; Example 25, Southwest 
 Missouri, 195-200; Example 36, Wythe Co., Va., 201-203 189-303 
 
 Chapter VII. — Zinc Alone or with Metals other than Lead. 
 
 Introduction: Tables of analyses of zinc ores, 204; Example 27, 
 Saucon Valley, Penn., 204, 205; Example 38, Franklin Furnace and 
 Sterling, N. J., 303-311; Zinc in the Rocky Mountains, 211-213; in 
 New Mexico, 213; statistics, 313, 213 204-213 
 
 Chapter VIII. — Lead and Silver. 
 
 Introduction, 214; Rocky Mountain region and the Black Hills, 
 214-226; New Mexico, 214-216; Example 29, Kelley Lode, 214; Lake 
 Valley, 214-216; Colorado, 216-225; Example 30, Leadville, 216-219; 
 Example 30a, Ten-Mile, Summit Co., 219, 220; Example 306, Mon- 
 arch District, 220; Example 306, Eagle River, 220; Example 30d, 
 Aspen, 220 and 222-224; Example 30e, Rico, 224; Example 31, Red 
 Mountain, 224; South Dakota, Example 30/, 225; Montana -and 
 Idaho, Example 33, Glendale, 235; Example 32ra, Wood River, 
 225, 226; Example 33, Wickes, 226; Example 34, Coeur d'Alene, 226; 
 Region of the Great Basin, 226-232; Utah, Example 35, Bingham 
 and Big and Little Cottonwood, 226-228; Example 35a, Tooele Co., 
 228; Example 356, Tintic, 228; Example 30g, Hornsilver, 239; Ex- 
 ample 83a, Carbonate mine, Beaver Co., 229; Example 326, Cave 
 mine, 229; Nevada, Example 86, Eureka, 230, 231; Arizona, Cali- 
 fornia, 233 214-233 
 
 Chapter IX, — Silver and Gold. — Introductory: Eastern Silver 
 Mines and the Rocky Mountain Region of New Mexico and 
 Colorado. 
 
 Introduction, 233; Examples 37-42, defined, 233, 234; silver ores, 
 234; Example 33a, Atlantic Border, 335; Example 42, Silver Islet, 
 235; region of the Rocky Mountains and the Black Hills, 236-249; 
 New Mexico, geology, 236, 237; mines, 237, 238; Colorado, geology, 
 338, 339; San Juan region, 339-344; Gunnison District, 245; Eagle 
 Co., 345; Summit Co., 345; Park, Chaffee, Rio Grande and Conejos 
 Counties, 246; Custer Co., 246, 247; Gilpin, Clear Creek and Boulder 
 Counties, 248; El Paso Co., 249 233-249 
 
 Chapter X.— Silver and Gold, Continued.— Rocky Mountain Re- 
 gion, Wyoming, the Black Hills, Montana and Idaho. 
 
 Wyoming, 250; the Black Hills, 250-252; Montana, geology, 
 352; Madison, Beaverhead and Jefferson Counties, 253; Silver Bow 
 Co., 254, 355; Deer Lodge and Lewis and Clarke Counties, 355; 
 Missoula Co., 356; Idaho, geology, 256; Custer, Boise, Alturas and 
 other counties, 257 250-257 
 
xii TABLE OF CONTENTS. 
 
 CHArTER XL — Silver and Gold, Continued. — The Region op the 
 GsEAT Basin, in Utah, Abizona and Nevada. 
 
 Utah, geology, 258, Ontario and other mines, 359, 360; Silver 
 Reef, 360-361; Arizona, geology, 261; Northern Counties and the 
 Silver King mine, 363; Tombstone, 363; Pima and Yuma Counties, 
 363; Nevada, geology, 364; Lincoln Co., 364; Ney and White Pine 
 Counties, 365; Lander and other counties, 266; the Comstock lode, 
 367-271 358-371 
 
 Chapter XII. — The Pacific Slope. — Washington, Oregon and 
 California. 
 
 Washington, geology, 373; mines, 373; Oregon, geology, 373; 
 gold quartz and placers, 374; Example 44a, Port Orford, 374; Cali- 
 fornia geology, 375; Calico District, 376, 277; Example 44, aurifer- 
 ous gravels, 277-384; river gravels, 277-379; high or deep gravels, 
 379-383; general resume of geological history of gravels, 283-384; 
 Example 45, gold-quartz veins, 384-390 373-290 
 
 Chapter XIII. — Gold Elsewhere in the United States and Canada. 
 Example 45a, Southern States, 391; Example 456, Ishpeming, 
 Mich., 292; Alaska, geology, 292, 293; Example 46, Douglass Island, 
 293, 294; Example 456, Nova Scotia, 294; Example 45c?, gold else- 
 where in Canada, 395; statistics, 295, 296 391-296 
 
 Chapter XIV. — The Lesser Metals. — AnjMrNiaM, Antimony, Ar- 
 senic, Bismuth, Chromium, Manganese. 
 
 Aluminium, 397-300; antimony, 301, 302; Example 47, including 
 California, Nevada, Arkansas and New Brunswick, 301; Example 48, 
 Iron Co., Utah, 301, 303; arsenic, 302; bismuth, 303, 303; chromium, 
 303; Example 49, chromite in serpentine, 303; manganese; Example 
 50, manganese ores in residual clay, 304-308; statistics, 308 297-308 
 
 Chapter XV. — The Lesser Metals, Continued. — Mercury, Nickel 
 AND Cobalt, Platinum, Tin. 
 
 Mercury, 309; Example 50, New Almaden, 809, 310; Example 
 50as, Sulphur Bank, 310; Example 506, Steamboat Springs, 310, 311; 
 resume regarding mercury, 313; nickel and cobalt, 312-323; introduc- 
 tory, 812-314; Example 16c, pyrrhotite beds or veins, 314; Example 
 13a, Sudbury, Ont., Gap mine, Penn., 315-330; Example 49ffi, 
 Riddle's, Oregon, 831, 322; Example 23a, Mine la Motte, Mo., 322; 
 other occurrences of nickel ores, 322, 333; platinum, 333; tin, 
 324, 325; Example 51, Black Hills, 324 297-324 
 
 Chapter XVI. — Concluding Remarks. 
 
 Summation of such general geological relations among North 
 American ore deposits as can be detected 826-328 
 
LIST OF ILLUSTRATIONS. 
 
 FIGS. PAGE 
 
 1. Illustration of riftiog in granite at Cape Ann, Mass. After R. S. 
 
 Tarr 13 
 
 2. Open fissure in the Aubrey limestone (Upper Carboniferous), 25 miles 
 
 north of Canon Diablo Station, on the A. & P. R. R., Arizona. 
 Photographed by (J. K. Gilbert, 1892 15 
 
 3. Normal fault at Leadville, Colo. After A. A. Blow 17 
 
 4. Reversed fault at Holly Creek, near Dalton, Qa. After C. W. 
 
 Hayes 18 
 
 5. Illustration of one vein faulting another at Newman Hill, near Rico, 
 
 Colo. After J. B. Parish 20 
 
 6. Banded vein at Newman Hill, near Rico, Colo. After J. B. Parish. . 36 
 '^, Illustrations of the oxidized zone, or gossan, the zone of enrichment, 
 
 and the unchanged sulphides, at Ducktown, Tenn. After A. F. 
 
 Wendt 39 
 
 8. Section of the Hurst limonite bank, Wythe Co., Va., illustrating the 
 replacement of shattered limestone with limonite and the formation 
 
 of geodes of ore. After E. R. Benton 83 
 
 I 9. Geological section of the Low Moor, Va., iron-ore bed. After B. S. 
 
 Lyman 85 
 
 10. Geological section of the Amenia mine, Dutchess Co., N. Y., illus- 
 
 trating a Siluro-Cambrian limonite deposit. After B. T.Putnam.. 89 
 
 11. View of the Siluro-Cambrian brown hematite bank at Baker Hill, 
 
 Ala. Prom the Engineering and Mining Journal 92 
 
 12. Map and sections of the Burden spathic ore mines. After J. P. 
 
 Kimball 99 
 
 13. Clinton ore, Ontario, Wayne Co., N. T. After C. H. Smyth, Jr 103 
 
 14. Clinton ore, Clinton, N. Y. After C. H. Smyth, Jr 104 
 
 15. Clinton ore, Eureka mine, Oxmoor, Ala. After C. H. Smyth, Jr 105 
 
 16. Cross section of the SIoss mine. Red Mountain, Ala. From the f En- 
 
 gineering and Mining Journal 105 
 
 17. Map of the vicinity of Birmingham, Ala. After W. P. Barker 106 
 
 18. View of Cherry Valley mine. Mo. After F. L. Nason HO 
 
 19. Section of Cherry Valley mine. Mo. After P. L. Nason HI 
 
 20. Generalized section of Cherry Valley mine. Mo. After P. L. Nason. . Ill 
 
 21. Open cut in the Republic mine, Marquette range, showing a horse of 
 
 jasper. From a photograph by H. A. Wheeler 117 
 
 32. Cross sections to illustrate the occurrence and associations of iron ore 
 
 in the Marquette district, Michigan. After C. R. Van Hise 119 
 
 23. Plan of Ludington ore body, Menominee district, Michigan. After 
 
 P. Larsson 133 
 
xiv LIST OF ILLUSTRATIONS. 
 
 24. Sections of the Ashland mine, Iron wood, Mich 133 
 
 24a. Cross section of the Colby mine, Penokee-Gogebic district, Michi- 
 gan, to illustrate occurrence and origin of the ore. After C. R. 
 Van ,Hise 124 
 
 25. Open cut at Minnesota Iron Co.'s mine, Tower, Minn. Photographed 
 
 by J. F. Kemp 126 
 
 26. General cross section of ore body at Biwabik, Mesabi Range, Minn. 
 
 After H. V. Winchell 138 
 
 27. View of the Mesaba Mountain or Oliver mine, Virginia, Minn. Pho- 
 
 tographed by J. F. Kemp 130 
 
 28. Cross section of Pilot Knob, Mo. From a drawing by W. B. Potter. . 133 
 
 29. View of open cut at Pilot Knob, Mo., showing the bedded character 
 
 of the iron ore. From a photograph by J. F. Kemp 133 
 
 30. View of Iron Mountain, Mo. From a photograph by H. A. 
 
 Wheeler 134 
 
 31. Cross section of Iron Mountain, Mo., showing the knob of por- 
 
 phyry, with the veins of ore, the conglomerate, etc. After W. B. 
 Potter 135 
 
 33. View of open cut and underground work in Mine 21, Mineville, near 
 
 Port Henry, N. Y. From a photograph by J. F. Kemp 139 
 
 33a and 33J. Model of the Tilly Foster ore body. After F. S. Ruttmann 
 
 and the model itself 142 
 
 34. Section along the Cornwall Railroad from Lebanon to Miners' Village. 
 
 After E. V. d'Invilliers 147 
 
 35. Map of the Cornwall mines. After E. V. d'Invilliers 148 
 
 36. Illu.stration of overlapping lenses of pyrite. After A. F. Wendt 155 
 
 37. Cross section of the Bob-tail mine. Central City, Colo. After F. M. 
 
 Endlich 165 
 
 38. Geological sections of Keweenaw Point, Mich., near Portage Lake 
 
 and through Calumet. After R. D. Irving 167 
 
 39. Cross section of the St. Genevieve copper mine, illustrating the rela- 
 
 tions of the ore. After F. Nicholson 172 
 
 '40. Section at the St. Genevieve mine, illustrating the intimate relations 
 
 of ore and chert. After F. Nicholson 172 
 
 41. Geological map of the Morenci or Clifton copper district of Arizona. 
 
 After A. F. Wendt 173 
 
 42. Vertical section of Longfellow Hill, Clifton district, Arizona. After 
 
 Wendt 174 
 
 43. Horizontal sections of Longfellow ore body. After Wendt 174 
 
 44. Geological section of the Metcalf mine, Clifton district, Arizona. 
 
 After Wendt 175 
 
 45. Section of Copper Queen ore body, Bisbee district, Arizona. After 
 
 A. P. Wendt 176 
 
 46 View of the Copper Queen mine, Bisbee district, Arizona. From a pho- 
 tograph by James Douglass 177 
 
 47. Cross section of the Schuyler copper mine, N. J. After N. H. 
 
 Darton 181 
 
 48. Gash Veins, fresh and disintegrated. After T. C. Chamberlin 190 
 
LIST OF ILL U81 UA TIONS. xv 
 
 49. Idealized section of "flats and pitches," forms of ore bodies In Wis- 
 
 consin. After T. C. Cliamberlin 191 
 
 50. Verticle section of a typical zincblende ore body, near Webb City, Mo. 
 
 After C. Henrich 197 
 
 51. Geological section of the Bertha zinc mines, Wythe Co., Va. After 
 
 W. H. Case 200 
 
 58. Geological section, Altoona coal mines to Bertha zinc mines. After 
 
 W, H. Case 201 
 
 53. View of the Bertha zinc mines, Wythe Co., Va. From a photograph 
 
 by A. B. W. Miller 303 
 
 54 Cross section at Franklin Furnace, N. J. After J. F. Kemp 206 
 
 55. Geological map at Mine Hill, Franklin Furnace, N. J. After J. F. 
 
 Kemp 209 
 
 56. Geological map at Sterling Hill, Ogdensburgh, N. J. After J. F. 
 
 Kemp 209 
 
 57. Stereogram of ore body at Franklin Furnace, N. J. After J. F. 
 
 Kemp 210 
 
 58. Stereogram of ore body at Ogdensburgh, N. J. After J. F. Kemp. . . . 210 
 
 59. Geological cross section at Lake Valley, N. M. After Ellis Clark. . . . 215 
 
 60. Section of the White Cap chute, Leadville, showing the geological re- 
 
 lations of the ore, and its passage into unchanged sulphides in 
 depth. After A. A. Blow 218 
 
 61. Geological section of the Eagle River mines, Colo. After B. E. 
 
 Olcott 221 
 
 62. Geological section at Aspen, Colo. After A. Lakes 222 
 
 63. View of the Bunker Hill and Sullivan mines, Wardner, Idaho. From 
 
 a photograph loaned by B. E. Olcott 227 
 
 64. Section at Eureka, Nev. After a plate by J. S. Curtis 231 
 
 65. Geological cross sections of strata and veins at Newman Hill, near 
 
 Rico, Colo. After J. B. Farish 242 
 
 66. Geological cross sections of strata and veins at Newman Hill. After 
 
 J. B. Farish 243 
 
 67. View of Lower Creede, Colo. From the Engineering and Mining 
 
 Journal 244 
 
 68. Geological section of the Black Hills. After Henry Newton 251 
 
 69. Cross section of vein at the Alice mine, Butte, Mont. After W. P. 
 
 Blake 254 
 
 70. Two sections of the argentiferous sandstone at Silver Reef, Utah. 
 
 After C. M. Rolker ' 260 
 
 71. Section of Comstock lode. After G. P. Becker 267 
 
 72. Geological section of the Calico district, California. After W. 
 
 Lindgren 276 
 
 73. View of the Union diggings, Columbia Hill, Nevada Co., California. 
 
 From a photograph 277 
 
 74. View of the Timbuctoo diggings, Yuba Co., California. From a 
 
 photograph 278 
 
 75. Generalized section of a deep gravel bed, with technical terms. After 
 
 R. E. Browne 280 
 
xvi LIST OF ILL USTRATIONS. 
 
 76. Section of Forest Hill Divide, Placer Co., California, to illustrate the 
 
 relations of old and modern lines of drainage. After E. E. 
 Browne 281 
 
 77. Cross section of a bauxite deposit in Georgia. After C. Willard 
 
 Hayes 299 
 
 78. Sections of the Crimora mangansse mine, Virginia. After C. E. 
 
 Hall 305 
 
 79. Geological sections illlustrating the formation of the manganese ores 
 
 in Arkansas. After R. A. F. Penrose 306 
 
 80. The Turner mine, Batesville region, Arkansas. After R. A. F. 
 
 Penrose 807 
 
 81. Section of the Great Western cinnabar mine. After G. F. Becker. . . 310 
 
 83. Map and sections of Gap nickel mine, Penn. After J. F. Kemp 316 
 
 83. View of Copper CliB mine, Sudbury, Ontario. Photograph by T, G. 
 
 White 318 
 
 94. Horizontal section of the Etta granite knob. Black Hills. After W. 
 
 P.Blake 324 
 
ABBREVIATIONS 
 
 A, A. A. S.— Proceedings of the American Association for the Advance- 
 ment of Science. 
 A. O. or Amer. Geol. — American Geologist, Minneapolis, Minn. 
 
 A. J. S. or Amer. Jour. Sci. — American Journal of Science, also known 
 
 as Silliman's Journal. Fifty half-yearly volumes make a series. 
 
 The Journal is now (1893) in the third series. In the references the 
 
 series is given first, then the volume, then the page. 
 Ann. des Mines. — Annates des Mines. Paris, France. 
 Bost. Soc. Nat. Hist. — See Proceedings of same. 
 Bull. Oeol. Soc. Amer. or O. S. A. — Bulletin of the Geological Society of 
 
 America. 
 Bull. Mus. Comp. Zool. — Bulletin of the Museum of Comparative Zoology, 
 
 Harvard University. Cambridge, Mass. 
 
 B. und H. Zeitung. — Berg- und Huettenmdnnische Zeitung. Leipzig, 
 Germany. 
 
 M. E. — Transactions of the American Institute of Mining Engineers. 
 
 Neues Jahrb. — Neues Jahrbuch fiir Mineralogie, Geologic und Palaeon- 
 tologie, often called Leonhard's Jahrbuch. Stuttgart, Germany. 
 
 Oest. Zeit.f. Berg-u. Huett. — Oesterreichische Zeitschrift fiir Berg- und 
 Huettenwesen. Vienna, Austria. 
 
 Phil. Magazine. — Philosophical Magazine. Edinburgh, Scotland. 
 
 Proc. Amer. Acad. — Proceedings of the American Academy of Arts and 
 Sciences. Boston, Mass. 
 
 Proc. and Trans. N. 8. Inst. Nat. Sci. — Proceedings and Transactions of 
 the Nova Scotia Institute of Natural Science. Halifax, Nova Scotia. 
 
 Proc. Bost. Soc. Nat. Hist. — Proceedings of the Boston Society of Nat- 
 ural History. Boston, Mass. 
 
 Proc. Colo. Sci. Soc. — Proceedings of ^he Colorado Scientific Society. Den- 
 ver, Colo. 
 
 Raymond's Reports. — Mineral Resources West of the Rocky Mountains. 
 Washington, 1867-1876. The first two volumes were edited by J. Ross 
 Browne, the others by R. W. Raymond. 
 
xvm ABBREVIATIONS. 
 
 Trans. Min. Asso. and Inst., Cornwall. — ^Transactions of the Mining As- 
 sociation and Institute of Cornwall. Tuckingmill, Camborn, England. 
 Trans. N. Y. Acad, of /Sfci.— Transactions of the New York Academy of 
 
 Sciences, formerly the Lyceum of Natural History. 
 Zeit. d. d. g. Ges. — Zeitschriff der deutschen geologischen Qesellschaft. 
 
 Berlin, Germany. 
 Zeitsch. f. B., H. und S. im P. St.—Zeitschrift fur Berg-, Huetten-, und 
 
 Salinenwesen im Preussischen Staat. Berlin, Germany. 
 Zeitschr. f. Krys. — Zeitsehrift fur Krystallographie. Munich, Germany. 
 The remaining abbreviations are deemed self-explanatory. The num- 
 bering of the paragraphs is on the following principle : The first digit 
 refers invariably to the part of the book, the second two digits to the 
 chapter, and the last two to the paragraph of the chapter. 
 
PAET I. 
 
 INTRODUCTORY. 
 
CHAPTER I. 
 
 GENERAL GEOLOGICAL FACTS AND PRINCIPLES. 
 
 1.01.01.* In the advance of geological science the standpoints 
 from which the strata forming the earth's crust are regarded neces- 
 sarily change, and new points of view are established. In the last 
 few years two have become especially prominent, and there are 
 now two sharply contrasted positions from which to obtain a con- 
 ception of the structure and development of the globe. The first 
 is the physical, the second the biological. We may, for example, 
 consider the surface of the earth as formed by rocks, differing in 
 one part and another, and these different rocks or groups of rocks 
 are known by different names. The names have no special refer- 
 ence to the animal remains found in them, but merely indicate that 
 series of related strata form the surface in particular regions. On 
 the other hand, the rocks are also regarded as having been formed 
 in historical sequence, and as containing the remains of organisms 
 characteristic of the period of their formation. They illustrate the 
 development of animal and vegetable life, and in this way afford 
 materials for historical-biological study. In the original classifica- 
 tion the biological and historical considerations are all-important. 
 But when once the rocks are placed in their true position in the 
 scale, and are named, these considerations, for many purposes, no 
 longer concern us. The formations are regarded simply as mem- 
 bers in the physical constitution of the outer crust. The Interna- 
 tional Geological Congress held in Berlin in 1885 expressed these 
 different points of view in two parallel and equivalent series of 
 geological terms, which are tabulated on p. 4. They are now very 
 
 * The numbers at the beginning of the paragraphs are so arranged 
 that the first figure denotes the part of the book, the next two figures 
 the chapter, and the last two the paragraph. Thus 1.06.31 means Part 
 I., Chapter VI., Paragraph 31 under Chapter VI, 
 
4 KEMP'S ORE DEPOSITS. 
 
 generally adopted. For clearness in illustration, the equivalent 
 terms employed by Dana are appended. 
 
 Biological Terms. 
 
 Physical Terms. 
 
 Dana's Terms. 
 
 lUustrations. 
 
 Era. 
 
 Group. 
 
 Time. 
 
 Paleozoic. 
 
 Period. 
 
 System. 
 
 Age. 
 
 Devonian. 
 
 Epoch. 
 
 Series. 
 
 Period. 
 
 Hamilton. 
 
 Age. 
 
 Stage. 
 
 Epoch, 
 
 Marcellus. 
 
 The United States Geological Survey divides as follows : Era 
 and System, Period and Group, Epoch and Formation. In consider- 
 ing the ore deposits of the country, we employ only the physical 
 terms. We understand, of course, the chronological position 
 of the systems in the historical sequence, but it is of small moment 
 in this connection what may be the forms of life inclosed in them. 
 The purely physical character of the rocks — whether crystalline or 
 fragmental ; whether limestone, sandstone, granite, or schists ; 
 whether folded, faulted, or undisturbed — are the features on which 
 we lay especial stress. In all the periods the same sedimentary 
 rocks are repeated, and in the hand specimen it is often impossible 
 to distinguish those of different ages from one another. The 
 classification, briefly summarized, is as follows : 
 
 1.01.02. AKCHEAif Group. — I. Laurentian System. II. Hu- 
 ronian System. Additional subdivisions have been introduced by 
 Canadian and Minnesota geologists (Animikie, Montalban, etc.), 
 and there is a tendency to group all the latter clastic members, es- 
 pecially in the region of the Great Lakes, under the name Algon- 
 kian. (See discussion under Example 9.) 
 
 Paleozoic Group. — III. Keweenawan System. (This may be- 
 long with the Archeau.) IV. Cambrian System: (a) Georgian 
 Stage ; (6) Acadian Stage ; (c) Potsdam Stage. V. Lower Silurian 
 System. (A) Canadian Series : (a) Calciferous Stage ; (S) Chazy 
 Stage. (This will probably experience revision.) (23) Trenton 
 Series : (a) Trenton Stage ; (b) Utica Stage ; (c) Cincinnati or 
 Hudson River Stage. VI. Upper Silurian System. (A) Xiagara 
 Series : (a) Medina Stage ; (J) Clinton Stage ; (c) Niagara Stage. 
 (J?) Salina Series. ( C) Lower Helderberg Series. (Z>) Oriskany 
 Series. (The Oriskany may be made the base of the Devonian.) 
 YII. Devonian System. (A) Corniferous Series : (a) Cauda-Galli 
 Stage ; {b) Schoharie Stage ; (c) Corniferous Stage. (B) Hamilton 
 Series : (a) Marcellus Stage ; {b) Hamilton Stage ; (c) Genesee 
 
GENERAL GEOLOGICAL FACTS AND PRINCIPLES. » 
 
 Stage. (C) Chemung Series : (a) Portage Stage; (5) Chemung 
 Stage. (Z>) Catskill Series. VIII. Carboniferous System. (A) 
 Subcarboniferous or Mississippian Series. (B) Carboniferous 
 Series. ( C ) Permian Series. 
 
 Mesozoic Group. — IX. Triassic System. X. Jurassic System. 
 IX. and X. are not sharply divided in the United States, and we 
 often speak of Jura-Trias. A stratum of gravel and sand, along 
 the Atlantic coast, that contains Jurassic fossils has been called 
 the Potomac formation by McGee. XI. Cretaceous System. Sub- 
 divisions differ in different parts of the country. Atlantic Border : 
 (a) Raritan Stage ; (b) New Jersey Greensand Stage. Gulf States : 
 
 (a) Tuscaloosa Stage ; (S) Eutaw Stage ; (c) Rotten Limestone 
 Stage ; (d) Ripley Stage. Rocky Mountains : (a) Comanche 
 Stage ; (5) Dakota Stage ; (c) Benton Stage ; (d) Niobrara Stage ; 
 (e) Pierre Stage ; (/) Fox Hills Stage ; {g) Laramie Stage. Stages 
 (c), (d), (e), and (/) are sometimes collectively called the Colorado 
 Stage. Pacific coast : (a) Shasta Stage ; (b) Chico Stage ; (c) 
 Tejon Stage. The Tejoii is now regarded as Eocene. 
 
 Cenozoic Geoup. — XII. Tertiary System. (A) Eocene or 
 Alabama Series : Gulf States, (a) Claiborne St3,ge ; {b) Jackson 
 Stage ; (c) Vicksburg Stage. Western States, (a) Puerco Stage ; 
 
 (b) Wasatch Stage ; (c) Wind River Stage ; (d) Bridger Stage ; 
 (e) Uintah Stage. {£) Miocene or Yorktown Series, including 
 perhaps the Sumter of the Atlantic Border. On the Pacific Slope 
 it has the following : (a) White River Stage ; (b) John Day Stage ; 
 
 (c) Loup Fork Stage. ( C) Pliocene Series. (Of doubtful Ameri- 
 can determination.) XIII. Quaternary System. (A) Glacial 
 Series. (B) Champlain Series. ( C) Terrace Series. (Z>) Recent 
 Series. Pleistocene is sometimes employed as a name for the early 
 Quaternary, especially south of the Glacial Drift; In accord with 
 tlie practice of the U. S. Geological Survey, the Tertiary is now 
 generally divided into the Eocene and the Neocene (including 
 Miocene and Pliocene) series. 
 
 Other terms are also often used, especially when we do not wish 
 to speak too definitely. "Formation" is a word loosely employed 
 for any of the above divisions. "Terrane" is used much in the 
 same way, but is rather more restricted to the lesser divisions. A 
 stratum is one of the larger sheet-like masses of sedimentary rock 
 of the same kind; a bed is a thinner subdivision of a stratum. 
 " Horizon " serves to indicate a particular position in the geologi- 
 cal column ; thus, speaking of the JMarcellus Stage, we say that 
 shales of this horizon occur in central New York. 
 
6 KEMPS ORE DEPOSITS. 
 
 1.01.03. The rock species themselves are classified into three 
 great groups — the Igneous, the Sedimentary, and the Metamor- 
 phic. 
 
 The Igneous (synonymous terms, in whole or in part: mas- 
 sive, eruptive, volcanic, plutonic) include all those which have so- 
 lidified from a state of fusion. They are marked by three types 
 of structure — the holo-crystalline, the porphyritic, and the glassy, 
 depending on the circumstances under which they have cooled. 
 Under the first type of structure come the granites, syenites, dio- 
 rites, gabbros, diabases, and peridotites; under the second, quartz- 
 porphyries, rhyolites, porphyries, trachytes, porphyrites, andesites, 
 and basalt; under the third, pitchstone, obsidian, and other glasses. 
 
 The Sedimentary rocks are those which have been deposited in 
 water. They consist chiefly of the fragments of pre-existing rocks 
 and the remains of organisms. They include gravel, conglom- 
 erate, breccia, sandstone, — both argillaceous and calcareous, — shales, 
 clay, limestone, and coal. In volcanic districts, and especially 
 where the eruptions have been submarine, extensive deposits of 
 volcanic lapilli and fine ejectments have been formed, called tuffs. 
 With the sedimentary rocks we place a few that have originated 
 by the evaporation of solutions, such as rock salt, gypsum, etc. 
 
 The Metamorphic rocks are usually altered and crystallized 
 members of the sedimentary series, but igneous rocks are known to 
 be subject to like change, especially when in the form of tuffs. 
 They are all more or less crystalline, more or less distinctly bedded 
 or laminated, of ancient geological age or in disturbed districts. 
 They include gneiss, crystalline schists, quartzite, slate, marble, and 
 serpentine. 
 
 After a brief topographical survey, we shall employ the above 
 terms to summarize the geological structure of the United States. 
 The several purely artificial territorial divisions are made simply 
 for convenience. Nothing but intelligent travel will perfectly ac- 
 quaint one with the topographical and geological structure of the 
 country, and in this connection Maefarlane's " Geological Railway 
 Guide " and a geological map are indispensable. 
 
 1.01.04. On the east we note the great chain of the Appalachi- 
 ans, with a more or less strongly marked plain between it and the 
 sea. This is especially developed in the south, and is now generally 
 called the Coastal Plain. It is of late geological age and contains 
 the pine barrens and seacoast swamps. The Appalachians thern- 
 Belves consist of many ridges, running on the north into the "White 
 
GENERAL GEOLOGICAL FACTS AND PRINCIPLES. 7 
 
 Mountains, the Green Mountains, and the Adirondaoks. Farther 
 south the Highlands of New York and New Jersey, the South 
 Mountain of Pennsylvania, the Alleghanies, the Blue Ridge, and 
 the other southern ranges make up the great eastern continen- 
 tal mountain system. In western New York and Ohio we find a 
 rolling, hilly country; in Kentucky and Tennessee, elevated table- 
 land, with deeply worn river valleys. Indiana, Illinois, Iowa, and 
 Missouri contain prairie and rolling country, more broken in southern 
 Missouri by the Ozark uplift. In Michigan, Wisconsin, and Minne- 
 sota the surface is rolling and hilly with num^erous lakes. In Ar- 
 kansas, Louisiana, and Mississippi there are bottom lands along the 
 Mississippi and Gulf, with low hills back in the interior. Across 
 Arkansas and Indian Territory runs the east and west Ouachita 
 uplift. West of these States comes the great billowy prairie region, 
 and then the chain of the Rocky Mountains, consisting of high, 
 dome-shaped peaks and ridges, with extended elevated valleys 
 (the parks) between the ranges. Some distance east of the main 
 chain are the Black Hills, made up of later concentric formations 
 around a central, older nucleus, and also the extinct volcanic dis- 
 trict of the Yellowstone National Park. In western Colorado, Utah, 
 and New Mexico, between the Rocky Mountains and the Wasatch, 
 is the Colorado plateau, an elevated tableland. This is terminated by 
 the north and south Wasatch range and is traversed east and west 
 by the Uintah range. West of this lies the region called the Great 
 Basin, characterized by alkaline deserts, and subordinate north 
 and south ranges of mountains. Next comes the chain of the Sier- 
 ra Nevada, and lying between it and the Coast range is the great 
 north and south valley of California. This rises in the compara- 
 tively low Coast range, which slopes down to the Pacific Ocean. 
 To the north, these mountains extend into eastern Oregon and 
 Washington, with forests and fertile river valleys. These topograph- 
 ical features are important in connection with what follows, for the 
 reason that the ore deposits especially favor mountainous regions. 
 Mountains themselves are due to geological disturbances — upheav- 
 al, folding, faulting, etc. — and are often accompanied by great ig- 
 neous outbreaks. They therefore form the topographical surround- 
 ings most favorable to the development of cavities, waterways, 
 and those subterranean, mineral-bearing circulations which would 
 fill the cavities or replace the rock with useful minerals. 
 
 1.01.05. Geological Outline. I. iV^ew Migland, New York, 
 New Jersey, and Eastern Pennsylvania District. — In New Eng- 
 
8 KEMP'S ORE DEPOSITS. 
 
 land and northero New Tork the Archean is especially devel- 
 oped, forming the White Mountains, the Adirondacks, and the 
 Highlands of New York and New Jersey. These all consist of 
 granite and other igneous rock, of gneiss, and of crystalline schists. 
 There are also great areas of metamorphic rocks whose true age 
 may be later. The Green Mountains are formed of such, and were 
 elevated at the close of the Lower Silurian. In New England there 
 are small, scattered exposures of the undoubted Paleozoic (Devo- 
 nian, Carboniferous). In eastern New York, and to some extent in 
 New Jersey and eastern Pennsylvania, the entire Paleozoic, except 
 the Carboniferous, is strongly developed. Up and down the coast 
 there are narrow north and south estuary deposits of red Jura-Tri- 
 as sandstone, which are pierced by diabase eruptions. The Creta- 
 ceous clays are strong, and Tertiary strata occur at Martha's Vine- 
 yard, in Massachusetts, while over all as far south as Trenton is 
 found the glacial drift. Between the Archean ridges of the High- 
 lands and the first foldings of the Paleozoic on the west is found 
 the so-called Great Valley, which also runs to the south and is a 
 very important topographic and geologic feature. It follows the 
 outcrop of the Siluro-Cambrian limestones, to whose erosion it is due. 
 
 II. Eastern- Middle and Sovtheastern Coast District. — The 
 low plains of the coast are formed by Quaternary, Tertiary, and 
 Cretaceous, consisting of gravel, sand, shell beds, and clay. In- 
 land there are exposures of Jura-Trias, as in the north. The Ar- 
 chaean crystalline rocks are also seen at numerous points not far 
 from the ocean. Florida is largely made up of limestones, with a 
 mantle of calcareous sand. 
 
 III. Alleghany Region and the Central Plateau. — The Ap- 
 palachian mountain system, from New York to Alabama, con- 
 sists principally of folded Paleozoic (largely Carboniferous), with 
 Archean ridges on its eastern flank. There is an enormous devel- 
 opment of folds, with northeast and southwest axes. On the west 
 chey are succeeded by the plateau region of Kentucky and Tennes- 
 see, chiefly Paleozoic. Along central latitudes the Archean does 
 not again appear east of the Mississippi. 
 
 IV. Region of the Great Lakes. — In Michigan, "Wisconsin, and 
 Minnesota the Archean rocks are extensively developed, both 
 Laurentian and Huronian. Around Lake Superior are found the 
 igneous and sedimentary rocks of the Keweenawan, followed by 
 the lower Paleozoic. Lake Michigan and Lake Huron are sur- 
 rounded by Silurian, Devonian, and Carboniferous; Lake Erie, by 
 
GENERAL GEOLOGICAL FACTS AND PRINCIPLES. 9 
 
 Devonian ; Lake Ontario, by Silurian. Running south through 
 Ohio, we find an important fold known as the Cincinnati uplift, 
 with a north and south axis. It was elevated at the close of the 
 Lower Silurian. In the lower peninsula of Michigan and in eastern 
 Ohio and western Pennsylvania the Carboniferous is extensively 
 developed. 
 
 V. Mississippi Valley. — The head waters of the Mississippi 
 are in the Aichean. It then passes over Cambrian and Silurian 
 strata in Minnesota, Wisconsin, northern Iowa, and Illinois, which 
 in these States lie on the flanks of the Archean "Wisconsin 
 Island " of central Wisconsin. These are succeeded by subordi- 
 nate Devonian, and in southern Iowa, Illinois, and Missouri by Car- 
 boniferous. In southern Missouri the Lower Silurian forms the 
 west bank. Thence to the Gulf the river flows on estuary deposits 
 of Quaternary age, with Tertiary and Cretaceous farther inland. 
 
 VI. Gidf Region. — The Gulf States along the water front are 
 formed by the Quaternary. This is soon succeeded inland by very 
 extensive Tertiary beds, which are the principal formation repre- 
 sented. > 
 
 VII. Prairie Region. — West of the. Paleozoic rocks of the 
 States bordering on the Mississippi is found a great strip of Creta- 
 ceous running from the Gulf of Mexico to and across British 
 America, and bounded on the west by the foothills of the Rocky 
 Mountains. A few Tertiary lake deposits are found in it. Quite 
 extensive Triassic rocks are developed on the south. The surface 
 is a gradually rising plateau to the Rocky Mountains. 
 
 VIII. Region of the Rocl-y IIoimtaiuK, the Black Hills, and 
 the Yellowstone National Park. — The Rocky Mountains rise from 
 the prairies in long north and south ranges, consisting of Archean 
 axes with the Paleozoic in i-elatively small amount, but with abun- 
 dant Mesozoic on the east and west flanks. In the parks are found 
 lake deposits of Tertiary age. There are also great bodies of igne- 
 ous rocks, which attended the various upheavals. The principal 
 upheavals began at the close of the Cretaceous. The outlying 
 Black Hills consist of an elliptical Archean core, with concentric 
 Paleozoic and Mesozoic strata laid up around it. The National 
 Park consists chiefly of igneous (volcanic) rocks in enormous 
 development. 
 
 IX. Colorado Plateau. — The Rocky Mountains shade out on 
 the west into a great elevated plateau, extending to central Utah, 
 where it is cut off by the north and south chain of the Wasatch. 
 
10 KEMP'S ORE DEPOSITS. 
 
 The Uintah Mountains are an east and west chain in its northern 
 portion. The rocks on the north are chiefly Tertiary, with Meso- 
 zoic and Paleozoic in the mountains. To the south are found 
 Cretaceous and Triassic strata, with igneous rocks of great extent. 
 The principal upheaval of the Wasatch hegan at the close of the 
 Carboniferous and seems still to be in progress. 
 
 X. Region of the Great Basin. — Between the Wasatch and 
 the Sierra Nevada ranges is found the Great Basin region, once 
 lake bottoms, now very largely alkaline plains of Quaternary age. 
 The surface is diversified by subordinate north and south ranges, 
 formed by great outflows of eruptive rocks, and by tilted Paleozoic. 
 The ranges are extensively broken and the stratified rocks often 
 lie in confused and irregular positions. There is Jio drainage to 
 the ocean. 
 
 XI. Region of the Pacific Slope. — The depression of the Great 
 Basin is succeeded by the heights of the Sierra Nevada. On the 
 west the Sierras slope down into the Central Valley of California. 
 The flanks are largely metamorphosed Jurassic and Cretaceous 
 rocks with great developments of igneous outflows. The surface 
 rises again in the Coast ranges, which slope away farther west to 
 the ocean. In addition to the Jurassic and Cretaceous, the Tertiary 
 and Quaternary are also developed, and in the Coast ranges are 
 many outflows of igneous rock. The principal upheaval of the 
 Sierra Nevada began at the close of the Jurassic, that of the Coast 
 range at the close of the Miocene Tertiary. 
 
 XII. Region of the iVbriAwesi.— Washington and Oregon, 
 along the coast, are formed by Cretaceous and Tertiary strata 
 similar to California. But inland, immense outpourings of igneous 
 rocks cover the greater portion of both States and extend into 
 Idaho. On the north the Carboniferous is extensive, running east- 
 ward into Montana. Quaternary and Tertiary lake deposits are 
 also not lacking. 
 
 1.01.06. On the Forms Assumed hy Rock Masses. — All sedimen - 
 tary rocks have been originally deposited in beds, approximately 
 horizontal. They are not of necessity absolutely horizontal, be- 
 cause they may have been formed on a sloping bottom or in a delta, 
 in both of which cases an apparent dip ensues. We find them 
 now, however, in almost all cases changed from a horizontal posi- 
 tion by movements caused primarily by the compressive strain in 
 the earth's crust. Beds thus assume folds known as monoclines, 
 anticlines, and synclines. 
 
GENERAL QEULOOICAL FACTS AND PRINCIPLES. 11 
 
 A monocline is a terrace-like dropping of a bed without changing 
 the direction of the dip. There is usually a zone, more or less 
 shattered, along the folded portion, and such a zone may become 
 a storage receptacle. Monoclines of a gentle character in Ohio, 
 which have been detected by Orton in studies of natural gas, have 
 been called "arrested anticlines." An anticline is a convex fold 
 with opposing dips on its sides, while a syncline is a concave fold 
 with the dips on its sides coming together. We speak of the axis 
 of a fold, and this marks the general direction of the crest or 
 trough. The axis is seldom straight for any great distance. Folds 
 are often broken and faulted across the strike of their axes, and 
 this causes what is called a "pitch" of the axes and makes the 
 original dips run diagonally down on the final one. Folds are the 
 primary cause of the phenomena of dip and strike. Horizontal 
 beds have neither. A dome-like elevation of beds, with dips radi- 
 ating in every direction from its summit, is called a quaquaversal, 
 but it is a rare thing. An anticline or syncline with equal dips on 
 opposite sides of its axes is called a normal fold. If the dip is 
 steeper on one side than on the other, it is an overthrown fold ; if 
 the sides are crushed together, it is a collapsed or sigmoid fold. 
 
 Igneous rocks are in the form of sheets (the term " bed " should 
 be restricted to sedimentary rocks), knobs or bosses, necks, lacco- 
 lites, and dikes. A sheet is the form naturally assumed by surface 
 flows, and by an igneous mass which has been intruded between 
 beds. It has relatively great length and breadth as compared with 
 its thickness, and coincides with its walls in dip and strike. A 
 knob, or boss, is an irregular mass, of approximately equal length 
 and breadth, which may be related in any way to the position of 
 its walls. Such masses are often left projecting by erosion. A 
 neck is the tilled conduit of a volcano, which sometimes remains 
 after the overlying material has been denuded. A laccolite is a 
 lenticular sheet which has spread between beds radially from 
 its conduit, and thus has never reached the surface, unless re- 
 vealed by subsequent erosion. A dike is a relatively long and 
 narrow body of igneous rock which has been intruded in a fissure. 
 It is analogous to a vein, but the term " vein " ought not to be ap- 
 plied to an undoubtedly igneous rock. Some granitic mixtures, 
 however, of quartz, feldspar, and mica, leave us yet in uncertainty 
 as to whether they are dikes or veins. (See Example 51.) From 
 the above it will be seen at once that bosses, knobs, and necks may 
 be practically indistinguishable. 
 
CHAPTER II. 
 
 ON THE FORMATION OF CAVITIES IN ROCKS. 
 
 1.02.01. By Local Contraction. — In the contraction caused 
 by cooling, drying, or hardening, both igneous and sedimentary 
 rocks break into more or less regular masses along division planes, 
 called joints, or diaclases. Numerous cracks and small cavities are 
 thus formed. Basaltic columns, or the prismatic masses, formed 
 by the separation, in cooling and consolidating, of the heavier basic 
 rocks, along planes normal to the cooling surface, are good illustra- 
 tions of the first. Larger manifestations of them often become 
 filled with zeolites, calcite, and other secondary minerals. Granitic 
 
 Fig. 1. — Illustration of rifting in granite at Cape Ann, Mass. 
 After B. 8. Tarr. 
 
 rocks and porphyries break up less regularly from the same cause, 
 but still exhibit prismoids and polygonal blocks and benches. (J. 
 P. Iddings' paper on "The Columnar Structure in the Igneous 
 Rocks on Orange Mountain, IST. J.," Amer. Jour. Sci., III., xxxi. 
 320, is an excellent discussion.) Large cracks have been referred 
 to this cause, which have afterward formed important receptacles 
 for ores. (See Example 11a.) Very small microscopic cracks may 
 occasion lines of weakness and brecciation which are not readily 
 apparent. They afford a cleavage, called rifting, but are not well 
 understood. (See R. S. Tarr, " On Rifting in Cape Ann Granites," 
 Amer. Jour. Sci., April, 1891.) Joints are generally prominent in 
 
ON THE FORMATION OF CAVITIES IN ROCKS. 13 
 
 sedimentary rocks, and probably afford many of the regular planes 
 of separation which, are often seen crossing one or several beds. 
 They are chiefly due to drying and consolidation. Both the joints 
 formed by cooling and those formed by drying may be afterward 
 modified or increased by rock movements, so that it may be a 
 matter of difficulty to decide between the two forms of origin. 
 The undulatory tremors of an earthquake have been cited, with 
 great reason, by W. O. Crosby as a prolific cause of joints.* 
 
 1.02.02. Cavities Formed by More Extensive Movements in 
 the Earth's Crust. — The strains induced by the compression in the 
 outer portion of the earth are by far the most important causes of 
 fractures. The compression develops a tangential stress which is 
 resisted by the archlike disposition of the crust. (By the term 
 " crust " is simply meant the outer portion of the globe without 
 reference to the character of the interior.) Where there is insuf- 
 ficient support, gravity causes a sagging of the material into syn- 
 clinals, which leave salient anticlinals between them. Where the 
 tangential strain is also greater than the ability of the rocks to 
 resist, they are upset and crumpled into folds from the thrust. 
 Both kinds of folds are fruitful' causes of fissures, cracks, and 
 general shattering, and every slip from yielding sends its oscilla- 
 tions abroad, which cause breaks along all lines of weakness. The 
 simplest result, either from sagging or from thrust, is a fissure, on 
 one of whose sides the wall has dropped, or on the other of which 
 it has risen, or both, as will be more fully described under "Faults." 
 If the rocks are firm and quite thickly bedded, as is the case with 
 limestones and quartzites, the separation is cleanly cut ; but if 
 they are softer and more yielding, they are sheared downward on 
 the stationary or lifting side, and upward on the one which rela- 
 tively sinks. Such fissures may pass into folds along their strike, 
 as at Leadville, Colo. 
 
 *In addition to the usual text-books the following references may be 
 consulted : W. O. Crosby, "On the Origin of Jointed Structures," Boston 
 Soc. Nat. Hist., XXII., October, 1882, p. 73; Amer. Jour. Sci., III., xxv. 
 4'i6;Q. K. Gilbert, " On the Origin of Jointed Structures," Amer. Jour. Sci., 
 III., xxiv. 50, and xxvii. 47; J. H. Kinahan, Valleys, and their Relations 
 to Fissures, Fractures, and Faults, London, Trubner & Co. See also a 
 short letter in the Amer. Jour. Sci., III., xxiv., p. 68, on the " Origin of 
 Jointed Structures;" J. Leconte, "Origin of Jointed Structure in Undis- 
 turbed Clay and Marl Deposits," Amer. Jour. Sci., III., xxiii. 233; W. J. 
 McGee, "On Jointed Structure," Amer. Jour. Sci., III., xxv. 152, 476. 
 
14 KEMP'S ORE DEPOSITS. 
 
 1.02.03. A phenomenon which is especially well recognized in 
 metamorphic regions, and which is analogous to those last cited, 
 is furnished by the so-called " shear zones." A faulting move- 
 ment, or a crush, may be made apparent by changes in mineralogi- 
 cal composition and structure. Massive diabases, for instance, 
 pass into hornblende-schists or amphibolites for limited stretches. 
 Garnets and other characteristically metamorphic minerals ap- 
 pear, and pyroxenes alter to amphiboles. Strains are manifested in 
 the optical behavior of the minerals in thin sections of specimens 
 taken from such localities. These crushed strips, or shear zones, 
 may be formed with very slight displacement, but they aflPord 
 favorable surroundings for the formation of ore bodies. This con- 
 ception of the original condition of a line of ore deposition is a 
 growing favorite with recent writers, and combined with the idea 
 of replacement is often applicable. (See Example 17, Butte, 
 Mont.) Fahlbands, which are very puzzling problems, may have 
 originated as shear zones. 
 
 1.02.04. A more extended effect is produced by the mono- 
 cline, which has a double line of shattered rock marking both the 
 crest and the foot of its terrace. Anticlines and synclines occasion 
 the greatest disturbances. Comparatively brittle materials like 
 rocks cannot endure bending without suffering extended fractures. 
 When sirained beyond their limit of resistance, along the crest of 
 an anticline and in the trough of a syncline, cracks and fractures 
 are formed which radiate from the axis of each fold. As these 
 open upward and outward in anticlines, they become the easiest 
 points of attack for erosion, so that it is a very common thing to find 
 a stream flowing in a gorge, which marks the crest of an anticline, 
 while synclinal basins are frequently left to form the summits of 
 ridges, as is so markedly the case in the semi-bituminous coal basins 
 of Pennsylvania. It is quite probable, however, that the anticline 
 may have been leveled off at this fissured crest because it was up- 
 heaved under water and became exposed at its vulnerable summit 
 to wave action. 
 
 Ore deposits may collect in these fissured strips, of which the 
 lead and zinc mines of the upper Mississippi Valley (Example 24) 
 are illustrations. Such fissures are peculiar in that they exhibit no 
 displacement. The accompanying figure is from a photograph of 
 a gaping crack in the Aubrey (Upper Carboniferous) limestone, 
 twenty-five miles north of Caflon Diablo station, Ariz., on the At- 
 lantic and Pacific Railroad. It was caused by a low anticlinal 
 
ON THE FORMATION OF CAVITIES IN ROCKS. 
 
 15 
 
 roll, and contained water about one hundred feet below the top. 
 Its reproduction of the conditions of a vein, with horse, pinches 
 and swells, devious course, and all, is striking. The photograph 
 was made by Mr. G. K. Gilbert, of the United States Geological 
 Survey, and to his courtesy its use is due. 
 
 Fig. 3. — Ojjen fissure in the Aubrey limestone (Upper Carhoniferons), 35 
 
 -^niles north of Canon Diablo station, Ariz., on the A. & P. R. R. 
 
 Photogriqilu'it by 0. K. (Hlbert. 1?92. 
 
 While it is true that in many regions the folds and fractures 
 have resulted in this simple way, and exhibit the unmistakable 
 course through which they have passed, yet geological structure 
 is by no means always so clear. ExtemliMl disturbances, gi-eat 
 faults and displacements, combined with folds and the intrusion nf 
 
16 KEMFS ORE DEPOSITS. 
 
 igneous rocks, have often so broken up a district that it is a matter 
 of much difficulty to trace out the course through which it has 
 passed. Subsequent erosion, or the superposition of heavy beds of 
 gravel or forest growths, etc., may so obstruct observation even of 
 the facts as to add to the obscurity. The expense of making and the 
 consequent scarcity of accurate contour maps to assist in such 
 work are other obstacles. The profound dynamic effects wrought 
 by mountain-making processes, although in individual cases pro- 
 ducing only the simpler phenomena already cited, yet in general 
 are much more extensive, and must be considered in the study of 
 many large districts. When folds are the result of compression or 
 thrust, the dynamic effects are more marked than in those formed 
 by sagging. Faults are larger and more abundant. When sedi- 
 mentary beds have been laid down along an older axis of granite 
 or some equally resistant rock and the thrust crowds the beds 
 against this axis, the conditions are eminently favorable to great 
 fracturing and disturbance. The flanks of the Rocky Mountains 
 furnish such examples. 
 
 1.02.05. There are also great lines of weakness in the outer 
 portion of the earth, which seem to have been the scene of fault- 
 ing movements from a very early period. Thus on the western 
 front of the Wasatch Mountains, in Utah, is a great line of weak- 
 ness, that was first faulted, as nearly as we can discover, in 
 Archean times, and has suffered disturbances even down to the 
 present. A few instances of actual movements within recent 
 years have been recorded. In 1889 a sudden small fold and fissure 
 developed under a paper mill near Appleton, Wis., and heaved the 
 building four and a half inches. (See F. Cramer, "Recent Rock 
 Flexure," Amer. Jour. Set., III., xxxix. 220.) This occurred in 
 what was regarded a settled region and one not liable to disturb- 
 ance. 
 
 1.02.06. Wherever igneous rocks form relatively large por- 
 tions of the globe they necessarily share extensively in terrestrial 
 disturbances. Not being often in sufficiently thin sheets, they 
 rarely furnish the phenomena of dip and strike. Folds are largely 
 wanting. They are replaced by faults and shattering. The fis- 
 sures thus formed are at times of great size and indicate impor- 
 tant movements. The Comstock Lode fissure is four miles long 
 and in the central part exhibits a vertical displacement of three 
 thousand feet. (See 2.11.1 9.) Such fissures seldom occur alone, but 
 minor ones are found on each side and parallel with the main one. 
 
ON THE FORMATION OF CAVITIES IN ROCKS. 
 
 17 
 
 • 1.02.07. The intrusion of igneous dikes may start earthquake 
 vibrations which fracture the firm rock masses. Fissures caused 
 in this way radiate from the center of disturbance or else appear 
 in concentric rings. The violent shakings which so often attend 
 great volcanic eruptions, and the sinking of the surface from the 
 removal of underlying molten material, all tend to form cracks 
 
 f / X X ''sV\ 
 
 V « » "Ix" .« * '/x"x ^ 
 
 _ix:«\ " " \i 35 « ' " w< X X 
 
 Fig. 3. — Normal fault at Leadville, Colo. After A. A. Blow, 
 
 and cavities. They are possible causes which may well be borne 
 in mind in the study of an igneous district. 
 
 1.02.08. Faults. — When fractures ha\'e been formed by any of 
 the means referred to above, and the opposite walls slip past each 
 other, BO as not to corresjjond exactly at all horizons, they arc 
 called "faults," a terra which indicates this lack of correspondence. 
 
 The separation is chiefly due to the relative slipping down or sink- 
 ing of one side. The distance through which this has taken place 
 is called the amount of displacement, or throw. Faults are most 
 commonly inclined to the horizon, so that there is both a vertical 
 and a horizontal displacement. What would be the dip of an in- 
 clined stratum is in a fault now generally known as the "hade," 
 although the word formerly had a different meaning. Experience 
 has shown that where beds or veins encounter faults and opera- 
 
18 
 
 KEMP'S ORE DEPOSITS. 
 
 tions are brought to a standstill, the continuation is usually found 
 as follows, according to Schmidt's law. If the fault dips or hades 
 away from the workings, the continuation is down the hade ; if it 
 dips toward the workings, it should be followed upward. Such a 
 fault is called a normal fault, and is illustrated in the figure 
 on IX 17, after A. A. Blow. This is a natural result of the draw- 
 ing apart of the two sides. The least supponed mass would nWp 
 down on the one which has the larger base. Less commonly the 
 opposite movement results. Thus when the fault is due to com- 
 pression, the beds pass each other in the reverse direction, and 
 what is called a reversed fault results. The accompanying cut il- 
 lustrates a very extended one in the southern Appalachians. 
 While we would naturally think of a reversed fault as resulting 
 
 r—^-HS^^^''^:;^^^^ ~~^"5~5r Coivnasauga. Shales 
 
 TTv^ Cohuttoy Contjlomecate 
 
 Ocoee Slate 
 JCnax Dolomite 
 
 Fig. 4:.— Reversed fault at Holly Creek, near Dalton, Ga. After C. W- 
 Hayes, Bull. G. S. A., Vol, II., PI. 3, p. 152. 
 
 from a compressive strain, in that in this case the lower wedged- 
 shaped portion would be forced under the upper one, yet normal 
 faults can likewise, in instances, be explained by compression. If 
 we consider the fault to be caused by the vertical thrust or com- 
 ponent, that would always be present in the compression of a 
 completely supported arch, this would tend to heave upward the 
 portion next the fissure, that had the larger base. Along an in- 
 clined fracture such portion is manifestly the under one. It is also 
 important to note whether the fault plane, both in normal and in 
 reversed faults, cuts inclined beds in the direction of the dip or 
 across it. (See Margerie and Heim, DisloJcation der Erdrinde 
 Zurich, 1888.) 
 
 1.02.09. The movement of the walls on each other produces 
 grooves and polished sui-faces called slickensiJes, or slips. Thev 
 
ON THE FORMATION OF CAVITIES IN ROCKS. 19 
 
 are usually covered with a layer of serpentine or talc or some 
 such secondary product. The strain caused by the movement may 
 in rare instances leave the slips in such a state of tension that 
 when, from any cause such as excavation, the pressure is relieved, 
 they will scale off with a small explosion. (See A. Strahan, " On 
 Exjjlosive Slickensides," Geological Magazine, iv. 401, 622.) Ob- 
 servations on the directions of slips may, in cases of doubt, throw 
 some additional light on the direction of the movement which 
 caused the fault. But the best guide in stratified rocks is a knowl- 
 edge of the succession of the beds as revealed by drill cores or ex- 
 cavations. Attempts have been made to deduce mathematical 
 formulas for the calculation of the amount of downthrow or up- 
 throw, and when sufficient data are available, as is often the case 
 in coal seams, this may be done. The methods depend on the 
 projection of the planes in a drawing, on the jjrinciples of analytical 
 geometry, and on the calculation of the displacements by means of 
 spherical trigonometr}'. (See G. Koehler, Die Storuiujen der Gdnge, 
 ITotze unci Lager, Leipzig, 1886 ; William Engelmann. A transla- 
 tion by W. B. Phillips, entitled, "Irregularities of Lodes, Veins, 
 and Beds," appeared in the Engineering and Mining Journal, June 
 25, 1887, p. 454, and July 2, 1887, p. 4. A very excellent paper, 
 having a quite complete bibliography, is F. T. Freeland's "Fault 
 Rules," M. E; June, 1892.) Prof. Hans Hoefer has called attention 
 to the fact that in faulting there is frequently a greater displace- 
 ment in one portion of the fissure than in a neighboring 2jart, and 
 even a difference of hade. This causes a twisting or circular move- 
 ment of one wall on the other, and needs to be allowed for in some 
 calculations. ( Oestereich. ZeitRchrift fiir Herg- und Huettenvesen, 
 Vol. XXIX. An abstract in English is given by R. "W Raymond, 
 M. E; February, 1882.) In the Engineering und Mining Journal 
 for April and May, 1892, a quite extended discussion of faults by 
 several jirominent American mining engineers and geologists is 
 given, apropos of the question raised by Mr. J. A. Church as to 
 whether fissure veins are more regular on the dip or on the strike. 
 In a relatively uniform masnivo rook the regularity should be 
 greater on the dip, but in inclined and diversified stratified rocks 
 tiio many variables enter to warrant any sweeping assertions. In 
 soft r(joks like shales the fissure may become so split into small 
 stringers as to be valueless. Again, in very firm rock, where there 
 is little drawing apart, the fissure may be very tight. In the veins 
 of Xewman Hill, near Rico, Colo, (see 2.00.10), the fissure is so 
 
20 KEMPS ORE DEPOSITS. 
 
 narrow above a certain stratum as practically to fail. Quartzite 
 is a favorable rock for sucb effect. Despite all rules, faults are 
 often causes of great uncertainty, annoyance, and expensive ex- 
 ploration. 
 
 1.02.10. If a number of faults succeed one another in a short 
 distance they are called " step faults." An older and completed 
 vein may also be faulted by one formed and filled later. In such 
 a case the continuous one is the younger. The figure below 
 will illustrate each case. At the intersection of the two, the later 
 vein is often richer than in other parts. 
 
 1.02.11. If a faulted series of rocks is afterward tilted and 
 eroded, so as to expose a horizontal section across the strike of the 
 faulting plane, an apparent horizontal fault may result ; or if the 
 erosion succeeds normal faulting and lays bare two unconformable 
 beds each side of the fissure, a lack of correspondence in plan as 
 
 Fig. 5. — Illustration of one vein faulting another at Newman Hill, near 
 Rico, Colo. After J. B. Farish, Proa. Colo. Sei. Soc, April 4, 1892. 
 
 well as in section may be seen. Faulting fractures are seldom 
 straight ; on the contrary, they bend and corrugate. When the 
 walls slip past each other, they often stoj) with projection opposite 
 projection, and depression opposite depression. These irregularities 
 cause pinches and swells in the resulting cavity, and constitute one 
 of the commonest phenomena of veins. Fissures also graduall}- 
 pinch out at their extremities, or break up into various ramifica- 
 tions that finally entirely cease. They also pass into folds, as 
 stated above. 
 
 1.02.12. Secondary/ Ilodificatioiis of Cavities. — Fractures and 
 cavities of all sorts speedily become lines of subterranean drainage. 
 The dissolving power of water, and to a much smaller degree its 
 eroding power, serve to modify the walls very greatly. An en- 
 largement may result, and what was j^erhaps a small joint or fis- 
 sure may become a waterway of considerable size. This is 
 especially true in limestones, in which great caverns (like the 
 
ON THE FORMATION OF CAVITIES IN BOCKS. 21 
 
 Mammoth Cave and Luray's Cave) are excavated. Caves are, 
 however, almost always due to surface waters, and do not extend 
 below the permanent water level unless they have been depressed 
 after their formation. (See J. S. Curtis, Monograph VTI., U. S. 
 Geol. Survey/, Chap. VIII.) 
 
 The solvent action of water is vastly augmented by the car- 
 bonic acid which it gathers from the atmosphere, and this is the 
 chief cause of the excavations wrought by it in limestones. Pure 
 cold water has comparatively small dissolving and almost no ero- 
 sive power. It has also been advocated that various acids which 
 result from the decay of vegetable matter aid in such results. (A. 
 A. Julien, Amer. Asso. Adv. Set., 18T9, p. 311.) This may be true, 
 but in general carbonic acid is the chief agent. Iron in minerals 
 falls an easy prey, as well as calcium, and is dissolved out in large 
 amount. (See Example 1.) When charged with alkaline carbon- 
 ates, water has the power to attack other less soluble minerals, such 
 as quartz and the silicates, and by such action the walls of a 
 cavity in the crystalline rooks may be much affected. 
 
 1.02.13. Waters percolating to great depths in the earth, or 
 circulating in regions of igneous disturbances, become highly 
 heated, and this too at great pressure. Under such circumstances 
 the solvent action is very strongly increased, and all the elements 
 present in the rock-making minerals are taken into solution. 
 Alkaline carbonates are formed in quantity ; silica is easily dis- 
 solved ; alkaline sulphides result in less amount ; and even the 
 heaviest and least tractable metals enter into solution, either in the 
 heated waters themselves, or in the alkaline liquors formed by them. 
 The action on the walls of cavities and courses of drainage is thus 
 profound, and accounts for the frequent decomposed character of 
 the walls and the general lack of sharpness in their definition. 
 The vast amount of siliceous material, etc., deposited by hot springs 
 and geysers is additional evidence of its importance. 
 
 Magnesia is one of the alkaline earths readily taken into solu- 
 tion by carbonated waters, and when such waters again meet lime- 
 stone the effect is often very great, and constitutes one of the 
 most important methods of the formation of cavities. Solutions of 
 magnesium carbonate, on meeting calcium carbonate, effect a par- 
 tial exchange of the former for the lattei-. This leaves the rock a 
 double car.bonate of calcium and magnesium, which is the composi- 
 tion of the mineral and rock dolomite. The process is therefore 
 called dolomitization. (See Exan^ple 25.) It may bring about a 
 
22 KEMPS ORE DEPOSITS. 
 
 general shrinkage of eleven or twelve per cent. In any extended 
 thickness of strata this would cause vast shattering and porosity. 
 As an illustration of its results, the following analyses of normal, 
 unchanged Trenton limestone of Ohio, and of well drillings from 
 the porous, gas-hearing, dolomitized portions of the same, are 
 given. They are taken from a paper hy Edward Orton. {Amer. 
 Manvf. and Iron World, Pittshurg, Dec. 2, 1887.) 
 
 CaCO,.- 
 
 MgCOs. 
 
 Fe, 
 
 ,03.A1,03. 
 
 SiO,. 
 
 Unchanged Trenton limestone.. .79.30 
 
 0.93 
 
 
 7.00 
 
 12.00 
 
 " " ...82.86 
 
 1.67 
 
 
 0.58 
 
 12.34 
 
 Dolomitized " " ...53.50 
 
 48.50 
 
 
 1.25 
 
 1.70 
 
 ...51.78 
 
 36.80 
 
 
 
 
 1.02.14. Late studies in ore deposits hy Posepny, Curtis, and 
 Emmons indicate also that solutions of metallic ores may effect an 
 interchange of their contents with the carhonate of calcium or 
 magnesium, in limestones and dolomites, leaving an ore body in 
 place of the rocks. This change is effected molecule by molecule, 
 and is spoken of as a metasomatic interchange or replacement. 
 (See Example 30.) By "metasomatic" is meant an interchange 
 of substance without, as in pseudomorphs, an imitation of form. 
 Alteration of the metallic ores may follow and occasion cavities 
 from shrinkage. (See Example 36, and Cui-tis, on Eureka, Nev., 
 Monograph VII., TT. S. Oeol. Survey, Chap. VIII.) 
 
CHAPTER III. 
 
 THE MINERALS IMPORTANT AS ORES ; THE GANGUE MINERALS, 
 AND THE SOURCES WHENCE BOTH ARE DERIVED. 
 
 1.03.01. The minerals which form the sources of the metals 
 are almost without exception included in the following compounds : 
 the sulphides, the related compounds of arsenic and antimony, ox- 
 ides and oxidized compounds such as hydrous oxides, carbonates, 
 sulphates, phosphates, and silicates, and one or two compounds of 
 chlorine. A few metals occur in the native state. All the other 
 mineral compounds such as a chromate or two, a bromide or iodide, 
 etc., are rarities. It may be said that nine tenths of the produc- 
 tive ores are sulphides, oxides, hydroxides, carbonates, and na- 
 tive metals. The ores of each metal are subsequently outlined 
 before its particular deposits are described. 
 
 1.03.02. The most common gangue mineral is quartz, while in 
 less amount are found calcite, siderite, barite, fluorite, and in 
 places feldspar, pyroxene, hornblende, rhodonite, etc. The silicates 
 are chiefly present where the gangue is a rock and the ore is dis- 
 seminated through it. All the common rocks serve in this capaci- 
 ty in one place or another. 
 
 1.03.03. Source of the Metals. — The metallic contents of the 
 minerals which constitute ores must logically be referred to a 
 source, either in the igneous rocks or in the ocean. If the nebular 
 hypothesis expresses the truth, — and it is the best formulation that 
 we have, — all rocks, igneous, sedimentary, and metamorphic, must 
 be traced back to the original nebula. This, in cooling, afforded a 
 fused magma, which chilled and assumed a structure analogous to 
 the igneous rocks with which we are familiar. Igneous rocks must 
 thus necessarily be considered to have furnished by their erosion 
 and degradation the materials of the sedimentary rocks ; while 
 igneous and sedimentary have alike afforded the substances whose 
 alterations have produced the metamorphic rocks. It may also 
 be true that eruptive rocks, especially when basic, have been 
 
24 KEMPS ORE DEPOSITS. 
 
 formed, by the oxidation and combination with silica, of inner 
 metallic portions of the earth, for such is one of our most reason- 
 able explanations of volcanic phenomena, suggested alike by the 
 composition of basalts, by the high average specific gravity of the 
 globe, and by analogy with meteorites. 
 
 1.03.04. As opposed to this conception, there are those who 
 would derive the metallic elements of ores from the ocean, in 
 which they have been dissolved from its earliest condensation. 
 Thus it is said that substantially all the metals are in solution in 
 sea water. From the sea they are separated by organic creatures, 
 it may be, through sulphurous j)recipitation, attendant on the de- 
 cay of their dead bodies. The accumulations of the remains 
 of organisms bring the metals into the sedimentary strata. Once 
 thus entombed, circulation may concentrate them in cavities. 
 When present in igneous rocks, the latter are regarded as derived 
 from fused sediments. If the metallic contents of sedimentary 
 rocks do not come from the ocean in this way, the igneous rocks 
 as outlined above are the only jjossible source. No special men- 
 tion is here made of the metamorphic rocks, because in their origi- 
 nal state they are referable to one or the other of the two remain- 
 ing classes. But it is not justifiable, in the absence of special 
 proof, to consider them altered sediments, any more than altered 
 igneous rocks, and it is doubtless true that the too generally and 
 easily admitted sedimentary origin for our gneisses and schists has 
 materially hindered the advance of our knowledge of them in the 
 last forty years. 
 
 1.03.05. Microscopic study of the igneous rocks has shown 
 that, with few exceptions, the rock-making minerals separate from 
 a fused magma on cooling and crystallizing, in a quite definite 
 ordei'.' Thus the first to form are certain oxides, magnetite, spec- 
 ular hematite, ilmenite, rarely chromite and picotite, a few sili- 
 cates, unimportant in this connection (zircon, titanite), and the 
 sulphides pyrite and pyrrhotite. Kext after these metallic oxides, 
 etc., the heavy, dark-colored, basic silicates, olivine, biotite, au- 
 gite, and hornblende, are formed. All these minerals are character- 
 ized by high percentages of iron, magnesium, calcium, and alumi- 
 num. They are very generally provided with inclusions of the 
 first set. Following the bisilicates in the order of crystallization, 
 
 1 H. Eosenbusch, "Ueber das Wesen der Kornigen und Porphyrischen 
 Structur bei Massengesteine," Neues Jahrbuch, 1883, ii., I. 
 
THE MINERALS IMPORTANT AS ORES, ETC. 35 
 
 come the feldspars, and after these, when some residual silica re- 
 mains uncombined, it separates as quartz. 
 
 1.03.06. If we regard the igneous rocks as the source, the 
 metallic elements are thus to be ascribed to the first and second 
 series of crystallizations, while the elements of the gangue minerals 
 are derived from the last three. It is a doubtful point whether 
 the less common metals, such as copper, silver, and nickel, enter 
 into the composition of the dark silicates as bases, replacing the iron, 
 alumina, lime, etc., or whether they are present in them purely 
 as inclusions of the fii'st series. F. Sandberger ^ argues in 
 support of the first view, but his critics, notably A. W. Stelzner, 
 cast doubt upon his conclusions on the ground that his chemical 
 methods were indecisive. The case is briefly this : Sandberger, as 
 an advocate of views which will be subsequently outlined, sep- 
 arated the dark silicates of a great many rocks. By operating on 
 quantities of thirty grams he proved the presence in them of lead, 
 copper, tin, antimony, arsenic, nickel, cobalt, bismuth, a'nd silver, 
 and considered these metals to act as bases. The weak point of the 
 demonstration consists in dissolving out from the powdered silicate 
 any possible inclusions. There seems to be no available solvent 
 which will take the inclusions and be without effect on the silicates. 
 This is the point attacked by the critics, and apparently with 
 reason. It is, however, important to have shown the presence of 
 these metals, even though their exact relations be thus doubtful. 
 Quite recently in a series of " Notes on Chilean Ore Deposits " 
 (Tschermaks 3Iin. unci Petrog. Mittli. XII., p. 195) Dr. Moricke 
 mentions native gold in pearlstone (obsidian) from Guanaco, in 
 skeleton crystals in the glass, as inclusions in perfectly fresh 
 plagioclase and sanidine crystals, and in spherulites. The existence 
 of silver in quartz-porphyry has been demonstrated in this country 
 by J. S. Curtis, at Eureka, Nev.;'' both the precious metals have 
 been shown by G. F. Becker to be in the diabase near the Com- 
 
 1 The principal paper of Professor Sandberger is his " Untersuchungen 
 iiber Erzgange," 18*^3, ubstracted in the Engineering and Mining Journal, 
 March 15, £3, and 39, 1884; but a long series ot others might be cited in 
 which the investigations, notably at Pribram, Bohemia, are interpreted 
 as indicated above A. W. Stelzner, B. and H. Zeit. , xxxix.. No. 3. Zeitsch. 
 d.d.g. Gesell., xxxi. 644. " Die Lateral-secretions-Theorie, etc." Reprint 
 Freiberg, 1889. 
 
 ^ Monograph VII., U. 8. Oeol. Survey. 
 
26 KEMP'S ORE DEPOSITS. 
 
 stock Lode ; ' and, by the same investigator, antimony, arsenic, 
 lead, copper, gold, and silver were proved to be contained in the 
 granite near Steamboat Springs, Nev.^ S. F. Emmons has also 
 shown that the porphyries at Leadville contain appreciable, though 
 small, amounts of silver.' Of forty-two specimens tested, thi-rty- 
 two afforded it ; of seventeen tested for lead, fourteen yielded re- 
 sults. Undoubtedly the multiplication of tests will show similar 
 metallic contents in other regions. Thus the augite of the eastern 
 Triassic diabase will probably yield copper, for this metal is abun- 
 dant in connection with the outflows. 
 
 1.03.07. That the metals are so generally combined with sul- 
 phur in ore deposits seems to be due to the extended distribution 
 of this element, and to its being a vigorous precipitating agent of 
 nearly all the metals at the temperatures and pressures near the 
 surface. Sulphur is widespread as pyrite, an original mineral in 
 many igneous rocks, and one much subject to alteration ; while 
 sulphuretted hydrogen is common in waters from sedimentary 
 rocks, and is a very general result of organic decomposition. Nat- 
 ural gas and petroleum from limestone receptacles almost always 
 contain it. (See, in this connection, J. F. Kemjj, " The Precipita- 
 tion of Metallic Sulphides by Natural Gas," Engineering and 
 Mining Journal, Dec. 13, 1890.) Many sulphides, too, are soluble 
 under the pressures and temperatures prevailing at great depths, 
 but are deposited spontaneously at the pressures and temperatures 
 prevailing at or near the surface. 
 
 1.03.08. Where veins occur in igneous rocks the bases for 
 gangue minerals have been obtained from the rock-making silicates. 
 Calcium is afforded by nearly all the important ones ; silicon is 
 everywhere present ; barium has been proved in many feldspars, 
 in small amount ;* and magnesia is present in many pyroxenes and 
 amphiboles. Of the sedimentary rocks, limestone of course affords 
 unlimited calcium, and recently Sandberger reports that he has 
 identified microscopic crystals of barite in the insoluble residues of 
 one. [Sitzungsberichte d. Math. phys. Glasse d. h. hayer, ATcad. d. 
 Wiss., 1891, xxi. 291.) This is of interest, as barite is such a com- 
 mon gangue in limestone. 
 
 1.03.09. It may be remarked that the natural formation of both 
 
 1 Monograph III., XT. S. Oeol. Survey. 
 
 2 Monograph XIII. , Cf. 8. Oeol. Survey. 
 8 Monograph XII. . U. 8. Oeol. Stirmy. 
 
 * W. F. Hillebrand, "Tlie Widespread Occurrence of Barium and Stron- 
 tium in Silicate Rocks," Jour. Amer. Uhem. Soc, Feb., 1894, p. 81. 
 
THE MINERALS IMPORTANT AS ORES, ETC. 27 
 
 ore and gangue minerals has doubtless proceeded in nature with 
 great slowness, and from very dilute solutions. Both classes ex- 
 hibit a tendency to concentrate in cavities, even from a widely 
 dispersed condition through great masses of comparatively barren 
 rock. The formation may have proceeded when the walls were 
 far below their present position with regard to the surface, so that 
 to those inclined a wide latitude for speculation on origin is 
 afforded. It is also possible that in the earlier history of the globe 
 circulations were more active than they are now — a line of argu- 
 ment on which a conservative writer would hesitate to enlarge. 
 
CHAPTER IT. 
 
 ON THE FILLING OF MINERAL VEINS. 
 
 1.C4.01. Bearing in mind what precedes, the preliminaries for 
 the discussion of mineral veins are set in order. We have traced 
 the formation of cavities by the shrinkage of rock masses in cool- 
 ing or drying, by the movements and disturbances of the earth's 
 crust (which are far the commonest and most important causes), 
 and by dolomitization. The enlargement of such cavities by sub- 
 terranean circulations followed, and the general eifect of waters, 
 cold and heated. The sources of the elements of the useful min- 
 erals were pointed out so far as known. All these general and in- 
 disputable truths assist in the drawing of right conclusions. It 
 should be emphasized, as will appear later, that mineral veins or 
 cavity fillings do not embrace all metalliferous deposits. On the 
 contrary, the deposits which either form beds by themselves, or 
 which are disseminated through beds of barren rock and are of the 
 same age with them, do not enter into the discussion. They are 
 characterized by being younger than their foot walls and older 
 than the hanging. Their geological structure is far simpler, and, 
 as will appear in the discussion of particular examples, the work- 
 ing out of their origin does not so often carry the investigator into 
 the realms of speculation and hypothesis. And yet it is not to be 
 inferred from the prominence here given to the discussion of veins 
 that bedded dejiosits yield to them, in any degree, in importance. 
 Iron ores, for instance, are often in beds. 
 
 1.04.02. Methods of Filling. — Methods of filling were summed 
 up a very long time ago by Von Herder and Von Cotta,^ as fol- 
 lows : 1. Contemporaneous formation. 2. Lateral secretion. .3. 
 Descension. 4. Ascension by (a) infiltration, or (b) sublimation 
 with steam, or (c) by sublimation as gas, or (cT) by igneous injec- 
 tion. To these should be added the more recent theory of (5) re- 
 
 1 Erzlagerstatten, 3d ed., 1859, Vol. I., p. 172. 
 
ON THE FILLING OF MINERAL VEINS. 29 
 
 placement, which, however, is rather a method of precipitation 
 than of derivation. No one longer believes in contemporaneous for- 
 mation, and descension has an extremely limited, if, indeed, any 
 application. Ascension by sublimation as gas or with steam, or by 
 igneous injection, has few, if any, supporters. The discussion is 
 practically reduced to lateral secretion and to ascension by infiltra- 
 tion. 
 
 1.04.03. Lateral Secretinn. — By lateral secretion is understood 
 the derivation of tlie contents of a vein from the wall rock. The 
 wall rock may vary in character along the strike and in depth. 
 Three interpretations may be made, two of which approach a com- 
 nion middle ground with ascension by infiltration. It may first be 
 supposed that the vein has been filled by the waters near the surface 
 which are known to be soaking through all bodies of rock, even 
 where no marked waterway exists, and which seep from the walls of 
 any opening that may be afforded. Being at or within comparatively 
 short distances of the surface, the waters are not especially heated. 
 As they emerge to the oxidizing and evaporating influence of the 
 air in the cavity, their burden of minerals is deposited as layers on 
 the walls. The second interpretation supposes the walls to be 
 placed during the time of the filling at considerable depth below 
 the surface, so that the percolating waters are brought within the 
 regions of elevated temperature and pressure. Essentially the 
 same action takes place as in the first case. The third interpreta- 
 tion increases the extent of the rock leached. Thus if a mass of 
 granite incloses a vein and extends to vast depths, we may suppose 
 the waters to come from considerable distances, and to derive their 
 dissolved minerals from a great amount of rock of the same kind 
 as the walls. Portions of this may even be in the regions of high 
 temperature, while the place of precipitation is nearer the surface. 
 These last two interpretations have much in common with the 
 theory of ascension by infiltration, and on this common middle 
 ground lateral-secretionists and infiltration-asoensionists maybe in 
 harmony. 
 
 1.04.04. Ascension by InJilt7'ation. — The theory of infiltration 
 by ascension in solution from below considers that ore-bearing 
 solutions come from the heated zones of the earth, and tliat 
 they rise through cavities, and at diminished temperatures and 
 pressures deposit their burdens. No restriction is placed on the 
 source from which the mineral matter has been derived. Indeed, 
 beyond that it is "below," and yet within the limits reached by 
 
30 KEMP'S ORE DEPOSITS. 
 
 waters, all of which have descended from the surface, and that the 
 metals have been gathered up from a disseminated condition in rocks, 
 — igneous, sedimentary, and metamorphic, — no more definite state- 
 ment is possible. This theory is of necessity largely speculative, 
 because the materials for its verification are beyond actual inves- 
 tigation. 
 
 1.04.05. Lateral Secretion. — In favor of lateral secretion the 
 following arguments may be advanced. I. According to Sandberg- 
 er, actual experience witli the conduits, either natural or artificial, 
 of mineral springs, shows that a deposit seldom, if ever, gathers in 
 a moving current. It is only when solutions come to rest on the 
 surface and are exposed to oxidation and evaporation that precipita- 
 tion ensues. Deposits in veins have therefore formed in standing 
 waters, whose slight overfl.ow or evaporation has been best compen- 
 sated by the equally slight and gradual inflow from the walls. If in 
 hot springs there is a strong and continuous flow from below and 
 discharge from iibove, the mineral mattei- will reach the surface. 
 (Sandberger, U liter sucliungeu uber Erzgdiige, Heft I.) Hence the 
 deposit will be more likely to gather by the slow infiltrations from 
 the wall rock, which stand in cavities likti a well. We have, 
 however, some striking instances of deposits in artificial con- 
 duits. 
 
 Prof. H. S. Munroe has called the writer's attention to a case 
 recently met by him. The fourteen-inch column pipe of a pump 
 at the Indian Ridge Colliery, Shenandoah, Penn., which was rais- 
 ing ferruginous waters, became reduced in diameter to five inches 
 within two years by the deposit of limonite. The same amount 
 of water was forced through the five-inch as through the fourteen- 
 inch. By figuring out the stroke and cylinder contents, it was 
 found that in the clear pipe the water moved 162 feet per minute, 
 and in the contracted pipe 1268 feet. And yet the deposit gath- 
 ered. The conditions necessitated the continuous action of the 
 pump, and it was not idle over two hours in each two months 
 of that period. The boiler feed-pipes of steamers plying on the 
 Great Lakes also become coated with salts of lime. Years ago a 
 disastrous boiler explosion occurred from the virtual stoppage of 
 the feed by this precipitation. 
 
 1.04.06. II. If a vein were opened up, in mining, which ran 
 through two different kinds of rock, and if in the one rook one 
 kind of ore and gangue minerals were found, and in the other a 
 different set, the wall rock would clearly have some influence. 
 
ON THE FILLING OF MINERAL VEINS. 31 
 
 Thus in a mine at Schapbaah, in the Black Foi-est, investigated by 
 Sandberger, a vein ran through granite and gneiss. Tlie mica of 
 the granite contained arsenic, copper, cobalt, bismuth, and silver, 
 but no lead. The principal ore in this portion was gray copper. 
 The mica of the gneiss contained lead, copper, cobalt, and bismuth, 
 and the vein held galena, chalcopyrite, and a rare mineral, schap- 
 bachite, containing bismuth and silver, but probably a mixture of 
 several sulphides. No two ores were common to both parts of the 
 vein. Another well-established foreign illustration is at Klausen, 
 in the Austrian Tyrol. Lead, silver, and zinc occurred in the 
 veins where they cut diorite and slates, but copper where mica 
 schist and felsite formed the walls. In America there are a num- 
 ber of similar cases. At the famous Silver Islet Mine' on Lake 
 Superior the vein runs through unaltered flags and shales, and 
 then crosses and faults a large diorite dike. Where the diorite 
 forms the walls, the vein carries native silver and sulphides of 
 lead, nickel, zinc, etc., but where the flags form the walls, the 
 vein contains only barren calcite. Along the edges of the estuary 
 Triassic sandstones *of the Atlantic border, where they adjoin 
 Archean gneiss, a number of veins are found afEording lead min- 
 erals, while in the sandstones near the well-known diabase sheets 
 and dikes are others carrying copper ores. It was early remarked 
 by J. D. ^/''hitney that the lead was usually associated with the 
 gneiss, the copper with the diabase. 
 
 1.04.07. From instances like these it is infen-ed that the ores 
 were derived each from its own walls, and by just such a leaching 
 action by cold surface waters as is outlined above. As opposed 
 to this, it has usually been claimed that each particular wall ex- 
 erted a peculiar selective and pi-ecipitating action on the metals 
 found adjacent to it and none on the others ; so that if a solution 
 arose carrying both sets, each came down in its particular sur- 
 roundings, while the others escaped. Dr. W. P. Jenney has called 
 the writer's attention to such a case. The Head Centre mine, in 
 
 ' W. M. Courtis, " On Silver Islet," Engineering and Mining Journal, 
 Deo. 31, 1878. ilf. ^,, V. 474. 
 
 E. D. Ingall, Geol Survey of Canada, 1887-88, p. 27, H. 
 
 F. .\. Lowe, "The Silver Islet Mine," etc., Engineering and Mining 
 Journal, Dec. Ifl, 1882, p. 321. 
 
 T. MicFarlane, "Silver Islet," M. E., VIII. 226. Canadian Naturalist, 
 IV. 37. 
 
 McDermolt, Engineering and Mining Journal, January, 1877. 
 
32 KEMP'S ORE DEPOSITS. 
 
 the Tombstone district, Arizona, is on a vein which pierces elates, 
 and in one place forty feet of limestone. In the slates it carried 
 high-grade silver ores, with no lead, hut in the limestone, lead-sil- 
 ver ores. A rock like limestone might well exercise a precipita- 
 ting action, which, however, we cannot attribute to rocks composed 
 of the more inert silicates. Again, it has been said that the solu- 
 tions coming from below have varied in different portions of the 
 vein or at different periods. An earlier opening would thus be 
 filled with one ore, a later opening with another. This is hy- 
 pothetical, but has been advanced for Klausen by Posepny. (Ar- 
 chiv f. Praktische Geologie, p. 482.) A further general objection 
 to the first interpretation of lateral secretion is the weak dissolv- 
 ing power of cold surface waters, and this is a very serious one. 
 
 1.04.08. As opposed to the second interpretation, it may be 
 advanced that precipitation in a cavity at a great depth would be 
 retarded by the heat and the pressure, to just that extent to which 
 solution in the neighboring walls would be aided. The tempera- 
 ture and pressure being practically the same, the tendency to re- 
 main in solution would be great until the minerals had reached the 
 upper regions and filled the cavity by ascension. Under such cir- 
 cumstances ores would only be deposited below, by some such ac- 
 tion as replacement. To the third interpretation no theoretical ob- 
 jections can be made. 
 
 1.04.09. Infiltration by Ascension. — On the side of infiltration 
 by ascension, if two veins or sets of veins were found in the same 
 wall rock, but with different kinds of ores and minerals, the con- 
 clusion would be irrefutable that the respective solutions which 
 formed them had come from two different sources below. Thus at 
 Butte, Mont., there is a great development of a dark, basic granite. 
 It contains two series of veins, of which the southern produces copper 
 sulphides in a siliceous gangue, the northern sulphides of silver, 
 lead, zinc, and iron, also in a siliceous gangue, but abundantly associ- 
 ated with manganese minerals, especially rhodonite. No manganese 
 occurs in the copper belt, nor is any copper found in the silver belt. 
 Such results could originate only in different, deep-seated sources. 
 Again, at Steamboat Springs, Xev., and Sulphur Bank, Cal., the hot 
 springs are still in action and are bringing their burdens of gangue 
 and ore to the surface. The former has afforded a long series of 
 metals, the latter chiefly cinnabar, G. F. Becker^ has shown that 
 the cinnabar probably comes up in solution with alkaline sulphides. 
 
 1 G. F. Becker, " Natural Solutions of Cinnabar, Gold, and Associated 
 
ON THE FILLING OF MINERAL VEINS. 33 
 
 1.04.10. Replacement. — The conception of replacement is one 
 that has been applied of late years by some of the most reliable 
 observers. About 1873 it appears to have been first extensively 
 developed by Franz Posepny, an Austrian geologist, in relation to 
 certain lead-silver deposits at Raibl, in the Province of Kaernthen. 
 About the same time it was suggested by Pumpelly, then State 
 Geologist of Missouri, to Adolf Schmidt, who was engaged in 
 studying the iron deposits of Pilot Knob and Iron Mountain (see 
 Examples 11 and 11a), and by Schmidt it was considered applicable 
 to them. ("Iron Ores and Coal 'Fields,''' Missouri Geol. Survey, 
 1873.) Some ten years later J. S. Curtis based his explanation of 
 the formation of the Eureka (Nev.) lead-silver deposits on the 
 same idea, and according to Emmons (1886) it holds good forLead- 
 ville. R. D. Irving, who credited Pumpelly with bringing it to his 
 attention, published in 1886 an explanation of the hematite beds of 
 the Penokee-Grogebio range (Example 9c;), in which the idea is ap- 
 plied, and Van Hise has since elaborated it. In the process of re- 
 placement no great cavity is supposed to exist previously. There 
 is little, in fact, but a circulation or percolation of ore-bearing solu- 
 tions which exchange their metallic contents, molecule by molecule, 
 for the substance of the rock mass. We would not expect the ore 
 body to be as sharply defined against the walls as when it filled a 
 fissure, but rather to fade into barren material. Thus rock ma}' 
 be impregnated but not entirely replaced, and, while apparently 
 unchanged, yet carry valuable amounts of ore. Some of the ores 
 of Aspen, Colo. (Example ZOd), are at times only to be distinguished 
 by assay from the barren limestones. Yet decomposition may 
 bring out the limits of each. 
 
 1.04.11. The chemistry of the replacement process is none too 
 well understood, but it presents fewer difficulties when applied to a 
 soluble rock, like limestone or dolomite, than when rocks composed 
 of silicates and quartz have given away to ores. Acid solutions 
 would readily yield to calcium carbonate; but if the metals are pres- 
 ent as sulphates, some reducing agent, such as organic matter, is 
 necessary in order to change the metallic sulphate to sulphide.' 
 Or else, if the metallic sulphides come up in solution with alkaline 
 sulphides, some third agent is needed to remove the calcium car- 
 Sulphides," 4roer. Jomj". Sci., III., xxxili. 199; Eighth Ann. Rep. Direc- 
 tor U. S. Geol. Survey ; Monograph XIII., U. S. Qeol. Survey, p. 965. 
 
 1 Compares. F. Emmons, " On the Replacement of Leadville Limestones 
 and Dolomites by Sulphides," Monograph XIL, U. S. Geol. Survey, p. 563. 
 
34 KEMP'S ORE DEPOSITS. 
 
 honeite, pari passu, ]vLst before the metallic sulphide is precipitated. 
 It must be confessed that for enormous bodies of ore, like those of 
 Leadville, the small amount of organic matter present seems hard- 
 ly equal to the task assigned it, and the delicate balance of the lat- 
 ter case — causing deposition to tread so closely on the heels of rock 
 removal, in order to avoid assuming an extended cavity — makes it 
 appear that the entire chemistry of the process is perhaps hardly 
 understood. 
 
 1.04.12. When silicate rocks are replaced, leaving a siliceous 
 gangue, the process may have been somewhat as suggested by R. 
 C. Hills for the mines of the Summit district, Rio Grande County, 
 Colorado. (See Proc. Colo. iSci. Soc, Vol. I., ]>. 20.) Alkaline solu- 
 tions remove silica and have slight action on silicates, but solutions 
 acid with sulphuric acid attack silicates, such as feldspar and bio- 
 tite, remove the alumina or change it to kaolin, and cause the sep- 
 aration of free silica. In the alteration products abundant opportu- 
 nity would be afforded for the precipitation of sulphides, which 
 would in part at least replace the rock. Along a crack or line of 
 drainage definite walls would thus easily fade out. Such phenome- 
 na are afforded by innumerable ore deposits (see R. "W. Raymond, 
 discussion of S. F. Emmons' " Notes on the Geology of Butte, 
 Mont.," M. S., July, 1877), and often come under the notice of 
 every one familiar with mining. Yet we cannot but hope that 
 in tlie future our knowledge of the chemical reactions involved 
 will be increased. 
 
 It may again be stated that the formation of ore deposits has 
 proceeded with great slowness, and the solutions bringing the met- 
 als have been, beyond question, very dilute. The extremely small 
 amounts of the metals that have been detected in relatively large 
 amounts of igneous rocks, even by the most refined analytical meth- 
 ods, have necessarily made the progress of solution a protracted 
 one. Curtis records some careful observations on the growth of 
 ai-agonite at Eureka, Nev., where he found that in three weeks, 
 so long as wet by a drop of water, the crystals increased in one case 
 as a maximum, five eighths of an inch, and in another three eighths. 
 But this was where the whole inclosing mass of rock consisted of the 
 compound deposited. 
 
CHAPTER Y. 
 
 ON CERTAIN STRUCTURAL FEATURES OF MINERAL VEINS. 
 
 L05.01. Bayided Structvre. — Mineral veins sometimes exhibit 
 a banded structure, by which is understood the arrangement of 
 the ore and gangue in parallel layers that correspond on opposite 
 walls. They are most conspicuous where the walls are well de- 
 fined. The solutions which have brought the minerals have varied 
 from time to time, and the precipitated coatings correspond to 
 these variations. They alternate from gangue to ore, it may be, 
 several times repeated. The ore may be in small scattered masses 
 preserving a distinct lineal arrangement in the midst of the barren 
 quartz, calcite, barite, fluorite, siderite, etc., or itself be so abun- 
 dant as to afford a continuous parallel streak. The commonest 
 ores so observed are pyrite, chalcopyrite, galena, blende, and the 
 various sulphides of silver. The veins of the Reese River district, 
 in Nevada, furnish good illustrations of alternating ruby silver 
 ores and quartz. Those of Gilpin County, Colorado (Example 
 lla), afford alternations of pyrite, chalcopyrite, and gangue. (See 
 figures in Endlich's report, Hayderi's Survey, 1873, p. 280.) The 
 Bassick Mine, in Colorado, has pebbles remarkably coated. The 
 figure on p. 36 shows a vein at Newman Hill, near Rico, Colo. 
 
 Banded veins, however, except of a rude character, are not com- 
 mon in this country. They have received much more attention in 
 Germany, where, especially near Freiberg, they show remarkable 
 perfection. The famous Drei Prinzen Spat Vein, figured by Von 
 Weissenbach and copied in many books, has ten corresponding al- 
 ternations of six different minerals on each wall. 
 
 1.05.02. A line of cavities, or vuggs, is often seen at the cen- 
 tral portion of a vein, into which crystals of the last formed miner- 
 als emerge, forming a comb (see p. 36). These may project into 
 each other and interlock, — especially if quartz, — forming a comb 
 in comb. The same may occur between side layers. These cavities 
 are a most prolific source of finely crystallized minerals. If, after the 
 
36 
 
 KEMP '8 ORE DEPOSITS. 
 
 fissure — perhaps at the time small — has become once filled, subse- 
 quent movements take place, they may strip the vein from one wall 
 and cause a new series of minerals to be deposited, witii tlie previously 
 formed vein on one side and the wall rock on the other. This oc- 
 casions uns3'mmetrical fillings. But it may also happen that, with 
 otherwise symmetrical fillings, one layer may be lacking on one 
 side or the other. "Where portion- of the wall rock have been torn 
 off by the vein matter in these secondary movements, they may be 
 buried in the later deposited vein filling, and form great masses of 
 barren rock called horses. The vein then forks around them. If 
 the ore and thegangue have partly replaced the wall in deposition, 
 
 East 
 
 Fig. 6. — Banded vein at Newman Hill, near Rico, Colo. After J. B. Far- 
 
 ish, Proa. Colo. Sai. Soc, April 4, 1892; Engineering and Mining 
 
 Journal, Aug. 30, 1893. 
 
 unchanged masses of wall may also become inclosed and afford 
 horses of a different origin. An originally forked fissure gives an 
 analogous result. 
 
 It is a curious fact that veins are often most productive just at 
 the split. If the masses are small, or if the vein fills a shattered 
 strip and not a clean fissure, or if it occupies an old volcanic con- 
 duit, deposition and replacement may surround unchanged cores of 
 wall rock with concentric laj^ers of ores and minerals. Thus the 
 Bassick, at Rosita, Colo., referred to above, consists of rounded 
 cores of andesite, inclosed in five concentric layers of metallic sul- 
 phides. The Bull Domingo, in the same region, exhibits shells of 
 galena and quartz mantling nodules of gneiss. Such cores strongly 
 
ON STRUCTURAL FEATURES OF MINERAL VEINS. 37 
 
 resemble rounded, water-worn boulders, a similarity which has 
 suggested some rather improbable hypotheses of deposition. 
 
 1.0.5.03. Clay Selvage. — An extremely common feature is a 
 band of clay, most often between the vein matter and the wall. 
 This is called a selvage, gouge, flucan, clay seam, or parting. It 
 may come in also between layers of different minerals, and even 
 rests as a mantle on the crystals which line cavities. It is at times 
 the less soluble portion left by the decay and removal in solution 
 of wall rock (residual clay), at times the comminuted material re- 
 sulting from the friction of moving walls (attrition clay), and 
 again it may be taken up by currents and redeposited from bodies 
 of the first two sorts. Such layers of clay, being wellnigh imper- 
 vious to water, may have exercised an important influence in di- 
 recting the subterranean circulations. (See Becker on the Com- 
 stock Lode, 2.11.19.) 
 
 1.05.04. Pinches, Swells, and Lateral Enrichments. — The 
 swells and pinches of veins have been referred to above and ex- 
 plained. Aside from these thicker portions of the ore, it is often 
 seen that the richer or even the workable bodies follow certain 
 more or less regular directions, forming so-called " chutes." They 
 probably correspond to the courses taken and followed by the 
 richer solutions. J. E. Clayton observed that they follow the di- 
 rections of the slips, or strisB, of the walls rather more often than 
 not, and in the west this disposition or tendency is called Clayton's 
 law. Chute is sometimes spel 1 oil "shoot " or"shute." Chimney 
 and ore-courLj are synonyms of chute. Bonanza is used, especially 
 on the Comstock Lode, to indicate a localized, rich body of ore. 
 
 Lateral enrichments are caused by the spreading of the ore- 
 bearing cuiTents sidewise from the vein, and often along particu- 
 lar beds of rock, which they may replace more or less with ore. 
 Beds of limestone — it may be quite thin, when in a series com- 
 posed of shales or sandstones — are faA'orite precipitants, and from 
 such lateral enlargement the best returns may be obtained. The 
 valuable ore bodies of Newman Plill, near Rico, Colo., whose inter- 
 esting description by J. B. Farish has already been several times 
 cited, are found as lateral enrichments along a bed of limestone less 
 than three feet thick and embedded in shales. Above the lime- 
 stone the veins practically cease. Lateral enrichments may closely 
 resemble bedded deposits if the supply fissures are relatively small. 
 This interpretation is placed by W. P. Jenney on the disseminated 
 lead ores of southeastern Missouri (2.15.09), and he has suggested 
 
38 KEMP'S ORE DEPOSITS. 
 
 the expressive term "melon vein," tlius comparing them with a 
 vine and its melons. 
 
 1.05.05. Changes in Character of Vein Filling. — In discuss- 
 ing the influence of wall rock the changes that occur in veins 
 were briefly mentioned. But even where the walls remain uniform 
 there is always variation in contents, and of course in value, from 
 point to point. Ore, gangue, horses, and walls alternate both 
 longitudinally and in depth, and such changes must be allowed for 
 and averaged by keeping exploration well in advance of excava- 
 tion. Even a series of parallel veins may all prove fickle. In 
 illustration of the above the Marshall tunnel of Georgetown, Colo., 
 may be cited. It cut twelve veins below their actual workings, 
 and every one was barren at the tunnel though productive above. 
 (J. J. Stevenson, Wheeler's Survey, Geology, Vol. III., p. 351.) 
 
 1.05.06. Secondary Alteration of the Minerals hi Veins. — It 
 has already been stated that the chief ore minerals in vein fill- 
 ings are sulphides. Where these lie above the line of permanent 
 subterranean water they are exposed to the oxidizing and hydrat- 
 ing action of atmospheric waters, M-hich, falling on the surface, 
 percolate downward. The ores are thus subjected to alternating 
 soakings and dryings which encourage alteration. The sulpliides 
 change to sulphates, carbonates, oxides, or hydrous forms of the 
 same, and the metallic contents are in part removed in the acid 
 waters which are also formed. Pyrite, which is the most wide- 
 spread of the sulphides, becomes linionite, staining evervthing with 
 its characteristic color. Galena becomes cernssite or anglesite. 
 Blende affords calamine and sniithsonite. Copper ores, of which 
 the usual one is chalcopyrite, change to malachite, azurite, chryso- 
 colla, cuprite, and melaconite, and to the sulphide chalcocite. The 
 silver sulphides afford cerargyrite. The rarer metals alter to cor- 
 responding compounds of less frequency. These ujDper jjortions 
 are also more cellular and porous, being at times even earthy. The 
 rusty color from the presence of limonite often marks the outcrop 
 and is of great aid to the prospector. It has been called the iron 
 hat, or gossan. This feature has important economic bearings. 
 The character of ores may entirely change at a definite point in 
 depth, and the later products, if not lower in grade, as is often the 
 case, may demand different, perhaps more difficult, modes of treat- 
 ment. Oxidized ores are the easiest to smelt, and the benefit of 
 careful exploration before indulging in too confident expectations 
 may be emphasized. As examples, the Ducktown copper deposits 
 
ON STRUCTURAL FEATURES OP MINKRAL VEINS. 
 
 39 
 
 (see Example 16), the Leadville silver mines (Example 30), the 
 boiithwest Virginia zinc deposits at Bonsacks (Example 26), the 
 copper and silver veins at Butte, Mont. (Example 17), and others 
 ill LliUK) County, Texas (Example lib), may be cited. At Duck- 
 town a considerable thickness of chalcocite, melaconite, and carbon- 
 ates accumulated just at the water line and abruptly changed to 
 low-grade, unworkable pyrite and chalcopyrite below it. At Bon- 
 sacks, near Roanoke, Va , very rich, easily treated earthy limon- 
 ite and smithsonite (30-40 ^ zinc) passed into a refractory, low- 
 grade (15-20 <fo zinc), intimate mixture of blende and pyrite. 
 Excavations in dry districts may not reach the water line for great 
 
 jPia. T.— Illustration of the oxidized zone, or gossan, the zone of enrich- 
 ment, and the unchanged sulphides, at Ducktown, Tenn. After 
 A. F. Wendt, School of Mines Quarterly, Vol VII., 1886. 
 
 depths. Thus at Eureka, Nev., in the rainless region of the Great 
 Basin, the oxidized ores continue to 900 feet. 
 
 It is worthy of remark in this connection that possibly some 
 deposits of oxidized ores may have been formed originally as such. 
 Wendt has argued this for the copper mines of the Bisbee dis- 
 trict, Arizona. (See Example 2Qb.) If oxidized ores are now 
 found below the water line, it may indicate a repression of the 
 rocks from a previous higher position. R. C. Hills has brought out 
 a very interesting instance of the concentration of gold and silver 
 in the lower part of the oxidized zone, or at least at a considerable 
 depth below the outcrop. The upper portion of the vein, in this 
 case with a quartz gangue, was impoverished. The gold is thought 
 
40 KEMP'S ORE DEPOSITS. 
 
 to have been carried down in solution with ferrous and ferric sul- 
 phates, which were decomposed by feldspar, while the precious 
 metal was thrown down. The ore bodies lie in the Summit district, 
 Rio Grande County, Colorado. (R C. Hills, Proc. Colo. Sci. Soc, 
 Vol. I., p. 32 ; S. F. Emmons, quoting Hills, Engineering and Min- 
 ing Journal, June 9, 188.3.) 
 
 1.05.07. The waters of mines which have opened up and ex- 
 posed sulphides to oxidation are often charged with sulphuric acid 
 and even metallic salts. This is especially true of mines in copper 
 sulphides, and the pumps are much corroded. In instances con- 
 siderable metallic copper has been recovered by passing the mine 
 drainage over scrap-iron, as at Ducktown, Tenn., and as has been 
 lately introduced experimentally at Butte, Mont. Mine timbers 
 have been preserved very long periods by the deposition of copper 
 on them, from their reducing action on the solutions. Pumps and 
 timbers placed by the Romans in the Rio Tinto mines, in Spain, 
 are still in good preservation. Even gold has been detected in 
 Australian mine waters. (See School of Mines Quarterly, Vol. 
 XI., p. 364, for review of literature bearing on this subject.) 
 
 1.05.08. Electrical Activity, — A theoretical agent for the pre- 
 cipitation of ores in veins, which was a great favorite among the 
 writers fifty or sixty years ago, was electrical action, and careful 
 experiments were made in England and Germany to detect it. By 
 connecting the opposite ends of a vein with a wire, in which was a 
 galvanometer, the attempt was made again and again to establish 
 the existence of galvanic action. At times the results gave some 
 grounds for belief ; but at others they were contradictory or un- 
 certain, so that no very definite or reliable conclusions were 
 established. Other experiments were made in Germany about 
 1844, by Reich, while lately quite elaborate investigations have 
 been canied out by Dr. Carl Earns on the Comstock Lode, and at 
 Eiii-eka, Kev. Great difliculties are met in preserving the neces 
 sary insulation throughout the wet and devious underground work- 
 ings, and amid such surroundings in detecting the currents, which 
 would be necessarily small. With Barus the thesis was not alone 
 to establish a galvanic action, such as might be a precipitating 
 agency, but also to observe what efl^ect, if any, was exerted by the 
 intervention of an ore body on the normal tei-restrial currents. 
 Had this latter been proved of suflicient amount, the existence of 
 such bodies might be indicated by plotting electrical observations. 
 While in some respects of interest, the results of Dr. Barus are not 
 
ON STRUCTURAL FEATURES OF MINERAL VEINS. 41 
 
 very decisive, and this line of investigation is hardly to be con- 
 sidered a promising one. The importance attached to it in former 
 years may be illustrated by these words of De la Beche, one of 
 the ablest of English writers, in 1839. Speaking of veins in general, 
 after discussing those of Cornwall in particular, he says : " Mineral 
 veins result from the filling of fissures in rocks by chemical deposits, 
 from substances in solution in the fissures, such deposits being 
 greatly due to electro-chemical agency." 
 
 Note. — The superficial alteration of ore deposits lias lately been discussed 
 by R. A. F. Penrose, Jr., at length, and the cbange.s which take place in various 
 ores traced out under the head of eacb. iJoarnrd of Oeologn, April-May, 
 1894, p. 388.) 
 
CHAPTER VI. 
 
 THE CLASSIFICATION OF ORE DEPOSITS, A REVIEW AND A 
 SCHEME BASED ON ORIGIN. 
 
 1.06.01. In the classification of ore deposits the same syste- 
 matic arrangement is not to be expected as in the grouping of plants, 
 animals, or minerals. Ore deposits have not the underlying afiin- 
 ities and relationships of living organisms or of definite chemical 
 compounds. The series of objects is too diverse, and, in the na- 
 ture of the case, the standards of appeal must be different. The 
 subject is, however, one of great practical importance as well as 
 of great scientific interest. A vocabulary of intelligible terms is 
 indispensable for description and comparison, and, under our min- 
 ing laws, often for valid titles, while as a vehicle for the spread of 
 knowledge and reasonable conceptions regarding these phenomena, 
 its importance cannot be overestimated. 
 
 1.06.02.' All schemes of classification rest on these principles : 
 form, origin, — or the genetic principle (including method, relative 
 time of origin as contrasted with the walls, etc.), — state of aggre- 
 gation, and mineral contents. Of these, the princij)le of form is 
 usually esteemed the weightiest, and is given the greatest promi- 
 nence, partly because it has been thought to be the one most close- 
 ly affecting exploitation, and partly because it involves less that is 
 or has been, iip to very recent times, more or less hypothetical. 
 Yet form is largely fortuitous, and it has, of course, no law, while, 
 with sufiicient knowledge, the genetic principle is the one giving a 
 far more thoroughly scientific basis. Every one, in opening up or 
 searching for an ore body, must be infiuenced by some hypothesis, 
 either of shape or of origin. It is the conviction of the writer 
 that, with all our deficiencies of knowledge, the genetic pi-inciple 
 is also the best guide, even in practical development. 
 
 1.06.03. Very early in the development of mining literature 
 the distinction was made between those ore bodies which are 
 parallel to the stratification and those which break unconformably 
 
CLASSIFICATION OF ORE DEPOSITS. 43 
 
 across it. This took place long before tlie epoch-making time of 
 Werner, and even before the conception of the relative ages of 
 strata had been at all generally grasped. Thus among the Ger- 
 mans we find the terms "Lager " and "Flotze " ^ on the one side, 
 being set off in contrast to " Gang " (vein) on the other. Werner, 
 writing in 1791, quotes Von Oppel's distinctions between Flotze 
 (strata, beds) and Gange (veins), which were published in 1749 ; 
 but without doubt, as mining terms, they go much further back. 
 Beyond this simple indication of the views of the older writers, no 
 attempt will be made here to quote authorities earlier than 1850. 
 This is justifiable because the important works, like De la Beche's 
 Geology of Cornwall and Devon, and Henwood's Metalliferous 
 Deposits of Cornwall and Devon, are rather discussions of veins 
 than systematic attempts at classification. 
 
 In the following pages the principal schemes of classification 
 are grouped according to certain relationships and similarities 
 that run through them. It would be interesting to arrange them 
 in chronological order, but points of likeness and unlikeness would 
 not be thus brought out, nor can the influence of one writer on 
 another be so clearly manifested. The underlying object, aside 
 from showing in a bird's-eye view what has been done, is to lead 
 up to an attempt at a purely genetic classification from which 
 
 1 Lager and Flotze are difficult to render into English while retaining 
 their native shades of meaning. The later writers in Germany (Serlo, 
 Gatzschmann, Von Groddeck, Kohlir) define them as being interbedded 
 bodies, each later than the foot wall in formation, and older than the 
 hanging ; and that Lager are much more limited in horizontal extent than 
 Flotze. R. Wabner shows, however, in the Berg. u. Huet. Zeitung, Jan. 
 2, 1891, p. 1, that writers in the earlier part of the century did not entirely 
 restrict the term Lager as regards age relative to tlie foot and hanging, 
 but applied it to ore bodies, which follow the general bedding, although 
 they may have been introduced much later than the formation of the 
 walls. Thus the frequent occurrence of lead ores in limestone along cer- 
 tain beds (southeast Missouri, for example) would be called Lager. W« 
 would apply the terms impregnation, or dissemination, or bed-vein, to 
 such. Flotz we would call stratum, and Lager, as defined by the later 
 authors, " bed " or "seam." Werner, for instance, in his classification 
 of the rock formations of the globe, made : I. Urgebirge (Primitive, Pri- 
 mary, etc., having no fossils). II. Secondary, subdivided into A. Ueber- 
 ganggebirge (Transition, more or less metamorphosed sediments, butfos- 
 siliferous). B. Flotzgebirge (Unaltered strata). From this the meaning 
 of Flotz can be grasped. By contrast, a magnetite lense is a good illus- 
 tration of Lager. 
 
44 KEMP'S ORE DEPOSITS. 
 
 mere form is eliminated to the last degree, and well-recognized 
 geological phenomena are brought to the foreground. It has in- 
 deed been said with force that the origin of ore deposits is a sub- 
 ject which is very largely a matter of hypothesis, and that it in- 
 volves profound subterranean causes, of which we know but little. 
 Still, it is held that an acquaintance with what has been accom- 
 plished in recent years by our best workers, and a rigid adherence 
 to well-recognized principles in geology and mineralogy, especially 
 as developed in rock study {i.e., in that department of geology 
 that of late years we have grown to call petrography), will estab- 
 lish much that cannot be questioned, and will aid in differentiating 
 the cases which are still objects of reasonable doubt. It is, how- 
 ever, true that among the subjects on which human imagination, 
 often superstitious, has run to wild extremes, and on which cranky 
 dreamers have exercised their wits, the origin of ore deposits 
 stands out in particularly strong relief. 
 
 1.06.04. A. Schemes Involving only the Classifieation of 
 Veins. 
 
 (1) 
 G. A. von Weissenbach^ {Gangstudien, 1850, p. 12). 
 
 (a) Sedimentargange (Sedimentary Veins). 
 
 (5) Kontritionsgange (Attrition Veins). 
 
 (c) Stalactitisohe oder Infiltrationsgange (Stalactitic or In- 
 
 filtration Veins). 
 
 (d) Plutonische oder Gebirgsmassengange (Masses, dikes, 
 
 knobs, bosses, etc., not necessarily with ores). 
 
 (e) Ausscheidungsgange (Segregated Veins). 
 (/■) Erzgange (True or Fissure Veins). 
 
 (2) 
 B. von Cotta, in comments on Von Weissenbach's Scheme. 
 Gangstudien, 1850, p. 79. According to the vein 
 ■filling. 
 
 1. Gesteinsgange (Dikes). 
 
 (a) Not crystalline (Sandstone). 
 
 (5) Crystalline (Granite). 
 
 2. Mineralgange (Veins). 
 
 («) Of one non-metallic mineral. 
 
 (6) Of several non-metallic minerals. 
 
 3. Erzgange. Ore veins. 
 
 1 S-e iils > Wliitney's Metallic Wealth of the U. 8., 1854, p. 44. 
 
CLASSIFICATION OF ORE DEPOSITS. 45 
 
 (3) 
 B. von Cotta, idem, p. 80. According to Shape and Position. 
 I. Wahre, einfache Spaltengange (Fissures). 
 
 (a) Querdurchsetzende, Cross fissures, 
 {b) Lagergange, Bed veins. 
 
 (c) Kliifte (Cracks), Adern (Veinlets). 
 II. Gangziige (Linked Veins).^ 
 
 III. Netzgange (Reticulated Veins). 
 
 IV. Contaktgange (Contact Veins). 
 V. Lenticulargange (Lenses). 
 
 VI. Stockformige Gange (Stocks, Masses). 
 
 (4) 
 B. von Cotta, idem, p. 80. According to the texture of the 
 vein filling. 
 I. Diohte Gange (Compact Veins). 
 II. Krystallinische Gauge. 
 
 III. Krystallinisch, kornige (granular) Gange. 
 
 IV. Krystallinisch, massige (massive) Gange. 
 
 V. Gange niit Lagentexlur (Banded veins). 
 
 {a) Ohne Symmetric der Lagen (unsymmetrical). 
 
 (b) Mit Symmetric der Lagen (symmetrical). 
 VI. Gange mit Breccien oder Conglomerattextur. 
 
 (5) 
 J. Leconte, Amer. Jour. Sci., July, 1883, p. 17. 
 
 1. Fissure Veins. 
 
 2. Incipient Fissures, or Irregular Veins. 
 
 3. Brecciated Veins. 
 
 4. Substitution Veins. 
 
 5. Contact Veins. 
 
 6. Irregular Ore Deposits. 
 
 1.06.05. In Von Weissenbach's table the sedimentary veins 
 are much the same as the " sandstone dikes " which J. S. Diller 
 has recently described. {Bull. Geol. Soc. Amer., I. 411.) They 
 and the stalactitic veins have small practical value, although of 
 great scientific interest. Under {d), the stockworks with tin ores 
 
 ' Gang-ziige is happily translated "linked veins," by Mr. G. F. Becker 
 (Quicksilver Deposits, p. 410). Any attempt to render the original by 
 preserving the figure of a flock of birds or of a school of fish, etc., is, as 
 Mr. Becker remarks, infelicitous, if not impossible. 
 
46 KEMP'S ORE DEPOSITS. 
 
 are the principal illustration of economic prominence. The attri- 
 tion veins are an important class, and increasing study has wid- 
 ened the application of this or synonymous terms. Segregated 
 veins and true veins are well-known forms. In the comments of 
 Von Cotta, which follow Von Weissenbach's paper, veins are 
 grouped from every possible standpoint, Von Weissenbach's 
 scheme being taken as the one based on origin. Nos. 2 and 4 have 
 small claims to attention. No. 3 foreshadows the drift of many 
 subsequent writers. The meanings of the terms are self-evident, 
 except perhaps Oangzuge (linked veins). This refers to a group of 
 parallel and more or less overlapping veins, deposited along a 
 series of openings, evidently of common origin. It is a convenient 
 term. 
 
 The terms used by Leconte may be passed without comment 
 as being self-evident in their meaning, except (4) and (6). The 
 scheme was devised, as a perusal of the citation will show, after 
 the author had set forth some original views of the causes which 
 lead to the precipitation of ores, and had forcibly stated others very 
 generally accepted. In the explanatory text some quite curious as- 
 sociations are found, which are cited by way of illustration. Thus 
 under group (4), stalactites, caves, gash veins, and the Leadville ore 
 bodies are considered examples, and under group (6) the grouping 
 together of beds, igneous masses, and all other forms of so-called 
 irregular deposit is decidedly open to criticism. This is the more 
 emphatic because the concluding sentences of the paper (of whose 
 general value and excellence there can be no question) give the im- 
 pression that the author felt he had cleared up all the points in the 
 origin of ore bodies which would be of interest or importance to a 
 purely scientific investigator as contrasted with a practical miner. 
 
 1.06.06. B. General Schemes Based on Form. 
 
 (6) 
 
 Von Cotta and Prime. Ore Deposits, New York, 1870. 
 I. Regular Deposits. 
 
 A. Beds. 
 
 B. Veins. 
 
 {a) True (Fissure) Veins. 
 (5) Bedded Veins. 
 (e) Contact Veins. 
 {d) Lenticular Veins. 
 n. Irregular Deposits. 
 
CLASSIFICATION OF ORE DEPOSITS. 47 
 
 C. Segregations. 
 
 (a) Recumbent. 
 (5) Vertical. 
 
 D. Impregnations (Disseminations). 
 
 (^) 
 Lottner-Serlo, Leitfaden zur BergbauJeunde, 1869. 
 
 I. Eingelagerte Lagerstatten (Inclosed Deposits). 
 
 A. Plattenformige (Tabular). 
 
 (a) Gange (Veins). 
 
 (5) Flotze und Lager (Strata, beds, seams). 
 
 B. Massige Lagerstatten (Massive Deposits). 
 
 (a) Stocke \ ^r_„„„, 
 
 ib) Stock werke [ ^^'^^^es. 
 
 C. Andere unregelmiissige Lagerstatten (other irregu- 
 
 lar deposits), 
 (a) Nester (Pockets). 
 (5) Putzen. 
 (c) Nieren (Kidneys). 
 II. Aufgelagerte Lagerstiltten (Superficial Deposits). 
 
 D. Triimmerlagerstutten (Placers). 
 
 E. Oberflachliche Lager (Surface beds). 
 
 (8) 
 Koehler, Lehrbuch der Bergbaukunde, ISSV. 
 
 I. Plattenformige Lagerstatten (Tabular Deposits). 
 
 (a) Gange (Veins). 
 
 (b) Flotze und Lager (Strata, beds, seams). 
 
 II. Lagerstatten von unregelmiissige Form (Deposits of 
 irregular Form). 
 (a) Stocke und Stockwerke (Masses). 
 (5) Butzen, Nester, und Nieren (Pockets, concre- 
 tions, etc.). 
 
 (9) 
 Gallon, Lectures on Mining, 1866 (Foster and Galloway's 
 translation). 
 I. Veins. 
 II. Beds. 
 III. Masses (i.e., not relatively long, broad, and tbin). 
 
 1.06.07. The scheme of Von Gotta and Prime carries out the 
 principle of form to its logical and somewhat trivial conclusion. 
 
48 KEMPS ORE DEPOSITS. 
 
 Thus under irregular deposits it is a matter of extremely small 
 classificatory moment whether an ore body is recumbent or vertical. 
 Otherwise the scheme is excellent, and its influence can be traced 
 through most of those that are of later date. The original draft 
 came out in the German in 1859. All the others are from treatises 
 on mining, in which this subject plays a minor r61e, and indicates 
 the tendency, referred to above, of mining engineers, when writing 
 theoretically, to imagine certain fairly definite forms, which are to 
 be exploited. As previously remarked, however, considering the 
 uncertainty of ore bodies and their variability in shape, it is here 
 argued that the genetic principle might better take precedence. 
 Several of the German terms are difficult to render into English 
 mining idioms, as for example. Stock, Butzen (Putzen), Nester, and 
 Nieren. 
 
 1.06.08. C Schemes, Partly Hased on lorm, Partly on Origin. 
 
 (10) 
 
 J.. D.Whitney, Metallic Wealth, 1854. 
 I. Superficial. 
 n. Stratified. 
 
 (a) Constituting the mass of a bed or stratified 
 
 deposit. 
 (5) Disseminated through sedimentary beds, 
 (c) Originally deposited from aqueous solution, 
 but since metamorphosed. 
 III. Unstratified. 
 
 A. Irregular. 
 
 (a) Masses of erujjtive origin. 
 
 (6) Disseminated in eruptive rocks, 
 
 (c) Stockwork deposits. 
 
 (t?) Contact deposits. 
 
 (e) Fahlbands. 
 
 B. Regular. 
 
 if) Segregated veins. 
 
 {g) Gash veins. 
 
 (A) True or fissure "veins. 
 
 (11) 
 J. S. Newberry, School of Mines Quarterly, March, 1880, 
 May, 1884 
 I. Superficial. 
 
CLASSIFICATION OF ORE liEPOSlTS. 4S 
 
 II. Stratified. 
 
 (a) Forming entire strata. 
 
 (b) Disseminated through strata. 
 
 (c) Segregated from strata. 
 III. Unstratitied. 
 
 (a) Eruptive masses. 
 
 (b) Disseminated through eruptive rock. 
 
 (c) Contact deposits. 
 
 (d) Stockworks. 
 
 (e) Fahlbands. 
 (/) Chambers. 
 
 {ff) Mineral veins. 
 
 1. Gash veins. 
 
 2. Segregated veins. 
 
 3. Bedded veins. 
 
 4. Fissure veins. 
 
 (12) 
 
 J. A. Phillips, Ore Deposits, 1884. 
 I. Superficial. 
 
 (a) By mechanical action of water. 
 {h) By chemical action. 
 II. Stratified. 
 
 (a) Deposits constituting the bulk of metalliferou-s 
 beds formed by precipitation from aqueous 
 solution. 
 (J) Beds originally deposited from solution but sub- 
 sequently altered by metamorphism. 
 (c) Ores disseminated through sedimentary beds, in 
 vsrhich they have been chemically deposited. 
 III. TJnstratified. 
 
 (a) True veins. 
 
 (6) Segregated veins. 
 
 (c) Gash veins. 
 
 (d) Impregnations. 
 
 (e) StockvForks. 
 (/) Fahlbands. 
 
 [g) Contact deposits. 
 (A) Chambers or pockets. 
 
 1.06.09. It is at once apparent that Whitney's scheme contains 
 the essentials of the others, which are merely slight modifications. 
 Newberry introduces impregnations, chambers, and bedded veins. 
 
50 KEMP'S ORE DEPOSITS. 
 
 The first named is a useful term, although it is not always easy to 
 distinguish impregnations from otbers earlier given. Thus, they 
 may be very like the division, disseminated through strata, or dis- 
 seminated through, eruptive rock, or, if in metamorphic rock,fahl- 
 bands. The word is also used to indicate places along a vein 
 where the ore has spread into the walls. The term " chambers," 
 or " caves," nas found application in the West, and is a useful ad- 
 dition. Bedded veins appear also in Von Cotta above (No. 6). 
 Phillips seeks to explain the methods of origin in his use of Whit- 
 ney's scheme and clearly feels the importance of emphasizing the 
 genetic principle more strongly. Much of it is implied in the 
 simpler phraseology, however, and the extended sentences lack the 
 incisiveness of the earlier schemes. The arrangement as set forth 
 by Whitney is worthy of high praise, and the scheme is one of 
 the many valuable things in a book that has played a large part in 
 the economic history of the United States. 
 
 1.06.10. D. Schemes Largely Based on Origin. 
 
 (13) 
 J. Grimm, Lagerstdtten, 1869. 
 
 I. Gemengtheile oder grossere Einschliisse in den 
 
 Gebirgsgesteinen. Einsprengung, Impragnation. 
 
 (Essential component minerals and inclusions in 
 
 country rock. Impregnations.) 
 
 (a) Urspriingliche Einsprengung. (Original with 
 
 the inclosing rock.) 
 
 (5) Von anderen Lagerstatten weggefiihrte Bruch- 
 
 theile, etc. (Fragments brought from a dis- 
 tance. Placers, ore-bearing boulders. Brec- 
 cias.) 
 II. Untergeordnete Gebirgsglieder oder besondere Lager- 
 statten. (Subordinate terranes or special forms 
 of Deposits.) 
 (a) Plattenformige Massen. (Tabular masses.) 
 
 1. Lager oder Flotze. Bodensatzbildung. 
 
 (Beds, strata.) 
 
 2. Gauge, Kliifte, Gangtriimmer, etc. (Veins 
 
 of varying sizes.) 
 
 3. Plattenformige Erz-ausscheidungen und 
 
 Anhiiufungen. (Segregated veins.) 
 
 (6) Stocke und regellos gestaltete Massen. (Stocks 
 
 and irregular masses.) 
 
CLASSIFICATION OF ORE DEPOSITS. 51 
 
 1. Lagerstocke Linsenstocke, Linsen. (Len- 
 
 ticular deposits, etc.) 
 
 2. Stocke, Butzen, Nester, etc. (Masses, 
 
 pockets, etc.) 
 
 3. Stockwerke. (Stockworks.) 
 
 (14) 
 A. von Groddeck, Lehre voti den Lagerstdtten, etc., 18 79, p. 84. 
 I. Urspriingliche Lagerstatten (Primary deposits). 
 
 A. Gleichzeitig mit dem Nebengestein gebildet. 
 
 (Formed at the same time with the walls.) 
 
 1. Geschichtete. (Stratified.) 
 
 (a) Derbe Erzflotze. (Entire beds in fossiliferous 
 
 strata.) 
 (6) Ausscheidungsflotze. (Disseminated in beds.) 
 (c) Erzlager. (Lenticular beds, mostly in schists.) 
 
 2. Massige. (Massive; the word is nearly 
 
 synonymous with igneous.) 
 
 B. Spater wie das Nebengestein gebildet. (Formed 
 
 later than the walls.) 
 
 3. Hohlrauinsfiillungen. (Cavity fillings.) 
 (a) Spaltenfiillungen oder Gange. (Fissure fillings 
 
 or veins.) 
 
 (1) In massigen Gesteinen. (In igneous rocks.) 
 
 (2) In geschichteten Gesteinen. (In strati- 
 
 fied rocks.) 
 (5) Hohlenfullungen. (Chambers.) 
 
 4. Metamorphische Lagerstatten. (Altera- 
 
 tions, replacements, etc.) 
 II. Triimmor-lagerstatten. (Secondary or detrital deposits.) 
 (15) 
 R. Pumpelly, Johnson^ s Encyclopoedia, 1886, VI. 22. 
 I. Disseminated concentra- 
 tion, 
 (a) I m p r e g n at i o n s , 
 Fahlbands. 
 XL Aggregated Concentration. 
 (a) Lenticular aggrega- 
 tions and beds. 
 (5) Irregular masses, 
 (c) Reticulated veins. 
 {d) Contact deposits. 
 
 Forms due to the text- 
 ure of the inclosing 
 rock, or to its mineral 
 constitution, or to both 
 causes. 
 
5-Z KEMP'S ORE DEPOSITS. 
 
 III. Cave deposits. ] Forms chiefly due to pre- 
 
 IV. Gash veins. V existing open cavities 
 V. Fissure veins. ) or fissures. 
 
 VI. Surface deposits. 
 
 (a) Residuary deposits. 
 
 (b) Stream deposits. 
 
 (c) Lake or bog deposits. 
 
 1.06.11. These three are all excellent, and give some interest- 
 ing variations in the several points of view from which each writer 
 regarded his subject. There are instances in the two German 
 schemes where it is difficult to render the original into a corre- 
 sponding English term and recourse has been had to the explana- 
 tory text. Grimm especially writes an obscure style. He divides 
 accordingly as the ore forms an essential and integral part of the 
 walls or a distinct body. Von Groddeck has in view the relative 
 time of formation as contrasted with the walls, Grimm afterward 
 •emphasizes geometrical shape, but this Von Groddeck practically 
 ■does away with, and continues more consistently genetic. His 
 scheme might perhaps come more appropriately in the next section. 
 
 Pumpelly's conception varies considerably from the others. He 
 Tvrites, as his full paper states, in the belief that the metals have 
 all been derived primarily from the ocean, whence they have 
 passed into sedimentary, and, by fusion of sediments, into igne- 
 ous rocks. The group of residuary surface deposits, carrying out 
 as it does a favorite idea of Professor Pumpelly, as set forth in 
 his papers on the secular decay of rocks, is an important distinction. 
 
 1.06.12. E. Schemes Entirely Based on Origin. 
 
 (16) 
 H. S. Munroe. Used in the Lectures on Mining in the School 
 of Mines, Columbia College. 
 I. Of surface origin, beds. 
 
 (a) Mechanical (action of moving water). 
 
 1. Placers and beach deposits. 
 (J) Chemical (deposited in still water). 
 
 1. By evaporation (salt, gypsum, etc.). 
 
 2. By precipitation (bog ores). 
 
 3. Residual deposits from solution of lime- 
 
 stone, etc. (hematites), 
 (c) Organic. 
 
 1. Vegetable (coal, etc.). 
 
CLASSIFICATION OF ORE DEPOSITS. 53 
 
 2. Animal (limestone, etc.). 
 (d) Complex (cannel coal, bog ores, etc.). 
 II. Of subterranean origin. 
 
 (a) Filling fissures and cavities formed mechani- 
 
 cally. 
 
 1. Fissure veins, lodes. 
 
 2. Cave deposits — lead, silver, iron ores. 
 
 3. Gash veins. The cavities of 2 and 3 are 
 
 enlarged by solution of limestone. 
 
 (b) Filling interstitial spaces and replacing the walls. 
 
 1. Impregnated beds. 
 
 2. Fahlbands. 
 
 3. Stockworks. 
 
 4. Bonanzas. 
 
 5. Masses. 
 
 1.06.13. This scheme covers all forms of mineral deposits, 
 whether metalliferous or not, while most of those previously given, 
 as well as the one that follows, concern only metalliferous bod- 
 ies. The scheme is consistently genetic and was elaborated be- 
 cause such a one filled its place in lectures on mining better than 
 one based on form. The general principle on which the main sub- 
 division is made differs materially from any hitherto given. De- 
 posits formed on the surface are kept distinct from those originat- 
 ing below, even though the first class may afterward be buried. 
 
 (17) 
 
 1.06.14. J. F. Kemp, 1892. Revised from the School of Mines 
 Quarterly, November, 1892. 
 
 I. Of Igneous Origin. Excessively basic developments 
 of fused and cooling magmas. Peridotite, forming 
 iron ore at Cumberland Hill, R. I.' Magneti'.e, Jacu- 
 piranga, Brazil.^ Titaniferous magnetite in Min- 
 nesota gabbros'; in Adirondack gabbros " ; in Swe- 
 dish and Norwegian gabbros. Nickeliferous pyrrho- 
 tite in gabbros and diorites derived from them.'' 
 
 1 M. E. Wadswortb, Bull. Mm. Gomp. ZoiJl, 1880, VII. 
 
 2 O. A. Derby, Amer. Jour. ScL, April, 1891. 
 
 3 N. H. Winchell, TentA Ann. Rep. Minn. Oeol. Survey, pp. 80-83. 
 Bull. VI. of same Survey, p. 135. 
 
 4 J. F. Kemp, Bull. Geol. Sod. Amer., V. 333, 1894. 
 
 6 J. H. L. Vogt, Oeol. Foren. i. Stockholm- Furhand, XIII. 476, May, 1891. 
 Englisli abstract and review by J. J. H. Teall. Oeol. Mug., February, 1892. 
 Seea.lsoZeitschr.f'iirPraktischeOeologie.l. 4, 125, 257; 11. 41, 184, and 173. 
 
54 KEMP'S ORE DEPOSITS. 
 
 II. Deposited from Solution. 
 
 1. Surface precipitations, often forming beds, 
 
 and caused by — 
 (a) Oxidation. Bog ores. Ferruginous oolites, as 
 
 in some Clinton ores.' 
 {b) Sulphurous exhalations from decaying organic 
 
 matter etc. (Pyrite.) 
 
 (c) Reduction, chiefly by carbonaceous, organic 
 
 matter. (Pyrite from ferrous sulphate.) 
 
 (d) Evaporation, cooling, loss of pressure, etc. 
 
 (Hot spring deposits, as at Steamboat 
 Springs, Nev.^) 
 
 (e) Secretions of living organisms. (Iron ores by 
 
 algEB.') 
 Note. — The first four causes of precipitation operate in subter- 
 ranean cavities, although not again specially referred to. 
 
 2. Disseminations (impregnations) in par- 
 
 ticular beds or sheets, because of — 
 (a) Selective porosity. (Silver Cliff, Colo., silver 
 ore in porous rhyolite.* Amygdaloidal fill- 
 ings, as in copper-bearing amygdaloids, 
 Keweenaw Point, Santa Rita, N. M.^ Im- 
 pregnations of porous sandstone, as at Silver 
 Reef, Utah.«) 
 (5) Selective precipitation by limestone. (Lateral 
 enlargements at Newman Hill, near Rico, 
 Colo.') 
 
 3. Filling joints, caused by cooling or drying. 
 
 (Mississippi Valley gash veins in part.) 
 
 4. Occupying chambers (caves) in limestone. 
 
 (Cave Mine, Utah.«) 
 
 > C. H. Smyth, Jr., Amer. Jour. Sci., June, 1893, p. 487. 
 
 ' U. F. Becker, Monograph XIII., U.S. Geol. Survey, pp.331, 468; 
 Laur, Ann. des Mines, 1863, p. 421; J. Leconte, Amer. Jour. Sci, June, 
 1883, p. 434, July, p. 1; W. H. Weed, idem, August, 1891, p. 166. 
 
 " SjogTun, Berg- und HiUt. Zeit., 1865, p. 116. 
 
 * Clark, Engineering and Mining Journal, Nov. 2, 1878, p. 314. 
 
 ^ A. F. Wendt, Trans. Amer. Instit. Min. Eng., XV. 27. 
 
 « C. M. Rolker, idem, IX. 21. 
 
 ' J. B. Farish, Proc. Colo. Sci. Soc, April 4, 1892. 
 
 " J. S. Newberry, School of Mines Quarterly, March, 1880. See also 
 J. P. Kimball, on Santa Eulalia, Chihuahua, Amer. Jour. Sci., II., xlix. 161. 
 
CLASSIFICATION OF ORE DEPOSITS. 55 
 
 5. Occupying collapsed, (brecciated) beds, 
 
 caused by solution and removal of sup- 
 port, or from dolomitization of limestone. 
 (Southwest Missouri zinc deposits.^) 
 
 6. Occupying cracks at Monoclinal bends, 
 
 Anticlinal summits, Synclinal troughs, 
 often with replacement of walls. (Gash 
 veins in part ; galena deposits at Mine 
 la Motte, Missouri ; zincblende deposits 
 in the Saucon Valley, Pennsylvania.') 
 
 7. Occupying Shear-zones, or dynamically 
 
 crushed strips along faults, whose dis- 
 placement may be slight, closely re- 
 lated to No. 8. (Butte, Mont.*) 
 
 8. True veins filling an extended fissure, often 
 
 with lateral enlargements. See also un- 
 der 5. 
 
 9. Occupying Volcanic necks, in agglom- 
 
 erates. (Bassick and Bull Domingo 
 Mines, near flosita, Colo.'*) 
 
 10. Contact deposits. Igneous rocks almost al- 
 
 ways form one wall. Fumaroles. (Mar- 
 quette hematites, Michigan." Greisen.) 
 
 11. Segregations formed in the alteration of 
 igneous rock. (Chromite in serjientine.) 
 
 III. Deposited from Suspension. Residual Deposits. 
 
 1. Metalliferous Sands and Gravels, whether 
 
 now on the surface (placers, magnetite 
 beach-sands), or subsequently buried. 
 (Deep gravels, magnetite lenses ?) 
 
 2. Residual Concentrations, left by the 
 
 weathering of the matrix. (Iron Moun- 
 tain, SIo., hematite in part.') 
 
 1 F. L. Clerc, Lead and Zina Ores ia Southwest Missouri Mines, 
 Carthage, Mo., 1887; A. Schmidt, Missouri Geol. Survey, 1874, p. 384. 
 
 = T. C. Charaberlin, Wis. Geol. Survey, IV., 1882, 367. 
 
 " F. L. Clerc, Mineral Resources, 1883, p. 361; H. 8. Drinker, Trans. 
 Amer. Inst. Min. Eng., I. 367. 
 
 4 S. F. Emmons, Trans. Amer. Inst. Min. Eng., XVI. 49; W. P. Blake, 
 idem, XVI. 65. 
 
 " C. W. Cross, Proc. Colo. Soi. Soc., 1890, p. 389. 
 
 « C. R. Van Hise, Amer. Jour. Sci , February, 1893, p. 116. 
 
 ' R. Pumpelly, Bull. Geol. Soc. Amer., II., p. 330. 
 
56 
 
 KEMPS O^E DEPOSITS. 
 
 1.06.15. It is believed that under the above heads are included 
 all the forms of ore bodies which constitute well-recognized and 
 fairly well understood geological phenomena. To these catego- 
 ries year by year we are enabled, by the results of extended and 
 careful investigation, to refer many that have been obscure. A 
 number of familiar terms for ore bodies in mining literature fail 
 to appear, but are mentioned in the classitications quoted from 
 others. Many of these refer only to form, and geologically con- 
 sidered are only convenient admissions of ignorance as to origin. 
 Some other ore bodies whose methods of origin are involved in the 
 processes of regional metamorphism are placed by themselves 
 farther on. The explanations of them are as yet hypothetical. A 
 few comments on the scheme may now be added, although in the 
 main it explains itself. 
 
 1.06.16. I. Much attention has been given of late years to 
 processes of rock formation from igneous magmas. Of these the 
 excessively ba,sic are the only ones primarily concerned with ores. 
 It is well known that in the series of igneous i-ocks we have suc- 
 cessively those with less and less silica. It is quite conceivable 
 that local develojjments might bring about such a decrease of the 
 silica and such an increase of one of the oommonest of the bases, 
 iron oxide, that the limits of an ore might be reached. Such bod- 
 ies are almost always highly titaniferous, so much so that in this 
 country they are not available. Not a little attention was direct- 
 ed in earlier years to the Cumberland Hill outcrop in Rhode 
 Island, but it was found to be too high in this element to be suited 
 to furnace practice, j^o analyses are at hand of the Brazilian ex- 
 ample, but a considerable percentage of titanium might be ex- 
 pected. The presence of these ores in Canada, the Adirondacks, 
 and Minnesota is very familiar. It is possible, as indicated by 
 Vogt, that when magnetite crystals had formed in the still fused 
 magma, they became aggregated by magnetic currents in the 
 earth. And it is also conceivable that these early and heavy 
 crystallizations may have settled to the lower portions of the mag- 
 ma ai.J have become concentrated. Much that is more or less 
 speculative is involved in these explanations. 
 
 The increasing importance of nickel has directed especial at- 
 tention to its deposits and their geological relations. Except in 
 New Caledonia, the metal is chiefly obtained from bodies of 
 nickeliferous pyrrhotite which are associated with rocks of the 
 diorite and gabbro families and are found on the outer rims of in- 
 
CLASSIFICATION OF ORE VEPOSITS. bl 
 
 triisions. Many such are known in Norway, in the Sudbury dis- 
 trict of Canada, and in other places of which the famous but now 
 abandoned Gap Mine in Lancaster Co., Penn., is an excellent ex- 
 ample. An explanation of these relations has been sought in what 
 IS known as Soret's principle.' It was proved by experiments in 
 1879 by Soret, a French chemist, that if differences of temperature 
 are induced in a solution of common salt or otlier substance in 
 water, the dissolved material will become relatively concentrated in 
 those portions in which the temperature is lowest. It has also 
 been shown ihat this would follow from the laws of osmosis, and 
 that the relative degrees of concentration would be to one another 
 inversely as the absolute temperatures (i. e. temperature Centigrade 
 plus 273). The lower the temperature, therefore, the more dis- 
 solved material would collect in such chilled portion. If now, we 
 consider a fused rock-magma as a complex solution of several 
 silicates, oxides, sulphides and one or two rarer compounds, some 
 in others, and if we regard as the least soluble those that crystallize 
 first in the process of cooling, we are led by Soret's principle to in- 
 fer that these would tend to become concentrated in the portions 
 first cooled, and that in such portions they would be especially 
 abundant after consolidation. The portions of an igneous intrusion 
 that are first cooled are obviously those next the wall rock. The 
 minerals which crystallize first are, as set forth earlier under 1.03.05, 
 magnetite, ilmenite, apatite, pyrite, pyrrhotite and several minor 
 ones. 
 
 In the case of nickeliferous pyrrhotite the ore bodies are 
 especially rich along or near the contacts of gabbroitic and dioritic 
 intrusions, with their walls, and the paper of J. H. L. Vogt, 
 cited on page 53, has served to bring out some extremely inter- 
 esting facts. The geological relations are more fully set forth 
 later on under nickel and in connection with several American 
 occui'rences, but it may be here added that away from the outer 
 wall the ore bodies fade (at least at tne Gap Mine, Penn.), into 
 barren gabbro, by a fairly gradual transition. In these respects 
 they conform quite closely to conditions which would result from a 
 
 ' The bearing of this explanation of magmatic differentiations in igneous 
 rocks upon these nickeliferous deposits has been especially set forth by J. H. 
 h. Vogt of Kristiania, Norway, in the ZeitscJirift fur PraktiscJie Oeologie, I. 135, 
 1898, under the title Sulphidische Ausscheidungen von Nickel-sulphid-erzen. 
 Other related papers appear in the same, I. 4 and 357; II. 41, 134 and 173. 
 
58 KEMP'S ORE DEPOSITS. 
 
 development according to Soret's principle. We also find in such 
 ore bodies much the same association of minerals, wherever they 
 are mined. Pyrrhotite is in greatest amount and contains the 
 nickel and cobalt, replacing a portion of its iron; as the rarer 
 mineral pentlandite,' or as secondary coatings of millerite in cracks. 
 Chalcopyrite is invariably present, often in important quantity. 
 Vogt has sought to trace out some constancy in the relative 
 amounts of these several metals, but the attempt is not specially 
 successful. He also cites in connection with a discussion of their 
 early formation and combination with sulphur in the fused magma 
 the laws which we know apply in the metallurgical processes in- 
 volving slags and mattes.^ 
 
 The writings of Lagorio, Iddings, Roseubusch and others re- 
 garding the development of rocks from igneous magmas have 
 emphasized the fact that the laws of solution do not fail to apply, 
 because materials are raised to very elevated temperatures and that 
 they hold good for liquid, molten rock-magmas as well as for 
 heated water or any other solvent. But we find that it is difficult 
 to decide where solution ends and composite fusion begins; and in 
 a heated complex aggregate to determine which is solvent and 
 which dissolved mineral. It is also difficult to be certain that in 
 so viscous a mass as a fused rock there would be sufficient free- 
 dom in the movement of molecules or "ions"^ to enable them to 
 respond to Soret's principle. But it must be admitted that the 
 
 1 S. L. Penfield, "Pentlandite from Sudbury, Ont., etc.'' Amer. Jour. Sci., 
 June, 1893, 493. Pentlandite is a sulphide of iron and nickel, isometric, non- 
 magnetic, and with a somewhat varying percentage of nickel, which reached at 
 Sudbury 34.23. The general formula from Penfield's analysis is (Xi Fe) S. 
 
 2 As is well known the common metals can be ranged in the following order 
 ("Foumet's Series") according to their decreasing afiLnitv for sulphur, Cu, 
 Ni, Co, Fe, Sn, Zn, Pb, Ag, Sb, As, see Vogt, 1. c. p. 263. In their bearings 
 on geological phenomena these metallurgical laws were discussed many years 
 ago by V. Leonhard in Huttenerzeugnisse und andere auf KiXiutlicliem Wege 
 gebildete Mineralien aZs StiUzpunkte geologiaher Hypothesen, Stuttgart, 18.58. 
 
 3 The term "ion" as employed in modern chemistry is more easily il- 
 lustrated than defined. Thus if in a bath used for electroplating we hang at 
 one pole an ingot of metal and turn on the current, we cause the metal to pass 
 to the other pole. The condition of the atoms during transit and while prevented 
 by the electrical force from forming compounds with other elements or stable 
 combinations among themselves is indicated by speaking of them as constitut- 
 ing " ions." 
 
CLAaSIfflGATION OF ORE DEPOSITS. 59 
 
 form and relations of these ore bodies are what would be developed, 
 did Soret's principle act effectively and have free play. 
 
 As opposed to the igneous view others have regarded them as 
 contact deposits, brought about by solutions circulating along the 
 outer portions of the intrusions and replacing or impregnating the 
 gabbro, more or less, with ore. The conception is a time-honored 
 one; it involves nothing unreasonable and has the support of some 
 of our ablest investigators, as Emmons 'and Posepny.^ 
 
 1.06.17. Under II. 1, the precipitating agencies are men- 
 tioned, which are the cliief causes in the chemical reactions of de- 
 position, and tliese run through all the subterranean cavities as 
 well. The general application is esteemed self-evident. The 
 large part played by organic matter, both when living and when 
 dead and decaying, is notable. Its office even in precipitating the 
 gangue minerals in surface reactions we are just beginning to 
 appreciate. Siliceous sinters have been shown by "W. H. Weed to 
 be formed around the hot springs of the Yellowstone Park through 
 the agency of algae, and A. Rothpletz has recently proved that the 
 calcareous oolites around the Great Salt Lake are referable to mi- 
 nute organisms. Many accumulations of iron ores have, with reason, 
 been attributed to the same agency; but for this metal ordinary 
 and common chemical reactions are oftenest applicable. When or- 
 ganic matter decays, sulphurous gases are one of the commonest 
 products, and likewise one of the most vigorous of precipitants. 
 Thus under Example 24, Paragraph 2.06.03, when speaking of the 
 Wisconsin zinc and lead mines, it will be seen that such an agency 
 from decaying seaweeds has been cited by both Whitney and 
 Chamberlin. When the products of such decomposition become 
 imprisoned in the rocks as oils and gases, their action is unmistak- 
 ably important and is especially available in limestones. Organic 
 matter is a powerful reducing agent as well, and in this way is ca- 
 pable of bringing down metallic compounds. The silver-bearing 
 sandstones of southern Utah are cases in point, as they afford plant 
 impressions now coated with argentite. The purely physical agen- 
 cies cited under (d) have also an important role. 
 
 1.06.18. Under 2 (a) the uprising solutions may be diverted by 
 porous strata so as to soak through them and become subject to 
 
 1 S. F. Emmons, "Geological Distribution of the Useful Metals in the 
 United States," Trans. Amer. Inst. Min. Eng., Chicago, 1893. Reprint pp. 
 18-19. 
 
 ^ F. Posepny, "The Genesis of Ore Deposits," Idem. Beprint p. 194. 
 
60 KEMP- 8 ORIS DEPOSITS. 
 
 precipitating agents of one kind or another. They furnish the 
 simplest kind of cavities, and starting with these the scheme is de- 
 veloped in a crescendo to the most complicated. The purely chem- 
 ical action of limestone beds, however, seems at times to come into 
 play and to cause precipitation along them. Of all rocks they are 
 the most active chemical reagent. It may be questioned with rea- 
 son as to whether caves or caverns (4), properly so called, have ever 
 formed a resting-place for ores. So many which have been cited as 
 such may with greater reason be referred to shrunken replacements 
 that a doubt hangs over their character. 
 
 1.06.19. Under (5) brecciated beds whose fragments are coat- 
 ed and whose interstices are filled with ore are, with great reason, 
 referred to the collapse from the removal of a supporting layer. In 
 addition to the illustration cited, the red hematite deposits of Dade 
 and Crawford counties, Missouri, have been thought to have had a 
 similar origin. Such phenomena are only to be expected in regions 
 that have long been land. Cracks at the bends of folds may, in 
 cases, have occasioned impregnations and disseminations, even when 
 their character is obscured. The cracks need be but small and nu- 
 merous to have occasioned far-reaching results. If a fault fissure, 
 as a possible conduit of supply, crosses the axis of the fold, the 
 necessary conditions are afforded for extended horizontal enrich- 
 ment. Recent explorations with the diamond drill at Mine la Motte 
 seem to corroborate such an hypothesis. Should the anticline 
 or roll afterward sink toward the horizontal, a very puzzling de- 
 posit might originate. Shear zones have been already discussed at 
 length (1.02.03), as have true veins and volcanic necks (see also 
 2.09.20). As regards contact deposits, the igneous rock, which 
 usually forms one wall, may serve two different purposes. It may 
 act merely as an impervious barrier which directs solutions along its 
 course, or serves to hold them, either because it is itself bent into 
 a basin-like fold, or because it forms a trough with a dense bed 
 dipping in an opposite direction. Such relations occur in the Mar- 
 quette and Gogebic ranges of the Lake Superior iron region. It is 
 not apparent that in these cases the igneous rock has in any degree 
 stimulated circulations. In the more characteristic " contact depos- 
 its " the igneous rock has apparently been a strong stimulator of 
 ore-bearing circulations, and often the source of the metals them- 
 selves. This form of deposit becomes, then, an attendant phenom- 
 enon, or even a variety, of contact metamorphism. Under 11 
 chromite is the chief illustration. The mineral is practically limit- 
 
CLASSIFICATION OF ORB DEPOSITS. 61 
 
 ed to serpentinons rocks, and is distributed through them in irreg- 
 ular masses. It appears to be an auxiliary product of alteration. 
 
 1.06.20. III. The debris that results from the weathering of 
 rock masses under the action of frost, wind, rain, heat, and cold is 
 washed along by the drainage system of a district, and the well- 
 known sorting action transpires, which is so important in connec- 
 ^'on with the formation of the sedimentary rocks. Minerals of 
 great specific gravity tend to concentrate by themselves, while 
 lighter materials are washed farther from the starting point, and 
 settle only in still water. Stream bottoms supply the most favor- 
 able situations, and in their bars are found accumulations of the 
 heavier minerals which are in the surrounding rocks. The com- 
 monest of these are magnetite, garnet, ilmenite, wolframite, zircon, 
 topaz, spinel, etc., and with these, in some regions, native gold, 
 platinum, iridosmine, etc.; in other places cassiterite, or stream tin, 
 as described under tin. Even an extremely rare mineral such as 
 monazite may make a sandbar of considerable size. (See O. A. 
 Derby, Amer. Jour. Sci., III. xxxvii., p. 109.) The action of surf 
 or smaller shore waves is also a favorable agent. The throw of the 
 breaker tends to cast the heavier material on the beach, where its 
 greater specific gravity may hold it stationary. The heavier min- 
 erals may be sorted out of a great amount of beach sand. Mag- 
 netite sands, which have accumulated in this way, are of quite 
 wide distribution, and at present are of some though not great 
 importance. (Example 15.) With the magnetite are found grains 
 of garnet, hornblende, augite, etc., and often ilmenite. Gold is 
 concentrated in the same way along the Pacific by the wash of 
 surf against gravel clifiEs. In abandoned beaches of Lake Bonne- 
 ville, near Fish Springs, Tooele County, Utah, placers of rolled 
 boulders of argentiferous galena have been worked. 
 
 A superficial deposit of somewhat different origin is the bed of 
 hematite fragments that mantles the flanks of Iron Mountain, Mis- 
 souri, and runs underneath the Cambro-Silurian sandstones and 
 limestones. This seems to have been formed by the subaerial decay 
 of the inclosing porphyry. The heavier specular ore has thus been 
 concentrated by its greater specific gravity and resistant powers. 
 (See R. Pumpelly, " The Secular Disintegration of Rocks," Proc. 
 Geol. Soc. Amer., Vol. II., December, 1890.) 
 
 1.06.21. There remain a few of great importance, but whose 
 geological history is less clearly understood. They are nearly all 
 involved in processes of regional metamorphism, and therefore in 
 
63 KEMP'S OS E DEPOSITS 
 
 some of the most difficult problems of the science. Lenticular beds 
 or veins of magnetite and pyrite that are interbedded. with schists, 
 slates, or gneisses are the principal group. Such magnetite bodies 
 have been regarded as intruded dikes, as original bodies of bog ore 
 in sediments which have later become metamorphosed, and as 
 concentrated delta, river, or beach magnetite sands. It is possible 
 that in instances they may be replaced bodies of limestone, after- 
 ward metamorphosed. The lenticular shape and the frequent over- 
 lapping arrangement of the feathering edges in the foot wall are 
 striking phenomena. 
 
 The overlap was referred by H. S. Munroe in the School of 
 Mines Quarterly, Vol. III., p. 34, to stream action during mechanical 
 deposition, and a figure of some hematite lenses in the Marquette 
 region was given in illustration. The arrangement in instances 
 also suggests the shearing and buckling processes of dynamic meta- 
 morphism and disturbance. The individual lenses, now in linear 
 series, were thus all one original bed. The crumpling of the 
 schistose rocks has pinched them by small buckling folds and 
 shoved the ends slightly past each other in the process so familiar 
 in the production of reversed faults from monoclines. Sheared 
 granitic veins on a small scale are a not uncommon thing in areas of 
 schistose rocks, such as Manhattan Island, in the city limits of 
 New York, and suggest strongly this explanation. Should the 
 compression not go so far as to bring rupture of the bed, but only 
 a thickening by the formation of a sigmoid fold, it would occasion 
 an enlarged cr£)ss section, as has been suggested by B. T. Putnam 
 (Tenth Census, Vol. XV. 110) for the great magnetite ore body 
 at Mine 21, Mineville, in the Lake Champlain region. 
 
 , 1.06.22. Quartz veins, often auriferous and of a lenticular 
 character, furnish another puzzling ore body. They are commonly 
 called segregated veins, and lie interbedded in slates or schistose 
 rocks. If in a pre-existing cavity, it must have been formed, 
 either by the opening of beds under compression, or by displace- 
 ment along the bedding, so that depressions came opposite each 
 other. Replaced lenses of limestone which had been squeezed into 
 this shape from an original, connected bed should also be instanced 
 as a possibility. The name "segregated" would imply a filling 
 by lateral secretion, but it is by no means impossible that solutions 
 have come from below. The veins are another attendant feature 
 on regional metamorphism, and as such deserve more investiga- 
 tion. 
 
GLASSIFTCATION OF ORE DEPOSITS. 63 
 
 1.06.23. The veins that contain cassiterite in many parts of 
 the world, and that yet have the mineralogical composition of 
 granite, are another product of metamorphic action, both contact 
 and regional. The gangue minerals, feldspar, quartz, and mica, 
 are quite characteristic of acid, igneous rocks, but the coarseness 
 of the crystallization in the comparatively narrow veins bars out a 
 true igneous form of origin. All our artificial methods of repro- 
 ducing these minerals lead us to infer that the veins were filled at 
 a high temperature and pressure, therefore at considerable depths, 
 and through the aid of steam. Cassiterite has also been detected 
 in a few rare cases, under such circumstances that it seemed to be 
 an original mineral in igneous granite. It is probable, therefore, 
 that it may be an original and early crystallization from an igne- 
 ous magma, much as is magnetite. More observed cases would be 
 welcome as evidence. 
 
 1.06.24. The great iron ore bodies of Vermilion Lake have 
 been referred by N. H. and H. V. Winchell, in the American 
 Geologist, November, 1889, p. 291, to a precipitation from oceanic 
 waters in the vicinity of submarine volcanic eruptions from whose 
 ejectamenta they derived their iron and silica. The hypothesis is 
 regarded as sufficient to account as well for the siliceous deposits 
 associated with the ore. In the words of the authors : "Chemical 
 precipitation in hot oceanic waters, united with simultaneous sedi- 
 mentary distribution, might produce the Keewatin orrs in a man- 
 ner consistent not only with the physical conditions that prevailed 
 at the time of their formation, and with the structnial peculiari- 
 ties which they exhibit, but also in accordance with the known 
 reactions of heated alkaline waters, and with the chemical char- 
 acter which the ores are known to possess." This hypothesis in- 
 troduces new conditions and relations which are necessarily some- 
 what speculative; and while it has claims to attention, it may 
 best be tested by the general consideration of the geological pub- 
 lic before being placed with the more simple and certain reactions 
 grouped in the scheme. 
 
 1.06.25. Fahlbands should be mentioned here. The term re- 
 fers to belts of schists, which are impregnated with sulphides, but 
 not in sufficient amount in the locality where the name was first 
 applied (Kongsberg, Norway) to be available for ores. The de- 
 composition of the sulphides gave the schists a rusty or rotten ap- 
 pearance that suggested the name. Whether the ores are an 
 introduction into the schist, subsequent to metamorphism, or a 
 
64 KEMP'S ORE DEPOSITS. 
 
 deposit in and with the original sediment, is a doubtful point. The 
 practical importance of these fahlbands lies in the enriching in- 
 fluence that they exert on the small fissure veins that cross them. 
 l."06.26. lu the report of the State Geologist of Michigan for 
 1891-92 (issued January, 1893) pp. 144, 145, Dr. M. E. Wadsworth 
 has published a "Preliminary Classification of Metalliferous or 
 Ore Deposits." The main outline is as follows : 
 
 I. Eruptive Deposits {a) Non-Fragmental. 
 
 (5) Fragmental. 
 II. Mechanical Deposits (a) Unconsolidated. 
 (5) Consolidated. 
 III. Chemical Deposits (a) Sublimations. 
 
 (V) Water Deposits. 
 
 (c) Impregnations or Replacements. 
 
 (d) Segregations or Cavity Deposits. 
 
 Each of the above except III. {d) is then subdivided so that 
 the table becomes practically a classification of rocks. Indeed, a 
 moment's consideration will show that the scheme in its main divis- 
 ions is closely modeled after the prevailing classification of rocks. 
 III. {d) Segregations or Cavity Deposits contains the following : 
 1. Pockets. 2. Chambers. 3. Contact Deposits. 4. Veins, in- 
 cluding Gash Veins, Segregated Veins, Reticulated Veins or Stock- 
 work, Contact Veins, Fissure or Fault Veins. 
 
 The author states in some appended comments that the table 
 is not limited to those deposits now practically worked (which we 
 ordinarily understand the expression ore deposits to mean), but is 
 intended to include all that have been or may be of value. But in 
 this respect there is good ground for preferring to make our clas- 
 sifications in ore deposits, as in mineralogy, zoology, etc., embrace 
 only the authenticated varieties, expecting additions to be incor- 
 porated as discovered and suitably described. 
 
 The same general grouping as this scheme employs is adopted 
 by E. S. Tarr, in the Economic Geology of the United States, 1894. 
 
 1.06.27. For the meeting of the American Institute of Mining 
 Engineers, held in connection with the various congresses at the 
 "World's Fair in Chicago, July, 1893, Professor Franz Posepny of 
 Vienna contributed a grand essay on the " Origin of Ore Deposits." 
 The materials for it were specially assembled by Prof. Posepny 
 while giving a course of lectures at the Przibram Mining Academy 
 in the ten years following 1879. The paper is a theoretical 
 discussion of the origin of ores, with illustrations selected 
 
CLASSIFIUA TION OF ORE DEPOSITS. 65 
 
 from all parts of the world, but especially from Europe and 
 America. It forms one of the most important contributions 
 to the literature that has yet been made. Posepny distinguishes 
 at the outset between rocks and mineral deposits; i. e., between 
 original materials, such as wall rock, and secondary intro- 
 ductions, such as veins, etc. The former he calls " idiogenites," 
 the latter " xenogenites," basing the names on the familiar 
 Greek terms that run through all our literature. The latter 
 are especially characterized by "crustification," by which term 
 is indicated what has been called "banded structure," on p. 
 35. The subject of cavities is then taken up, and, while minute 
 pores are stated to be in all rooks, a distinction is made between 
 the larger openings, which originate in a rock mass as a part of 
 its own structure, such as contraction joints in igneous rocks, 
 amygdaloids, and the like, and those induced by outside causes, 
 such as fault fissures. 
 
 The circulation of water through these is next treated : first, 
 surface waters or"vadose" circulations, which descend; second, 
 ascending waters from great depths, such as springs in deep mines, 
 hot springs, etc. The common salts in solution in these latter are 
 tabulated, being of course mostly alkaline carbonates, sulphates, 
 chlorides, etc. The " exotic " metallic admixtures which would 
 bear on the origin of ores are next discussed, so far as possible 
 with analyses of actual cases. The alterations produced by miner- 
 al springs in rocks and the structural relations of the deposits of 
 mineral springs, especially as expressed by " crustification," are 
 then described. This preliminary material clears the way for the 
 general discussion of the origin of ore bodies. The argument run- 
 ning all through the paper is that ore bodies, even when apparently 
 interbedded with sedimentary rocks, are of secondary introduction 
 and, in general for veins, are from deep-seated sources. Precipita- 
 tion from descending solutions and filling by lateral secretion are 
 strongly controverted. 
 
 The discussion of origin follows in its arrangement the follow- 
 ing classification of ore deposits : 
 
 I. Filling of spaces of discission (fissures). 
 
 II. Filling of spaces of dissolution in soluble rocks. 
 
 III. Metamorphic deposits in soluble rocks; in simple sedi- 
 ments ; in crystalline and eruptive rocks. 
 
 IV. Hysteromorphic {i.e., later or last formed) deposits. 
 Secondary deposits due to surface action {i.e., placers, etc.). 
 
66 KEMP 'S ORE DEPOSITS. 
 
 The treatment, both in tlie introductory pages and in the later 
 discussions, is often strikingly similar to that of this book, and the 
 underlying argument is much the same. The standpoint in both 
 essays is essentially a genetic one, and the main difference lies in 
 the fact that the one is an exposition of an individual's views, 
 fortified by examples from all parts of the world; the other 
 endeavors to be a judicial statement with a complete description of 
 the ore bodies of the United States alone. 
 
 1.06.28. An extended treatise on the useful minerals, earthy as 
 well as metallic, by MM. E. Puchs and L. De Launay, has recently 
 appeared {Traite des Gites Mineraux et Metalliferes, Paris, 1893). 
 The book is based on the lectures on economic geology delivered 
 in the Ecole Superieure des Mines, at Paris, in the last fifteen 
 years by the two authors. (Professor Fuchs died in 1889, and was 
 succeeded by Professor De Launay.) A vast amount of valuable 
 information is brought together and discussed from various points 
 of view, useful applications and methods of treatment being set 
 forth as well as geological occurrence. The work is encyclopedic 
 in scope and affords a reader descriptions of mineral resources and 
 references to their literature in every quarter of the world. 
 So far, however, as the United States are concerned the authors 
 have suffered from the unavoidable limitations of those not native 
 and conversant in a discriminating way with our literature. Nev- 
 ertheless they have endeavored to give a large share of their space 
 to this country, and where prominent monographs have appeared 
 they have been read with care, but in many cases, if not in most, 
 the descriptions consulted by them have been from older German 
 or other foreign sources, and the results are often antiquated and 
 confused. It is to be hoped that a later edition will correct most 
 of these. 
 
 1.06.29. The classification of ore deposits as well as other 
 useful minerals on a genetic principle has evidently been in many 
 minds in the last few years. Mr. Frederick Danvers Power, ^ of 
 Melbourne, Victoria, reviewed the subject in 1892, and after giving 
 the schemes of others and summing up the various characteristics 
 of veins, has formulated a classification whose main divisions are 
 as follows : I. Contemporaneous ; Indigenous. II. Metasomatic 
 or Chemical Alteration of the Original Constituents. III. Subse- 
 
 1 ' ' The Classification of Valuable Mineral Deposits, ' ' Trans, of the 
 Australasian Institute of Mining Engineers, 1893. 
 
VLASSIFIGATION OP ORE DEPOSITS. 67 
 
 quently Introduced ; Exotic. Each of these has then a number of 
 subdivisions too numerous to be repeated here. Prof. William 0. 
 Crosby/ of Boston has recently discussed the same subject in a 
 very suggestive way. The main headings are : A. Deposits of 
 Igneous Origin (Igneous rocks); B. Deposits of Aqueo- Igneous 
 Origin ; 0. Deposits of Aqueous Origin. The first and last are 
 then subdivided at considerable length, but the second is chiefly 
 limited to the pegmatite (granitic) veins which attend many plu- 
 tonic intrusions. Lack of space prevents the full reproduction of 
 both these schemes, but sufficient has been mentioned, it is hoped, 
 to indicate the line of attack and to place a reader desiring to look 
 the subject up in touch with the originals. 
 
 1.06.30. The phraseology of the above schemes will be employed 
 in the subsequent descriptions. In addition, much emphasis will be 
 placed on the character of the rocks containing the deposits, 
 whether unaltered sedimentary, igneous, or metamorphic, and 
 whether in the first and last cases igneous rocks, are near, for these 
 considerations enter most largely into questions of origin. The 
 ore deposits are illustrated by examples, somewhat as has been 
 done by the best of modern writers abroad, Von Groddeck. The 
 word "example" is preferred to "type," which was employed by 
 Von Groddeck, because it implies less of an individual character. 
 We may cite deposits under different metals thus which all might 
 belong to one type. Under each metal will be given, first, a list 
 of general treatises and papers. These will be marked " Hist." 
 when especially valuable as history, and "Rec." when recom- 
 mended for ordinary examination. If not marked by either, they 
 are more adapted for special investigations. 
 
 1 " A Classification of Economic Greological Deposits based on Origin 
 and Original Structure, " Arner. Geologist, April, 1894, p. 849. The paper 
 also appears in the Technological Quarterly. 
 
68 KEMP'S ORE DEPOSITS. 
 
 GENERAL REFERENCES ON ORE DEPOSITS. 
 
 Ansted, D. T. " On Some Remarkable Quartz Veins," Quar. Jour. 
 Geol. Sci., XIII. 246. 
 
 Bai-us, Carl. "The Electrical Activity of Ore Bodies," M B., 
 XIII. 417. (See also Heeler's Monograph on the Gomstock 
 Lode, p. .310, for references to other papers.) 
 
 Becker, G. F. "The Relations of the Mineral Belts of the Pacific 
 Slope to the Great Upheavals," Amer. Jour. Sci., III. 28, 
 209. 1884. 
 
 Belt, Th. Mineral Veins: an Inquiry into their Origin, founded on 
 a Study of the Auriferous Quartz Veins of Australia. Lon- 
 don, 1861. 
 
 Bischof, G. " On the Origin of Quartz and Metalliferous Veins," 
 Jamesoii's Journal, April, 1845, p. 344. Abstract, Amer. 
 Jour. Sci., I. 49, 396. Advocates aqueous deposition. 
 
 Brown, A. J. "Formation of Fissures and the Origin of their 
 Mineral Contents," M. E., II. 215. 
 
 Bulkley, F. G. " The Separation of Strata in Folding," 3f. E., 
 XIII. 384. 
 
 Campbell, A. C. " Ore Deposits," Engineering and Jifi7iing Jour- 
 nal, July 17, 1880, p. 39. 
 
 Von Cotta-Prime. Ore Deposits. German, 1859; English, 1870. 
 Reo. 
 
 Emmons, E. American Geology, 134, 1853. General discus- 
 sion. 
 
 Emmons, S. F. " The Structural Relations of Ore Deposits," M. 
 E, XVI. 304. Rec. 
 " ISJ^otes on Some Colorado Ore Deposits," Proc. Colo. Sci. 
 
 Soc, II., Part II., p. 35. 
 " On the Origin of Fissure Veins," Proc. Colo. Sci. Soc, II., 
 
 p. 189. Rec. (See also R. C. Hills, idem, III., p. 177.) 
 "The Genesis of Certain Ore Deposits," M. E, XV. 125. 
 Rea 
 
 Endlich, F. M. Hayden^s Survey, 1873, p. 276. General descrip- 
 tion of veins. 
 
 Foster, C. L. " What is a Mineral Vein ? " Abstract in Geol. 
 Mag., Vol. I., 513. 
 
CLASSIFICATION OF ORE DEPOSITS. GO 
 
 Fox, R. W. " Formation of Metallic Veins by Galvanic Agency," 
 Amer. Jour. Sci., I. 37, 199. Abstract from London and 
 Edinburgh Phil. Mag., January, 1839. 
 " On the Electro-Magnetic Properties of Metalliferous Veins 
 in the Mines of Cornwall," Amer. Jour. Sci., I. 20, 136. 
 Abstract of paper before the Royal Society. 
 
 Grimm, J. "Die Lagerstiitten der Nutzbaren Mineralien," 1869. 
 
 Von Groddeok, A. " The Classification of Ore Deposits," Engineer- 
 ing and Mining Journal, .June 27, 1885, p. 437. 
 " Die Lehre von den Lagerstatten der Erze," 1879. Rec. (See 
 also Engineering and Mining Journal, Jan. 3, 1880, p. 2, 
 for a review of same.) 
 
 Hague, J. D. Mining Industries, Paris Exposition, 1878. 
 
 Henrich, C. " On Faults," Engineering and Mining Journal, 
 Aug. 24, 1889, p. 158. 
 
 Hunt, T. S. " The Geognostical History of the Metals," M. E., I. 
 331. 
 " The Origin of Metalliferous Deposits," in " Chemical anc^ 
 
 Geological Essays." 
 " Contributions to the Chemistry of Natural "Waters," Amer. 
 Jour. Sci., n. 39, 176. 
 
 Julien, A. A. " On the Part played by Humus Acids in Ore 
 Deposit, Wall Rook, Gossan," etc., Froc. A. A. A. S., 1879, 
 pp. 382, 385. 
 
 Keck, R. "The Genesis of Ore Deposits," Engineering and 
 Milling Journal, Jan. 6, 1883, p. 3. 
 Review of Ore Deposits in Various Countries. Denver, 1892. 
 31 pages. 
 
 Kemp, J. F. " A Brief Review of the Literature on Ore Deposits," 
 School of Mines Quarterly, X. 54, 116, 326; XI. 359; XII. 
 219. 
 " On the Filling of Mineral Veins," School of Mities Quar- 
 terly, October, 1891. 
 " The Classification of Ore Deposits," School of Mines Quar- 
 terly, November, 1892. 
 "On the Precipitation of Metallic Sulphides by Natural Gas," 
 Engineering and Mining Journal, December, 1890. 
 
 Kleinschmidt, J. L. " Gedanken ueber Erzvorkommen," B. and H. 
 Zeit., 1887, p. 413. 
 
 Koehler, G. " Die Storungen der Gange, Flotze, u. Lager." Leip- 
 zig, 1886. Translated by ^Y. B. Phillips under title of "Ir- 
 
70 KEMPS ORE DEPOSITS. 
 
 regularities of Lodes, Veins, and Beds," Engineering and 
 Mining Journal, June 25, 1887, p. 454; also July 2, p. 4. 
 Leconte, J. " Mineral Vein Formation in Progress at Steamboat 
 Springs and Sulphur Bank," Amer. Jour. Set., III. 25, 424. 
 " Genesis of Metalliferous Veins," Amer. Jour. Sci., July, 
 1883. See other references under "Mercury." 
 Miller, A. Erzgange. Basel, 1880. 
 
 Necker. " On the Sublimation Theory," Proc. Geol. Soc. of Lon- 
 don, Vol. I., p. 392; also Ansted's Treatise on Geology, 
 Vol. II., p. 271. Hist. 
 Newberry, J. S. " The Origin and Classification of Ore Deposits," 
 School of Mines Quarterly, I., 1887, 1880. Engineering and 
 Mining Journal, June 19 and July 23, 1880. A. A. A. S., 
 Vol. XXXIL, p. 243, 1883. Rec. 
 " The Deposition of Ores," School of Mines Quarterly, V. 
 329, 1884; Engineering and Mining Journal, July 19, 1884. 
 *' Genesis of Our Iron Ores," School of Mines Quarterly, II. 1, 
 1880 ; Engineering and Mining Journal, April 23, 1881. 
 See also under "Iron." 
 ■"Genesis and Distribution of Gold," School of Mines Quar- 
 terly, III., 1881; Engineering and Mining Journal, Dec. 24 
 and 31, 1881. Rec. 
 Ochsenius, Carl. " Metalliferous Ore Deposits," Geol. Mag., I. 
 
 310. Hist. 
 Pearce, Rich. " On Replacement of Walls," Chem. News, March 
 
 3, 1865. 
 Phillips, J. A. " The Rocks of the Mining District of Cornwall 
 and Their Relations to Metalliferous Deposits," Quar. Jour. 
 Geol. Soc, XXXI. 319. 
 "A Contribution to the History of Mineral Veins," Quar. 
 
 Jour. Geol. Soc, XXXV. 390. 
 "Treatise on Ore Deposits," London, 1884. 
 Pumpelly, R. Johnson's EicycL, Vol. VI., p. 22. Rec. 
 Raymond, R. W. "What is a Pipe Vein?" Engineering and 
 Mining Journal, Nov. 23, 1878, p. 361. 
 Translation of Lottner, and general remarks on classification. 
 
 Min. Stat. West of Eochy Mountains, 1870, p. 447. 
 Indicative Plants, M. E., XV. 645. 
 
 " Geographical Distribution of Mining Districts in the United 
 States," M. E., I., p. 33. 
 Sandberger, F. " L'ntersuchungen iiber Erzgange," 1882; " Theo- 
 
CLASSIFICATION OF ORE DEPOSITS. 71 
 
 lies of the Formation of Mineral Veins," Engineering and 
 Mining Journal, March 15, 22, 29, 1884, pp. 197, 212, 232. 
 
 Wabner, R. " Ueber die Eintheilung der Minerallagerstatten nach 
 ihrer Gestalt, sowie die Anwendung und die Beniitzung der 
 "Worte, Lager und Flotz," B. und H. Z., Jan. 2, 1891, p. 1. 
 
 Wadsworth, M. E. " The Theories of Ore Deposits," Proc. Bos- 
 ton Soc. Nat. Hist., 1884, p. 197. Rec. 
 " The Lateral Secretion Theory of Ore Deposits," Engineer- 
 ing and Mining Journal, May 17, 1884, p. 364. 
 " Classification of Ore Deposits," Mep. of Mich. State Geolo- 
 gist, 1891-92, p. 144. Rec. 
 
 Whitney, J. D. " Remarks on the Changes which take place in 
 the Structure and Composition of Mineral Veins near tke 
 Surface," Amer. Jour. Sci., ii. XX. 53. 
 " Metallic Wealth of the United States," 1854. Rec. 
 
 Whittlesey, C. " On the Origin of Mineral Veins," A. A. A. S., 
 XXV. 213. 
 
 Williams, Albert. "Popular Fallacies Regarding the Precious 
 Metal Ore Deposits," Fourth Ann. Bep Director U. S, 
 GeoL Survey, pp. 257-278. 
 
 Crosby, W. 0. "A Classification of Economic Geological Deposits 
 
 based on Origin and Original Structure," Amer. Geologist, 
 
 April, 1894, p. 349. Eec. Also in Technology Quarterly. 
 Emmons, S. F. " Geological Distribution of the Useful Metals in 
 
 the United States," Trans. Amer. Inst. Min. Eng., Chicago 
 
 Meeting, 1893. Eec. 
 Moreau, George. " Etude Industrielle des Gites Metallif^res," 
 
 Paris, 1894. 
 Posepny, F. " The Genesis of Ore Deposits," Trans. Amer. Inst. 
 
 Min. Eng., Chicago Meeting, 1893. Rec. 
 Power, F. D. " The Classification of Valuable Mineral Deposits," 
 
 Trans. Australasian Inst. Mining Eng., 1893. 
 Tarr, E. S. "The Economic Geology of the United States,', 
 
 1894. 
 Vogt, J. H. L. " Bildung von Ezlagerstatten durch Differen- 
 
 tiationsprocesse in basischen Bruptivmagmata," Zeitschrift 
 
 f. pralctische Geologie, 1893, pp. 4, 143, 257. 
 " Ueber die Kieslagerstatten vom Typus Roros," etc., Idem, 
 
 1894, pp. 41, 117, 173. 
 
PART II. 
 
 THE ORE DEPOSITS. 
 
CHAPTER I. 
 
 THE IRON SERIES (IN PART).— INTRODUCTORY REMARKS ON 
 IRON ORES.— LIMONITE.— SIDERITE. 
 
 GENERAL LITERATURE. 
 
 Birkinbine, J. " Prominent Sources of Iron Ore Supply," M. E., 
 XVII. 715. Statistical; Rec. 
 Various statistical papers in the volumes on Mineral Re- 
 sources, U. S. Genl. Survey, especially 1886, p. 39 ; 1887, 
 p. 30. 
 
 t!hester, A. H. " On the Percentage of Iron in Certain Ores," M. M, 
 IV. 219. 
 
 Dunnington, F. P. " On the Formation of the Deposits of Oxides 
 of Manganese," Anier. Jour. Sci., iii., XXXVI. 175. The 
 paper treats of Iron also. 
 
 Hewitt, A. S. "Iron and Labor," M. M, September, 1889. The 
 paper contains valuable statistics. 
 "A Century of Metallurgy," M. M, V. 164. 
 
 Hunt, T. S. " The Iron Ores of the United States," M. E., October, 
 1890. 
 
 Kimball, J. P. " Genesis of Iron Ores by Isomorphous and Pseudo- 
 morphous Replacement of Limestone," Amer. Jour. Sei., 
 September, 1891, p. 231. Continued in Amer. Geologist, 
 December, 1891. 
 
 Julien, A. A. "The Genesis of the Crystalline Iron Ores," Trans. 
 Phil. Acad. Nat. Sci., 1882, p. 335 ; Engineering and Min- 
 ing Journal, Feb. 2, 1884. 
 " Origin of the Crystalline Iron Ores," Trans. JV. Y. Acad. 
 Sci., II., p. 6 ; Amer. Jour. Sci., iii., XXV. 476. 
 
 liesley, J. P. " The Iron Manufacturer's Guide," 1866. Hist. Rec. 
 
 Newberi-y, J. S. International Review, November and De- 
 cember, 1874. 
 " Genesis of the Ores of Iron," School of Mines Quarterly j 
 November, 1880. Rec. Amer. Jour. Sci., iii., XXI. 80. 
 
76 
 
 KEMPS ORE DEPOSITS. 
 
 " Genesis of the Crystalline Iron Ores," Trans. iV. Y'. Acad, 
 
 ScL, II., October, 1882. Rec. 
 Newton, H. " The Ores of Iron : Their Distribution with Ref- 
 erence to Industrial Centers," M. E., III. 360. 
 Pumpelly, R., and Othei-s. Tenth Census, Vol. XV., 1886, especially 
 
 pp. 3-17. Rec. 
 Reyer, E. "Geologic des Eisens," Oest. Zeit. f. B. und H., 1882, 
 
 Vol. XXX., pp. 89, 109. 
 Rogers, W. B. " On the Origin and Accumulation of the Proto- 
 
 carbonate of Iron in the Coal Measures," Proc. Host. Soc. 
 
 Nat. Hist., 1856. 
 Smock, J. C. " On the Geological Distribution of the Ores of 
 
 Iron," M. E; XII. 130. 
 " Iron Mines and Iron Ore Districts in New York," Hull. N. IT. 
 
 State Mas., June, 1889. Rec. 
 Swank, J. M. Chapters on iron in Mineral Mesources, U. S. Geol. 
 
 Survey, since 1883. 
 "History of the Manufacture of Iron in All Ages." 1891. 
 Whitney, J. D. "Metallic Wealth of the United States," 1854, 
 
 p. 425. Hist. 
 " On the Occurrence of Iron in the Azoic System," A. A. A. S., 
 
 1855, 209 ; Amer. Jour. Sci., ii., XXII, 38. 
 Winchell, N. H. and H. V. " The Iron Ores of Minnesota," Dull. 
 
 N'o. 6, 3Iin)i. Geol. Survey. Part IV. contains an exhaustive 
 
 review of methods of origin, and Part V. a very complete 
 
 annotated bibliography. 
 
 Table of the Iron Ores, Limonite, Siderite, Hematite, Magnetite, Pyrite. 
 
 Limonite (brown hematite, bog ore), 2Fe.,03 
 SHjO 
 
 Siderite (Spathic ore, clay ironstone, black- 
 band), FeCO^ 
 
 Hematite (rpd and specular), FejOj 
 
 Magnet. tn, FeCFejOs or FegOj 
 
 Pyrite, FeSj 
 
 Fe. 
 
 59.89 
 
 48.27 
 70.0 
 73.4 
 46.7 
 
 H,0. 
 
 14.4 
 
 CO,. 
 
 37.93 
 
 S. 
 
 53.3 
 
 2.01.01. No one of the iron ores ever occurs pure in large 
 amounts. Only a few approach this condition. The Lovers' Pit 
 opening, Mineville, N. Y., yielded 40,000 tons of magnetite that 
 averaged 68.6^ Fe., with carloads at 72f»'. The micaceous specular 
 
THE IRON SERIES (IN PART). 77 
 
 of the Republic Mine, Mich., was shipped an entire season at 69^. 
 The mines, near Tower, Minn., have cleared cargoes at fiS to 
 68.4^. In general the ores run much less. The richest are the 
 mines of the Lake Champlain district have produced the former, 
 and Lake Superior mines the latter, at 63 to 65^, or even more. 
 The separated ores in the Lake Champlain district run about 65^. 
 The unseparated ores have much less, and indeed all percentages from 
 60 to 65. Thus the lump ore (shipped as mined) from Chateaugay, 
 N. Y., has about 50%. The Cornwall (Penn.) magnetite holds even 
 less. The Clinton red hematites from Xew York afford about 44^ in 
 the furnace, as the result of long experience. The limonites, as usu- 
 ally mined, produce from 40 to 50^. The crude spathic ores are the 
 lowest of all, and in the variety black-band may even be about Z0%. 
 They are easily calcined, however, and on losing their carbonic 
 acid, moisture, and bituminous matter the percentage of iron rises 
 a third or more. A. H. Chester found in 1875, as the result of an 
 endeavor to determine the average yield of certain standard ores in 
 the furnace. Lake Superior specular, 62.5iJ ; Lake Superior limonite, 
 49.5^ (much too low to be salable to-day); Rossie (N. Y.) red 
 hematite, 54.5^; Wayne County (N. Y.) Clinton ore, 40^. 
 
 2.01.02. The common impurities in iron ores are the common 
 elements or oxides that enter most largely into rocks, and those 
 which make up the walls of the deposit are usually the ones that 
 appear most abundantly in the ore. Silica (SiO^), alumina (AljOj), 
 lime (CaO), magnesia (MgO), titanium oxide (TiOj), carbonic acid 
 (CO2), and water (HjO) appear in large amounts and determine to 
 a great extent the character, fluxing properties, etc., of the ore- 
 With these, and of more far-reaching influence, are smaller amounts 
 of sulphur and phosphorus. The last two and titanium chiefly de- 
 termine the character of the iron which is yielded in the furnace 
 and are the first foreign ingredients sought. The suljjhur is present 
 in pyrite, the phosphorus in apatite. As is well known, 0.1^ of 
 phosphorus is set as the extreme limit for Bessemer pig irons, and 
 as ores for these command the best market, they are eagerly 
 sought. To obtain the allowable limit of phosphorus in the ore, its 
 percentage in iron is divided by 1000. Thus a 65.3^ ore should 
 not have over 0.065^ phosphorus to be ranked as Bessemer. If at 
 the same time, with sufficiently low phosphorus, the gangue is 
 highly siliceous, a composition desirable for Bessemer practice, 
 ores have been of value, although of comparatively low grade and 
 
78 KEMP'S ORE DEPOSITS. 
 
 remotely situated. For Lake Superior ores the buyers insist to-day 
 on a still lower Bessemer limit, and do not call any ore over 0.05^ 
 phosphorus a strict Bessemer ore. The ore is required to be low 
 enough to carry the phosphorus in both fuel and flux, and still 
 yield a pig iron of not over 0.1^ P. On the other hand a moderate 
 amount of phosphorus is not only no drawback for ordinary foundry 
 irons, and such as are subjected to tool treatment, but is a prime 
 necessity. Exoessivo amounts are desired only for weak but very 
 fluid irons. Considerations like these, which are rather metallur- 
 gical than geological, largely determine the availability of a deposit, 
 and to some extent the present locations of the mining districts. 
 
 2.01.03. Iron itself is one of the most abundant and widely 
 disseminated elements entering into the composition of the earth. 
 Several writers have attempted to deduce the general composition 
 of the outer portions of the globe,' but the most reliable computa- 
 tion is that of F. W. Clarke in Bulletin 78 of the U. S. Geol. 
 Surv., pp. 34—43. The crust to a depth of ten miles below sea- 
 level is the subject of the estimate, and the air and ocean are in- 
 cluded. The composition of the solid crust is reached by averaging 
 analyses of igneous and crystalline rocks, 880 in all; 321 from the 
 United States, 75 from Europe, and 486 from all quarters. 
 Igneous rocks, being the ultimate source of the others, furnish a 
 good average. The final result is the following, in which amounts 
 less than 0.01^ are omitted. The total is 100. 
 
 
 
 49.98 
 
 Xa 
 
 . . . .2.28 
 
 P 
 
 0.09 
 
 Si 
 
 ....25.30 
 
 K 
 
 ....2.23 
 
 Mn . . . , 
 
 0.07 
 
 Al 
 
 7.26 
 
 H 
 
 . . . .0.94 
 
 S 
 
 0.04 
 
 Fe 
 
 5.08 
 
 Ti 
 
 ....0.30 
 
 Ba 
 
 0.03 
 
 Ca 
 
 .... 3.51 
 
 C 
 
 ....0.21 
 
 N 
 
 0.02 
 
 Mg . . . . 
 
 2.50 
 
 CI. Br.... 
 
 ....0.15 
 
 Cr 
 
 . ...0.01 
 
 From this it is seen that iron is much the most abundant of the 
 useful metals, and that its common impurities, titanium, phos- 
 phorus and sulphur are all present in appreciable amounts. 
 
 2.01.04. A general comparison of tabulated analyses of igneous 
 rocks (Eoth's Gestcinsanalysen and Allg. Geol.) shows that granites 
 contain 0.0-7^ iron oxides, porphyries 0.0-14f^, rhyolites 0.0-8^, 
 diorites and diabases 4-16^, andesites 3-15^, basalts 12-20^. 
 
 1 Compare Alex. Winchell, Geological Studies, pp. 19-20 — and Prestwicb's 
 Geology, I. p. 10 — both of wbicli were quoted in the first edition of tbis work. 
 
THE IRON SERIES {IN PART). 79 
 
 Limestones invariably have at least small amounts, and at times 
 very considerable percentages. Sandstones are often low, but not 
 seldom are stained through and through. The metamorphic rocks 
 offer close analogies to the igneous. In general distribution and in 
 quantity, iron leads the list of the distinctively metallic elements. 
 Its peculiar property of possessing two oxides, of different chemical 
 quantivalence, assists greatly in the formation of ores and the 
 general circulation of the metal. This is set forth under the 
 following examples. 
 
 LIMONITE. 
 
 2.01.05. Example 1. Bog Ore. — Beds of limonite, superficially 
 formed in marshes, swamps, and pools of standing water. The 
 general circulation of water through the rocks enables it very 
 frequently to take up iron in solution. Ferruginous minerals are 
 among the first and easiest that fall a prey to alteration. Car- 
 bonic acid in the water aids in dissolving the iron, which thus, in 
 waters containing an excess of COj, passes into solution as the 
 protocarbonate FeCOj. Organic acids may also play a part. The 
 alteration of pyrite affords sulphuric acid and ferrous sulphate, 
 and the latter enters readily into solution. On meeting calcium 
 carbonate, both ferric and ferrous sulphate are decomposed, yield- 
 ing in the first case calcium sulphate, ferric hydrate, and carbonic 
 acid; in the second, if air is absent, ferrous carbonate and calcium 
 sulphate, but on the admission of air ferric hydrate soon forms. 
 (See F. P. Dunnington, Anier. Jour. ScL, iii., XXXVI. 176. Ex- 
 periments 10 and 11.) 
 
 2.01.06. Bodies of limonite that become exposed to a reduc- 
 ing action from the favorable presence of decaying organic mat- 
 ter likewise furnish the protocarbonate. In general it may be 
 stated that free oxygen must be absent or only in small quantity 
 where solution takes place. Sooner or later the ferruginous (or 
 chalybeate) waters come to rest, especially in swamps. The proto- 
 salt is exposed to the evaporation of the excess of COj, that held 
 it in solution, and also to the action of oxygen. Two molecules 
 of carbonate, together with one atom of oxygen and some water, 
 break up into COj and FcjOj, x IT^O. The latter forms as a scum 
 and then sinks to the bottom and accumulates in cellular masses. 
 The eesquioxide is insoluble, and as against ordinary waters free 
 from reducing agents it remains intact. Deposits of mud and 
 peat forming above may cover the beds with a protecting layer. 
 
80 KEMP'S ORE DEPOSITS. 
 
 Hardly a bog exists which does not show, when cut in cross sec- 
 tion, the bog ore beneath. Frequent associates of the ore are 
 diatomaceous earth and shell marl, formed by the remains of or- 
 ganisms which once inhabited the waters. At times excellent im- 
 pressions of leaves and shells are preserved in the ore. Such ore 
 bodies are not often practically available on account of the low 
 percentage in iron, due to the abundance of sand and silt washed 
 in, and to the frequent large amounts of sulphur and phosphorus 
 which they contain. The sulphur is present in pyrite and the 
 phosphorus in vivianite, sometimes in sufficient quantity to be 
 visible (Mullica Hill, N. J., var. Mullicite). In certain parts of 
 the country bog deposits have been and others may yet be utilized. 
 
 2.01.0'/. In eastern North Carolina bog-ore beds are frequent 
 and are found lying just below the grass roots. Scattered nodules 
 occur in the overlying soil, which are succeeded by a bed three 
 feet or less in thickness, resting on sand.' 
 
 In Hall's Valley and Handcart Gulch, Park County, Colorado, in- 
 teresting and extensive deposits of limonite are in active process of 
 formation. The iron comes from neighboring great beds of pyrite.^ 
 
 Bog ore of good quality has recently been reported from the 
 vicinity of Great Falls, Mont.' 
 
 At Port Townsend Bay, in the vicinity of Puget Sound, and at 
 the Patton mines, near Portland, Ore., the ores are of such quality 
 as to be available.* 
 
 Attention has been lately directed to the great deposits of bog 
 ore in the Three Eivers district of the province of Quebec in 
 Canada. Three Eivers is on the St. Lawrence about midway be- 
 tween Montreal and Quebec but the district which furnishes the 
 bog ores extends from nortlieast of Quebec to a point west of 
 Ottawa, an area stated by GriflBn to be 400 miles long by 40-60 
 broad. The drainage of the old Archean heights of the Lauren- 
 tides, the range that suggested the name Laurentian, crosses the 
 belt and being more or less laden with ferruginous solutions it de- 
 posits the ore in swamps, streams and lakes, wherever the water is 
 
 1 W. C. Kerr, Geology of mrth Carolina, 1875, p. 218. B. Willis, 
 Tenth Census, Vol. XV., p. 303. H. B. C. ISTltze, BuU. I., N. C. Geol. 
 Survey, 1893. 
 
 2 R. Chauvenet, ' ' The Iron Resoiirces of Colorado, "J/. E., Jxme, 
 1889. ' ' Notes on Iron Prospects in Northern Colorado, ' ' Ann. Rep. Colo. 
 School of Mines, 1886. 
 
 " Mineral Resources, U. 8. Oeol. Survey, 1888, p. 34. 
 * B. T. Putnam, Tenth Census, Vol. XV , p. 496. 
 
THE IRON SERIES {IN PART). 81 
 
 for a time stationary or choked with vegetation. The ore beds 
 furnish ideal illustrations of bog ore deposits in all their forms. 
 Beginning as a light film the ore gradually accumulates on the 
 bottom, where it hardens into thick crusts. These are exposed in 
 the dry season in the shallower reaches and become dried to very 
 hard cakes. The succeeding wet season buries them again under 
 more ore, or sand and ore. until the thickness attained is very con- 
 siderable. The ore precipitates also in running water and has been 
 obtained from ravines in goodly amount. Even in the pipes used 
 at the furnace at Eadnor Forges for conveying the necessary water 
 supply from the neighboring Eiviere au Lard the limqnite de- 
 posits. The river flows from the swamp called Grand P16, in tlie 
 midst of which is a shallow lake called Lac-a-la-Tortue. Ore is 
 dug in the swamp and dredged in the lake. The supply is renewed 
 after being removed. The deposits present many analogies with 
 those of the Swedish lakes, later mentioned, but they supply caked 
 ore rather than the oolitic form of the latter. The iron industry 
 began in the region in 1730 and has continued more or less inter- 
 mittently to date.' The iron furnished has especial excellence for 
 oar-wheels and chilled castings. The lake ores seem to run some- 
 what richer than those of the bogs. The latter contain about 42.5 
 Fe, the former 49. Both have a little over 0.3 P and less than 0.1 0. 
 These ore bodies are of great scientific interest for they illustrate 
 (as has been recognized for many years) the formation of bodies of 
 other kinds of iron ores when in sedimentary series and even when 
 metamorphosed. 
 
 2.01.08. A somewhat different variety of Type 1 is formed when 
 the ferruginous waters come to rest in the superficial hollows of 
 the rock which has furnished the iron. Depressions in the serpen- 
 tines of Staten Island, N. Y., carry such deposits, and the iron is 
 referred by N. L. Britton to the leaching of the underlying rock. 
 The ore contains a notable percentage of chromium, which is 
 known to occur in the serpentine. The mines have been in former 
 years quite large producers. Similar limonltes occur at Eye, N. Y. * 
 
 1 See especially, P. H. Griffin, ' ' The Manufacture of Charcoal -iron 
 from the Bog and Lake-ores of the Three Rivers District, ' ' Trans. Amer. 
 Inst. Min. Eng., Feb., 1893. Also J. H. Bartlett, Idem, 1885. 
 
 " N. L. Britton, School of Mines Quarterly, May, 1881. Compare 
 also Amer. Jour. 8oi., iii., XX. 32, and XXII. 488. 
 
82 KEMP'S ORE DEPOSITS. 
 
 At the Prosser mines, near Portland, Ore., deposits of limonite 
 are found in the superficial hollows of a Tertiary basalt of the 
 Cascade range. The ore contains roots and trunks of trees, and is 
 covered by a later flow of basalt. Similar bodies of limonite re- 
 sulting from basalt are known in the German province of Hesse 
 and in Ireland.' 
 
 3.01.09. The limonite sand, or oolite, that forms in the Swedish 
 lakes about ten meters from the banks and in water up to ten 
 meters in depth is another variety of this type. A layer half a 
 meter and less in thickness accumulates every fifteen to thirty 
 years and is periodically dredged out. The ore precipitates first 
 as a slime that breaks up afterward into small concretions. It 
 has been thought that the formation of these and similar bodies of 
 limonite has been aided by small algoe and other plants or micro- 
 scopic organisms. ^ 
 
 2.01.10. Example 2. Bodies of limonite in cavities of fer- 
 ruginous rocks, on the outcrop, or below the surface, which have 
 resulted either from the alteration of the rock in situ or from its 
 partial replacement by limonite. Residual clay, quartz, and other 
 remains of alteration usually occur with the ore. Ferruginous 
 limestones are the commonest sources of such deposits, but otlier 
 rocks may afford them. The deposits are not limited to any one 
 geological series, but in different parts of the country occur when- 
 ever the conditions have been favorable. Some of the ore may 
 have been brought in by subterranean circulations which have 
 leached the neighboring rocks. Considerable limonite has also re- 
 sulted from the weathering of clay-ironstone nodules and black- 
 baud beds in the Carboniferous system (to be mentioned later), and 
 not infrequently from the alteration of nodular masses of pyrites. 
 
 "■ B. T. Putnam, Tenth Census, Vol. XV., p. 16, on the Oregon ore. 
 Tasche, Berg.- uad Hutt. Zeit., 1886, p. 209; also Wurtemberger, Xeues 
 ,/ahrb. 1867, p. 685, on the Hessian ores. Tate and Holden, "On the Iron 
 Ore Associated with the Basalt of Northeastern Ireland, " Qnar. Jour. 
 Geol. Soc, XXVI. lul. 
 
 2F. M. Stapflf, Zeitschr. d. d. geolog. Gesellsh., 1866, Vol. XVm., p. 8, 
 on the geology of the ores. Sjognm, Berg.- imd Huett. Zeit., 1865, p. 116, 
 on the agency of algae. On the general formation of bog ores the fol- 
 lowing papers are of interest : Gr. J. Brush and C. S. Rodman, ' ' Ob- 
 servation on the Native Hydrates of Iron," Amer. Jour. Sci., ii. , XLIV. 
 319; J. S.Newberry, School of Mines Quarterly, Novembei, 1880; J. Roth, 
 Cliem. mid Phys. Geologic, I., pp. 58, 97, 331; F. Senft, Humus, Marsch, 
 Torf- und Limonil-hildaiigen. 
 
THB IRON SEUIES (IN PART). 
 
 83 
 
 The limonite is in cellular lumps, in pipes, pots, and various imita- 
 tive forms which often have a beautiful luster. The hollow masses 
 have in general resulted form the filling of reticulated cracks in 
 shattered rock. The ore thus deposits around the cores of country 
 rock, which afterward are removed, leaving a hollow shell or geode. 
 (See Tenth Census, Vol. XV., pp. 275, 369, 370.) 
 
 2.01.11. Reserving the Siluro-Cambrian limonites for a subtype 
 the ore bodies are described in order from east to west, taking up 
 first the Alleghany region, then the Mississippi Valley, and lastly 
 
 Fig. 8. — Section of the Hurst limonite bank, Wythe County, Virginia, 
 
 illustrating the replacement of shattered limestone with limonite 
 
 and the formation of geodes of ore. After E, B. Benton, 
 
 Tenth Census, Vol. XV., p. 275. 
 
 the Rocky Mountains. The limonites of Xew England and New 
 York belong in the subsequent subtype, as do those of eastern 
 Pennsylvania and the more important ones in Virginia, Tennessee, 
 Georgia, and Alabama. In central and western Pennsylvania, 
 however, not a small amount is obtained from the higher lying 
 terranes. The Hudson River slates furnish small amounts in 
 Franklin County, which are thought by McCreath to have resulted 
 from the alteration of nodules of pyrites. (Second J-'enn. Geol. Sur- 
 vey, M.3, p. X.) The Medina sandstones contain highly ferrugi- 
 nous portions in Huntingdon County. (McCreath, Second Penn. 
 Geol. Survey, MM, p. 198.) The Lower Helderberg and Oriskany 
 
84 KEMP 'S ORE DEPOSITS. 
 
 are locally quite productive in Blair County, affording several great 
 banks of ore. (Report MM, 196, M3, p. 33.) The Oriskany is of 
 greater importance in Virginia than in Pennsylvani'a. East of 
 these last mentioned exposures, and in southern Carbon County, is 
 a bed of paint ore between the Oriskany and the Marcellus. (C. 
 E. Hesse, « The Paint-Ore Mines at Lehigh Gap," M K, New York 
 meeting, 1890.) The Marcellus is the most productive of the Devo- 
 nian stages. It affords considerable ore in Perry County (Report 
 MM, p. 193 ; M3, p. 29), Juniata County, Mifflin County, Hunting- 
 don County (Report M, p. 66 ; MM, p. 194 ; M3, p. 140), Fulton 
 County (Report M3, p. 42), and Franklin County (Report M3, 
 p. 1). All these are in southern Pennsylvania. Lesley states 
 {Iron Manufacturer S Guide, p. 650) that the ore is weathered car- 
 bonate. As shown under Example 4, beds of carbonate ore occur in 
 Ulster County, New York, in the Marcellus. (Additional details 
 on the above Pennsylvania deposits will be found in the geological 
 reports on the particular counties.) 
 
 2.01.12. As already remarked, the greater part of the limonites 
 in Virginia belong under the Siluro-Cambrian division and are there 
 described, but in the James River basin, on Purgatory and May's 
 Mountains, there are deposits in sandstones of the Clinton. (J. L. 
 Campbell, The Virginias, July, 1880.) Other limonite beds occur 
 in the Oriskany on Brushy Mountain (Longdale mines), on Rich 
 Patch Mountain (Low Moor mines, called by Lyman, Marcellus), on 
 Warm Spring Mountain, and on Peter Mountain. lu the Shenan- 
 doah Valley, on Massanutton Mountain, the limonite is referred by 
 Prime to the Clinton stage. {The Virginias, March, 1880, p. 35.) 
 On North Mountain it lies in the Oriskany, according to Camp- 
 bell {The Virginias, January, 1880, p. 6), and on the Great 
 North Mountain in the Upper Silurian. Considerable oxide of 
 zinc collects in the tunnel heads of the furnaces running on Low 
 IMoor ores, indicating the presence of this metal in the limonite.' 
 
 The Oriskany ores (including those referred by Lyman to the 
 Marcellus) were formerly the chief sources of Vii'ginia iron, and at 
 Longdale and Low Moor afforded very large amounts, but lately 
 
 ' B. S. Lyman, ' ' Geology of the Low Moor, Va. , Iron Ores, ' ' Trans. 
 Amer. Inst. Min. Eng., Feb., 1886. E. C. Means, "Flue Dust at Low 
 Moor, Va. , ' ' Trans. Amer. Inst. Min. Eng. , 1888. E. C. Pechin, ' ' Vir- 
 ginia Oriskany Iron Ores, " Engineering and Jlining Journal, Aug. 18, 
 1892, p. 150. " Iron Ores of Virginia, " etc. , Trans. Amer. Inst. 2Iiu. 
 Eng., XIX. 1016, 1890. 
 
THE IRON SERIES (IN PART). 
 
 85 
 
 the Siluro- Cambrian have talcen pi'ecedence. Tlie Oriskany ores 
 yielded from 40 to 43^ Fe in tlie furnace (Pechin), and were non- 
 Bessemer. They had au excellent reputation for foundry and mill- 
 work. Another prominent source of brown hematite ores in 
 Virginia has been of recent years the weathered and oxidized npper 
 portions of the great pyrites deposits in Floyd, Grayson and Carroll 
 Counties, in the southwestern part of the State. This belt extends 
 over 20 miles and is known as the "Great Gossan Lead." 
 Although uniformly pyrites or pyrrhotite below the water line, it 
 is sufficiently oxidized above to yield an ore of about 40 to 41^ Fe, 
 with the sulphur not much over one per cent. The greatest depth 
 is attained where the belt crosses tlie iiills. The ores supply 
 a useful mixture for the neighboring Siluro-Cambrian brown 
 hematites. 1 
 
 Fig. 9. — Geological Section of the Low Moor, Va., Iron-ore Bed. After 
 
 B. 8. Lyman, Trans. Amer. Iiust. Min. Eng.. Feb., 1886. 
 
 A — Marcellus Shale ; B — Oriskany Sandstone ; C — Lower 
 
 Helderberg Limestone; D — Clinton Shales. 
 
 The iron ores in Kentucky are found in three widely separated 
 districts, one near Greenup, in the northeastern corner of the »State, 
 known as the Hanging Eock region; the second near the central 
 part along the Red and Kentucky Rivers, known as tlie Kentucky 
 and Red River region; and the third in the southwestern part near 
 Lyon and Trigg Counties, known as the Cumberland River region. 
 Although the first two contain much limonite, it has altered from 
 nodules of carbonate, and the ores are therefore described under 
 Example 5. One locality near Owingsville, in the second region, 
 has limonites altered from the Clinton hematite. (See Example 
 6.) The Cumberland region affords limonites in the Subcarbonif- 
 erous. They are in rounded masses, either solid or hollow, and 
 are distributed through a red clay along with angular fragments 
 
 1 E. C. Moxham, ' ' The Great Gossan Lead of Virginia, ' ' 
 Amer. Inst. Min. Eng , XXI. 133, 1892. 
 
 Trans. 
 
86 KEMP 'S ORE DEPOSITS. 
 
 of chert. The limonite pots are themselves filled with clay or 
 water, i 
 
 2.01.13. In Tennessee the limonites of the eastern portion come 
 mostly under Example 2a. In the west they are a southern ex- 
 tension of the pot-ore deposits of Kentucky, and show the same as- 
 sociated chert and clay. Safford has called the rocks containing 
 them the Siliceous Group. The west Tennessee district projects 
 into Alabama to a small extent.^ 
 
 2.01.14. The principal limonite deposits of Alabama come under 
 Example 2a, as do those of western North Carolina and Georgia. 
 Some limonite is produced in Ohio, but it is all weathered carbon- 
 ate and is mentioned under Example 5. Hydrated ores are abundant 
 in the Lake Superior region, but are mentioned in connection with 
 hematite. (See also 2.01.3^.) Deposits of brown hematite are 
 worked in a small way in the southeastern part of Missouri, where 
 they rest upon Cambrian strata and have a marked stalactitic char- 
 acter. (P. N. Moore, Geol. Survey of Missouri, Eeport for 1874; 
 F. L. Nasou, Mo. Geol. Survey, 1892, II., p. 158.) Limonites re- 
 ferred to the Cretaceous by N. H. Winchell occur in weste«L 
 Minnesota. {Bull. VI., Minn. Geol. Survey, p. 151.) 
 
 2.01.15. Tlie Annual Reportofthe Geological Survey of Arkan- 
 sas, Vol. I., consists of a report by E. A. F. Penrose on the ''Iron 
 Deposits of Arkansas." It at once appears that there is little pros- 
 pect of Arkansas producing any notable amounts of iron ore. Such 
 deposits as have been found are practically all limonite (brown 
 hematite) and are generally very low in iron. The ores occur in 
 five districts, viz: Northeastern Arkansas, northwestern Arkansas, 
 the valley of the Arkansas Eiver, the Ouachita Mountains, and 
 southern Arkansas. They are generally associated with sandstones 
 or cherty limestones. The first named district makes the best 
 showing. In it the ores are in Lower Silurian (Calciferous or 
 Lower) sandstones, cherts and limestones. In the second district 
 they are in Lower Silurian cherts, and Lower Carboniferous sand- 
 stones. In the third they occur with Carboniferous and Lower 
 Carboniferous strata, but are also in the form of recent spring de- 
 posits. In the Ouachita Mountains they are witli Lower Silurian 
 
 1 W. B. Caldwell, "Report on the Limonite Ores of Trigg, Lyon, and 
 Caldwell Counties," Kentucky Oeol. Survey, New Series, Vol. V., p. 251. 
 
 ^W. M. Chauvenet, Tenth Census, Vol. XV., p. 357; T. H. Saflford, 
 Geology of Tennessee, p. 350. 
 
THE IRON mnilCS (IN PART). 87 
 
 shales and novaculites. In this district the magnetite or natural 
 lodestone of Magnet Cove occurs, but it is only an interesting 
 mineral and of no practical importance. The last district has the 
 ores in sands and clays oE the Eocene. Its continuation in Texas 
 and Louisiana is referred to below. 
 
 In eastern Texas, along the latitude of the northern bound- 
 ary of Louisiana, extended beds of limonite are foniid cap- 
 ping the mesas or near their tops, and associated with glauconitic 
 sands oi Tertiary age. They are described by Penrose {Mrst 
 Ann. Bep. Texas Geol. Survey, p. 66; also G. S. A., III. 44) as 
 (1) Brown laminated ores, (2) Nodular or geode ores, (3) Conglom- 
 erate ores. The first form extended beds whose firmness has 
 prevented the erosion of the hills, and which are thought to have 
 originated by the weathering of the pyrites in the greensands and 
 from the iron of the glauconite itself. The second group occur 
 just north of the last, and have probably resulted from the altera- 
 tion of clay ironstone nodules (Cf. Example 5), while the third has 
 formed in the streams by the erosion of the first two and from the 
 smaller ore-streaks and segregations. Limonite also occurs in 
 northwestern Louisiana. [Mineral Resources, 1887, p. 51.) Mr. 
 Lawrence C. Johnson has also written of these ores {Fiftieth Con- 
 gress, First Session, Exec. Doc. No. 195), but the most complete 
 account has been given by W. Kennedy (" Iron Ores of East 
 Texas," Trans. Amer. Inst. Min. Eng., Feb., 1894). Mr. 
 Kennedy speaks of the available ores as the " Laminated Ores " 
 and the "Nodular Ores," both belonging, in serious amount, 
 to the greensand beds of the upper Eocene. An abundant 
 series of analyses are given which show the ores to be in general 
 rather rich for limonites, and not high in sulphur or phosphorus. 
 According to the grade of ore now demanded and obtained on Lake 
 Superior, they are seldom Bessemer ores, but ought to yield excel- 
 lent foundry irons. While the quantity is large, the situation pre- 
 cludes the use of any fuel but charcoal, and the remoteness of 
 markets will mostly restrict the output to the comparatively 
 limited local demand. The ore can be won by shallow stripping 
 or from exposed beds, up to two feet or so in thickness. The 
 geological relations of these ores are interesting and important in 
 that they are derived from greensands, whicli consist so largely of 
 glauconite, the double silicate of iron and potassium, and which are 
 comparatively deep-sea deposits. The formation of glauconite by 
 precipitation from sea-water, and as a filling of the small chambers 
 
88 KEMP'S ORE DEPOSITS. 
 
 in minute shells and organisms indicates^ a marine method for the 
 concentration of iron oxide. It is significant that J. E. Spurr 
 has lately advocated a similar source for the ores of the Mesabi 
 range, Minn. (See Example 9e.) Limonite is known in a num- 
 ber of localities of Colorado. The chief productive mines lie in 
 Saguache County, near Hot Springs. They furnish a most excel- 
 lent ore from cavities in limestones, which are generally, but with 
 no great certainty, considered Lower Silurian. K. Chauvenet 
 states that the ores yield about 43^ Ee in the furnace.^ 
 
 A great body of limonite nodules, bedded in red, residual clay, 
 has been reported from the Clinton series of Allamakee County, 
 Iowa. (E. Orr, Amer. Geologist, Vol. I., p. 129.) 
 
 Much limonite occurs at Leadville in connection with the lead- 
 silver ores, and is used as a flux by the lead smelters. Some grades 
 low in silver and rich in manganese have even been used for spiegel 
 at Pueblo. For the geological relations, see Example 30. 
 
 2.01.16. Limonites in supposed Carboniferous limestone occur 
 in the East Tintec mining district in Utah, and seem to be as- 
 sociated with a decomposed eruptive rock, somewhat as at Lead- 
 ville. The limonite is chiefly used as a flux by lead-silver smelters.^ 
 
 2.01.17. Example 2a. Siluro- Cambrian Limonites. — Beds of 
 limonite in so-called hydromica (talcose, damourite), slates and 
 schists, often also with limestones of the Cambrian and Lower 
 Silurian systems of the Appalachians. The great extent, the geo- 
 logical relations, and the importance of these deposits warrant their 
 grouping in a subt3-pe by themselves. They extend along the Ap- 
 palachians from Vermont to Alabama, and are in the " Great 
 Valley," as it was early termed, which marks the trough between 
 the Archean on the east and the first corrugations of tlie Paleozoic 
 rocks, often metamorphosed, on the west. The masses of limonite 
 are buried in ochreous clay, and the whole often preserves the gen- 
 eral structure of the schistose rocks which they have replaced. The 
 
 1 On the formation of greensands, see W. B. Clark, Journal of Ge- 
 ology, II., 161, 1894. 
 
 " R. Chauvenet, ' ' Preliminary Notes on the Iron Resources of Col- 
 orado, " Ann. Rep. Colo. State School of Mines, 1885, p. 31; "Iron Re- 
 sources of Colorado, " .V. E., 1889. F. M. Endlich, Hoyden's Reports, 1873, 
 p. 333. B. T. Putnam, Tenth Census, Vol. XV., p. 482. C. M. Rolker! 
 "Notes on Certain Iron Ore Deposits in Colorado, ' ' M. E., XIV. , 266. Rec. 
 
 8B. T. Putnam, Tenth Cen.ivs, Vol. XV., p. 490. 
 
THE IRON SERIES (IN PART). 89 
 
 original stringers of quartz remain following the original folds. 
 Dolomitic limestone often forms one of the walls, and still less 
 often (but especially in New England) masses of siderice are found 
 inclosed. Manganese is at times present, and in Vermont is of some 
 importance of itself. 
 
 2.01.18. The deposits begin in Vermont, where in the vicinity 
 of Brandon they have long been ground for paint. A curious pocket 
 of lignite occurs with them and affords Tertiary fossils. This 
 prompted President Edward Hitchcock, about 1850, to refer all the 
 limonites to the Tertiary, making an instructive example of the oc- 
 casional hasty generalizations of the early days. Lignite has also 
 been found at Mont Alto, Penn. In northeastern Massachusetts, 
 at Richmond and West Stockbridge ; and just across the State line, 
 in Columbia and Dutchess counties. New York, and at Salisbury, 
 Conn., the mines are large, and were among the iirst worked in the 
 
 A 
 
 San^ J ^ 1 Engine House 
 KwilH-5.nd Gra vel a K 
 
 Pit 
 
 Ore 
 
 Fig. 10. — Geological section nf the Amenia Mme, Dutchess County, New 
 
 York, illustrating a Siluro-Cambrian limonite deposit. After 
 
 B. T. Putnam, Tenth Census, Vol. XV., p. 133. 
 
 United States. The limonite forms geodes, or "pots," pipes, 
 stalactitio masses, cellular aggregates, and smaller lumps from 
 which the barren clays and ochers are removed by washing. The 
 ore is but a fraction of the material mined and occurs in irregular 
 streaks through the clays, etc. It is mostly obtained by stripping 
 and open cuts, and only rarely by underground mining, which 
 would present difficulties with such poor material for walls.' 
 
 ' J. D. Dana, " Occurrence and Orlg-ln of the New York and New Eng- 
 land Limonites," Amer. Jour. Sei., iii., XIV. 1.S3, and XXVIIl. 398. Rec. 
 E. Hitchcock, "Description of a Brown Coal Depjfit at Brandon, Vt., 
 with an Attempt to determine the Geological Age of the Principal Ore 
 Beds of the United States," Amer. Jour. Sci., ii., XV. 95 ; Hist. 6eol. 
 Survey of Vermont, I. 333. See also Lesley, below. A. L. Holley, " Notes 
 on the Salisbury (Conn.) Iron Mines and Works," M. E., VI 220. J. P. 
 Lesley, "Mont Alto (Penn.) Lignites," Proc. Amer. Acad. Sri., 1864, 463- 
 483 ; Amer. Jour. Sci., ii., XL. 119. L. Lesquereux, " On the Fts 11 Fruits 
 found in Connection with the Lignite at Brandon, Vt.," Amer. Jour. Sci., 
 
90 KEMP'S OUK DEPOSITS. 
 
 A gap occurs in the succession of the deposits across southern 
 New York and New Jersey, although a few minor ones are known 
 in the western part of the latter State, in the magnesian limestone 
 of the valleys between the hills of gneiss.' 
 
 2.01.19. In Lehigh County and to the southwest through York 
 County, in eastern Pennsylvania, the limonites are again developed 
 in great amount, and run southwesterly, with few gaps, to Alabama. 
 It is in this portion that the " Great Valley " (called also the 
 Cumberland Valley, or Valley of Virginia) is especially marked. 
 Wherever the great limestone formation, No. II. of Rogers, is 
 developed the ores are found. This corresponds to the Calciferous, 
 Chazy, and Trenton of New York. Limonites also occur still 
 lower in the Cambrian at about the horizon of the Potsdam sand- 
 stone or in the overlying slates. According to McCreath, they are 
 distinguishable in Pennsylvania as ores at the top, ores in the 
 middle, and ores at the bottom of the great limestone No. II. 
 Those at the top form the belt along the central part of the valley 
 where the Trenton limestone underlies the Utica or Hudson River 
 slates. Those in the middle are connected with various horizons 
 of ferruginous limestones in the Chazy and Calciferous. Those at 
 the bottom along the north or west part of the South Mountain- 
 Blue Ridge range are geologically connected with the Potsdam 
 sandstone, or the slates which intervene between it and the base of 
 the Calciferous. {Second Penn. Survey, Rep. MM, p. 199.) Cobalt 
 has been detected on those of Chester Ridge by Boye, but it is a 
 rare and unique discovery.^ 
 
 ii., XXXII. 355. H. Carvill Lewis, "The Iron Ores of the Brandon Pe- 
 riod," ^mer. 4. ^. Sci., XXIX. 437, 1880. J. F. Lewis, "The Hematite 
 (Brown) Ore Mines, etc., East of the Hudson Eiver," M. E., V. 216. J. G. 
 Percival, Rep. on the Oeol. of Conn., p. 132 ; also, Amer. Jour. Sci., ii., 
 11.268. R. A. F. Penrose, " Report on Manganese Ores," Geol. Survey 
 ArTc., 1890, Vol. I. (Contains many valuable descriptions of Vermont 
 limonites.) B. T. Putnam, Tenth Census, Vol. XV. C. N. Shepard, "No- 
 lice, etc., of the Iron "Works of Salisbury, Conn.," Amer. Jour. Sci., i., 
 XIX. 311. J. C. Smook, Bull. VIl. New York State Museum, pp. 12, 52. 
 N. H. and H. V. Winohell, " Taconic Ores of Minnesota and Western New 
 England," Amer. Geol, VI. 263. 1890. 
 
 1 B. T. Putnam, Tenth Census, Vol. XX., p. 176. See also Oeol. Sur- 
 vey Neiv Jersey, 1880. 
 
 ° Dr. Boye, "Oxyd of Cobalt with the Brown Hematite of Chester 
 Ridge, Penn., Amer. Phil. Soc, January, 1846. P. Eraser, Second Geol. 
 Survey Penn., Reps. C and CC ; " Origin of the Lower Silurian Limonites 
 
THE IRON SKRIKS (IN PART). 91 
 
 2.01.20. The Siluro-Cambrian limonites run across Maryland in 
 Carroll and Frederick counties, and are mined to small extent. 
 (E. R. Benton, Tenth Census, Vol. XV., p. 254.) 
 
 These limonites are again strongly developed in the Shenandoah 
 Valley along the western base of the Blue Ridge, and in south- 
 western Virginia in the Cripple Creek and New River belt. The 
 ores occur in connection with calcareous shales, calcareous sand- 
 stones, and impure limestones, but have not justified the expecta- 
 tions formed of them. In Carroll County, Virginia, the gossan of 
 the great deposit of pyrite is dug for iroa ore. The walls, however, 
 are older than the Cambrian.' 
 
 2.01.21. The limonites of eastern Tennessee are the southern 
 prolongation of the area of southwest Virginia. They lie between 
 the Archean of the Unakn range on the east, and the Upper Silurian 
 strata in the foot of the Cumberland tableland on the west. The 
 ores outcrop in the longitudinal valleys or " coves." The bottoms 
 of these valleys, according to Safford (p. 449), are formed by the 
 shales, slates, and magnesian limestones of the Knox group, and in 
 
 of York and Adams Counties." Proc. Amer. Phil. Soc, March, 1875. J. W. 
 Harden, "The Brown Hematite Ore Deposits of South Mountain between 
 CaiLsle,Waynesborough, and the Southeast Edge of Ihe Cumberland Val- 
 ley," M. E., I. 136. J. P. Lesley, Summary, Final Repjrt, Vol. I., 1892, 
 pp. 205, 341. Rec. A. S. McCreath, Second Oeol. Survey Penn., Vol. 
 MM, 199. F. Prime, Second Geol. Survey Penn., Reps. D and DD ; "On 
 the Ocfiirrence of tlie Brown Hematite Deposits ot the Great Valley," 
 M. F., i;i. 410 ; Amer. Jour. Sci., ii., IX. 433 ; also, XI. 63, and XV. 361. 
 Rec. B. T. P.itaam, Tenth Census, Vol. XV., p. 181. 
 
 1 D. R. Benton, Tenth Census, Vol. XV., p. 261. J. L. Campbell, 
 "Report on the Mineral Prospects of the St. Mary Iron Property," etc., 
 The Virginias, February, 1883, p. 19. See also The Virginias, January, 
 1880, p. 4 ; March, p. 43. F. P. Dewey, " The Rich Hill Iron Ores," M. E., 
 X. 77. W. M. Fontaine, "Notes on the Mineral Deposits of Certain Lo- 
 calities in the Western Part of the Blue Ridge," The Virginias, March, 
 1883, p. 44 ; April, p. 55 ; May, p. 73 ; June, p. 93. B. S. Lyman, "Oa the 
 Lower Silurian Brown Hematile Beds of America," -.4. A. A. S., XVII. 
 114. A. S. McCreath, " The Iron Ores of the VaUey of Virginin," ;)/. £■., 
 XII. 103; Engineering and Mining Journal, June, 1883, p. 334. E. C. Mux- 
 ham, " The Great Gossan Lead of Virginia," M. £•., February, 1892. E. C. 
 Pechin, "The Iron Ores at Bupna Vista, Rockbridge County, Virginia," 
 Engineering and Mining Journal, Aug. 3, 1889, p. 92; "Mining of Potsdam 
 Brown Ores in Virginia," Engineering and Mining Journal, Sept. 19, 1891, 
 p. 337; "Iron Ores of Virginia and Their Developments,'' M. E., XIX. 101; 
 "Ore Supply for Virginia Furnaces," Engineering and Mining Journal, 
 Vol. LI., 1891, pp. 323, 349. R"c. 
 

 '1 
 
 s 
 
 - -^ 
 
 i « 
 
 -"M 
 
 - ^ ^*. 
 
 
 
 I 
 
 ^ 
 
 ^ 
 
THE IRON SEUIEa (IN PART). 93 
 
 the residual clay left by their alteration the ore is found. The gos- 
 san of the neighboring veins of copper pyrites, best known at Duck- 
 town (see Example 16), were originally exploited for iron.' 
 
 The Tennessee limonite extends across northwestern Georgia, 
 and still farther east the Hiironian limestones of North Carolina 
 also enter the State. But as even these Huronian schists and as- 
 sociated marbles have been considered by F. P. Bradley to be 
 metamorphosed Silurian (Cambrian), the ores may also belong un- 
 der Example 2a. The well-determined Siluro-Cambrian rocks 
 form but a narrow belt of no great importance in North Carolina.' 
 
 The limonites are again strongly developed in Alabama and 
 furnish a goodly proportion of the ore used in the State. They 
 form a belt lying east of the Clinton ores (Example 6), later de- 
 scribed. As in Tennessee, they are associated with strata of the 
 Knox group.' 
 
 3.01.22. Extensive deposits of hydrated ores also occur in all 
 the Lake Superior iron ranges. They are often yellow aud 
 ochreous, but they are not true limonites as their percentage in 
 iron often reaches 62^. They are partially hydrated hematites. 
 
 2.01.23. Origin of the Silvro- Cambrian Limonites. — Dr. Jack- 
 son of the First Pennsylvania Survey argued in 1839* that they 
 originated in situ ; that is, by the alteration of the rocks in and 
 with which they occur. Percival, in his report on the Geology of 
 Connecticut, in 1842 (p. 132) attributed them to the alteration of 
 pyrite in the neighboring mica-slate. Prime, in Pennsylvania, 
 in 1875 and 1878 (Reports D and DD), considers that the iron has 
 been obtained by the leaching of the neighboring dolomites and 
 slates, it being in them either as silicate, carbonate, or sulphide ; 
 that the ore has reached its position associated with the slates, be- 
 cause, being impervious, they retained the ferruginous solutions ; 
 and that the potash abundantly present in the slates probably as- 
 sisted in precipitating it.* Frazer, in 1876,' in studying the beds of 
 
 1 J. M. Safford, Geol. of Tenn., p. 448, 1869. B. Willis, Tenth Census, 
 Vol. XV., p. 331. 
 
 2 F. P. Bradley, " The Age of the Cherokee County Bocks, North 
 CaroliQa," Amer. Jour. ScL, iii., IX. 379 and 320; B. "Willis, Tenth Cen- 
 sus, Vol. XV. , p. 367. H. B. C. Nitze, Bull. I. , N. C. Geol. Survey, 1893. 
 
 » W. M. Ctiauvenet, Tenth Census, Vol. XV., p. 383. For other ref- 
 erences to Alabama iron ore deposits, see under Example 6. 
 * Ann. Bep. First Penn. Survey, 1839. 
 5 M. E., II. 410. 
 ' Second Penn. Survey, Rep. C, p. 136. 
 
94 KEMP'S ORE DEPOSITS. 
 
 York and Adams counties, Pennsylvania, found the Iiydromica 
 slates filled with the casts of pyrite crystals, and held these to 
 have been the sources of the iron, by affording ferrous sulphate 
 and sulphuric acid. The latter reacted on the alkali of the slates, 
 producing sodium sulphate. This, meeting calcium carbonate, af- 
 forded calcium sulphate and sodium carbonate, which later precipi- 
 tated the iron. Calcium carbonate alone is, however, abundantly 
 able to precipitate iron carbonate and oxide from both ferrous and 
 ferric sulphate solutions (even when natural) without the intro- 
 duction of the alkali, although this might account for the alteration 
 of the slates.^ 
 
 2.01.24. J. D. Dana has written at length on the Kew England 
 and New York deposits, and finds them always at or near the junc- 
 tion of a stratum of limestone, proved in many cases to be ferrif- 
 erous, and sometimes entirely siderite, and one of hydromica 
 slate or mica schist. In several mines bodies of unchanged spathic 
 ore are embedded in the limonite. Hence Professor Dana explains 
 the limonite as derived by the weathering of a highly ferruginous 
 limestone, from which the limonite has been left behind by the 
 removal of the more soluble elements, so as practically to replace 
 the limestone in connection with other less soluble matter. The 
 limonite has also at times replaced the schists, probably deriving 
 its substance in part from iron-bearing minerals in them, and 
 changing these rocks to the ochers and clays now found with the 
 ores. These views are undoubtedly very near the truth for the 
 region studied. (Cf. also Example 4.) Weathering limestones do 
 furnish residual clay, ocher, etc., as is shown by the deposits of 
 western Kentucky and Tennessee under Examjale 2. 
 
 2.0 .25. Another hypothesis early formulated and advocated 
 by many is that the limonites have been derived by the surface 
 drainage of the old Appalachian highlands and then precipitated in 
 still water where they are now found. A precipitation around the 
 shores of a ferruginous sea has also been urged on the analogy of 
 certain explanations of the Clinton ore. (Example 6.) Their sup- 
 posed Tertiary age has already been remarked. All these views are 
 essentially hypothetical.^ 
 
 1 See F. P. Dunnington, "On the Formation of Deposits of Manga- 
 nese," Amer. Jour. Sci., iii., XXXVI., p. 175. (Experiments 10 and 11.) 
 
 2 See H. D. Rogers, Trans. Asso. Amer. Qeol. and Nat., 1843, p. 345 ; 
 E. Hitchcock, Geol. Vt., Vol. I., p. 233 ; J. P. Lesley, Iron Man., p. 501 ; 
 Rep. A , Second Penn. Survey, p. 83 ; J. S. Newberry, International Re- 
 view, November and December, 1874. 
 
THE IRON SERIES (IN PART). 
 
 95 
 
 ANALYSES OF LIMONITBS. 
 
 2.01.26. All published analyses, except when forming a suflB- 
 ciently large and continuous series from the output of any one mine, 
 are to be taken with caution. Ores necessarily vary much, and a 
 single analysis or a selected set may give a very wrong impression. 
 The percentage in iron is different for different parts of the same 
 ore body. The few that follow have been selected to show the 
 range and the average. The highest are exceptionally good, the 
 lowest less than the average, and the medium values indicate ap- 
 proximately the general run. Limonites afford from 40 to 50% Fe 
 as actually exploited, but it is not difficult to find individual analy- 
 ses that run higher. They are not, generally speaking, Bessemer 
 ores. 
 
 Analyses of Limonites. 
 
 „ H,0. 
 
 Berkshire County, Mass 
 
 Connecticut 
 
 Dutchess County, New York 
 
 Staten Island 39.73 0.05J 0.39114.19 3.59 13.41 
 
 Pennsylvania 
 
 Virg-inia (Low Moor) 
 
 Tennessee (Lagrange Furnace) 
 
 Alabama 
 
 Colorado 
 
 Colorado, average 43.00 0.080 30. 13. 
 
 Prosser mine, Oregon 
 
 Pure mineral 59.93 14.4 
 
 Fe. 
 
 P. 
 
 S. 
 
 SiO, 
 
 Al.Os 
 
 47.53 
 
 0.187 
 
 
 
 
 50.48 
 
 0.858 
 
 
 
 
 46.45 
 
 0.370 
 
 
 14.10 
 
 3.05J 
 
 39.73 
 
 0.05J 
 
 0.391 
 
 14.19 
 
 3.59 
 
 56.3 
 
 0.135 
 
 0.03 
 
 5.165 
 
 
 43.34 
 
 0.636 
 
 
 
 
 50.91 
 
 0.337 
 
 
 
 
 50.89 
 
 0.335 
 
 
 
 
 58.37 
 
 0.034 
 
 0.30 
 
 7.90 
 
 0.70 
 
 43.00 
 
 0.080 
 
 
 30. 
 
 
 44.71 
 
 0.666 
 
 
 
 
 59.93 
 
 
 
 
 
 SIDEEITE, OR SPATHIC ORE. 
 
 2.01.27. Siderite is the protocarbonate of iron. As a mineral 
 it often contains more or less calcium, magnesium, and manganese. 
 AVhen of concretionary structure, embedded in shales and contain- 
 ing much clay, the ore is called clay ironstone. When the concre- 
 tions enlarge and coalesce, so as to form beds of limited extent, 
 generally containing much bituminous matter, they are called 
 black-band, and are chiefly developed in connection with coal 
 seams. 
 
 2.01.28. Example 3. Clay Ironstone. — The name is applied to 
 isolated masses of concretionary origin (kidneys, balls, etc.) which 
 may at time coalesce to form beds of considerable extent. They 
 are usually distributed through shales, and on the weathering of 
 the matrix are exposed and concentrated. They are especially 
 
96 KEMP'S ORE DEPOSITS. 
 
 characteristic of Carboniferous strata and differ from black-band 
 only in the absence of bituminous matter and in the consequent 
 drab color. They -weather to limonite, generally in concentric shells 
 with a core of unchanged carbonate within. Fossil leaves or shells 
 often furnish the nucleus for the original concretion, and are thus, 
 as at Mazon Creek, 111., beautifully preserved. When in beds the 
 ore is sometimes called flagstone ore; when broken into rectangular 
 masses by joints, it is called block ore. 
 
 2.01.29. Example 3a. Black-hand. — The name is applied to 
 beds consisting chiefly of carbonate of iron with more or less earthy 
 and bituminous matter. They are of varying thickness, though 
 rarely more than six feet, and are almost invariably associated 
 with coal seams. They are thus especially found in the Carbonif- 
 erous system, and to a far less degree in the eastern Jura-Trias. 
 They are also recorded with the Cretaceous coals of the West. It 
 is not possible to separate the two varieties in discussing their dis- 
 tribution. The various productive areas are taken up geograph- 
 ically, beginning with the Appalachian region. 
 
 2.01.30. The carbonate ores are of great importance in the 
 Carboniferous of western Pennsylvania and in the adjacent parts of 
 Ohio, West Virginia, and Kentucky. In these States the system is 
 subdivided in connection with the coal, from above downward, as 
 follows : I. The Upper Barren Measures, Permo-Carboniferous, or 
 Dunkard's Creek Series ; II. The Upper Productive Coal Meas- 
 ures, or Monongahela River Series ; III. The Lower Barren Meas- 
 ures, or Elk River Series ; IV. The Lower Productive Coal 
 Measures, or Alleghany River Series ; V. The Great or Pottsville 
 Conglomerate. In the Upper Barren Measures of Pennsylvania, 
 according to McCreath, there is hardly a stratum of shale or sand- 
 stone without clay ironstone nodules, but no continuous beds are 
 known.^ The deposits are not of great actual importance, and are 
 worthy of only passing mention. In the Upper Productive Coal 
 Measures some ore occurs associated with the Waynesburg Coal 
 seam, and again, just under the Pittsburg seam, there is consider- 
 able known as the Pittsburg Iron Ore Group. This latter ore be- 
 comes of great importance in Fayette County and extends through 
 several beds.^ The Lower Barren Measures in Pennsylvania also 
 contain carbonate ore in a number of localities. The most per- 
 
 1 Second Penn. Survey, Rep. K, p. 386 ; MM, p. 159. 
 
 2 Rep. MM, p. 162 ; KK, p. Ill ; L, p. 98. 
 
THE IRON SKllIKH (/.V PATIT.) 07 
 
 sistent is the Johnstown ore bed, near the base of the series. There 
 are two additional beds just over the Mahoning sandstone. 
 
 The Lower Coal Measures are the chief ore producers in all the 
 States. They furnish balls of clay ironstone in very many localities 
 in western Pennsylvania, which will be found recorded with many 
 additional references in Report MM, p. 174, Penn. Geol. Survey. 
 The nodules are scattered through clay and shales. The so-called 
 Ferriferous Limestone, which lies a few feet below the Lower Kit- 
 taning Coal Seam, affords in its upper portion varying thicknesses 
 of carbonate ore, known as " buhrstone ore," which is altered in 
 large part to limonite. Some little carbonate ore was found in 
 the early days in the anthracite measures of eastern Pennsylvania. 
 Several beds of the same occur in the Great Conglomerate and 
 its underlying (Mauch Chunk) shales. They are chiefly developed 
 in southwestern Pennsylvania (Report KK), and may form either 
 entire beds or disseminated nodules. The limonites of the Mar- 
 cellus stage that pass into carbonate in depth in Perry and the 
 neighboring counties have already been mentioned under Example 
 2. In West Virginia both Upper and Lower Measures afford the 
 ore. From the latter black-band is extensively mined on Davis 
 Creek, near Charleston.' 
 
 2.01.31. In Ohio a number of nodular deposits are known, but 
 practically no ore is produced above the Mahoning sandstone of 
 the Lower Coal Measures. Below this sandstone the ores are ex- 
 tensively developed. They extend up and down the eastern part 
 of the State and are both black-band and clay ironstone. Orton 
 identifies twelve different and well-marked horizons distributed 
 through the Lower Measures. He distinguishes the stratified ores 
 mostly black-band, and the concretionary ores, including kidney 
 ores, block ores, and limestone ores.^ 
 
 2.01.32. The general distribution of the iron ores of Kentucky 
 has already been outlined under Example 2. The Hanging Rock 
 region is a southern prolongation of the Ohio district of the same 
 geological horizon. P. N. Moore has classified the local ores as 
 limestone ores which are associated with limestone, block ores, and 
 kidney ores. The last two names refer to the fracture or shape of 
 
 1 M. F. Maury and W. M. Fontaine, Resources of West Virginia, 1876, 
 p. 247. 
 
 ^ Oeol. of Ohio, V., p. 378, and supplemental report on the Hanging 
 Rock region in Vol. III. 
 
98 KEMP'S ORE DEPOSITS. 
 
 the masses. They occur associated with the usual clay and shale. 
 Farther west, between the Kentucky and Red rivers, are the 
 other deposits, the principal one of which comes low in the series, 
 just over the Subcarboniferous limestone.' 
 
 2.01.33. Small quantities of black-band have been found in the 
 Deep River coal beds, in North Carolina, associated with the Tri- 
 assic coals.^ 
 
 A large bed, or series of beds, has recently been reported from 
 Entei'priee, Miss., in strata of the Claiborne stage. They run from 
 ten to eighteen feet in thickness and extend for miles.' Scattered 
 nodules have been noted at Gay Head, Martha's Vineyard.* Car- 
 bonate ores are as yet of no importance in the coal measures of the 
 Mississippi Valley. They have been found associated with the 
 Cretaceous coals of Wyoming and Colorado, — and indeed the first 
 pig iron of the latter State was made from them in' Boulder 
 County, — but they are not an important source of ore.^ An ex- 
 tended bed of very excellent carbonate has recently been discov- 
 ered with coal near Great Falls, in the Sand Coulee region of 
 Montana. Being near coal, limestone, and other iron ores, it prom- 
 ises to be of considerable importance.^ 
 
 2.01.34. Example 4. Burden Mines, near Hudson, K Y. 
 Elongated lenticular beds of clay ironstone, passing into sub- 
 crystalline siderite, inclosed conformably between underlying slates, 
 and overlying calcareous sandstone, of the Hudson River stage. 
 The ore occurs in four "basins," which outcrop along the western 
 slope of a series of moderate hills, just east of the Hudson Riv- 
 er. The hills have been shown by Kimball to be the eastern 
 halves of anticlinal folds now reduced by erosion to easterly dip- 
 ping monoclines. The western half of the ore bodies has been 
 eroded away, leaving an outcrop forty-four feet thick as a maxi- 
 mum, which pinches out along the strike and dip. The basins ex- 
 
 1 P. N. Moore, "On the Hangdog Rock District ia Kentucky,'' Ken- 
 tucky Geol. Survey, Vol. I., Part 3. 
 
 « B. WillU, Tenth Census, Vol. XV., p. 306 ; W. C. Kerr, Geology of 
 North Carolina, 1875, p. 225. 
 
 5 A. F. Brainard, " Spathic Ore at Enterprise, Miss.," M. E.,XIV. U6. 
 
 * W. P. Blake, "Notes on the Occurrence of Siderite at Gay Head, 
 Mass.," 31. E., IV. 112. 
 
 = R. Chauvenet, " Notes on the Iron Resources of Colorado," Ann. 
 Rep. Colo. School of Mines, 1885, 1886 ; Trans. Amer. Inst. Min. Eng.. 
 Colorado meeting, 1889. 
 
 " O. C. MortsoD, Mineral Resources V. S., 1888, p. 34. 
 
THE IRON 8BRIE8 {IN PART.) 
 
 99 
 
 tend from southwest to northeast, parallel to the trend of the hills. 
 The beds are more or less faulted. The southern part of the second 
 basin affords Bessemer ores, but the others are too high in phos- 
 phorus. At this point the principal mining has been done. Ac- 
 
 cording to Olmstead, some varieties are richer in phosphorus than 
 others, but they are so intimately mixed as not to be practicably 
 separated. Up to 1889 the mines had produced 450,000 tons of 
 roasted Bessemer ores. 
 
■^QQ KEMP '8 OltE DEPOSITS. 
 
 2.01.35. In their geological relations the ores are of the greatest 
 interest, as they occur on the western limit of the metamorphic belt, 
 which forms the basis of the Taconic controversy, yet in strata 
 which have been identified by fossils. Beds of limonite hitherto 
 regarded as Slluro-Cambrian occur to the east ; and should further 
 study, on the lines developed chiefly by J. D. Dana, W. B. Dwight, 
 and C. D. AValcott, clear up their stratigraphical relations, the 
 woi-k done in developing the structure of the siderite basins, as 
 pointed out by Kimball, may be of great aid in explaining them. 
 Very similar bodies of siderite occur with these limonites. (Ex- 
 ample 2a.) The Burden ores are relatively high in magnesia, and 
 this leads Kimball to suggest their original deposition from the 
 ofE-shore drainage of the basic rocks of the Archean highlands. 
 Further, it may be added that the ores in their lenticular 
 shape are highly suggestive of a possible origin for magnetite de- 
 posits, and they are again referred to under " Magnetite." Other 
 deposits of siderite in the shales of the Marcellus stage are known 
 and were formerly worked at Wawarsing, Ulster County, across 
 the Hudson River.^ 
 
 2.01.36. Examples. Eoxbnry, Conn. A fissure vein in gneiss, 
 six to eight feet wide, of crystalline siderite, with which are as- 
 sociated quartz and a variety of metallic sulphides, galena, chal- 
 copyrite, zincblende, etc. Although productive in former years, it 
 is no longer worked, and is of scientific more than economic inter- 
 est, being a unique deposit. It has furnished many fine cabinet 
 specimens.^ 
 
 2.01.37. The spathic ores are the lowest in iron of all, and in 
 the raw state are often, if not always, far below the limit of profita- 
 ble treatment. Calcination, however, drives ofE the carbonic acid 
 and moisture and brings the percentage of iron up to a merchant- 
 able grade. The later development of the iron industry in this 
 country has been unfavorable to spathic ores, and year by year 
 their amount has decreased until now it is nearly obliterated, being 
 about one per cent, of the total. 
 
 1 J. P. Kimball, " Siderite Basins of the Hudson River Epoch," 4mer. 
 Jour. Sai., III., xl. 155. I. Olmstead, " Distribution of Phosphoius in the 
 Hudson River Carbonate," M. E., 1889. R. W. Raymond, "The Spathic 
 Ores of the Hudson River," 31. E., IV. 309. J. C. Smock, Bulletin of New 
 York State Muxeum on Iron Ores, p. 62. 
 
 = J. P. Lesley, Iron Manufacturers' Guide, p. 649. C. U. Shepherd, 
 " Report on the Geology of ConDecticut," 1837, p. 30, Amer. Jour. Sei., I,, 
 xix. 811. 
 
THE IRON SEJiTES (IN PART.) 101 
 
 3.01.38. The subjects of limonibe ami siderite cannot well be 
 passed without further reference to their genetic relations as con- 
 nected with limestone. Tiie processes involved concern not alone 
 these ores, but also the more metamorphic forms — hematite and 
 magnetite — into which they may pass by reason of subsequent 
 changes. It was stated earlier (3.01.05) that calcium carbonate 
 precipitated from ferric salts, ferric hydrate, and from ferrous salts, 
 ferrous carbonate, which in the presence of oxygen quickly changed 
 to ferric hydrate. J. P. Kimball ^ has recently added a note on 
 the chemistry of the process which modifies it somewhat. He 
 brings out tlie fact that it is the hydrous carbonate of iron which 
 is precipitated from ferruginous salts by the various alkaline car- 
 bonates, and that, being an unstable salt, it quickly oxidizes to a 
 hydrous oxide. From this the argument is made that bodies of 
 siderite, or anhydrous ferrous carbonate, could not have originated 
 by direct precipitation, but must have done so by pseudomorphous 
 replacement of limestone. Dr. Kimball then follows out the pos- 
 sible metamorphism or changes of these bodies to other forms of 
 iron ore, citing, however, among many that are unexceptionable, 
 some instances as possible examples for which the field relations give 
 but slight justification. The specular ores with tlie porphyries of 
 Missouri are of this latter cliaracter, and the work of C. H. 
 Smyth, Jr., later cited, on the oolitic Clinton hematites gives strong 
 ground for thinking them accumulations in shallow waters as con- 
 centric layers upon original nuclei of quartz. 
 
 3.01.39. While the importance of limestone as a cause 
 of the formation of bodies of iron ore cannot be too highly 
 emphasized, and it is quite possible that some puzzling ones, such 
 as many magnetite beds, have originated in this way and that the 
 limestone has so entirely disappeared as to give slight clue to its 
 original presence; yet it must not be overlooked that siderite 
 often does form in nature quite independently of calcite, and that 
 conditions must be often such as to make this possible. If vuggs 
 with free crystals, or if cleavage masses with the proper angle occur 
 ill a deposit, we must admit that the siderite is produced under 
 circumstances not different from those which prevailed during the 
 formation of the walls or of the massive mineral. Repeated ex- 
 perience indicates that tiiese are not extraordinary. 
 
 ' J. P. Kimball , ' ' Genesis of Iron Ores by Isomorphous and Pseu- 
 domorphous Replacement of Limestone," Amer. Jour. 8ui., Sept., 1891. 
 p. 231, and conclusion in the Amer. Geol , Dec, 1891. 
 
CHAPTER IL 
 
 THE IRON SERIES CONTINUED.— HEMATITE, BED AND 
 SPECULAR. 
 
 2.02.01. The sesquioxide of iron, F2O3, is always of a red 
 color when in powder. If it is of earthy texture, this color shows 
 in the mass, and the ore is called red hematite ; if the ore is 
 ■crystallized, the red color is not apparent, and the brilliant luster of 
 the mineral gives it the name specular hematite. The red hematites 
 are first treated. 
 
 2.02.02. Example 6. Clinton Ore. — Wherever the Clinton 
 ■ stage of the Upper Silurian outcrops, it almost invariably contains 
 one or more beds of red hematite, interstratified with the shales 
 and limestones. These ores are of extraordinary persistence, as 
 ■they outcrop in Wisconsin, Ohio, and Kentucky in the interior, and 
 then beginning in New York, south of Lake Ontario, they run 
 easterly across the State. Again in Pennsylvania they follow the 
 waves of the Appalachian folds, and extend south into West 
 Virginia and Virginia in great strength. They are found in east- 
 ern Tennessee and northwestern Georgia, and finally in Alabama are 
 of exceptional size and importance. The structure of the ore varies 
 somewhat. At times it is a replacement of fossils, such as crinoid 
 stems, molluscan remains, etc. (fossil ore) ; again as small oolitic 
 concretions, like flaxseed (flaxseed ore, oolitic ore, lenticular ore) ; 
 while elsewhere it is known as dyestone ore. The ore in many 
 places is really a highly ferruginous limestone, and below the 
 water level in the unaltered portion it often passes into limestone, 
 while along the outcrop it is quite rich. 
 
 2.02.03. In Dodge County, southeastern AVisconsin, the ore is 
 14 to 26 feet thick and consists of an aggregate of small len- 
 ticular grains.^ In Ohio it outcrops in Clinton, Highland, and 
 
 1 T. C. Cbamberlin, Geol. Survey Wis., Vol. I., p. 179. R. D. Irving, 
 " Mineral Resources of Wisconsin," M. E., VIII. 478; Oeol. Survey Wis., 
 Vol. I., p. 62^5, 
 
THE IRON SERIES CONTINUED. 
 
 103 
 
 Adams counties, in the southwestern portion of the State along the 
 flanks of the Cincinnati Arch, but it is thin and poor in iron, al- 
 though rich in fossils.' A small area of the Clinton has furnished 
 considerable ore in Bath County, Kentucky, where it is altered to 
 limonite.'' 
 
 2.02.04. Coming eastward, the limestones and the shales of the 
 Clinton outcrop in the Niagara River gorge in New York, but show 
 no ore. This appears first in quantity in "Wayne County, a hundred 
 miles east and just south of Lake Ontario. One bed reaches 20 to 
 22 inches. Farther east are the Sterling mines, in Cayuga County ; 
 and again near Utica, in the town of Clinton, which first gave the 
 ore its name, it is of great economic importance. There are two 
 
 Fig. 13. — Clinton Ore, Ontario, Wayne County, New York. After 
 C. H. Smyth, Jr. 
 
 workable beds, the upper of which, with a thickness of about two 
 feet, is the only one now exploited. Beneath this are 12 or 15 
 inches of shale, and then the second bed of 8 inches of ore.' Some 
 25 feet over the upper bed is still a third, which is too low grade 
 for mining. It is four to six feet thick, and is locally called red 
 flux. It consists of pebbles and irregular fragments of fossils, 
 which are coated with hematite and cemented with calcite. 
 
 2.02.05. The rooks of the Clinton thicken greatly in Pennsyl- 
 vania and run southwestwai'd through the central part of the State. 
 
 1 J. S. Newberry, Geol. of Ohio, Vol. III., p. 7. E. Orton, Geol. of 
 Ohio, Vol. v., p. 371. 
 
 2 N. S. Shaler, Geol. of Ky., Vo\ III., 163. 
 
 ° A. H. Cliestt^r, "The Iron Rpg-lon of Ceotral New York;" address 
 before the Utica Merchants and Munufacturt'is' Association, Utica, 1881. 
 J. C. Smock, Bull, of N. Y. State Museum. C. H. Smyth, Jr., "On the 
 Clinton Iron Ore," Amer. Jour. Sci., June, 1893, p. 487. 
 
104 
 
 KEMP'S ORE DEPOSITS. 
 
 Six different ore beds have been recognized, of which the lower are 
 probably equivalent to the southern dyestone ores.^ 
 
 The ores are of chief importance in the Juniata district. The 
 belt extends southwestward across Maryland and eastern West 
 Virginia, where the beds are quite thick, although as yet not much 
 developed, and appears in the extreme southwest comer of Virginia. 
 Thence it runs across eastern Tennessee, and is of very great im- 
 
 ■<,;.|-..-.;.~ 
 
 
 ^■G^.^ 
 
 - 1 ' 
 
 ' " ' *~( 
 
 
 
 •ij --1 
 
 ~-'~T T"' , ■ 
 
 ?^ 
 
 -. ...- ^ . — ^ 
 
 
 
 r?iE 
 
 .' • ' •- 
 
 = 
 
 — 
 
 
 
 Calcareous Sandstone 
 
 and f 
 
 thin Shale layers T'O- 
 
 Non-Oolitic Ore / 
 (Red Flux) 6 
 
 Calcareous r 
 Sandstone 6 
 
 Blue Shale 
 
 and thin , 
 
 Sandstone layers 15' 
 
 Oolitic Ore 2 
 
 Shale 2' , 
 
 Oolitic Ore 1 
 _ Blue Shale 
 — I and thi.n , 
 
 Sandstone layers TOO i 
 
 Fig. li.— Clinton Ore, Clinton, New York, After C. H. Smyth, Jr. 
 
 portance. The lines of outcrop are known as "dyestone ranges." 
 Tbey lie west of the Siluro-Cambrian limestones (Example 2a) and 
 in the edges of the Cumberland tableland. Four or five are 
 known, of which the largest extends across the State. This ore is 
 
 1 J. H. Dewees, "Fossil Ores of the Juniata Valley," Penn. Geol. 
 Survey, Rep. F. E. d'Invilliers, Ibid., Eep. F3 (Union, Snyder, Mifflin, 
 and Juniata counties). A. S. McCreath, Ibid., Rep. MM, p. 231. J. J. 
 Stevenson, Ibid., Reps. MM and T3 (Bedford and Fulton counties). I. C. 
 White, Ibid., Reps. MM and T3 (Huntington Counts'). H. H. Stoek, "Ores 
 at Danville, Montour County," M. E., October, 1891. 
 
THE IRON SERIES CONTINUED. 
 
 105 
 
 more fossiliferous toward the south and more oolitic toward the 
 north. It is very productive in the Chattanooga region.' 
 
 2.02.06. The Clinton just appears in northwestern Georgia, and 
 continues thence into Alabama, where it is again of great importance, 
 
 Flc. 15. — Clinton Ore, Eureka Mine, Oxmoor, Ala. After C. H. Smyth, Jr. 
 
 and, with the less productive Siluro-Cambrian limonites, furnishes 
 practically all the ore of the State. The outcrop can be traced 
 almost continuously for 130 miles. The ore is rich in fossils and 
 occurs in several beds, which, although averaging much less, may 
 
 Fig. 16. — Cross section of the Sloss Mine, Red Mountain, Ala. 
 
 aggregate, as at the Eureka furnace, as much as 34 to 37 feet. The 
 chief mines are in Red Mountain, a northeast and southwest ridge, 
 east and south of Birmingham. Folds and faults have brought the 
 beds into close proximity with the coal and limestone of the 
 region, and thus into a position very favorable for economic 
 working.' 
 
 1 Killebrew and Safford, Resources of Tennessee. E. C. Pecliin, "The 
 Iron Ores of Virginia," etc., M. E., XIX. 1016. ,1. B. Porter, " Iron Ores, 
 Coal, etc., in Alabama, Georgia, and Tennessee," M. E., XV. 170. J. M. 
 Safford, 6leol. of Tenn. P. N. Moore, Virginias, May, 1880, p. 78. 
 
 2 A. F. Brainerd, ' ' On the ' Iron Ores, Fuels, etc. , of Birmingham, 
 
Fig. 17. — Maj> of the Vicinity of Birmingham, Ala. From the Transac- 
 tions of the American Institute of Mining Engineers, Vol. XIX., " 
 
 Plate IV. 
 
THE IRON SEItlKS, CONTINUED. 107 
 
 The accompanying map, Fig. 17, illustrates tlie geography and 
 ecoiioniic geology of the Birmingham district. In explanation it 
 may be said, that the three coal fields, the Warrior, the Cahaba^ 
 and the Coosa, make three elevated basins formed in part by 
 synclinal foldings and in f)art by faulting. The intervening strips 
 are relatively depressed and constitute the so-called valleys, each of 
 which has its own name. Thus there is a long valley in which 
 Birmingham is situated and which forks at the northeast corner of 
 the map. The central portion of it consists of Cambrian and 
 Lower Silurian rocks, Avhich yield brown hematite ores, as indicated 
 on the map. They, liowever, are a minor feature and do not form 
 over 10 per cent, of the total furnace supply. On each side of the 
 valley there is a ridge called Eed Mountain, mostly formed by 
 Clinton strata, with Trenton limestone beneath and black Devonian 
 shale above. The Clinton reaches a thickness of 150 feet, but is 
 quite variable in character. It may contain as many as five or 
 more beds of ore of differing thickness and somewhat contrasted 
 composition and structure. The best of these are worked. The 
 Clinton beds in Eed Mountain dip on each side away from the 
 centre of the valley, and really are the remains of an anticline 
 eroded at its crest. The anticline is of the usual Appalachian type 
 with steeper dips on one flank (in this case the northwestern) than 
 on the other, and the crest is nearer the northwest side than the 
 northeast. The dip at one important mine is shown in Fig. 15. 
 The most productive points are east and south of Birming- 
 ham, and along this line the largest mines are situated. The ore 
 is chiefly won by open cuts, and is laid bare by stripping off the 
 hanging. Curiously enough, for an ore in the midst of limestone 
 and limey shales, it is prevailingly silicious, so that non-silicious or 
 calcareous varieties are much sought for mixtures. The red hema- 
 tites are also exposed in Murphrees Valley and are developed in 
 some large and productive openings. While on the west this valley 
 has the normal anticlinal flank, it is faulted along the east so that 
 the Clinton measures lie against the Cambrian shales and are over- 
 thrown to a steep northwesterly dip. 
 
 Ala.," Jtf. ^., XVII. 151. "The Sloss Iron Ore Mines," Engineering 
 and Mining Journal, Oct. 1, 1893, p. 318. T. S. Hunt, "Coal and Iron 
 in Alabama," M. E.,X1. 236. J. B. Porter, "Iron Ores, Coal, etc., in 
 Alabama, Georgia, and Tennessee," M. E., XV. 170. E. A. Smith, 
 Alabama Geol. Survey, 1876 ; also A. A. A. S., XXVII, 346. 
 
 1 A detailed description of the Cahaba field, with a large geological 
 
108 THE IRON SERIES, CONTINUED. 
 
 2.02.07. Red hematite, supposed to be of the Clinton stage, oc- 
 curs in Nova Scotia in very considerable amount, in Pictou and 
 Antigonish counties.* 
 
 2.02.08. In general the Clinton ore is characterized by a high 
 percentage of phosphorus, and is seldom, if ever, available for Bes- 
 semer pig. It is chiefljr employed for ordinary foundry irons. The 
 percentage in iron varies much. Experience at Clinton, N. Y., 
 shows that it averages about 44^ Fe in the furnace. These hema- 
 tites have undoubtedly originated in some cases by the weathering 
 of ferruginous limestones above the water level. I. C. Russell has 
 shown that the unaltered limestones at the bottom of a mine in 
 Atalla, Ala., 250 feet from the surface, contained but 7.75^ Fe, 
 while the outcrop afforded 57.52^. J. B. Porter has recorded the 
 gradual increase of lime also in another Alabama mine, from a 
 trace at the outcrop to 30.55^ at 135 feet. Other writers have ex- 
 plained these beds as due to the bringing of iron in solution into 
 the sea of the Clinton age and to its deposition as small nodules, 
 etc., or as ferruginous mud. (Roger, Lesley, Newberry.) In this 
 way an oolitic mass has originated, as in the modern Swedish 
 lakes (Newberry). (See Example 1.) N. S. Shaler has argued, on 
 the basis of the Kentucky beds, that the iron has been derived from 
 the overlying shales, and descending in solution has been precipi- 
 tated by the lower lying limestones. As the shales are themselves 
 calcareous, this seems improbable. A. F. Foerste has shown that 
 the ore is very often deposited either in the interstices of frag- 
 ments of bryozoans or as replacing their substance. The rounded, 
 water-worn character of the original fragments is regarded as oc- 
 casioning the apparent concretionary character. Admirable work 
 upon the origin of the ore has also been done by C. IT. Smyth, 
 Jr. He finds that the small oolites, or concretions, as they occur 
 at Clinton, N. Y., and many other localities, have a water-worn 
 grain of quartz as a nucleus. The character of the grain is such 
 that it has evidently been derived from granitoid or schistose 
 rocks. The hematite comes off at times in concentric layers, when 
 
 map of it and the Birmingham valley was issued in 1890 by the Ala. 
 Qeol. Survey, entitled " Report on the Cahaha Coal-Field by Joseph 
 Squire. " A. M. Gibson, ' ' Report on the Geological Structure of Mur- 
 phrees Valley, " Ala. Geol. Survey, 1893. 
 
 1 Sir J. W. Dawson, Acadian Geology, p. 591. Fletcher, Can. Geol. 
 Survey, 1886. 
 
KEMPS ORE DEPOSITS. 109 
 
 tapped gently. It la^y also be dissolved away bo as to leave a 
 siliceous cast or skeleton of the spherule. Dr. Smyth thus makes a 
 strong argument that the ores in such cases are concretionary, and 
 that they were formed in shallow waters around the nuclei of sand. 
 But he also admits, as others quoted above have indicated, that the 
 replacement of bryozoa and the weathering of ferruginous lime- 
 stone have in many localities played their part. The iron ore is in 
 the latter case a residual product, but now the mine waters are de- 
 positing calcium carbonate rather than removing it.^ 
 
 2.02.09. Glenmore Estate, Greenbrier County,West Virginia. A 
 bed of red hematite in Oriskany sandstones. Limonites are abundant 
 in the Orisk.any of Virginia, and the hematite may have been de- 
 rived from such ^ or vice versa. 
 
 2.02.10. Mansfield Ores, Tioga County, Pennsylvania. Three 
 beds of ore are found in the strata of the Chemung stage of Tioga 
 County, Pennsylvania. They are known as the (1) Upper or Spi- 
 rifer Bed, (2) the Middle or Fish Bed, and (3) the Lower Ore Bed. 
 No. 1 is full of shells and is about 200 feet below the Catskill red 
 sandstones, and at Mansfield is two to three feet thick. No. 2 is 
 oolitic, resembles the Clinton ore, and affords fish remains. It lies 
 about 200 feet below No. 1 and varies up to six or seven feet thick. 
 No. 3 is 100 to 200 feet lower, and contains small quartz pebbles.' 
 The ore is not rich, and but little has been mined. It is a brown- 
 ish red hematite.' 
 
 2.02.11. Beds of red hematite are reported by Schmidt in the 
 Lower Carboniferous of western central Missouri.* 
 
 1 A. F. Foerste, "Clinton Group Fossils, with Speciul Reference to 
 Collections from Indiana, Tennessee, and Georgia," Amer. Jour. Sci., iii., 
 XL. 252. (Abstract; original not cited.) " Clinton Oolilio I onOres," ^mer. 
 Jour. Sci, iii.,XLI.28. Rec. " Notes on Clinton Group Fossils, with Spe- 
 cial Reference to Collections from Maryland, Tennessee, and Georgia, "Proc. 
 Bast. Soc. Nat. Hist., XXIV. 263. J. P. Lesley, Iron Manufacturers' 
 Guide, p. 611. J. S. Ne wberr^', "Genesis of the Ores cf Iron ," School of Mines 
 Quarterly, November, 1880, p. 18. Rec. H. D. Rogers, Geol. of Penn., 
 Vol. n., p. 127. N. S. Shaler, Geol. ofKy.,Yo\. III., p. 163, C. H. Smyth, 
 Jr., " On the Clinton Iron Ore,'' Amer. Jour. Sci., June, 1892. p. 487. Rec. 
 
 2 W. N. Page, "The Glenmore Iron Estate, Greenbrier County, West 
 Virginia," M. E., XVII. 115. 
 
 * A. S. McCreath, Rep. MM, Second Penn. Survey, p. 831. 
 
 * J. P. Lesley, Geol.of Penn., 1888, Vol. I., p. 811. A. Sherwood, Rep. 
 G, Second Penn. Survey, pp. 83, 87, 41, 42, 67. A. S. McCreath, Rep. MM, 
 Second Penn. Survey, p. 351. 
 
 "> A. Schmidt, " Iron Ores and Coal Fields," Missouri Geol. Survey, 
 1873, p. 169. P. L, Nason. ' ' Iron Ores of Missouri, ' ' Idem, pp. 70-83. 
 
110 
 
 KEMP'S OIIE DEPOSITS. 
 
 2.02.12. Example 7. Crawford County, Missouri. Bodies of 
 finely ei-ystalliue specular hematite, associated with chert, sand- 
 stone fi'agments, residual clays and some pyiite, in couical or 
 rudely cylindrical depressions in the Cambrian (Ozark) Series. A 
 broad area of upheaval runs across central Missouri from the east, 
 near St. Louis, to the southwestern part of the State. lu theeastern 
 and central portions it is chiefly composed of Cambrian and Silurian 
 strata, but to the southwest Lower Carboniferous come in (see 
 2.0C.06). The hematites here consiiiered belong in the Cambrian. 
 Li the region of the mines there is a heavy sandstone stratum, 
 earlier called the " Second Sandstone," but in the later i-eports de- 
 scribed as the Roubidoux. It is underlaid by a heavy limestone 
 stratum locally called the Gasconade. The Ozark uplift was 
 foi'med at the close of the L-ower Carboniferous and has remained 
 exposed to atmospheric agencies ever since. Their effects are 
 
 
 --a 
 
 V 
 
 
 .. -:'^f.,'»ZA.-. ...,i-7-..-r:S^.^: 
 
 Fig 1^ — ] II 11 Hi ( Ii III/ T ill ii l/m \li n nuj sini<hti)ne inth >i/ide)- 
 
 li/niij ihiiti/ iluij Ihf ■^lUKhtoUL dijii wut/iea^t iiniaid 
 
 tmvaril the ore. After F. L. Na.mn, Kept, on 
 
 Iron Oi-e.'iofJIis.iuuri, p. 125. Plate YI. 
 
 shown in the great mantles of residual clay, which are widely dis- 
 tributed, and m the phenomena of the hematite deposits. Dr. A. 
 Schmidt of the Missouri Survey of 1872 (Ueport on "L'on Ores," 
 p. (16) thought that these had replacetl pre-existing rock, or had 
 been deposited in hollows in the then existing surface. Pumpelly, 
 however, in 1885 {Tenth Census, Vol. XV., p. 12) advanced a more 
 probable hypothesis, which is strongly supported by F. L. Xason. 
 The region is and has long been one of sink-holes caused by sub- 
 
THE IRON SERIES, CONTINUED. 
 
 Ill 
 
 terranean drainage through the Gasconade limestone and the cav- 
 ing in, at times, of the overlying sandstone. Cavities were thus 
 afforded in which ferruginous waters might stand and precipitate 
 their dissolved burden of ore. Nason shows that several of the larg- 
 est mines are along lines of old drainage valleys. The edges or 
 walls of the pits are formed by the sandstone which dips inward, 
 as shown in the accompanying figures. Just how much overlying 
 
 Fig. 19. — Section of the northern end of the Cherry Valley Mine. 1, Clay 
 detritus; 2, Sandstone; 3, Cherty and slaty clay; 4, Ore; 5, 
 Blocks of sandstone. After F. L. Nason, Re- 
 port on Iron Ores of Missouri, p. 131. 
 
 Fig. 30. — Cross section of the Cherry Valley Mine. 1, Sandstone; 2, Clay 
 
 and chert; 8, Sandstone dipping inward; 4, Magnesian 
 
 limestone. After F. L. Nason, Report on the 
 
 Iron Ores of Missouri, p. 134. 
 
 rock has washed away does not appear with all desirable certainty, 
 but the presence of large amounts of chert mixed with the ore in- 
 dicates that the cap must have been to a great extent limestone 
 with interbedded layers of this rock. As Nason states ("Iron 
 Ores of Missouri," p. 138) the limestone that fell into the cavities 
 has been replaced witli ore. It is very probable that the former 
 was an important precipitating agent to the latter. A fossil crinoid 
 was found at Cherry Valley, replaced by hematite, giving evidence 
 that even Lower Carboniferous strata had been present. The 
 leaching of these old, overlying beds and the superficial drainage 
 seem to indicate the method of derivation of the ore. 
 
 The most productive counties are Crawford, Phelps and Dent, 
 
] 13 KEMP 'S OR E DEPOSITS. 
 
 but smaller deposits occur in several others. The largest mines 
 are the Cherry Valley, with a total product of over half a million 
 tons, the Simmons Mountain, which has yielded about half as 
 much and the Meramec with three hundred and seventy-five thou- 
 sand. 
 
 The total product of all the mines is computed by Nason at 
 about two and one-quarter millions of tons. A sample from a 
 stockpile made up at St. Louis furnaces from several mines, 
 yielded Fe 56.43, P. 0.065 (Nason, I.e. p. 157) but many are much 
 lower in iron. In former years 100,000 to 200,000 tons were an- 
 nually produced; recently, however, much less. Some anomalous 
 features are presented by these ores in that they are specular 
 hematite in a practically unmetamorphosed sandstone, whereas 
 some less crystalline form would naturally be expected. Nason be- 
 lieves that they were originally sulphides and that the heat 
 generated by the decomposition of this mineral has afEected the 
 change to specular.^ 
 
 3.02.13. Example 8. Jefferson County, New York. Large 
 but irregular bodies of red hematite associated with crystalline 
 limestone, serpentine, and pyritous gneiss and overlain by Pots- 
 dam sandstone. The crystalline limestone is certainly pre-Cam- 
 brian, and would be called Algonkian in the later use of this term, 
 and later Laurentian in the earlier nomenclature.^ In a forthcom- 
 ing report to James Hall, State Geologist, C. H. Smyth, Jr., has 
 named the limestone series the Oswegatchie. The ore bodies 
 occur along a northeast belt, from Philadelphia, Jefferson County, 
 to Gouverneur, St. Lawrence County. They range up to 30 or 40 
 feet in thickness and consists of red, earthy hematite in porous or 
 cellular masses, with some specular. Many interesting minei-als, 
 including siderite, millerite, chalcodite, quartz, etc., are found in 
 cavities. The alignment of the mines along a marked belt has 
 given some ground for thinking them interbedded deposits, and 
 their association with Potsdam sandstone has created the impres- 
 
 1 "W. M. Chauvenet, Tenth Census, Vol. XV., 1885, p. 403. F. L. 
 Nason, " Report on Iron Ores," pp. 119-156, 218-331. Missouri Geol. 
 Survey, 1893. Rec. R. PumpeUy "On Origin," Tenth Census, Vol. 
 XVI. , p. 13. Rec. A. Schmidt, ' 'Iron Ores and Coal Fields, ' ' Missouri 
 Geol. Survey, 1872, p. 124. 
 
 2 C. H. Smyth, Jr. , " Geological Reconnaissance in the Vicinity of 
 Grouverneur, N. Y.," Trans. N. Y. Acad. ScL, XII. 97, 1893. 
 
THE IRON 8EB1E8, CONTINUED. 113 
 
 sion that they are of Cambrian (or, as it was then called, Lower 
 Silurian) age.' J. P. Kimball has stated that they are replace- 
 ments of Calciferous limestone.' E. Emmons in the "Eeport on 
 the Second District in the early New York Survey," regarded the 
 associated crystalline limestone as an intruded igneous mass, and 
 the same method of origin was applied to the ores and accompany- 
 ing serpentine. The latter was called Rensselaerite by Emmons. 
 Brooks gave the following section, taken at the Caledonia Mine: 
 1. Potsdam sandstone, 40 feet. 2. Hematites, 40 feet. 3. Soft, 
 schistose, slaty, green, magnesian rock with pyrite and graphite, 
 90 feet plus. 4. Granular, crystalline limestone, with phlogopite 
 and graphite. 5. Sandstone (like 1), 15 feet. 6. Crystalline lime- 
 stone with beds and veins of granite. 0. H. Smyth, Jr., has re- 
 corded the stratigraphical observations, cited earlier, and has form- 
 ulated the following explanation of origin. Tiie lineal arrange- 
 ment of the ore-bodies is referred to their association with a great 
 stratum of pyritous gneiss belonging to the Oswegatchie Series. 
 This weathers deeply and becomes light and porous (constituting 
 thus a "fahlband.") It contains considerable disseminated 
 magnetite. The so-called serpentine or rensselaerite only occurs iu 
 association with ore and itself v_ries in chariicter, so that one is 
 justified in regarding it as an ttltered form of several different 
 kinds of rocks. Smyth infers that the decay of the ferruginous 
 minerals, but especially of pyrite in the pyritous gneiss, has fur- 
 nished the iron-bearing sdlutions, which following down the dip 
 have replaced the crystalline limestone where the presence of in- 
 tended granites or the flattening of the dip checked the circula- 
 tions. The action of the acidulated ferruginous waters has altered 
 the granites and gneisses in the limestone series to the so-called 
 serpentine.' 
 
 These views are fortified by microscopic study of the rocks, 
 
 1 See T. B. Brooks, Amer. Jour. Sci. iii. , TV. 23. 
 
 2 J. P. Kimball, Amer. Geologist, Dec. , 1891, p. 368. 
 
 3 T. B. Brooks ' ' On Certain Lower Silurian Rocks in St. Lawrence 
 Co., New York," Amer. Jour. Sci., iii., IV., p. 23. Rec. G. S. 
 Colby, Jour. U. S. Assoc. Charcoal IronWorhers, XL, p. 268. E. Emmons, 
 N. Y. Geol. Survey, Second District, p. 93. T. S. Hunt, ' ' Mineralogy of 
 the Laurentian Limestones of North America, ' ' ^Ist Ann. Rep. Regents 
 N. Y. State Univ., 1871, p. 88. J. C. Smock, Bull. N. Y. State Mus., 
 No. 7, 1889, p. 44. Reo. C. H. Smyth, Jr., "Forthcoming Report of 
 James Hall, ' ' State Gteologist, submitted March, 1894. Reo. 
 
114 KEMP '8 ORE DEPOSITS. 
 
 and though advanced only as an hypothesis are worthy of great 
 confidence. 
 
 The mines have afforded in the past a moderately rich (50 to 55^ 
 Fe), non-Bessemer ore. The best known and largest producers are 
 the Old Sterling, the Caledonia and Kearney properties, but they 
 are not now operated and are not likely to be reopened in the im- 
 mediate future. 
 
 2.02.14. Ji,xample 9. Lake Superior Hematites. Bodies of 
 hematite, both red and specular, soft and hard, in metamorphic 
 rocks. They vary widely in shape, although at times quite per- 
 fectly lenticular. They are usually associated with jasper and 
 chert, and have for a footwall a relatively impervious rock of some 
 sort. Magnetite is at times present. Although of varying physical 
 structure and associations, all the Lake Superior hematites are here 
 grouped under one general example, in order to avoid unnecessary 
 subdivisons, and to emphasize their related characters. There are 
 live principal ore-producing belts or districts, which are also called 
 in instances "ranges," as they follow ranges of low hills. They 
 are, in the order of their chronological exploitation, the Marquette, 
 just south of Lake Superior, in Michigan ; the Menominee, on the 
 southern border of the Upper Peninsula and partly in Wisconsin ; 
 the Gogebic or Penokee-Gogebic, on the northwestern border be- 
 tween Michigan and "Wisconsin ; the Vermilion Lake, in Minnesota, 
 northwest of Lake Superior ; and the Jlesabi (Mesaba), in the same 
 general region as the last. 
 
 2.02.15. The geology of these districts has been a subject of 
 much controversy, not alone in the relations of the separate areas, 
 but in the subdivisions of a single one. The ever-present difficulty 
 of classifying and correlating metamorphic rocks has here been 
 very great. Moreover, there are other separate districts, of re- 
 lated geological structure, which ought also to be brought into 
 harmony, and only at a very recent date has this been even par- 
 tially attained. 
 
 2.02.16. The ores and their inclosing rooks have usually been 
 called Huronian, as this is the name formerly applied to the 
 
 1 T. B. Brooks, "On Certain Lower Silurian Rocks in St. Lawrence 
 County, New York," Amer. Jour. Sci., iii. IV., p. 32. G. S. Colbj', Jour. 
 U. S. Asao. Charcoal Iron Workers, Vol. XI., p. 263. E. Emmons, N. Y. 
 Oeol. Survey, Second District, p. 93. T. S. Hunt, "Mineralogy of the 
 Lanrentian Limestones of North America," 2T.st Ann. Report Regents of 
 N. Y. State Univ., 1871, p. 88. J. C. Smock, Bulletin of N. Y. State Museum. 
 
TEE IRON SERIES, CONTINUED. 115 
 
 schistose and metamorphic rocks overlying what was conceived to 
 be the basal, gneissic Laurentian. The later and more careful work 
 has essentially modified such grouping. The reorganization has 
 been chiefly brought about by K. D. Irving, C. E. Van Hise, 
 Alexander Winchell, M. E. Wadsworth, and the Canadian geolo- 
 gists, especially A. C. Lawson, who has worked in the Rainy Lake 
 region. The definite introduction of Iluronian in the classification 
 is especially due to Logan (ISST). Previously Foster and "Whitney 
 had merely called all the metamorphic rocks concerned with the 
 iron ores in the Lake Superior regions "Azoic." T. B. Brooks in 
 the Marquette district distinguished twenty members (ISVS), but, 
 as Major Brooks frankly states, the classification was chiefly in- 
 tended to aid explorations for ores. Rominger made the classi- 
 fication much simpler (1884), and many others have since written 
 on the subject.' 
 
 2.02.17. As now viewed, the Laurentian is regarded as con- 
 sisting of granites and gneisses and a higher series of gneisses and 
 schists. They are grouped under the name of " Fundamental Com- 
 plex" by Irving and Van Hise (Cascade Formation of Wads- 
 worth, 1892), but the upper series is called Coutchiching in the 
 Rainy Lake Region by Lawson. The unconformity is an eruptive 
 one. Above these, after an unconformity not always clearly 
 marked, comes the succession of schistose rocks, which are grouped 
 together under the name Algonkian. They consist of a lower 
 series, called by various names in the different regions, but which 
 in the Marquette, Menominee, and Vermilion Lake districts contains 
 some of the most important mines. It is variously denominated 
 Lower Huronian, Lower Marquette, Keewatin, Lower Vermilion, 
 and Menominee proper in the different exposures, and probably 
 the great cherty limestone of the Penokee-Gogebio series is its 
 local equivalent. In the Marquette district "Wadsworth has re- 
 cently divided it still further into the Republic and Mesnard forma- 
 tions. The upper part follows an unconformity and is called in the 
 different regions Upper Huronian, Animikie, Upper Vermilion, Up- 
 per Marquette, "Western Menominee, and Penokee-Gogebic proper. 
 
 1 See Hr. E. Wadsworth, Notes on the Oeology of the Iron and Copper 
 Districts, 1880; N. H. Winchell, "A Last "Word wuh the Huronian," 
 Oeol. Sac. Amer., "Vol. II., p. 85 ; C. R. "Van Hise, "An Attempt to Har- 
 monize some apparently conflicting Views ot Lake Superior Strati- 
 graphy." Amer. Jour. Sci., ii., XLI. 117 ; and Tenth Ann. Rep. Director 
 U. 8. Oeol. Survey. The papers give many references. 
 
116 KEMP'S ORE DEPOSITS, 
 
 For the Marquette region this nas also oeen further divided hy 
 "Wadsworth into two, the Hoiyoke and the Negaunee formations. 
 It is much less metamorpnosed than the lower member, and in the 
 Marquette district contains some ore. In the Menominee region 
 of Wisconsin it affords the deposits there -wrought and carries the 
 ore in tne Gogebic range. Still higher, after another unconformity 
 foiio-ws the Keweenawan (Keweenian) or Nipigon. This closes 
 tne Aigonkian. Still above is the Potsdam sandstone. 
 
 2.02.18. Example 9a. Marquette District. The Marquette 
 district was earliest known and has been most thoroughly studied ; 
 out owing to the confused geological structure, there has been, as 
 already remarked, much discordance of interpretation. In the Mar- 
 quette district the Huronian Algonkian rocks form a broad syn- 
 clinal trough with many subordinate folds and several tongues or 
 projections running out from the main body. They rest on and are 
 bounded by Laurentian gneiss. They consist of green schists, 
 ■quartzites, banded jaspers, slates, ore bodies, and dikes altered to 
 ■" soapstone " or " soaprock." Brooks divided them into twenty 
 members, of -which Beds YL, X., XIII., and a horizon below V. 
 afford the ore. Bed XIII. contains the magnetite, -which increases 
 in amount to-^vard tlie -western portion of the iield. Rominger in 
 Vol. IV. of the Jlinhi j:iii S-iroey, 1884, reduced the number to 
 seven. Irving and Vtin llise have contributed much in late years 
 toward a solution of the gsology. Irving regarded the series as 
 separable into a lower division of greenstone schists and more 
 acidic rocks, both of which are dynamically metamorphosed erup- 
 tive rocks, and an unconformable, overl3dng, iron-bearing division 
 of sedimentary origin. (See papers cited below.) Van Hise, how- 
 ever, in his latest paper places a break above the most important 
 ore bodies. 
 
 3.02.19. The ores were classed by Brooks under five heads — {ii) 
 Ked specular, (h) Magnetic, (c) Mixed, (d) Soft Hematites, au<i (p) 
 Flag ores ; and tlie grouping illustrates very well their physical 
 characters. The opening of other ranges and the unprecedented 
 supplies of rich ores have raised the merchantable grade to a point 
 far beyond what it was when Brooks wrote. Class (c), including 
 the banded jaspery varieties, would not at present be salable, nor 
 would class (e) which iucluded very ferruginous forms of certain 
 schists. As stated earlier the ores must now contain at least 60^ 
 metallic iron, and the best grades are guaranteed 64^ or over. The 
 principal varieties to-day are hard ores and soft ori.'s. The former 
 are mostly specular and requiie blasting and are shipped as com- 
 
/-- 
 
 , * 
 
 , V. 
 
 "• M 
 
 «i^. 
 
 ,•*-• 
 
 ' .;' ''^• 
 
 ^v 
 
 1^ 
 
 
 
 FiQ. i7._02xrn ewf m the RejmbJio vnne, Miirqiiette range, shoving a 
 Iiornc iifjtisjier. From a ])liiit<griijiJi hij H. A. }'\lieeh:i\ 
 
118 KEMP 'S ORE D EPOSITS. 
 
 paratively large lumps. The latter may be blue, red or brown and 
 occur as snuill fragments and dirt. When hydrated more or less 
 they resemble limonites, but they contain more iron than does 
 limonite. 
 
 2.02.20. The ore bodies have been in earlier years generally 
 regarded as true beds of greater or less extent and often of great 
 irregularity. They approximate a lenticular shape in the simplest 
 development, as is better shown in the other less disturbed districts. 
 In the Marquette region this is at times obscured by the excessive 
 disturbances. They often follow the foldings of the walls, partic- 
 ularly in synclinal troughs. Later developments have brought 
 out the fact that the ore bodies are associated with some underly- 
 ing rock that is relatively impervious. The favorite one is the so- 
 called soaprock, an altered igneous intrusion that is chiefly in 
 dikes. Beds of jasper seem to play the same role. Yan Hise, in 
 his paper of February, 1892, notes four varieties — (1) Deposits on 
 the contact of a quartzite conglomerate (the base of the Upper 
 Marquette) and the ore-bearing formation ; (2) deposits resting 
 upon soaprock, which grades into massive diorite ; (3) deposits 
 resting upon dikes of soaprock, which follow along or cut across 
 the ore-bearing formations ; (4) deposits interbedded in the jasper 
 or chert. In Figure 18a generalized section taken from Van Hise 
 exhibits these diflferent varieties. The soft ores lie in synclinal 
 basins just below the conglomerate, which, quartzitic in its upper 
 portion, forms the base of the Upper Marquette. The hard specu- 
 lar ores constitute lenses in the conglomerate and are due to the 
 mechanical concentration of ore grains which were supplied by the 
 erosion of the soft ores. South of the Marquette region and be- 
 tween it and the Menominee is found the Felch Mountain area. It 
 is a narrow synclinal, now cnt off by erosion from the main exposures. 
 
 2.02.21. The origin of these ore bodies has been a subject of 
 much controversy. Detailed descriptions of the various hypoth- 
 eses will be found in Wadsworth's monograph.^ Only the im- 
 portant attempts at explanation are instanced here. The early 
 survey of Foster and "Whitney (1851) attributed an eruptive origin, 
 and the same diflicult thesis has since been attempted by "Wads- 
 Avorth (1880), who bases his argument chiefly on the analogy of 
 the banded jaspers to laminated felsites, and to the fact that they 
 and the ore curve around masses of inclosing schist or break across 
 
 1 M. E. Wadsworth, " Notes on the Iron and Copper Districts of Lake 
 Supacior," Ball. Mus. Comp. Zool., Vol. V[I., No. 1, July, 1880. 
 
THE IRON SERIES, CONTINUED. 
 
 110 
 
 them, like intruded dikes. Wadsworth mentions Dr. Selwyn of 
 the Canadian Survey, and tiie late C. E. Wright, as sup])orters of 
 this view. AVhile it may not as yet Ije possililo to demonstrate 
 beyond question the true origin, it is quite inconceivahlo that 
 
 Fig. 18. — Cross sections to illustrate the occurrence and associations of 
 
 iron ore in the Marquette district, Michigan. After C. R. Van Hise, 
 
 Amer. Jour. Sci., February, 1892; Eugineering and Minting 
 
 Journal, July 9, 1893. 
 
 a nearly pui-e siliceous rock and an equally pure Lasic oxide should 
 he side by side and intimately associated as intrusive masses. They 
 would combine. Quite large masses of iron oxide may and do oc- 
 cur as segregations of basic magmas ; not, however, in any amount 
 in acidic. All other geologists who have given the matter atten- 
 tion concur in some form of sedimentary origin, or in origin by re- 
 
120 KEMPS ORE DEPOSITS. 
 
 placement. The beds thus formed may have been afterwarc 
 metamorphosed. Credner, Brooks, Wright in his published work, 
 and at first Irving, described them as having formed as beds of 
 limonite. These were conceived to have been metamorphosed in 
 the general metamorphism of the region. Brooks thought it pos- 
 sible that the hematites were altered magnetites, an idea confirmed 
 by the presence of martite, but he considered all to have been 
 limonite originally. Irving's views are set forth under Example 9c. 
 Van Hise's latest work traces much the same relations as in the 
 less disturbed Gogebic district. He emphasizes the almost in- 
 variable occurrence of the ore along the contact of chert and in- 
 trusive dikes, which are now altered to so-called soapstone. This 
 relation is shown in Fig. 18. The ores are thought to have re- 
 placed these walls, synclinal troughs having been favorite points 
 of deposition. E. Reyer considered that the iron had been leached 
 from the neighboring, basic eruptive rocks (green schists), and had 
 been precipitated as hydrate. The eruptives are, in this view, 
 regarded as subfnarine, and the similar association of basic erup- 
 tives with the iron ores of Elba is commented on. 
 
 2.02.22. It was in the forties that the importance and extent of 
 the ore bodies were first vaguely suspected. The trouble that they 
 made with the compasses of the early land surveyors indicated 
 their existence. Important mining began in 1854. Somewhat 
 over 100,000 tons were produced in 1860, over 800,000 in 1870, 
 nearly 1,500,000 in 1880. In 1877 the Menominee region was 
 opened, and in 1885 the Penokee-Gogebic and Vermilion districts 
 began to ship. The total shipments from the Lake Superior region 
 in 1890 were 8,982,531 tons. The total production to 1891 of the 
 Marquette district was 32,700,000 tons. A quite complete citation 
 of the literature is to be found in Wadsworth's monograph, already 
 referred to, and in Irving's " Copper-bearing Rocks of Lake 
 Superior," Monograph No. V., U. S. Geol. Survey. See also under 
 Examples 96, 9c, and 9d. Only the most important or most recent 
 papers are mentioned here.^ 
 
 1 J. Birkinbine, "Resources of the Lake Superior District,'' M. E , 
 July, 1887. T. B. Brooks, Geol. Survey of Michigan, Vol. I., 1873; Geol. 
 Survey of Wisconsin, Vol. III., p. 450. H. Credner, " Die vorsilurischen 
 Gebilde der oberen Halbinspl von Miohigau in Nord Amerika," Zeitsch. d. 
 d. Geol. Ges., 1869, XXI. 51&; also Berg.- und Huett. Zeit., 1871, p. 369. 
 Foster and Whitney, Geol. of the Lake Superior District, Vol. I., "I-dn 
 Land?," 1851. R. D. Irving-, " OatheOrig;inof the Ferruginous Sohi~ts and 
 
THE IRON SERIES, CONTINUED. 121 
 
 2.02.2a. Example 95. Menominee District. The Menominee 
 River, which gives the district its name, forms the southeasterly 
 boundary between the Upper Peninsula of Michigan and Wiscon- 
 sin. The mines are situated about forty miles south of the Mar- 
 quette group, and the same distance west of Lake Michigan. The 
 larger number are in Michigan, but the productive belt extends 
 also into Wisconsin. They lie along the south side of an east and 
 west range of hills, which rise from 200 to 300 feet above the 
 surrounding swampy land. The geological section immediately 
 associated with the ore involves the following, all of which corre- 
 sponds to the Lower Marquette as outlined in the introduction. The 
 cherty limestone is local. (1) Norway limestone (named from the 
 Norway mine), a belt of siliceous limestone, 1200 feet thick; (2) 
 Quinnesec ore group, consisting of limestone, siliceous or jaspery 
 slates, black and flesh-colored, hydromica schists and slates and ore 
 beds, 1000 feet ; (3) Lake Hanbury slate group, slates and schists 
 with quartzose bands. Unconformably on these lies the hori- 
 zontal Potsdam sandstone. The ore occurs along two or three 
 
 Iron Ores ot the Lake Superior Rfgion," Amer. Jour. Sci., iii., XXXII. 268; 
 "Preliminary Papir on an Invest'gation of the Archaean of the North- 
 western States," Fifth Ann. R p. Director V. S. Oeol. Survey, p. 131 ; 
 Seventh Ann. Rep., p. 431 ; also, Administrative Reports, in subsequent 
 volumes. J. P. Kimball, " Thi> lion Ore of the Marquette District,'' Amer. 
 Jour. Sci., ii., XXXIX. 290. B..S.M\Jinroe, Schoolof Mines Quarterly, III., 
 p. 43. E. Reyer, "Geologie der Amerikanischon Eisenerzlagerstatten 
 (insbeFondere Michigan)," Oest. Zeit. f. Berg.- u. Hiltt., Vol. XXXV., pp. 
 120, 131, 1887. C. Rominger, Geol. Survey of Michigan, Vol. IV., 1884. 
 C. R. Van Hise, " An Attempt to Harmonize Some Apparently Conflicting 
 Views of Lake Superior Stratigraphy," Amer. Jour. Set., iii., XLL, p. 117, 
 February, 1891; Tenth jinn. Rep. Director U. S. Geol. Survey ; " The Iron 
 Ores of the Marquette Dis'rict of Michigan,'' Amer. Jour. Sci., February, 
 1892, p. 115. M. E. "Wadsworth, "Notes on the Inn and C >pper Districts 
 of Lake Superior," Bull. Mus. Comp. Zool., VII. 1, 1880 ; "On the Ori :in 
 of the Iron Ores of the Marquette Distrkt, Lake Superior," Proc. Dust. 
 Soc. Na,t. Hist., Vol. XX., p. 470 ; Enginrering and Mining Journal, Oct. 
 29, 1881, p. 286 ; Ann. Rep. Mich. State Geologist, 1891-93. "The Geology 
 of the Lake Superior Ri'g-ion," in a parr phlet issued by the Duluth, South 
 Shore and Atlantic R. R., 1892. Dr. Wadsworth announces a new subdi- 
 vision of Formations in this and in AnLer. Jour. Sci., J.inuary, 1893, p. 73. 
 n. 'Wedding. Zeitsch. f. Berg.-, IliVt -, und Salincnwcscn in Preus. Staat., 
 XXIV., p. 339. C. E. Wright and C. D. Lawton, Reps, of the Commis- 
 sioners of Mineral Statistics of Michigan, 1880, and annually to date. 
 G. H. Williams, " Greenstone Schist Areas < f the Menominee and Mar- 
 quet'e Regions of Michigan," introduction by R. D. Irving, Bull. 63, ?7. S. 
 Geol. Survey. 
 
123 
 
 KF.MFS ORE DEPOSITS. 
 
 planes of deposition in (2) and not far from the contact with (1), 
 while minor bodies have been found in the Potsdam, which seem 
 to have resulted by the erosion of the older lenses in the Potsdam 
 times. (See paper by J. Fulton, cited below.) Especially instruc- 
 tive exposures of green schists are found which have furnished 
 some of the best evidence that they are metamorphosed, igneous, in- 
 trusive rocks. The ores are generally soft, blue, earthy hematites, 
 which give a red powder and consist of very finely divided parti- 
 cles of specular. The brown hematites are of very limited occur- 
 rence, being known only in the Emmet mine. The lenticular shape 
 of the ore bodies is better shown than in the Marquette district, and 
 even the large masses clearly exhibit this cross section. They strike 
 about N. 75° W., and dip 70° to 80° N. They also pitch to the 
 
 FiQ. 19. — Plan of Ludington ore tody, Menominee district, Michigan, 
 After P. Larsson, M. E., July, 1887. 
 
 west; i.e., run down diagonally on the dip. (Cf. New Jersey Mag- 
 netite, Example \Zd). There were produced up to 1891 a grand 
 total of 12,800,000 tons since mining began.^ 
 
 2.02.24. Example 9c. Penokee-Gogebic District. This lies in 
 an east and west range of hills, which crosses the westerly boun- 
 dary of the Upper Peninsula and Wisconsin, and is from ten to 
 twenty miles south of Lake Superior, and eighty to one hundred 
 
 1 T. B. Brooks, Geol. Survey of Wisconsin, Vol. III., 430-663. D. H. 
 Browo, "Distribution of Phosphorus In the Ludington Mine," M. E., 
 XVI. 525. J. Fulton, "Mode of Depositioa of the Iron Ores of the Me- 
 nominee Range, Michigan," M. E., XVI. 535. Per. Lirsson, "The 
 Chapin Mine," M. E., XVI. 119. C. E. Wright, Geol. Survey cf Wiscon- 
 sin, III. 666, 784. G. H. Williams, "Greenstone-Schist Areas of the Me- 
 nominee and Marquette Regions of Michigan, with an Introduction by R. 
 D. Irving," Bull. 62, U. 8. Geol. Survey. 
 
lU 
 
 KEMP'S ORK DEPOSITS. 
 
 miles west of the Marquette mines. The rocks are less metamor- 
 pliosed than in the previous two districts. The strata run east and 
 west with a northerly dip of 60° to 80°, and with no subordinate 
 folds. They consist of cherty limestone at the base, followed by 
 quai-tz, slates, quartzite, iron ore, and ferruginous cherts, and final- 
 ly slate and schists. The strata are traversed by dikes. The ore 
 is a soft, red, somewhat hydrated hematite, with more or less man- 
 ganese, which is often considerable and is most abundant in the 
 southern mines. Hard specular is rare. Irving first showed that these 
 ore bodies had originated from the replacement of dolomitic or 
 
 Fig. 34. — Cross section of the Colby mine, Penokee Gogebio district, Mich- 
 
 igan, to illustrate occurrence and origin of the ore. After C. R. 
 
 Van Hise, Amer. Jour. Sci., January, 1891. 
 
 calcific beds with iron oxide. Since then Van Hise has proved 
 them to be in the troughs formed by the intersection of northerly 
 dipping compact quartzites and southerly dipping trap dikes. He 
 has traced the iron to a source in the layers of cherty carbonates, 
 parallel with the quartzites and above them. From this it has 
 been leached out by the percolating water and has been deposited 
 in the apices of the troughs, where it has replaced the original car- 
 bonate rooks. Somewhat the same process is outlined for the Mar- 
 quette ores in his latest paper. Up to 1891, there were jiroduced 
 a grand total of 8,300,000 tons of ore.' 
 
 1 R. D. Irving, Geol. Survey of Wisconsin, III., pp. 100-167, 1880. " Or- 
 igin of the Ferruginous Schists ar:d Iron Ores of the Lake Superior Re- 
 
THE mow SEBiaS, CONTINUED. 125 
 
 2.02.25. Example 9(?. Vermilion Lake, Minnesota. Beds of 
 hard specular with but little soft, intimately associated with jas- 
 per (or jaspilyte, as locally called), and both contained in green 
 schists. The district is situated in the northeastern corner of 
 Minnesota, and northwest of Lake Superior. Two Harbors, the 
 shipping point, is twenty-six miles east of Duluth, and Tower, 
 the chief mining town, is sixty-seven miles from the docks. Leav- 
 ing the lake, the railroad first crosses the north flank of the Lake 
 Superior synclinal, consisting of southerly dipping igneous rocks 
 belonging to the Keweenawan. Underlying these are a series of 
 gabbros and augite-syenites that contain titaniferous magnetite 
 and may be a parallel to the Adirondack norites. Next follow the 
 black slates of the Animikie, and then a bed of quartzite called the 
 Pewabic quartzite. N. H. Winchell applies to these collectively 
 the name Taconio, a term which the best work in the East rejects 
 in its home. They form the Mesabi range of hills. Sedimentary, 
 gneissic, and eruptive exposures, referred to the Laurentian, suc- 
 ceed in the north. Next come the Vermilion mica and hornblende 
 schistc, and after these the Keewatin sericitic schists, jaspilyte, 
 etc., containing the ore bodies at Tower. The Laurentian rocks 
 appear again on the north, and beyond to the northwest is the 
 Rainy Lake region, studied by A. C. Lawson. All the formations 
 referred to above run in belts, having a general direction north and 
 east. The ore bodies which are important as yet are all in the 
 Keewatin. They vary in size from small bodies up to masses, 
 which extend as much as a mile on the strike. They approximate 
 the lenticular shape so characteristic of crystalline iron ore de- 
 posits. The jasper, or jaspilyte, is everywhere associated, often 
 very intimately, in parallel bands with the ore, while the contain- 
 ing rock is a green schist which is regarded as an altered igneous 
 rock or tuff. The principal mines are located at Tower, on Ver- 
 milion Lake, and at Ely, which is twenty-three miles farther north- 
 east. N. H. and H. V. Winchell, in the Bulletin referred to be- 
 
 gion," Amer. Jour. Sei., iii., XXXII. 263,265; see also under Van Hise. 
 C. D. Lawton, "Gop,'ebic Iron Mines,' Engineering and Mining Journal, 
 Jan. 15, 1887, p. 42. C. R. Van Hise, "On the Origia of the Mica 
 Schists and Black Mica Slates of the Penokee-Gogebic Iron bearing- Se- 
 ries," Amer. Jour. Sai., iii., XXXI. 453-459. "The Iron Ores of the 
 Penokee-Gogebic Series in Michigao and Wisconsin," Amer. Jour. Sci., 
 iii., XXXVII. 33. 0. E. Wright, Geol. Survey of Wisconsin, III., pp. 239- 
 301. 
 

 
 "li., •i:>.—<ij>eii-<iit lit 2Iiiiiiisiita Iron f'nmpann's JUiie, Soiirlrni, near 
 Toirer, in south view looking n-e.d. Photograph hij J. F. Eeiitp. 1894. 
 
THE IRON SERIES, CONTINUED. 127 
 
 low, draw a isarallel between the more crystalline rocks and the 
 Vermilion schists on the one hand, and the more sericitio and 
 hydrated rocks of the Keewatin on the other. The latter consist 
 chiefly of a chloritic mineral, a sericitio mineral, a feldspathio min- 
 eral, mostly plagioolase, and of hematite. The former exhibit a 
 hornblendic mineral, a micaceous mineral, a feldspathic mineral, 
 mostly orthoclase, and magnetite. A passage of one series of 
 rocks into the other is not at all an inconceivable metamorphio 
 process. But the whole region needs careful and detailed strati- 
 graphical work and views now published will probably be more or 
 less revised. The parallelism with the better known ranges on the 
 south shore of Lake Superior is in many respects striking. About 
 half the ores from Tower (hard specular) and all the ore from Ely 
 (Chandler mine, soft ore) are Bessemer. Nearly 400,000 tons of all 
 kinds were shipped in 1887 and 891,910 in 1890, making a grand 
 total of 3,300,000. 
 
 2.02.26. N. H. and H. V. Winohell have argued that these 
 ores originated as marine chemical precipitates. The great extent of 
 igneous rocks associated with them leads to the suggestion that the 
 inclosing rocks have been formed by submarine volcanoes, whose 
 lapilli, etc., have largely contributed their materials. Deposits of 
 iron and silica are thought to have formed from the heated over- 
 lying waters. Somewhat similar views of the extensive ore bodies 
 of Elba are held abroad.' 
 
 The general geological relations are also discussed in many of 
 the papers cited under the other districts, especially those of Irving 
 and Van Hise. 
 
 2.02.27. Example 9e. Mesabi Range. Of much more recent 
 development than the other districts is the Mesabi range of 
 Minnesota. The mines began to make important shipments of 
 ore in 1898. The indications are that the deposits are not less 
 extensive than in any other of the Lake Superior localities, if in- 
 
 1 A. H. Chester, Eleventh Ann. Rep. Minn. Oeol. Survey, 155, 167. 
 T. B. Comstock, "Vermilion Lake District in British America," M. E., 
 July, 1887. H. V. Winohell, ' ' The Diabasic Schists containing the Jaspilyte 
 Beds of Northeastern Minnesota," Amer. Geo!., II. 18. N. H, and H. V. 
 Winohell, ' ' On a Possible Chemical Origin of the Iron Ores of the Keewal in 
 in Minnesota," Amer. Geol., IV. 391, 389; "The Taconic Iron Ores of 
 Minnesota and of Western New England,'' Amer. Oeol.,yi. 263; "The 
 Iron Ores of Minnesota," Bull. VI., Minn. Oeol. Survey. Rec. Ann. Re- 
 ports of the Minn. Oeol. Survey. 
 
128 
 
 KEMP'S ORE DEPOSITS. 
 
 deed tliey are not even larger and of a form to be more easily 
 mined. The present developments are situated southwest of Ver- 
 milion Lake, and nearer Duluth and Lake Superior. The ore lies 
 under the black slates called Animikie in the section given in 
 Paragraph 2.02.25, and over the quartzite, there called the Pewa- 
 bic ; but they are situated twenty miles or so west of the line of 
 that section. The ore bodies are all south of the granite ridge 
 called the Giants' range. Upon the southern slopes of this range 
 lie the green schists of the Keewatin, which are unconformably 
 overlain by the Pewabic quartzite. On this rests the ore-bearing 
 
 Fk;. 26. — General trross section of ore body at Biwubik, Mesabi Range, 
 Minn. After H. V. Winchell, 20th Ann. Rep. Minn. State Geologist. 
 
 rock, which is a jaspery chert, called taconyte by H. V. Win- 
 chell. Over this, in order, come greenish siliceous slates and 
 cherts, black slates (referred to the Animikie), and great masses of 
 gabbro. On the flanks of the Giants' range the dip is steep, but 
 it flattens out nearly to hovizontality away from the granite. All 
 the formations above the Keewatin are called Taconic by the Win- 
 chells. 
 
 2.02.28. The ore bodies lie on the southerly slopes of low hills, 
 and are found immediately below the mantle of glacial drift, which 
 varies up to 100 feet in thickness. Ore indications have long been 
 known on the range, and various reports have been made in previ- 
 ous years, although always unfavorably. The indications then 
 
THE IRON aWRlES, CONTINUED. 129 
 
 available showed only siliceous limonites of low grade. Deep test 
 pits, which penetrated these caps and the drift, have, however, 
 rewarded persistent prospecting. The ores are blue and brown and 
 of soft, earthy texture, with occasional hard streaks. They lie 
 from 10 to as much as 180 feet below the surface as now mined, 
 aud where the stripping is sufficiently thin, it is removed with steam 
 shovels, and then after being shaken up with black powder the ore 
 is excavated in the same way. The ore bodies are lenses, which at 
 times, as at the Mesaba Mountain or Oliver Mine in Virginia, ap- 
 pear to form a basin. In the central part of this mine, a drill 
 hole has shown 335 feet of ore, but the general run is less. The 
 ore bodies have usually a southeasterly trend and are longer than 
 wide. The blue ores are richest in iron and purest as regards 
 phosphorus, and they are the ores specially desired. Ores for 
 foundry iron also occur in large amount, but are at present less 
 sought for. The rock most intimately associated with them is the 
 chert, called taconyte. The underlying quartzite is occasionally 
 shown in the mines as well as the overlying slates, but the whole 
 region is so completely buried in drift that outcropping rock is 
 a rare thing. 
 
 The ores are thought by H. V. Winchell to have originated by 
 replacement of the taconyte. The rock contains calcareous streaks 
 which have perhaps aided in furnishing the carbonic acid which, it 
 is thought, has dissolved the silica of the taconyte in the replacement 
 process. Kecently, valuable observations on the geology of the ores 
 have been accumulated by J. E. Spurr, while in the field for the 
 Minnesota Geological Survey, in whose Bulletin X. the detailed re- 
 port has appeared. A preliminary paper in the American Geologist 
 for May, 1894, gives an abstract of the results. As in the Penokee- 
 Grogebic and Marquette district, the western end of the Mesaba 
 range is least disturbed and metamorphosed. The stratigraphy is 
 the same as is already outlined in preceding paragraphs^ but the 
 quartzite is simply called by Spurr, Animikie, and not Pewabic. 
 The iron-bearing series is stated to be from 500 to 1000 feet thick, 
 with an average of 800 feet. The unaltered rock is described as con- 
 sisting of " cryptocrystalline, chalcedonic or finely phenocrystalline 
 silica" thickly "strewn with rounded or subangular bodies made 
 up chiefly of a green mineral," regarded as glauconite, the hydrated 
 silicate of protoxide of iron and potash. Analyses of the rock cor- 
 roborate this determination, because they indicate a constant but 
 small percentage of potash. Layers of the rock, rich in calcite 
 
51 
 
 > =^ 
 
 
THE IRON SEItlKS, CONTINUED. 131 
 
 (probably miigiiesinii) also occur. Spnrr is thus led to regard the 
 lock as an altered gieeiisand, to which view similar conclusions re- 
 garding tlie much more recent and unmetamorphosed ores of Texas 
 and Lonisiana (see 3.01.15) give support. Tiie chemistry of the 
 deposition is considered by Spun- to be the following. Atmos- 
 pheric waters, with dissolved carbonic acid, and some alkaline 
 salts have filtered into the cracks and become charged with 
 ferrous carbonate where the conditions prevented oxidation. The 
 greater solubility of the ferrous salt led to its solution before the 
 alkali attacked the silica. 
 
 Later, reaching more open and fissured portions, the ferrous salt 
 was oxidized and deposited while the silica was attacked and re- 
 moved by the alkali. In time, thus the iron oxide was concen- 
 trated along fissured strips, near faults, and the like, whereas the 
 silica was removed. It is recognized as well that the ferrous salt 
 was precipitated as carbonate, amid deoxidizing conditions. The 
 change from silicate or carbonate to hydrous oxide of iron led to 
 shrinkage and shattering, and the passage from hydrous oxide to 
 carbonate, where such occurred, to expansion and shattering. It 
 follows from the explanation that the regions of rich ore bodies 
 would be those of notable geological disturbances, so that faults 
 are presumed near Virginia, Biwabik and elsewhere. * 
 
 2.02.39. Example 10. James River, Virginia. Specular hema- 
 tite in narrow beds (lenses), interstratified with quartzitesand slates 
 of metamorpbic character and Archean age. Tliey run four to six 
 feet, or less, in thickness, with prevailingly vertical dip, but they 
 also pitch diagonally down on the dip like tlie lenses of magnetite, 
 later described. They furnish a very excellent grade of ore. Tiie 
 ore bodies are found along both sides of the James River, a few 
 miles above Lynchburg. Some magnetite also occurs in the region, 
 and some limoniDe. More or less clay accompanies tiie ore.^ 
 
 2.02.30. Similar lenses of specular ore and magnetite are found 
 
 1 H. V. Winchell, Tioentieth lAnn. Rep. Minn. State GeologiU, p. 113, 
 1893 ; reprinted M. E. , 1893. Reo. The Nevr York Tiiiies of Deo. 14, 
 1898, has a quite extended account. H. V. Winoheii and J. T. Jones, 
 "The Biwabik Mine, " M. E., February, 1893. 
 
 '^ E. B. Benton, Tenth Cemns, Vol. XL, p. 363 (on Virginia). J. L. 
 Campbell, Oeologij and Resources of the James River Valley, p. 49, New 
 York, 1883. B. Willis, Tenth Census, Vol. XV., p. 301. The Virginias, 
 a monthly formerly published by Jed. Hotchkiss, at Staunton, contains 
 much information on Virginia in general. 
 
133 
 
 KEMP'S ORE DEPOSITS. 
 
 in central Nortli Carolina, in schistose 
 rocks, which have been referred to the 
 Huronian. 
 
 2.02.31. Lenses of specular hem- 
 atite of very excellent quality are found 
 also in metamorphio rocks, north of Fort 
 Laramie, Wyoming, which may prove 
 productive in time. But little is as yet 
 known about them. 
 
 2.02.32. Example 11. Pilot Knob, 
 Mo. Two beds of hard specular hem- 
 atite separated by a thin seam of so- 
 called slate (probably volcanic tuif), and 
 interstratified with breccias and sheets 
 of porphyry. Along the eastern limit 
 of the Ozark uplift of Missouri and 
 Arkansas a series of knobs of granite 
 and porphyritic rocks project through 
 the Cambrian limestones and sand- 
 stones. They are older than the lime- 
 stones, and clearly were not intruded 
 through them. The limestones and 
 sandstones lie up against the porphyry 
 and in the valleys between. The un- 
 derlying porphyry has been found in 
 the valley near Pilot Knob, after pene- 
 trating four hundred feet of sediment- 
 ary rocks. The porphyry and ores 
 have often been called Huronian, but 
 in view of the recent reorganization of 
 the Huronian (see Example 9), this is 
 not done, nor ever has been, on any ac- 
 curate grounds. Pilot Knob is formed 
 by one of these eruptive knobs. It con- 
 sists of sheets of porphyries that are 
 capped by porphyry breccia, the two 
 ore beds, and the intervening tuff. The 
 beds strike and dip 13° S. S. W. The 
 hill is over 600 feet high. The lower 
 bed has furnished most of the ore, run- 
 ning from 25 to 40 feet thick, and af- 
 fording a dense bluish, specular hema- 
 tite of from 50 to 60^ Fe, siliceous, and 
 very low in phosphorus. The upper bed 
 
THE IRON SERIES, GONriNUED. 
 
 133 
 
 is ii'i-egular and of lower grade and rnii.s from G to 10 feet tbidc. 
 Tlio Pilot Knob mines in this solid ore are now sulistantially 
 exhausted. 
 
 Recent drill holes ou the northerly slope and below the out- 
 cropping face of ore have shown that under the Cambrian strata of 
 
 M 
 
 ../' 
 
 Fia. 29. — Vieiv of open cut at Pilot Knob, Mo., shouting the bedded char- 
 acter of the iron ore. From a photograph by J. F. Kent}:!, 1888. 
 
 tlie valley there is a great bed of ore boulders or breccia in clay, 
 much as is the case at Iron Mountain, later described. Analyses 
 of cores were not, however, sufficiently encouraging for devehip- 
 ment during the present low prices for iron. Doulitless the be<I 
 will afford important reserves. 
 
 2. 02. .3-3. Near Pilot Knob are two other hills of porjihvry, 
 
134 
 
 KEMP'S OBE DEPOSITS. 
 
 g 
 
 s. 
 
 to 
 
 ■^-, 
 
 p 
 
 
 Sbeplicrd Mountain and 
 Cedar 3[ountain, whose 
 ores arc .structurally more 
 related to Example 11(^. 
 The first contains three 
 veins, the Champion, the 
 North, and the South. They 
 are long and narrou' (4 to 
 10 feet), strike north 60" 
 to 70° east, and dip 70° 
 north. Tlie Champjion vein 
 contained a little streak of 
 natural lodestone, but the 
 ore is mostly specular. 
 
 The North vein shows 
 a good breast of ore five 
 feet wide, but too full of 
 p)'rite to be available. Ce- 
 dar Mountain has a vein of 
 specular ore. Neither hill 
 ha.s been an important pm- 
 (lucer. ]\[iuor veins ha"\'e 
 fjeen fnuud cm neigliboring 
 porphyry ]r!lIs(nufor.l, IIo- 
 gan, and T>e\\is mountains), 
 s<une of which eoiitain 
 much manganese. 
 
 2.0l\:T4. p]xam]ile 11 -^ 
 Iron ^lountain, Missouri, 
 Veins of hard, specular 
 hematite ii-regularly seam- 
 ing a knob of poi'plivrv. 
 Iriin ?.loun1ain is fi\'e or 
 six miles iioi'di i_ii' Pilot 
 Knob, and is a low liill willi 
 a westerly spur called Lit- 
 tle j\[()untain, and has also 
 a northei'ly spur. It con- 
 sists of feldsparporphyries, 
 more or less altered. These 
 
THE IRON SERIES, CONTINUED. 
 
 135 
 
 are seamed with one large, and on the 
 west somewhat dome-shaped, parent 
 mass of ore, and innumerable minor 
 veins that radiate into the surrounding 
 rock. Upon the flanks of the porphyry 
 hill rests a mantling -succession of sedi- 
 Tnentary rocks, that dip away on all 
 sides. The lowest member is a con- 
 glomerate of ore fragments, weathered 
 porphyry, and residual clay left by its 
 alteration. It is regarded by Pumpelly 
 as formed by pre-Silurian surface dis- 
 integration and not by shore action, 
 inasmuch as sand does not fill the in- 
 terstices, while white porphyry clay 
 does. It is, however, overlain by a thin 
 bed of coarse, friable sandstone, which 
 marks the advance of the sea, and whose 
 formation preceded the limestones. 
 This conglomerate is now the principal 
 source of the ore. It is mined under- 
 ground, hoisted and washed by hy- 
 draulic methods, like those employed 
 in the auriferous gravels of California, 
 and then jigged. The apatite has largely 
 weathered out of it. The rock of the 
 mountain itself, in the cuts of the mines, 
 is largely kaolinized, and exhibits every- 
 where the effects of extreme alteration. 
 The smaller veins that penetrate the 
 porphyry show at times casts or much 
 altered cores of apatite crystals. 
 
 2.02.35. The porphyries of Pilot 
 Knob and Iron Mountain, in thin sec- 
 tion, are seen to belong to quartz-por- 
 phyries, feldspar-porphyries, and por- 
 phyrites. Both orthoclase and plagio- 
 clase are present in them, and many 
 interesting forms of structure. One 
 significant fact is that they are every- 
 where filled with dusty particles of iron 
 c side, probably magnetite. Our knowl- 
 
 ^ 
 
 O a 
 
 
 ^ »• 
 
 <si. ;:5 
 
 !=i. o 
 
 O 
 
 a-c 
 
 o c S- 
 
 stta 
 
 fe: 
 
 a, 
 
 m 
 
136 
 
 KEMP'S ORE DEPOSITS. 
 
 edge of the chemical composition of the jjorphyries is, however, as 
 yet very imperfect. An eruptive origin was originally assigned to 
 these ores by J. D. Whitney (Metallic Wealth of the United States, 
 p. 479, 1854), just as to the Lake Superior hematites. The later 
 investigations of Adolph Schmidt for the Missouri Survey in 1871 
 arrived at a different conclusion. Dr. Schmidt considered them, 
 whether occurring in an apparent bed, as at Pilot Knob, or in 
 various more or less irregular veins, as at Iron ]\[ountain, to have 
 been formed either by a replacement of the porphyries with iron, 
 oxide deposited from solution, or by a filling in the same way of 
 fissures, probably formed by the contraction of the porphyry in 
 cooling. In the valuable report on iron ores by F. L. Xason in 
 the Missouri Geological Survey a sedimentary origin is advo- 
 cated for the Pilot Knob beds. They are conceived to have been 
 deposited in a body of water in a hollow, between formerly exist- 
 ing porphyry hills, which rose above. In the course of weathering, 
 the hills became the valleys and the early sedimentary beds the hill- 
 top. It is, however, somewhat difficult to understand how the more 
 or less incoherent sediments withstood degradation better than the 
 hard, firm porphyry hills. Some such origin as sedimentation or re- 
 placement is, however, the only reasonable one. It is not improbable 
 that the Pilot Knob ores originated in the saturation and more or less 
 complete replacement of tuf aceous layers with infiltrating iron oxide. 
 An extended table of analyses of Iron Mountain ores will be 
 found in Mineral Resources of the United States, 1889-90, p. 47.^ 
 
 ANALYSES OF HEMATITES, EED AN'D SPECULAR. 
 
 (The same discrimination must be employed in looking over these 
 analyses that was emphasized under limonite.) 
 
 Clinlon, N. Y. (fossil ore) 
 
 Wiscoasin (fossil ore) 
 
 Pennsylvania (MiiHin ore) 
 
 Tenne-see (Meigs County) 
 
 Birtuinghara, Ala 
 
 Antwerp, N. Y 
 
 Missouri (Crawford County) 
 
 Marquette dist., Mich, (specular), 
 
 Menominee district, Michigan. . 
 
 Iron Mountain, Mo. 
 
 Pilot Knob, Mo 
 
 James River (Maud vein) 
 
 Elba 
 
 Pure mineral 
 
 Fe. 
 
 44.10 
 
 51.75 
 
 44.4 
 
 51.63 
 
 56.4 
 
 46.33 
 
 59.41 
 
 68.4 
 
 64.83 
 
 60.47 
 
 65.5 
 
 51I.15 
 
 49.89 
 
 61.81 
 
 70.0 
 
 0.6-)0 
 1.393 
 0.115 
 0.345 
 0.34 
 0.883 
 0.085 
 0.53 
 0.067 
 .009 
 0.040 
 0.015 
 0.139 
 0.02 
 
 0.33 
 0.038 
 
 0.010 
 0.17 
 
 S.O, 
 
 12.63 
 
 16.8 
 
 2 07 
 
 3 60 
 3.38 
 5.75 
 
 13.37 
 
 5.97 
 
 Al,0, 
 
 5.45 
 0,5 
 
 2.03 
 
 3.19 
 3.47 
 
 3.77 
 
 G. C. Broadhead, "The Geological History of the Ozark Uplift, 
 
THE IRON SERIES, CONTINUED. 137 
 
 These analyses are mostly taken from State reports and from 
 Mineral Resources of the United States. They are intended to 
 illustrate the general run of compositions, but for Birmingham and 
 Marquette are high. Analyses vary widely. 
 
 Amer. Geol., III. 6. J. E. Gage, "On the Occurrence of Iron Ores in Mis 
 souri," Trans. St. Louis Acad. Set., 1873, Vol. III., p. 181. E. Harrison, 
 " Age ot the Porphyry Hills," Ibid., Vol. II., p. 504. E. Haworth, " A Con- 
 tribution to the Archaean Geology of Missouri," Amer. Geol., I. 280-363 ; 
 "Age and Origin of the Crystalline Rocks of Missouri," Bull. V., Mo. Geol. 
 Survey, 1891. A. V. Leonhard, "Notes on the Mineralogy of Missouti," 
 Trans. St. Louis Acad. Sci., Vol. IV., p. 440. F. L. Nason, "Report on 
 the Iron Ores of Missouri," Mo. Geol. Survey, II. Rec. R. Pumpelly, 
 " Geology of Pilot Knob and Vicinity," Mo. Geol. Survey, 1872, p. 5 ; see 
 also remarks on Iron Mountain, Bull. Geol. Soc. Amer., Vol. II., p. 220. 
 Rec. W. B. Potter, "The Iron Ore Regions of Missouri," Journal U. S. 
 Asso. Charcoal Iron Workers, Vol. VI., p. 23. Rec. F. A. Sampson, "A 
 Bibliography of the Geology of Missouri," Bull. II., Mo. Geol. Survey, 1890. 
 (This is a valuable book of reference.) F. Shepherd, Ann. Rep. Mo. Geol. 
 Survey, 1853-54. Hist. A. Schmidt, " Iron Ores of Missouri," Mo. Geol. 
 Survey, 1872, p. 45, and especially p. 94. Rec. J. D. Whitney, Metallic. 
 Wealth of the U. S., p. 479 
 
CHAPTER III. 
 
 MAGNETITE AND PYRITE. 
 
 2.03.01. Example 12. Magnetite Beds. Beds of magnetite, 
 often of lenticular shape, interstratifled with Archean gneisses and 
 crystalline limestones. They are extensively developed in the 
 Adirondacks, in the New York and New Jersey Highlands, and in 
 western North Carolina. The presence of magnetite in Michigan 
 (Example 9a), in Minnesota (Example 6b), on Shepherd Mountain 
 in Missouri (Example 11), and in Virginia (Example 12) has 
 already been referred to. Other magnetite bodies are known in 
 Colorado, Utah, California, and Wyoming, and will be mentioned 
 subsequently. Titanium is often present in such amounts as to 
 render the ore of no value. The same is true of pyrite and pyrrho- 
 tite. Apatite is always found, although it may be in very small 
 quantity. Chlorite, hornblende, augite, epidote, quartz, feldspar, 
 and a little calcite are the common associated minerals. In New 
 Jersey the beds occur in several parallel ranges or belts. 
 
 2.03.02. Example 12a. Adirondack Region. The magnetite 
 deposits occur in the foothills of the Adirondacks on all sides, 
 and to a less extent in the mountains themselves. The mountains 
 are very largely knobs of a rock, which is chiefly labradorite, with 
 some hypersthene and other bisilicates, and is variously called lab- 
 rador-rock, norite, hypersthene-rock, anorthosite, etc. Whether 
 this is igneous or a series of metamorphosed sediments, it is not yet 
 generally admitted, as the geology of the region largely remains to 
 be worked out. It certainlj' exhibits both metamorphie and igne- 
 ous facies and is undoubtedly a more or less metamorphosed igne- 
 ous rock. Associated with it, especially in the foothills, are gneiss 
 and crystalline limestones, in the former of which occur the mag- 
 netite deposits now wrought, but field work in the summer of 
 1892 has convinced the writer that there are large bodies of magne- 
 tite in true igneous gabbros in the town of Westport, if not else- 
 where. At Lyon Mountain, on the north, the Chateaugay ore body 
 
MAGNETITE AND PVRITE. 
 
 139 
 
 is really a bed of gneiss very rieh in magnetite, ricli enongli in 
 jilaces t(j afford a nierchantaljle ore. The greater part of it, Low- 
 ever, reijuii-es concentration. It is known for several jnilcs on the 
 outcrop. On either side the ore sliades out into the walls of bar- 
 ren rock. The Little River mines on the west side, in St. Law- 
 
 FlG. 32,— Vietr (if ojieii cut ami invh'r(jr(iiniil irork in iline 21, MineviVe, 
 near Part Henry, N. Y. Photogrrqihcd by J. F. Kciii^i, 1893. 
 
 reiicc County, apiieai- to he a similar hut larger lied or group of 
 ocds of h.'au ore, said to ho fn m sOo to looo fec^t \\ide and 1 v.'o 
 mil<'s long. The Barton Hill mine,;, near ]\Iine\ille, ai-<' openings on 
 a sincde coiincef ed zone aiul cxteml. togi'tlier with l<'ishcr 1 lill, (.>\(T 
 a mile on thi' slriki.'. 
 
 '2.0:!.():i. IJesides these extended bed,^ there arc otiuu dejiosits 
 
140 KEMPS ORE DEPOSITS. 
 
 exhibiting more perfectly the peculiar lenticular shape characteris- 
 tic of magnetite, and to this class are to be referred the greater 
 number of smaller bodies (Hammondville). They pinch and swell, 
 roll and fold and feather out, and often come off sharply from the 
 walls. They frequently follow and overlap one another like shin- 
 gles, the second one succeeding the first in the footwall. They are 
 not infrequently cut by trap dikes and are thrown by these and b}' 
 normal faults. At Hammondville small gulches seem to cut off 
 the ore, and are probably due to faults. Other deposits are of 
 enormous size, as at Mineville (200 to 300 feet clear ore between 
 the walls), and their relations are less clear. They may be large 
 lenses doubled over in a sigmoid fold. The Champlain magnetite is 
 quite notably granular as contrasted with New Jersey, which tends 
 rather more to break in prisms. 
 
 2.03.04. C E. Hall has divided the metamorphic rooks of the 
 Adirondacks into the (a) Lower Laurentian Magnetite Iron Ore 
 series, containing the most important ore beds, {b) The Lauren- 
 tian Sulphur Ore Series, (c) The Limestones and the Labrador or 
 Upper Laurentian, with Titaniferous Iron Ores, (c) is thought to 
 be certainly later than (a), but the relations of (6) are uncertain. 
 T. S. Hunt also states that the titaniferous ores are associated with 
 the Labradorite series or Norian, which he places as of later age 
 than the gneisses with the good ore. 
 
 Commercially the ores are divided into (1) ores high in phos- 
 phorus but low in sulphur ; (2) ores low in both phosphorus and 
 sulphur ; (3) pyritous ores ; (4) titaniferous ores ( Tenth Census, 
 Vol. XV.). Under class (4) come numerous beds which are worth- 
 less, but which if the titanium could be neutralized would be very 
 valuable (Lake Henderson; see 2.03.11). Mineville is by far 
 the most productive region. It ships 400,000 to 500,000 tons yearly. 
 Chateaugay and Hammondville are next. The Arnold mines pro- 
 duce some, while the Palmer Hill mines with the decline of the 
 bloomaries have gradually ceased. The mines on the west side of 
 the mountains are less important. They afford, so far as developed, 
 a low grade of ore, that, however, with the improvements in mag- 
 netic concentration, seems to promise well. The largest openings 
 are at Jayville and Little River. 
 
 There are numerous magnetite deposits in Canada of analogous 
 geological relations, but they are often highly titaniferous.' 
 
 1 L. C. Beck, Mineralogy of New York, Part I., pp. 1-38. J. Blrkin- 
 
MAGNETITE AND PTRITR!. 141 
 
 2.03.05. Example 135. New York and New Jersey Highlands, 
 and the South Mountain of Pennsylvania. Beds of lenticular shape 
 in Archean gneiss and crystalline limestone. From Putnam County, 
 New York, a ridge of Archean rocks runs southwest across the 
 Hudson River, traversing Orange County, New York, and northern 
 New Jersey, and running out in Pennsylvania. Lenses of magne- 
 tite occur throughout its entire extent. They are not as large as 
 in the Adirondacks, but are more regularly distributed. East of 
 the Hudson, in Putnam County, the Tilly Foster mine is the most 
 important, and the descriptions and figures of it are the best illus- 
 trations of the shape of lenses published. West of the Hudson, in 
 Orange County, the Forest of Dean mine affords considerable ore 
 yearly. It is cut by an interesting trap dike. As the results of 
 study of the Archaean of this region, N. L. Britton has divided it 
 into a Lower Massive group, a Middle Iron Bearing, and an Upper 
 Schistose. {Geol of N'. J., 1886, p. '77.) F. L. Nason has also 
 sought to classify it on the basis of rock types, of which he makes 
 four, named, from their typical occurrences. Mount Hope type, 
 Oxford type, Franklin type, and Montville type. They are ar- 
 
 bine, " Crystalline Magnetite in the Port Henry (N, Y.) Mines,'' M. E., Feb- 
 ruary, 1890. Eec. H. Credner, Zeitsch. d. d. g. GeselL, 1869, XXI., p. 516; 
 B. und H. Ze.it., 1871, 369. J. D. Dana, "On the Theories of Orig-in," 
 Amer. Jwir. iSci.,iii., XXII. 153, 403. E. Emmons, Geology of Neio York, 
 Second District, pp. 87, 98, 331, 355, 291, 309, 850. Hist. C. E. Hall, 
 "Laurentian Magnetite Ore Deposits of Northern New York," Z'Zd Ann. 
 Rep. State Museum, 1884, p. 133. Rec. J. F. Kemp, " Notes on the Miner- 
 als Occurring near Port Henry, N. Y.," Amer. Jour. Sci., iii., XI. 63, and 
 Zeitsch. f. Kryst., XIX. 183. G. W. Maynard, "The Iron Ores of Lake 
 Champlain," Brit. Iron and Steel Inst., Vol. I., 1874. "W. C. Redfield, 
 "Some Account of Two Visits to the Mountains of Essex County, N. Y., 
 in 1836-37," Amer. Jour. Scl, i., XXXIII. 301. Hist. B. Silliman, "Re- 
 marks on the Magnetites of Clifton, St. Lawrence County, N. Y.," M. E., 
 I. 364. J. C. Smock, " Iron Mines of New York," Bull. VII., N. Y. State 
 Museum. Rec. J. Stewart, "Laurentian Low Grade Phosphate Ores," 
 M. E., February, 1892. Wedding, Zeitschr. f. B., H., und S. im. p. St., 
 XXIV. 330, 1876. See also the general works on Iron Ores cited at begin- 
 ning of Part II. On Canadian magnetites the following papers may be 
 mentioned. F. P. Dewey, "Some Canadian Iron Ores," M. E., XII. 193. 
 B. J. Harrington, " On the Iron Ores of Canada," Can. Geol. Survey, 1873- 
 74. T. S. Hunt, Can. Geol. Survey, 1866-69, pp. 261, 362. T. D. Ledyard, 
 " Some Ontario Magnetites," M. E., XIX. 28, and July, 1891. W. H. Mer- 
 ritt, " Occurrence of Magnetite Ore Deposits in Victoria County, Ontario," 
 A. A. A. S., XXXI. 413, 1882. 
 
142 
 
 KEMP'S ORE DEPOSITS. 
 
 ranged in their order of probable age. Tliej^ correspjond in some 
 respects to Britton's grouping, but differ materially in others. 
 (Geol. of i\\ J., 1889, p. 30.) Four courses, or mine-belts, have 
 been recognized in Kew Jersey, — the Rauiapo, the Passaic, the Mus- 
 conetcong, and the Pequest, — in order from east to west. The 
 lenses strike northeast with the gneisses, and usually have, like 
 them, high dips. In addition they have also a so-called "pitch" 
 
 Fig. 3.3a. Fig. mb. 
 
 Figs. ^Z-:i riixl ?M.—Jfiide7 of the Ttlly Foster ore hody. 33a, Top xieu\ 
 
 sUowiitij faulted slviidder. After F. S. Ruttmann, Trans. Amer. 
 
 Inst. Mill. Eiiij.. -IT. 79. 336, Yieir of bottom of same. 
 
 Photoijraplted by .J. F. Kemp from the model now 
 
 at the School of Jlines, Columbia College. 
 
 along the strike, s(j that they run diagonallv down the di]). They 
 have been obser\ed to pitch northeast with an easterlvdip and 
 southwest with a westerly. Either by the overiapjiing c,f lenses 
 or li\' an approximation to an elongated bed, thev sometimes, as at 
 Ililici-iiia, extend a mile or more in unbroken series. ^\gain, they 
 may be alim.jst circular in cross section (Kurd mine). At Frank- 
 lin Fiirn.'ice one is found in crystalline limestone.' 
 
 1 E. S. Breidentiangli, "Ori the Minerals Found at the Tilly Foster 
 Mine. New Y..rk,'' Amer. Jour. Sci., ii ., VI. 207. J. F. Ivemp, " Diorite 
 
MAGNETITE AND PYRITE. 143 
 
 2.03.06. South Mountain, Penn. Small lenses of magnetite oc- 
 cur in Berks, Bucks, and Lehigh counties of southeastern Pennsyl- 
 vania, in the metamorphic rocks of the South Mountain belt. They 
 are very like those to the north in New Jersey, but are lower in 
 both iron and phosphorus. Their product is about 100,000 tons 
 yearly. The Cornwall magnetite is described under Example 13, 
 for its geological structure is entirely different from the lenses.' 
 
 2.03.07. Example 12c. Western North Carolina and Virginia. 
 Beds of magnetite, of the characters already described, in Archean 
 gneisses and schists. The ore body at Cranberry, N. C, is the lar- 
 gest and best known. It occurs in Mitchell County, and has lately 
 been connected by rail with the lines in east Tennessee. Accord- 
 ing to Kerr, the principal outcrop is 1500 feet long and 200 to 800 
 feet broad ; but, of course, all of this is not ore. The mines can 
 afford very large quantities of excellent Bessemer grade. Pyrox- 
 ene and epidote are associated with the ore. Kerr has referred the 
 magnetite to the Upper Laurentian. In the southern central por- 
 tions of North Carolina other magnetites occur in the mica and tal- 
 cose schists, which have been referred to the Hnronian. (SeeH. B. 
 C. Nitze, Bull. I. N. C. Geol. Survey, for detached report.) (Ex- 
 ample 10.) Magnetite has also been lately reported from Franklin 
 and Henry Counties, Virginia, and Stokes County, North Caro- 
 lina. Some doubt, however, is cast on its amount and quality.^ 
 
 Dike at the Forest ot Dpcan Mine," Amer. Jour. Sci., iii., XXXV. 331. 
 F. H McDowell, " The Rpopeniog of the TiUy Foster Mioe," M. £., XVII. 
 758 ; Engineering and Mining Journal, Sept. 7, 1889, 206. F. S. Ruttnian, 
 "Notes on the Geology of the Tilly Foster Ore Body, Putnam County, 
 New York," M. £•., XV. 79. Rec. J. C. SmocXi, Bull. VII., N. Y. State 
 Museum. Rec. A. F Wgndt, " The Iron Mines of Patnatn County,'' 3£ ^., 
 XIII. 478. "Iron Mines of New Jersey," School of Mines Quarterly, iv., 
 III. N. L. Britton, Ann. Rep. N. J. Survey, 1886, p. 77. Rec. G. H. 
 Cook and J. C. Smock, Oeol. of N. J., 1868. Rec. (See aUo subsequent 
 annual reports, especially 1873, p. 12.) F. L. Nason, Ann. Rep. N. J. 
 Survey, 1889. Rec. J. W. Pullmann, "The Production of the Hibeinia 
 Mine, New Jersey," M. E., XIV. 904. J. C. Smock, "The M.ignetite Iron 
 Ores of New Jersey," M. E., II. 314 ; " A Review of the Iron Mining In- 
 dustry of New Jersey," M. E., June, 1891. Rec. 
 
 1 E. D'Invillieis, Rep. D3, Penn. Survey, "VoX. II. (South Mountain 
 Belt of Berks County). Rec. F. Piime, Rep. D3, Vol. I. Penn. Survey 
 (Lehigh County). B. T. Putnam, Tenth Census, Vol. XV., p. 179. 
 
 2 W. C. Kerr, Geol. of N. C, 1875, 264. H. B. C. Nitze, " On Some ot 
 the Magnetites of Southwestern Virginia, etc., and Discussion of Same, 
 by E. C. Pechin," M. E., June, 1891. B. Willis, Tenth Census, Vol. XV., 
 p. 335. E. & M. Journal, Jan. 7, 1888. Kerr & Hanna, " Ores of North 
 Carolina," 1893. 
 
144 KEMPS ORE DEPOSITS. 
 
 2.03.08. Example \2d. Colorado Magnetites. Beds of mag- 
 netite of a lenticular character in rocks described as syenite (Chaf- 
 fee County) and diorite (Fremont County). With these a number of 
 others are mentioned which vary from the example, but of which 
 more information is needed before they can be well classified. The 
 last are mere prospects. The mines in ChafPee County have been the 
 only actual producers. There are three principal claims — the Cal- 
 umet, Hecla, and Smithtield. They extend continuously over 4000 
 feet. The wall rock is called syenite. Chauvenet describes them 
 as having resulted from the oxidation of pyrites, and as being in 
 rocks of Silurian age. They average 57^ Fe, with only 0.009 P, 
 but are comparatively high in S, reaching 0.1 to 2.0^. These mines 
 and those at the Hot Springs, mentioned under Example 2, have 
 furnished the Pueblo furnaces with most of their stock. The de- 
 posit in Fremont County is at Iron Mountain, but is too titanifer- 
 ous to be valuable. It is a lenticular mass in so-called diorite. A 
 large ore body has been reported from Costillo County, in limestone 
 (Census Report) or syenite (Rolker). In Gunnison County, at the 
 Iron King and Cumberland mines, excellent ore occurs in quartz- 
 ites and limestones, called Silurian. At Ashcroft, near Aspen, 
 high up on the northern side of the Elk Mountains, is a great bed 
 or vein of magnetite, in limestones of Carboniferous age, with 
 abundant eruptive rocks near. It is thought by Devereux to be al- 
 tered pyrite. Still, pyrite is a common thing with magnetite else- 
 where. There are other smaller deposits in Boulder County and 
 elsewhere in the State.' 
 
 2.03.09. In Wyoming an immense mass of titaniferous magne- 
 tite is known near Chugwater Creek. It is described by Hague as 
 resembling a great dike in granite.^ Gabbro is in the neighborhood. 
 
 2.03.10. Example 12e. California Magnetite. Beds of mag- 
 netite of lenticular shape in metamorphic slates and limestones on 
 the western slope of the Sierra Nevada. Others of different char- 
 acter are also known. In Sierra and Placer counties lenses of 
 excellent ore are found, accompanying an extended stratum of lime- 
 
 1 E. Chauvenet, " Papers on Iron Prospects of Colorado," Ann. Reps. 
 Colo. State School of Mines, 1885 and 1887 ; a'so M. E., Denver meeting, 
 1889. Eeo. W. B. Devereux, " Notes on Iron Prospects in Pitkin County, 
 Colorado," M. E., XII. 608. B. T. Putnam, Tenth Census, Vol. XV., p. 
 472. Eec. C. M. Rolker, " Notes on Iron Ore Deposits in Colorado," 
 M. E., XIV. 306. Rec. 
 
 2 " Iron Mountain, Wyoming," 40<7i Parallel Survey, Vol. II., p. 14. 
 
MAGNETITE AND PYBITE. 145 
 
 stone in chlorite slate. A great ore body of magnetite described 
 as a vein has lately been reported from San Bernardino County. 
 It is said to be from 30 to 150 feet thick, and to lie between dolo- 
 mitic limestone and syenite.' A great bed of a kind not specified 
 is reported from San Diego County.^ 
 
 2.03.11. Example 13. Masses of titaniferous magnetite in 
 igneous rocks which are most often gabbros or related types. 
 General comments were made upon these in 1.06.14 and 1.06.16. 
 In many cases such ore bodies seem undoubtedly to be excessively 
 basic segregations of fused and cooling magmas. Whether the 
 tendency of these early crystallizations to concentrate is due to 
 Soret's principle, to magnetic currents or attractions, or to the high 
 specific gravity of the mineral which might cause it to sink in the 
 magma is perhaps not always clear, for all these explanations have 
 been suggested. The masses are not yet of practical value in North 
 America, and hence are not, strictly speaking, ores, but no one fa- 
 miliar with their size and amount can resist the conviction that 
 they will ultimately be utilized. The commonest rocks form- 
 ing the walls are gabbros, norites, diorites or peridotites, all 
 of which are close relatives. Later metamorphism, such as moun- 
 tain-making processes and the like, sometimes give the wall-rock a 
 gneissic structure and stretch out the ore into apparent beds. In 
 the great series of labradorite rocks, which is so extensive in 
 Canada and the Adirondacks, and which was called by T. S. Hunt 
 the Norian, these ores are very abundant. What are doubtless the 
 largest masses of them in this region occur at the headwaters of 
 the Hudson Kiver near Lake Sanford and Lake Henderson. Prof. 
 E. Emmons, of the New York Geological Survey in 1835-40, de- 
 scribed them at length in his report on the Second District. For 
 some 15 or 20 years a small charcoal furnace treated them to ad- 
 vantage but was blown out before the war. A recent survey by 
 Uno Sebenius has indicated even more ore than was known to 
 Emmons, although he recorded a mass 500 feet wide and 1600 
 
 1 Ann. Rep. State Mineralogist, 1889, p 335. 
 
 2 Ibid., 1889, p. 154. J. R. Browne, " Mineral Resources West of the 
 iJocky Mountains," 1868. C. King and J. D. Hague, "Mineral Resources 
 West of the Rocky Mountains," 1874, p. 44. H. G. Hanks and W. Irelan, 
 Ann. Reps. State Mineralogist, California. (Very little on iron.) F. von 
 Eichthofen, private reports quoted in Tenth Census, Vol. XV., p. 495. 
 J. D. Whitney, Oeol. Survey Cal, Vol. I. 
 
146 KEMP '8 ORE DEPOSITS. 
 
 feet long. Smaller bodies are frequent elsewhere in the Adiron- 
 dacks^ (as at the Split Kock Mine, Westport, the Crag Harbor, 
 Port Henry, the Humbug Vein, Mineville). The TiOj ranges up 
 to about 15^ and with it is much AI2O3, but on the other hand 
 very little sulphur or phosphorus. Whether the TiOo is present 
 in mechanically mixed non-magnetic ilmenite (menaccanite) or in 
 an actually titaniferous magnetite is not always clear. This ques- 
 tion has its practical bearings, for hopes have been entertained that 
 magnetic concentration might reduce the TiO^- It cannot be 
 relied on, however, for 0. A. Derby has mentioned to the writer 
 natural lodestone from Brazil with 20^ TiOg. 
 
 Fairly high titaniferous ores occur in New Jersey on Schooley's 
 Mountain and to the southwest of it. Small percentages up to 1^ 
 TiOj are known in many other magnetites.^ The wall rocks of 
 these ores deserve microscopic determination so as to compare them 
 with the Adirondack gabbros. 
 
 Titaniferous ores are also known in Virginia and North Caro- 
 lina,3 in the gabbros of Minnesota (2.02.35), in "Wyoming (2.03.09), 
 and in Colorado (2.03.08). Microscopic determinations of the wall 
 rock in the western cases would be of great interest. The geolog- 
 ical relations of these ores have long been known in Sweden and 
 Norway, but an igneous form of origin has of late received especial 
 attention from J. H. L. Vogt (see 1.06.16). 
 
 2.03.12. Example 14. Cornwall, Pa. Deposits of soft mag- 
 netite, resting against igneous dikes and associated with green, 
 pyritous shales, Siluro-Cambrian limestone and Triassic sandstone. 
 These ore-bodies are to be classed among the largest ever mined. 
 They form three hills extending in an east and west direction and 
 called respectively Big Hill, Middle Hill and Grassy Hill. As 
 the accompanying contour map shows. Big Hill is the highest and 
 
 ' E. Emmons, Rep. on Second District, N. Y. State Survey, pp. 244- 
 255, 1843. J. F. Kemp, ' ' Iron Ores in Moriah and Westport Townships, 
 Essex County, N. Y. , in Rep. of F. J. H. Merrill on the K. Y. State Ex- 
 hibit at the World's Fair. A. J. Rossi, "Titaniferous Ores in Blast 
 Furnace,'' Trans. Amer. Inst. Min. Eng., Feb., 1893. J. C. Smock, 
 Bulletin N. Y. State Museum, p. 37. 
 
 2 B. F. Fackenthal, Trans. Amer. Inst. Min. Engineers, XXI. 378. 
 R. W. Raymond, Ihid., 374. 
 
 " H. B. C. Nitze, ' ' Notes on Some of the Magnetites of Southwest 
 Virginia and the Contiguous Territory of North Carolina, ' ' Trans. Amer. 
 Inst. Min. Eng., XX. 174; " Magnetite Iron Ores of Ashe Co. , N. C. , Ibid., 
 XXI. 372 ; "Iron Ores of North Carolina, ' ' Bull. I., X. C. Geol. Sur., 1893. 
 
MAGNETITE AND P TRITE. 
 
 147 
 
 narrowest, while Middle Hill contains the most ore. The hills lie 
 just at the southeastern edge of the Great Valley and are six miles 
 from the flourishing little city of Lebanon. The geological section 
 (Fig. 34) illustrates the position of the strata. The Siluro-Cam- 
 brian series is cut by an immense diabase dike near its southeastern 
 limit, and on the south side of the dike which forms the northern 
 rampart of the three hills lies the ore. The ore is a soft, rather 
 
 .^cale ofjuil^a. 
 
 Fig. %^.— Section along Cormvall Railroad from Lebanon to Miner''s Vil- 
 lage. After E. V. Wlnvilliers, Amer. Inst. Min. Eng., Feb., 1886. 
 
 earthy magnetite, which occasionally sliows octahedra. While 
 richer and purer on the original weathered surface, it is now in 
 terlaminated and closely involved with layers of limy shales which 
 contain pyrite, at times in beautiful crystals. Most of the ore is 
 merchantable raw, but large quantities are so low from this admix- 
 ture of shales that they are being saved for possible future mag- 
 netic concentration. The presence of the pyrite makes it neces- 
 sary to roast all the raw ore before smelting, but the phosphorus is 
 so low that Bessemer pig is the chief resulting product. 
 
 Big Hill differs from the others in structure. The nothern dike 
 with a steep southerly dip has an offsetting and very heavy branch 
 to the southwest which forms with it a great trough or basin so fa'r 
 as one can see. The bottom of the ore has been reached by one 
 rather shallow hole, but it seems quite certain that the dikes will 
 come together at a point indicated by the several dips. The sur- 
 face of the southerly branch is strongly corrugated. The ore of 
 Middle Hill extends to a greater distance south from the dike than 
 that of Big Hill and is cut by one small and unimportant offset of 
 trap that is two or three feet across. At the western end of the 
 
MAGNETITK AND PTRITE. MiJ 
 
 workings, limestone is quite thick and in good exposure. It reaches 
 well over to Grassy Hill. Grassy Hill is smaller, and is much less 
 developed than either of the others. E. V. d'Invilliers has empha- 
 sized the important point that the dip of the ore in Big Hill is south- 
 west at such an angle as to bring it below the Middle Hill bed, and 
 that this latter also dips below the limestone and the Grassy Hill 
 beds. Such being the case enormous reserves must lie under the 
 two western hills. The depths of the several bore holes given on the 
 map and all in ore indicate its presence in very great amount, but 
 it is important to show in this connection the absence of faults, for 
 the map of Bailey Willis notes their presence, and observations of 
 the writer corroborated their existence. 
 
 The pyrite in the calcareous shales is occasionally replaced by 
 chalcopyrite in irregular nodules or veiulets. The presence of 
 copper was early noted, and some mining was done for it near the 
 surface. Fine museum specimens of moss-copper, azurite, mala- 
 chite, etc., were afforded. Even during the earlier iron-mining 
 some copper ore was set aside as a small by-product. Copper is 
 still present in the mine-water, for bright shovels left in it become 
 coated, and the bones of dead animals thrown out on the ore banks, 
 as well as chips of wood, etc., become tinted a bright green. 
 
 Much difEerence of opinion has prevailed about the age and geo- 
 logical relations of these ores. Some have thouglit them Mesozoio 
 and a part of the Triassic, while others, and notably J. P. Lesley, 
 have regarded them as belonging to the Siluro-Cambrian series and 
 analogous to the limonites of the Great Valley but metamorphosed. 
 The great trap dikes afford the most reasonable explanation or 
 cause of the change, and to these may be referred the alteration. 
 The apparent origin of many Siluro-Cambrian limonites from the 
 hydration and oxidation of pyritous shales and schists gives much 
 support to this view, and the association of limestone with the ore 
 and the general stratigraphical relations are hard to explain in any 
 other way.^ 
 
 The total production to date (April, 1894) is stated by Mr. 
 Boyd, the superintendent of the mines, to be upwards of 12,000,000 
 
 IE. V. d'Invilllers, "Cornwall Iron Ore Mines," Trans. Amer. 
 Inst. Min. Eng., XIV. 873. Rec. Lesley and d'Invilliers, Ann. Eep. 
 Second Penn. Oeol. Suv., 1885, 491. Reo. J. P. Lesley, Pinal Rep., I. 
 351, 1893. T. S. Hunt, "The Cornwall Mines, " etc., Trans. Amer. Inst. 
 Min. Eng., IV. 819. H. D. Rogers, First Penn. Oeol. Svrv., II. 718. B. 
 WiUis, Tenth Census, XV. 233. 
 
150 KEMP'S UBK DEPOSITS. 
 
 tons, while an annual output of 800,000 can be easily maintained. 
 The on; varies from 40 to 55^ Fe. It almost never contains as much 
 as 0.02 P., but runs up to 4^ S. It is also siliceous. 
 
 2.03.13. Several other mines of somewhat related character to 
 the Cornwall deposits are known along the edges of this Triassic 
 belt and associated with its trap intrusions. The mining districts lie 
 near its north and south boundaries, and not far from its contacts 
 with the older rocks. On the north side from east to west there 
 are the Boyertown (Berks County), the Fritz Island and the Wheat- 
 field, near Reading, and finally the Dillsburg in York County, west 
 of the Susquehanna. On the south side in the same order are the 
 Frencli Creek, St. Mary's and the Jones, all quite near together 
 and nearly south of Reading. Of these the Boyertown mines have 
 been most worked. ^ The Cornwall mines are between the Wheat- 
 field and the Dillsburg. At the Boyertown mines the ore lies both 
 between a brecciated limestone and Mesozoic sandstone and wholly 
 within the limestone, but trap dikes are not lacking. At Fritz 
 Island the ore is entirely enclosed in limestone, and is penetrated 
 by a trap dike. In the Wheatfield mines the same brecciated 
 limestone appears and has the ore intimately associated with 
 it. On both occurs the Mesozoic sandstone and the succession 
 is five times repeated by faulting. The usual trap penetrates the 
 ore. The French Creek and St. Mary's mines are unique in that 
 they are contained in gneiss. They are famous sources of fine 
 crystals of pyrite, chalcopyrite and other minerals. The Jones 
 mine exhibits the ore between trap and limestone, the trap being 
 over the ore in the north pit and under it in the south. A green 
 shale is also met here, as indeed in most of the other localities, 
 although not specially mentioned. At Dillsburg the evidence 
 against the Triassic age of the ores is less positive, and upon this 
 occurrence Fraser has based a strong argument for the latter view. 
 Triassic sandstone at times forms both walls, although there are 
 instances where limestone appears as the foot. In all these local- 
 ities the presence of copper is notable. It and the magnetic or 
 metamorphosed condition of the ore are probably leferable to the 
 trap. 
 
 ' B. WiUis, Tenth Census, Vol. XV., 323. Rec. P. Fraser, "Study 
 of the Specular and Hematite Ores of Iron of the New Red Sandstone, 
 in York County, Penn. , Trans. Amer. Inst. Min. Eng., V. 132. Also 
 Perm. Oeol. Survey, Bep. CC, 205, 217. H. Hoefer, "Die Kohlen und 
 Eisenerzlagerstatten Nord Amerika's, " 241. 
 
MAGNETITE AND P TRITE. 151 
 
 2.03.14. Example 14a. Iron County, Utah. Beds of mag- 
 netite and hematite bearing evidence of being metamorphosed 
 limonite, in h'mestones of questionable Silurian age, and associated 
 with eruptive rocks described as trachyte. The limestones have 
 been much upturned, metamorphosed, and pierced by dikes and 
 eruptive masses. The ore forms great projecting ridges and prom- 
 inent outcrops, locally called " blow-outs." The usual lenticular 
 shape is not lacking. They occur over an area of fifteen by five 
 miles, and are in the southern end of the Wasatoh Mountains. 
 The samples show rich ores, which at times exceed the Bessemer 
 limit of phosphorus. In the Star district the ore apparently lies 
 between quartzite and granite. Hematite occurs in large amount, 
 as does quartz, while some streaks have large crystals of apatite. 
 The importance of the deposits lies in the future. They are the 
 largest in the West, and are interesting in their bearing on the 
 general origin of magnetite. Coal, not proved to be good for 
 smelting, is near, but centers of iron consumption are very far 
 away.' 
 
 2.03.15. Example 15. Magnetite Sun>l8. Beds of magnetite 
 sands concentrated on beaches or bars by waves and streams. 
 The magnetite has been derived from the weathering of igneous 
 and metamorphic rocks, through which it is everywhere dis- 
 tributed. When in the sand of a sea beach, it and other heavy 
 minerals tend to be concentrated by the sorting action of the waves. 
 They resist the retreating undertow better than lighter materials. 
 Such deposits are very abundant at Moisie, on the St. Lawrence, 
 below Quebec, and in the United States are known in smaller de- 
 velopments on Lake Champlain ; at Quogue, L. I.; on Block 
 Island ; in Connecticut ; along the Great Lakes, and on the Pacific 
 coast. Grains of garnet, olivine, hornblende, etc., minerals of high 
 
 Also Penn. Survey, Rep. C2. E. V. D'lavilliers, "Cornwall Iron Ore 
 Mines,'' M. E., XIV. 873. Rec. Lesley and D'lQvilLers, Ann. Rep. Second 
 Penn. Survey, 1885. J. P. Lesley, Final Report, Vol. I., p. 351, 1892. Rec. 
 T. S. Hunt, "The Cornwall Mines," etc., M. E., IV. 319. H. D. Rogers, 
 First Penn. Geol. Survey, II. 718. B. Willis, Tenth Census, Vol. XV., p. 
 233. Rec. 
 
 1 W. P. Blake, "Iron Ore Deposits of Southern Utah," M. E., XIV. 
 809. J. S. Newberry, " Genesis of Our Iron Ores," School of Mines Quar- 
 terly, March, 1880. Rec. Engineering and Mining Journal, April 23, 
 1881, p. 286. Proc. National Academy, 1880. B.T.Putna,m, Tenth Census, 
 Vol. XV. 486. Rec. 
 
152 KEMP'S ORE DEPOSITS. 
 
 specific gravity, are also in the sands. Many are too high in 
 titanium to be of use, but there is no more difficulty in concentrat- 
 ing them than artificially crushed ore. In Brazil and New Zea- 
 land they have attracted attention. * 
 
 3.03.16. Onthe Origin of Magnetite Deposits. — It is important 
 to note that magnetite deposits are almost always in metamorphic 
 rocks, Avhich owe their character to regional metamorphism, or to 
 the neighborhood of igneous rocks (Pennsylvania and Utah). 
 Gneisses form the commonest walls, but so-called norites, or gab- 
 bros, and crystalline limestones also contain them. Where there 
 is lamination, or bedding, the magnetite conforms to it. As the his- 
 tory of the metamorjDhic rocks is so often uncei'tain, the magnetites 
 share the same doubt. In igneous rocks magnetite is the most 
 widely occurring of the rock-making minerals. In all explanations 
 the prevailing lenticular shape, the general arrangement in linear 
 order, and the existence of great beds must be considered. The 
 shape is very similar to that of dej>osits of specular hematite, with 
 which magnetite is often associated. (Examples 9 and 10.) The 
 following hypotheses have been advanced as to their origin : 1. As 
 intruded (eruptive) masses. This supposes an origin for the lenses 
 on the analogy of a trap dike. Though formerly much advocated, 
 it is now generally rejected. 2. As excessively basic portions of 
 igneous rocks. This supposes that large amounts of iron oxide 
 separate in the cooling and crystallizing of basic magmas. There 
 are such occurrences, although seldom, if ever, pure enough or 
 abundant enough for mining. The titaniferous magnetite of the 
 Minnesota gabbros has been alluded to (2.02.25), and also the 
 Brazilian ore and the Cumberland Hill (R. I.) peridotite. (See 
 also Dakyns and Teall, Q. J. G. S., XLYIII., p. 118.) Should 
 such igneous rocks be subjected to regional metamorphism and 
 the stretching action characteristic of it, the ore masses might be 
 drawn out into lenses. .3. As metamorphosed limonite beds. This 
 idea has been most widely accepted in the past. It presupposes 
 limonite beds formed as in Examples 1 and 2, which become buried 
 and subjected to metamorphism, changing the ore to magnetite 
 and the walls to schists and gneisses. Igneous rocks have ap- 
 parently changed limonites to magnetite at Cornwall, Penn., and 
 in Utah, but such changes by regional metamorphism are less easy 
 
 1 T. S. Hunt, Geol. Survey Canada, 1866-69, 361, 363; Canad. Nat, 
 VI. 79. A. A. Julieo, " The Genesis of the ( rystalline Iron Ores," Acad. 
 Nat. Sci., Phil., 1882, 335 ; Ewjineering and Mining Journal, Feb. 2, 1884. 
 
MAGNETITE AND PTBITE. 153 
 
 to demonstrate. The limonite may Lave resulted from, the oxida- 
 tion of lenses of pyrite. 4. As replaced limestone beds, or as sider- 
 ite beds subsequently metamorphosed. Such deposits may pass 
 through a limonite stage. The general process is outlined under 
 Example 9e, as developed by Irving and Van Hise in the Gogebic 
 district. The lenticular deposits of siderite at the Burden mines 
 (Example 4) are very suggestive, and some such original mass 
 might in instances be metamorphosed to magnetite. 5. As sub- 
 marine chemical precipitates. This is outlined under Example 9c?, 
 as applied by the Winchells in Minnesota. 6. As beach sands. 
 The lenses are regarded as having been formed as outlined under 
 Example 15. The same heavy minerals sometimes occur with 
 magnetite lenses as are found on beaches. (See B. J. Harrington, 
 Can. Geol. Survey, 1873, 193 ; A. A. Julien, Phil. Acad. Sci., 
 1882, 335.) v. As river bars. This regards the lenses as due to 
 the concentration of magnetite sands in rivers or flowing currents. 
 Hence the overlapping lenses, the arrangement in ranges or on lines 
 of drainage, and the occasional swirling curves found on the feather- 
 ing edges of lenses, as in the Dickerson mine, Ferromont, N. J. 
 (See H. S. Munroe, School of Mines Quarterly, Vol. HI., p. 43 — an 
 important paper.^ It is also reasonable to suppose that lakes or 
 still bodies of water may have occurred along such rivers, and have 
 occasioned the accumulation. 8. As segregated veins. By this 
 method the iron oxide is conceived to concentrate from a state of 
 dissemination in the walls by slow segregation in solution to form 
 the ore bodies along favorable beds. The action is analogous to 
 the formation of concretions and is illustrated on a small scale 
 by the well-known discs of pyrite, or of siderite, that form in clays 
 and shales. It is a curious fact, however, that some magnetites 
 are in wall rock that hardly shows a trace of a dark silicate. 
 The lenses at Hammondville, in the Lake Champlain district, are 
 in a white or light colored gneissoid rock, consisting of quartz, 
 acidic plagioclase, and a few scattered garnets. In such surround- 
 ings segregation could not be applieJ, but where the walls are sup- 
 plied with hornblende, and other ferruginous minerals, and are 
 reasonably basic, it might be advocated. 
 
 Several other hypotheses with small claims to credibility could 
 be cited. They are outlined at length in Bull. VI., Minn. Geol. 
 Survey, p. 224, but in this place there has been no desire to take up 
 any but those deserving serious attention. It may be said that while 
 one or the other of the above seven bypotlieses may in instances be 
 
154 
 
 KEMP'S ORE DEPOSITS. 
 
 applied with reason, yet most candid observers with widened ei- 
 perience have grown less positive in asserting them as axiomatic. 
 
 2.03.15. Of importance in connection with iron ore deposits 
 are the recent studies of the distribution of phosphorus along 
 certain lines in the beds, by a knowledge of which it is possible to 
 keep more valuable Bessemer ore distinct from less valuable. 
 Such lines have been found in Michigan, and have been called 
 by Mr. Browne " isochemic lines." Though less marked at the 
 Burden mines (Example 3), the phosphorus was characteristic of 
 certain varieties of the ore. Much work has also been done on 
 the same question at Iron Mountain, Mo.' 
 
 ANALYSES OF MAGNETITES. 
 
 (Caution in interpreting analyses is again emphasized .as under 2.01.26.) 
 
 Fe. 
 
 P. 
 
 S. 
 
 TiOa. 
 
 SiOj. 
 
 60.28 
 
 
 
 9.80 
 
 
 49.34 
 
 0.029 
 
 0.052 
 
 
 18.447 
 
 66.00 
 
 0.003 
 
 
 
 
 62.10 
 
 1.198 
 
 
 
 
 63.00 
 
 0.621 
 
 0.148 
 
 
 
 48.82 
 
 0.021 
 
 0.08 
 
 
 11.75 
 
 53.75 
 
 0.364 
 
 
 
 
 42.7 
 
 0.185 
 
 0.620 
 
 
 
 64.64 
 
 0.004 
 
 0.115 
 
 
 
 49.23 
 
 0.026 
 
 
 
 3.85 
 
 58.75 
 
 0.044 
 
 0.133 
 
 
 
 62.6 
 
 
 0.12 
 
 
 4.80 
 
 60.68 
 
 
 
 
 10.87 
 
 AljO, 
 
 Canada (Bideau Canal) 
 
 Chateaugay mines, N. Y . , lump . . 
 " " concentrated. 
 
 Mineville, N. Y. (Mine 21) 
 
 Orange County, N. Y. (Forest of 
 
 Dean) 
 
 Putnam County, N. Y 
 
 New Jersey (Hibernia) 
 
 Cornwall, Penn 
 
 Cranberry, N. C 
 
 Colorado (Calumet) 
 
 " (Iron King) 
 
 Utah (Iron County) 
 
 California (Gold Valley) 
 
 3.50 
 3.411 
 
 PYEITE. 
 
 2.03.16. Example 16. Pyrite Beds. Beds (veins) of pyrite, 
 often of lenticular shape and of character frequently analogous to 
 magnetite deposits, in slates and schists of the Cambro-Silurian or 
 Huronian systems, and less often in gneiss of the Archean. Slates 
 are most common, and gneiss least so. They extend from Canada 
 down the Appalachians to Alabama, being found at Capelton, 
 
 1 D. H. Browne, " On the Distribution of Phosphorus at the Ludding- 
 ton Mines." etc., M. E., XVII., p. 616. I. Olmsted, " The Distribution of 
 Phosphorus in the Hudson River Carbonates," M. E., Colorado meeting, 
 June, 1889. W. B. Potter, Analyses of Missouri ore published in Mineral 
 Resources, 1890, p. 47. 
 
MAGNETITE AND P 7 RITE. 155 
 
 Quebec ; Milan, N. H. ; Vershire, Vt. ; Charlemont, Mass. (An- 
 thony's Nose, N. Y., and the Gap mine, Pennsylvania, being pyr- 
 rhotite, will be mentioned under " Nickel " with other similar oc- 
 currences) ; Louisa County, Virginia ; Ducktown, Tenn. (see above, 
 Fig. 6), and at many points less well known in Alabama. Also 
 at Sudbury, north of Lake Superior, recent developments have 
 shown an enormous deposit, specially discussed under " Nickel." 
 
 2.03.17. The ore bodies lie interbedded in the slates, and often 
 the different lenses overlap and succeed each other in the footwall 
 and exhibit all the phenomena cited under magnetites. Chalco- 
 pyrite is usually present in small amount, and where the copper 
 reaches 3 to b% they are valuable as copper ores. (See under 
 
 ^^^^^2ZZZ2^ 
 
 y////y/////////////'/y//y^y^^''''^y^^^'''''''-'''''''>y 
 
 
 Fig. 86. — Illustration of overlapping lenses of pyrite. After A. F. Wendt, 
 School of Mines Quarterly, Vol. VIZ., 1886. 
 
 "Copper.") At present they are of increasing importance as a 
 a source of sulphuric acid fumes for the manufacture of sulphuric 
 aoid. Small amounts of lead and zinc sulphide are often present, 
 rarely a little silver. Nickel and cobalt occur especially in the pyr- 
 rhotitic varieties. They are worthless as a source of iron. The 
 auriferous pyrites of the Southern States will be mentioned under 
 "Gold." 
 
 2.03.18. They may have accumulated in a way analogous to 
 the bog ore hypothesis, cited under " Magnetite ; " but instead of 
 the iron being precipitated as oxide, it has probably come down as 
 sulphide from the influence of decaying organic matter, and has 
 subsequently shared in the metamorphism and solidification of the 
 
156 KEMP'S ORE DEPOSITS. 
 
 wall rock. At the same time it must be admitted to be an obscure 
 point. By many they are thought, with more reason, to have 
 originated like a bedded fissure vein whose overlapping, lenticular 
 cavities have been formed by the buckling of folded schists.* (Of. 
 '•' Gold Quartz," as later described.) 
 
 3.03.19. The excavations in some of the mines in the pyrite 
 beds of Canada, just north of the Vermont line, have shown dikes 
 of granite in close association with the ore. Thin sections of the 
 granite indicate that it has suffered extremely severe dynamic 
 metamorphism, for crushed and strained crystals make up nearly 
 all of its substance. It is quite probable that the disturbance 
 which caused the schistosity or slaty cleavage of the country lock 
 likewise developed the strains in the granite which must thus have 
 been intruded previous to its operation. Before the shattering the 
 dikes may have exerted a genetic influence in connection with the 
 ore body, but now the ore is usually lean near them. The ore 
 bodies are also cut by fine examples of the trap (camptonite) dikes 
 ■which are abundant in the Lake Champlain Valley. Prof. J. H. 
 L. Vogt, of Christiania, Norway, has written of late regarding the 
 origin of similar great bodies of sulphides in Europe, and when 
 they occur in connection with rocks, which though now gneissoid 
 have been originally igneous, he regards them as basic segregations 
 of an igneous magma. (See further 1.06.16.) Where they occur 
 in schists he attributes their formation to ore-bearing solutions, 
 penetrating along planes of weakness, and stimulated by neighbor- 
 ing igneous intrusions. In some of the instances cited the known 
 
 1 W. H. Adams, " The Pyrites Deposits of Louisa County, Virginia," 
 M. E., XII., p. 527. C. R. Boyd, " The Utilization of the Iron and Copper 
 Sulphides ot Virginia, North Carolina, and Tennessee," M. E., XIV., p. 81; 
 Resources of S. W. Virginia. H. Credner, " AtSt. Anthony's Nose, Hudson 
 River,'' B. und H. Zeit., 1866, p. 17 ; "Pyrite in Virginia, Tennessee, and 
 Georgia," B. und H. Zeit., 1871, p. 370. H. T. Davis, Mineral Resources 
 of the U. S., 1885, p. 501. H. M. Howe, " The Copper Mines of Vermort," 
 M. E., Baltimore meeting, February, 1892. William Marty n, Mineral Re- 
 nources, 1883-84, p. 877. E. C. Moxham, "The Great Grossan Lead of 
 Virginia " (altered pyrite in CarroU County), M. E., February, 1893. A. 
 F. Wendt, "The Pyrites Deposits of the AUeghanies, " School of Mines 
 Quarterly, Vol. VII. , and separate reprint ; also Engineering and 3Iining 
 Journal, June 5, 1886, p. 32 and elsewhere. Rec. H. A. Wheeler, 
 ' ' Copper Deposits of Vermont, ' ' School of Mines Quarterly, IV. 310. 
 Arthur Winslow, ' ' Pyrites Deposits of North Carolina, ' ' Ann. Kept. N. 
 C. Experiment Station, 1886. 
 
MAGNETITE AND PyRITB.. 157 
 
 igneous intrusions (as at Rammelsberg) are at some distance and 
 tlms are not directly associated, so far as one can see, witli the ore. 
 The genetic connection is therefore somewhat hypothetical. 
 
 3.03.30. The relative importance of the different kinds of 
 ore is shown by the following tables for 1880 and 1890. The 
 increase in red hematite is due to the Lake Superior region and to 
 Alabama. In the immediate future the soft ores of the Mesabi 
 district will help to greatly swell the total, but during 1893-94 
 there was great depression in the mining of iron ore throughout 
 the country. 
 
 1880. 
 
 Red hematite 2,512,',' l;j 
 
 Magnetite 2,390,389 
 
 Brown hematite 2,149,417 
 
 Carbonate 922,288 
 
 Per cent. 
 
 
 Per cent. 
 
 of Total. 
 
 1890. 
 
 of Total. 
 
 31.51 
 
 10,527,650 
 
 65.65 
 
 39.98 
 
 2,570,838 
 
 16.03 
 
 26.95 
 
 2,559,938 
 
 15.96 
 
 11.56 
 
 377,617 
 
 2.36 
 
 7,974,806 100.00 16,036,043 100.00 
 
 As indicating the relative importance of the different mining 
 regions, the following figures are of interest. No individual State 
 producing less than 100,000 tons is given. 
 
 states. Total in mo. States. Total in 1S90. 
 
 Michigan 7,141,656 New Jersey 495,808 
 
 Alabama 1,897 815 Tennessee 465,695 
 
 Pennsylvania 1,361,632 Georgia 344 088 
 
 New York 1,353,393 Missouri 181.690 
 
 Wisconsin 948,965 Ohio 169 088 
 
 Minnesota 891.910 Colorado 114 875 
 
 Virginia 543,583 All the others 326.455 
 
 Grand total 16,036,043 
 
 2.03.21. Note. Large quantities of excellent Bessemer hema- 
 tite are shipped to Baltimore and other Atlantic ports from the 
 mines on the southeastern coast of Cuba, in the Juragua Hills. 
 Santiago de Cuba is the largest town in this region and is some 
 twenty miles west of the mines. The coast range of hills consists 
 mainly of syenite, according to J. P. Kimball, and the syenite is 
 penetrated by many dikes and mantled by sheets of diorite with 
 which the ores are associated. Kimball refers the precipitation 
 of much of the iron oxide which came from the diorite to coral- 
 line limestone, which had been accumulated as coral reefs on the 
 syenite before the diorite was intruded, but he also mentions other 
 deposits in the diorite not associated with limestone. From observ- 
 
158 KEMP'S ORE DEPOSITS. 
 
 ations of another group of ores sixteen miles east of those studied 
 by Kimball, F. F. Chisholm reached a dififerent conclusion regarding 
 their origin. Chisholm refers them to a source below and apparently 
 regarded them as veins or replacements of dikes. The amount of 
 ore along this coast, both in place and as float is very great,' and 
 will be an important feeder to American furnaces. Between three 
 and four hundred thousand tons are now annually imported. Chis- 
 holm gives the following analysis: 
 
 Fe. s. p. 
 
 Juragua (Kimball) 64.75 0.146 0.037 
 
 Sigua (Graham) 64.00 0.040 0.016 
 
 Berraco (Chisholm) 60.00 0.037 0.027 
 
 Although not a source of supply for American furnaces, it is in- 
 teresting to note in this connection' that in Mexico vast deposits of 
 hematite and martite occur in Cretaceous limestone associated with 
 intrusions of diorite. The paper of K. T. Hill cited below gives a 
 review and full bibliography of the various localities. The notable 
 deposits so far as yet opened up are the Cerro de Mercado, in Du- 
 rango,^ the Sierra de Mercado, near Monclova in Coahuila,' and 
 
 ' J. P. Kimball, ' ' Geological Relations and Grenesis of the Specular 
 Iron Ores of Santiago de Cuba," Amer. Jour. ,Sci., Dec. , 1884, p. 416; 
 also "The Iron Ore Range of the Santiago District of Cuba, " Trans. 
 Amer. Inst. Min. Eng., XIII. 613; Eng. and Min. Jour., Dec. 20, 1884, p. 
 409. F. F. Chisholm, "Iron Ore Beds in the Province of Santiago, 
 Cuba," Proc. Colo. Sci. Soc, in. 259, 1890. H. Wedding, "Die Eisen- 
 erze der Insel Cuba," Stahl und Eisen, 1892, No. 12. Prof. J. W. 
 Spencer has been recently workiiig on the geology of Cuba and pre- 
 sented some of his results at the meeting of the American Association 
 in Brooklyn, August, 1894. 
 
 2 J. Birkinbine, ' ' The Cerro de Mercado or Iron Mountain of Du- 
 letngo," Trans. Amer. Inst. Mill. Eng., Xni. 189, 1884. J. P. Carson, 
 "Iron Manufacture in Mexico," Idem., VI. 899. R.T.Hill, "The Oc- 
 currence of Hematite and Martite Iron Ores in Mexico, " Amer. Jour. 
 ,S'ci., February, 1893, 111. B. SiUiman, "Mai-tite of the Cerro de Mer- 
 cado or Iron Mountain of Durango, and Certain Iron Ores of Sinaloa, ' ' 
 Amer. Jour. Sci., Nov., 1882, 875. See also on the Durango Iron Moun- 
 tain, Anales del Ministerio de Fomento de la Rep. Mej:icana Tomo., TIT. 
 1877 ; and Engineering and Mining Journal on "Iron in Mexico," Nov. 
 10, 1888, p. 891. 
 
 " P. Fraser, ' ' Certain Silver and Iron Mines in the States of Neueva 
 Leon and Coahuila, Mex.," Trans. Amer. Inst. Min. Eng., XII. 537. R. 
 T. HiU, as cited in previous footnote. 
 
MAGNETITE AND PTRITE. 159 
 
 others of minor importance in the States of Jalisco/ Guerrero^ and 
 elsewhere. Several of these are now the basis of a small local 
 smelting industry. 
 
 ^ J. P. Carson, as cited in second footnote, page 158. 
 
 ^ N. S. Manross, ' ' Notes on Coal and Iron Ores in State of Guer- 
 rero, Mex. , Amer. Jour. Sci., May, 1865, p. 309 ; Remarks by J. D. Dana, 
 p. 358. 
 
CHAPTER IV. 
 
 COPPER. 
 
 2.04.01. Copper Ores. 
 
 TABLE OF ANALYSES. 
 
 Cu. S. Fe. 
 
 Native copper (generally with some silver) 100. 
 
 Chalcocite, Cu^S 79.8 20.3 
 
 Chalcopyrite, CuFeSs 34.6 34.9 30.5 
 
 Bornite, CusFeSs 61.79 25.8 11.7 
 
 Tetrahedrite, 4CuS8Sb2S3 (variable) 26.50 Sb' 36.40 26.7 1.39 
 
 Enargite, Cu3AsS4(As.l9.1) 48.4 32.5 
 
 Cuprite, CusO. 88.8 
 
 Melaconite (tenorite), CuO 79.86 
 
 Malachite, 2CUO+CO2+H2O 57.4 
 
 Azurite, SCuO+COj+HaO 55.0 
 
 Chrysocolla, CuO+Si02+2H20 36.1 
 
 2.04.02. Example 16, Continued. Pyrite or pyrrhotite beds 
 (veins), with intermingled chalcopyrite. Whether the deposits 
 are true beds or veins parallel with the stratification is as yet a 
 matter of dispute. The resemblance to magnetite argues a bed, 
 and this view is generally taken by German writers. The Cali- 
 fornia mines occur closely associated with the auriferous (pyritous) 
 quartz bodies, which are always esteemed veins. The interbedded 
 lenticular deposits are placed by themselves as the main example. 
 The undoubted veins like Ore Knob, N. C, are then made a 
 sub-example. Pyrites and pyrrhotite (called mundic by the 
 miners) are the principal constituents of such bodies, but often the 
 copper reaches 4 to 5%, and then they are valuable for copper. 
 The ores are often roasted for sulphurous fumes in acid works, 
 and afterward the residues are returned to the copper smelters. 
 They have been or are being worked for this metal at Capel- 
 ton, Quebec, just north of Vermont. At Milan, N. H., there are 
 several deposits in argillitic schists, and in the same region are 
 numerous other locations. At Vershire, Vt., there is a belt some 
 
COPPER. 161 
 
 twenty miles long with three principal mining points. Of these 
 the middle one, containing the Ely mine, is the largest. Two 
 beds of ore occur, separated by from 10 to 20 feet of schists. The 
 lower averages about four feet, but fluctuates; the upfiev is still 
 more variable, and may reach 25 feet. They are both formed by 
 a succession of thin lenses. The ore is chalcopyrite, mingled with 
 pyrrhotite and quartz. At Ducktown, Tenn., which is in the ex- 
 treme southeast corner of the State, there are three ranges of ore 
 hills in a width of a mile. The outcrop is marked by great masses 
 of gossan, and below this, and along the contact with the sulphides, 
 was found the rich black ore which gave the early impetus to the 
 mines. When this was exhausted the sulphides alone remained. 
 They consist of chalcopyrite and pyrrhotite, with considerable 
 quartz and country rock, less often calcite. (See Fig. 7, p. 39.) 
 
 2.04.03. Example 16a. OreKnob, N. C This is described by 
 Kerr as a true fissure vein, extending 2000 feet on the strike, which 
 is parallel to that of the gneiss, but cutting the dip in descent. 
 The width averaged about 10 feet. The gossan extended to a 
 depth of 50 feet, and furnished the usual body of rich ore at the 
 contact with the sulphides. It has not been operated for some 
 years.^ 
 
 1 J. T. Bailey, " The Copper Deposits of Adams County, Pennsyl- 
 vania," Engineering and Mining Journal, Feb. 17, 1883, p. 88. H. Cred- 
 ner, "On Ducktown, Tenn.," B. und H. Zeit., 1867, p. 8. Engineering and 
 Mining Journal, Nov. 6, 1886, p. 337 (contains " The Elizabeth Copper Mines, 
 Vermont";) see also April, 1886. P. Fraser, "Some Copper Deposits of 
 Carroll County, Maryland," M. E., IX. 33; " Hypothesis of the Structure of 
 the Copper Belt of the South Mountain, Pennsylvania," M. E., XII. C. H. 
 Henderson, "Copper Deposits of the South Mountain, Pennsylvania," 
 M. E., XII. 85. C. H. Hitchcock, Geol. of N. H., Vol. III., Part III., p. 47. 
 H. M. Howe, "The Copper Mines of Vermont," M. E., February, 1892. 
 T. S. Hunt, "Ore Knob and Some Related Deposits," M. E., II. 135. 
 Kleinschmldt (on Virginia, Tennessee, and North Carolina), Gangstudien, 
 Vol. III., p. 356. (Agood, short, but oldaccount.) E E. Olcott, " Ore Knob 
 Copper Mine and Reduction Works," M. E., III. 391. Rho. Richardson, 
 ' Copper Ore of Stafford, Vt., Amer. Jour. Sci., I. 31, 383. Tripple and 
 Credner, "Report on the Ducktown Region to the American Bureau of 
 Mines," 1866. M. Tuomey, "A Brief Note of Some Facts Connected with 
 the Ducktown (Tenn.) Copper Mines," Amer. Jour. Sci., II. 19, 181. A. F. 
 Wendt, " The Pyrites Deposits of the AUeghanies," School of Mines Quar- 
 terly, Vol. VII., 1886 ; Engineering and Mining Journal, July 10 and fol- 
 lowing, 1886. Rec. H. A. Wheeler, "Copper Deposits of Vermont," 
 School of Mines Quarterly, Vol. IV., 319. Rec. 
 
163 KEMPS ORE DEPOSITS. 
 
 2.04.04. Example 165. Spenceville, Cal. Beds of pyrites 
 witli considerable chaloopyrite, in Jurassic slates, on the western 
 slopes of the Sierra Xevada. The Jurassic slates along the western 
 Sierras contain, in the gold belt, some mterbedded deposits of j)y- 
 rite with considerable chaloopyrite intermingled. The most im- 
 portant are at Newton, Amador County, Copperopolis and Campo 
 Seco, Calaveras County, and Spenceville, Nevada County. At the 
 first named there is a body of sulphides 7 to 8 feet wide and 
 proved about 400 feet. In the adjoining county of Calaveras, the 
 Union mine, at Copperopolis, is on a very large body of sulphides, 
 which impregnate the slates on each side without forming a very 
 sharp foot or hanging wall. The Campo Seco deposits are on the 
 same general line as the Copperopolis. The extension passes also 
 through those at Newton. A long distance north are the mines in 
 Spenceville, Nevada County. The general geology is similar, and 
 the ore body large. It affords from 3.50 to 5.50^ copper. All these 
 ores are worked by wet methods.' 
 
 Note. — For Examples 16c and I6cl see under "Nickel." 
 
 2.04.05. Example 17. Butte, Mont. Veins originally fissures, 
 or shear zones, but greatly enlarged by replacement of the walls 
 with ore, filled with copper sulphides, bornite, chaloopyrite, etc., in 
 a siliceous gangue. Much silver is associated with the copper. At 
 Butte there is a north and south valley six miles wide between high 
 granite ridges on the east and lower rhyolite ridges on the west. 
 The bounding heights north and south are still farther distant. 
 Near the middle of this valley the butte of rhyolite arises which 
 gives the town its name. Silver Bow Creek, which gives the name 
 to the county, flows south along the eastern ridge and then bends 
 westward at a point south of the butte, and, after flowing directly 
 across the valley, leaves it through the western ridge. In the half 
 of the valley east of the meridian of the butte is a very dark basic 
 granite, and also in the extreme west. It consists of quartz, 
 orthoclase, piagiocla.se, and an unusual amount of mica, augite, and 
 hornblende. In the part west and south of the butte is a highly 
 
 1 J. E. Ellis, "Oq the Speuceville Mines," Mineral Resources V. S., 
 1884, p. 340. H. G. Hanks, Rep. California State Mineralogist, 1884, p. 
 148. J. B. Hobson, "On Spenceville," Rep. California State Mineral- 
 ogist, 1890, p. 892. William Irelan, Jr., "On Calaveras County Mines," 
 Rep. California State Mineralogist, 1888, pp. 150-158. "On the Newton 
 Mines,'' ibid., p. 106. 
 
COPPER. 163 
 
 acidic, light-colored granite, which consists of quartz and ortho- 
 clase feldspar with a very little biotite. Dikes of quartz porphyry 
 penetrate the basic granite, and dikes of rhyolite are also found 
 associated with the ore bodies. Tongues of rhyolite are met, ap- 
 parently offshoots of the butte. 
 
 2.04.06. East of the butte and In the basic granite are found 
 the older mines along two strongly contrasted east and west zones. 
 A second, later-developed, group is west of the butte in the acidic 
 granite. Of the former, the southern affords argentiferous copper 
 ores, consisting of chalcocite, bornite, chalcopyrite, enargite, and 
 pyrite in a siliceous gangue. The northern zone contains silver 
 ores, chiefly sulphides of silver, lead, zinc, and iron, in a siliceous 
 gangue with much rhodonite. Strangely enough, hardly any cop- 
 per occurs in the silver zone, and no manganese is met in the copper 
 zone, except in the Gagnon vein, which also contains zinc. The 
 silver zone is mentioned again under " Silver." The zone west of 
 the butte is silver-bearing with manganese. The occurrence of 
 these two parallel systems of fissures in the same country rock and 
 not far from each other, yet filled with such contrasted ores, is a 
 very remarkable phenomenon and points to different and — at least 
 for one of them — deep-seated sources of the ores. 
 
 The copper-bearing zone begins on tlie west with the Gagnon 
 claim and runs eastward through the Original and Parrott. The 
 surface rises in a hill along this course, and the system of veins 
 with a jog to the north continues up-hill across the Anaconda and 
 St. Lawrence to the Mountain View on the summit. Thence it 
 passes down-hill through the Shannon, Colusa and Hattie Harvey. 
 The topography had an important influence on tlie character of 
 the veins when first exploited^ for wliile in the lower lying claims 
 (Gagnon, Original, Colusa and Hattie Harvey) the copper sulphides 
 were near the surface, because the water line was not far down, in 
 the claims on the hill (Anaconda and Mountain View) tlie upper 400 
 feet were practically leached of copper. The silver was however 
 left behind, as is the usual experience, so that the vein was first 
 mined as a silver-bearing vein. When the shafts reached the zone 
 of enrichment, they penetrated the immense masses of bornite and 
 chalcocite as much as 200 feet thick and 150 feet across. These ores 
 yielded up to bQfo or more of copper and were the ones which gave 
 the immense impetus to the copper mining in Butte. The similar 
 geological relations at Ducktovvn, Tenn., (see Fig. 7 — 1.05.06) are 
 worthy of remark. Below the zone of enrichment the ore is chang- 
 
164 KEMP'S ORE DEPOSITS. 
 
 ing to the usual pyritous aggregate, and will of necessity yield a 
 lower percentage of copper. (The yield averaged about 5.5^ in 1893.) 
 It is a curious fact that the oxidation of the upper ores yielded al- 
 most no carbonates, for the ores in the zone of enrichment were 
 higher in sulphides than the original vein filling. It would seem 
 from this to be a general experience that the carbonates form most 
 readily when the original sulphides are in limestone, whereas, when 
 granite or some similar crystalline rock constitutes the walls, chal- 
 cocite or bornite results. The Arizona copper deposits are cases in 
 point (see 2.04.19). In the Moreuci district the Longfellow Mine 
 in limestone yielded oxides and carbonates, while the Metcalf and 
 Coronado groups in porphyry, and the veins near Chase Creek, in 
 granite, yielded chalcocite. 
 
 Besides the chief veins at Butte, which furnish the largest 
 amounts of ore and are worked by the largest companies, there are 
 smaller side ones, whose aggregate is by no means unimportant. The 
 principal operators of the district are the Chambers syndicate, the 
 Boston and Montana and the Bntte and Boston. The ores from 
 the western end of the system of veins have proved richest in silver. 
 The productive ground stretches about two miles from east to west 
 and furnishes thus a remarkably extensive series of ore bodies, 
 whose eastern limit has been found foufl^ further from the center 
 than was at first suspected. The ores have been for the most part 
 concentrated when necessary and smelted to a matte in Butte. 
 The subsequent refining has been done in the East or in Europe, 
 but lately large works have been erected at Great Falls, Mont., by 
 the Boston and Montana Co., and the entire refining is contem- 
 plated. 
 
 2.04.07. The ore bodies do not, in general, present very sharply 
 defined walls, but the ores fade into the wall rock. From this 
 S. P. Emmons has suggested that they have formed along a series 
 of small fissures marking some line of disturbance, and not from 
 a general faulting, and have enlarged the original channels by re- 
 placement of the walls. It would seem probable that the frequent 
 dikes are connected with the butte, or with the same parent body 
 that sent it oif. The same eruptive activity probably shattered the 
 rock along the zones. In this event it must have been from an 
 easterly offshoot of the western rhyolite area, and have operated 
 with the same Assuring action which attends earthquakes from the 
 intrusion of subterranean dikes. The Butte district alone rivals 
 the Lake Superior copper mines in output, and has in recent years 
 
COPPER. 
 
 165 
 
 surpassed them. Reference will again be made to this regiotij 
 under "Silver." i 
 
 2.04.08. Example iVa. Gilpin County, Colorado. Veins 
 of pyrite and chalcopyrite, replacing gneiss (tlie rock may be 
 granite), and dikes of quartz-porphyry, and felsite along the planes 
 of joints, which cross the gneiss (or granite) perpendicularly to 
 the laminations. The veins are highly auriferous and are worked 
 primarily for gold, the copper being produced as a by-product. 
 The concentrates from the stamps are afterward treated for cop- 
 per. The veins occupy an area of only about a mile and a half 
 in diameter, centering about Central City. They show little indica- 
 tion of filling a fissure, as usually understood, but follow the cleav- 
 
 FlG. 37. — Cross section of the Bob-tail mine. Central City, Colo. After 
 F. M. EndUich, Hayden's Survey, 1873, p. 386. 
 
 age joints of the gneiss and replace the country rock on each side 
 of them. The joints also cross the porphyry dikes, and the veins 
 are often in the latter rock. They are closely related in structure 
 and origin to the galena veins of the neighboring Clear Creek 
 
 1 "Butte Copper Mines," Engineering and Mining Journal, June 19, 
 1886, p. 445 ; also April 34, 1886, p. 399. S. P. Emmons, ' ' Notes on the 
 Gteology of Butte, Mont. ," M. E., XVI. 49. Bee. Richard Pearce, ' ' The 
 Association of Minerals in the Gaguon Vein, Butte City, Mont. , ' ' M. E. , 
 XVI. 68. "On the Occurrence of Goslarite in the Gag non Mine, Butte 
 City, ' ' Proc. Colo. Sci. , Vol. II. , Part I. , p. 13. E. D. Peters, Mineral He- 
 sources of the U. S., 1888-84, p. 374. A. Williams and E. D. Peters, "On 
 Butte, Mont.," Engineeriny and Mining Journal, March 23, 1885, p. 208. 
 G. vom Rath, ' ' Ueber das Gangrevier von Butte, Mont. , ' ' Neues Jahr" 
 buck, 1885, I. 158. 
 
166 KEMP 'S ORE DEPOSITS. 
 
 County, which are referred to under " Silver," but the contrast in 
 mineral contents between the two is very marked. They were the 
 basis of the first extensive deep mining in Colorado, and were 
 located through the placer deposits in the neighboring gulches, i 
 
 2.04.09. Example 176. Llano County, Texas. Impregnations in 
 granite, and veins with quartz gangue in granite, carrying car- 
 bonates above, but sulphurets and tetrahedrite with some gold and 
 silver below. Contact deposits between slates and granite are also 
 known. It is not demonstrated as yet whether the ores are to be 
 actually productive. ^ 
 
 2.04.10. Example 18. Keweenaw Point, Mich. Native cop- 
 per, with some silver, in both sedimentary and interstratified 
 igneous rocks of the Keweenawan system. The metal occurs as a 
 cement, binding together and replacing the pebbles of a porphyry 
 conglomerate ; or filling the amygdules in the upper portions of 
 the interbedded sheets of massive rocks ; or as irregular masses, 
 sometimes of enormous size, in veins, with a gangue of calcite, epi- 
 dote, and various zeolites; or in irregular masses along the contacts 
 between the sedimentary and igneous rocks. 
 
 I 2.04.11. The rocks of the Keweenawan system are most 
 strongly developed on the south shore of Lake Superior, especially 
 in Keweenaw Point, which juts out northeasterly, cutting the lake 
 into two nearly equal portions. They extend some distance east 
 and west and are also known on the north shore. They consist of 
 sandstone and thin beds of conglomerate, interstratified with sheets 
 of diabase, both compact and amygdaloidal, and of melaphyre. 
 They are succeeded on the east by the Eastern Sandstone, which 
 on the south shore in some places abuts uncomforraably against 
 them, and in others passes under them from an overthrust fault. 
 The Eastern Sandstone forms a comparatively low flat bench 
 some miles across between the lake and the ridge of the Kewee- 
 nawan, whose rocks rise quite abruptly in a marked fault-scarp. 
 The several streams that fall over this scarp in cascades have served 
 
 1 S. F. Emmons, Tenth Census, Vol. XIII. , p. 68. The veins are de- 
 soritied as cited above. J. D. Hague, Fortieth Parallel Survey, UI. , p. 493. 
 The veins are called fissure veins by Mr. Hague. A. Lakes, Ann. Pep. 
 Col. State School of Mines. 1887, p. cii. A. W. Rogers, "The Mines and 
 Mills of Grilpin County, Colorado, ' ' J/. E. , 11. 39. Further references will 
 be found under ' ' Silver and Grold iu Colorado. ' ' 
 
 2T. B. Comstock, First Ann. Rep. Texas Geol. Survey, 1889, p. 334. 
 W. H. Streeruwitz, in Mineral Resources of the U. S., 1884, p. 342. 
 
168 KEMP'S ORE DEPOSITS. 
 
 by thrsir erosion to expose the coutacts. The best known are the 
 Hungarian and Douglas Houghton Elvers. On the west or north- 
 west side the escarpment is much less pronounced and the contact 
 is less well shown and has not been so sharply located. The sand- 
 stone is called the Western Sandstone. It is now pretty well shown 
 that the Eastern Sandstone is a close equivalent to the Potsdam, for 
 though itself lacking in fossils it is known to pass conformably be- 
 neath fossiliferous Lower Silurian limestone near L'Anse. 
 
 On Keweenaw Point the beds dip northwesterly and pass under 
 Lake Superior to reappear with a southeasterly dip on Isle Rovale 
 and the Canadian shore. Western Lake Superior occupies this 
 synclinal trough. In Keweenaw Point the dip is greatest on the 
 southwest, being about 60° at Hancock. To the northeast it 
 gradually flattens to 30° or less on the lake shore. (E'or the general 
 geology of the neighboring region see under Example 9.) 
 
 It is interesting to note that the early investigators of the 
 geology of this country drew a parallel between the sandstones 
 and traps of Lake Superior and the similar Triassic deposits of the 
 Atlantic coast (see Example 21), even going so far as to regard 
 the former as the western equivalent of the latter.^ 
 
 There are three principal mining districts — the Keweenaw 
 Point, on the end of the Point ; the Portage Lake, in the middle ; 
 and the Ontonagon, at the western base. Mines have also been 
 worked on Isle Royale, and copper is found in small amounts 
 on the north shore. The Portage Lake district is now the princi- 
 pal and almost the only producer. In the first-named district most 
 of the mines are on original fissures, which have later become 
 much enlarged by the alteration of the walls. They are usually 
 from 1 to 3 feet broad, but may reach 10, 20, and 30 feet, this last 
 in the looser textured rocks. These expansions are also richer in 
 copper. The veins stand nearly vertical and cross the beds at right 
 angles. They were the earliest discovered and the first to be ex- 
 tensively worked. The metallic masses, both large and small, 
 occur distributed through the gangue. The best known mines of 
 the district are the Central, Cliff, Phcenix and Copper Falls. All 
 these are now closed, the Central being the last to succumb (1894). 
 A bed of conglomerate cut off the fissure and appears to have 
 thrown the vein to some inaccessible point. Tlie other vein mines 
 in the prevailing low price of copper (189-1) cannot be profitably 
 
 1 C. T. Jackson, Amer. Jour. Sci. , i. , XLIX. , 1845, pp. 81-93. 
 
COPPER. 169 
 
 worked. The yein mines have been the great source of fine 
 minerals in the past, the Phoenix being well known for its zeolites. 
 
 2.04.12. In the Portage Lake district the mines are either in 
 conglomerate (Calumet and Hecla, Tamarack, Peninsula, etc.) or 
 in amygdaloidal, strongly altered diabase, certain very scoriaceous 
 sheets of which are known as ash-beds (Quincy, Franklin, Atlantic, 
 etc.). In the conglomerates the copper has replaced the finer frag- 
 ments, so as to appear like a cement, and often the boulders them- 
 selves, or particular minerals in them, are permeated with copper. 
 The rich portions are of limited extent along the strike as they 
 give way to barren rock, after a stretch it may be of several thou- 
 sands oi feet, and they go down as great chutes somewhat diag- 
 onally on the dip to very great depths. The Tamarack workings, 
 below the Calumet and Hecla have been pushed on the bed nearly 
 a mile below the outcrop and show no diminution or essential 
 change in the copper rock. Three copper-bearing conglomerates 
 have been identified, the Calumet and Hecla, the Albany and Bos- 
 ton (also called the Peninsula) and the Allouez. The first is much 
 the richest but has not been found productive at any other point 
 on the strike, than in the great mine which gives it its name. 
 The Amygdaloids have copper in their small cavities, but in the 
 open or shattered rock it fills all manner of irregular spaces, often 
 in fragments ot great size. It is associated with calcite, the 
 zeolites (often of great beauty), epidote, and chlorite, (the last 
 containing FcjOj). The distribution of the copper in the amyg- 
 daloidal sheets is much the same as in the conglomerates. It is 
 limited along the strike, and goes down at a slight diagonal in 
 great chutes whose ends have never yet been reached. This ar- 
 rangement must have an important bearing on the method of origin. 
 
 2.04.13. In the Ontonagon district the copper follows planes 
 approximately parallel to the bedding of the sandstones and igneous 
 rocks, and in one case at least (the National mine) along the con- 
 tact between the two. The copper is quite irregular in its distri- 
 bution, but has the same associates that are mentioned above. 
 
 On the Origin of the Copper. — The original source of 
 the copper was thought by the earlier investigators to be in the 
 eruptive rocks themselves, and that with them it had come in some 
 form to the surface and had been subsequently concentrated in the 
 cavities. Pumpelly has referred it to copper sulphides distributed 
 through the sedimentary, as well as the massive rocks from which 
 the circulating waters have leached it out as carbonate, silicate, 
 
170 KEMP '8 ORE DEPOSITS. 
 
 and sulphate. Althougli the traps are said by Irving to be devoid 
 of copper, except as a secondary introduction, it -would be interest- 
 ing to test their basic minerals for the metal in a large way, as has 
 been so successfully done by Sandberger on other rocks. It is 
 probable that these may be its source. 
 
 Irving states that the coarse basic gabbros of the system con- 
 tain chalcopyrite, but they do not occur near the productive mines. 
 The electro-chemical hypothesis of deposition was earliest advo- 
 cated (Foster and Whitney), and on account of the electrolytic 
 properties of the two metals copper and silver, at first thought it 
 has strong claims to probability. Still the unsatisfactory charac- 
 ter of all experiments made in other regions to detect such action 
 militates against it. Pumpelly, however, has worked out an ex- 
 planation much more likely to be the true one. He found, on 
 studying the mineralogical changes which have taken place in the 
 rocks, that the alteration had been very extensive ; that it had 
 proceeded through a series of minerals involving at one stage a 
 change in the iron present from protoxide to sesquioxide (which 
 would occasion a reducing action), and that at this stage the cop- 
 per was deposited. As stated in mentioning the great chutes 
 above, the circulations must have followed the general lines indi- 
 cated by them, and we are justified in thinking that the rich cur- 
 rents were of limited extent. The progress of mining will be 
 watched with interest to see if the native copper ever passes in 
 depth into sulphides. A little whitneyite and domeykite (copper 
 arsenides) and chalcocite occur in the amygdaloid, formerly worked 
 at the Huron mine, chalcocite has been found in the Bohemian 
 Mountains, and in the Copper Falls mine. Native copper changes 
 to chalcocite, 90 feet down in the Mamaisne mine, near the Sault 
 (L. L. Hubbard). A pocket of melaconite, the black oxide, was 
 opened in the early days at Copper Harbor. 
 
 2.04.15. The discovery of copper dates back to the explorations 
 of the French, who in the seventeenth century left the settlements 
 on the lower St. Lawrence and penetrated the Great Lakes. The 
 country was the scene of a great mining excitement in the forties. 
 After many vicissitudes and exploded schemes the district settled 
 down to the largest production of any American region. Within 
 the last few years, however, Butte, Mont., has temporarilv ex- 
 ceeded it. Many interesting traces of prehistoric mining were 
 found by the early explorers, for the copper was a much prized 
 commodity among the aborigines. 
 
COPPER. 171 
 
 2.04.16. Some important mining for copper has been done on 
 Isle Koyale, along the Canadian shore, and in Minnesota, but al- 
 though Keweenawan rocks are in great force, no large amount of 
 the metal has been found. * 
 
 2.04.17. Example 19. St. Genevieve, Mo. Beds of chalco- 
 pyrite associated with chert in magnesian limestone of the Cam- 
 brian system. St. G-enevieve is situated on the Mississippi, about 
 forty miles south of St. Louis. The Second Magnesian Limestone 
 of the Cambrian outcrops, with the Carboniferous on the 
 north, and more or less Quaternary in the vicinity. There are two 
 nearly horizontal beds of ore, of widths varying between three 
 
 ' It would be impos-ible and undesirable to give in this place com-- 
 plate references to the literature. Such bibliography will be found in Irv- 
 ing's monograph, and in Wadsworth's. The more important papers are 
 given below, with some additions to the lists mentioned above. 
 Blake, W. P., "Mass Copper of the Lake Superior Mines," etc., M. E., 
 
 IV. 110. 
 Credner, H., On the geology, etc., Neues Jahrbuch, 1869, p. 1. 
 
 Engineering and Mining Journal, ' ' History of Copper Mining in the 
 
 Lake Superior District," March 18, 1883, p. 141. 
 Foster and Whitney, Report on the Lake Superior Copper Lands, 1850. 
 Hall, C. W., "A Brief History of Copper Mining in Minnesota," Bull. 
 
 Minn. Acad. Nat. Sci., Vol. III., No. 1, p. 105. 
 Irving, R. D., " The Copper-bearing Rocks of Lake Superior," Monograph 
 
 v., IT. S. Geol. Survey, especially p. 419. Rec. 
 Jackson, C. T., "The Great Copper-bearing Belt of Canada," Boston Soe. 
 
 Nat. Hist., IX. 203. 
 LawsoD, A. C, "Note on the Occurrence of Native Copper in the Animi- 
 
 Ide Rocks of Thunder Bay," Amer. Oeol., V. 174. 
 Poole, H., " Michipicoten Island and its Copper Mines," Engineering and 
 
 Mining Journal, Aug. 6, 1893, p. 125 ; Sept. 3, p. 220. 
 Pumpelly, R., Oeol. Survey of Mich., 1873, Vol. I. 
 
 " On the Origin of the Copper," Amer. Jour. Sci., iii.. III. 183-195, 348- 
 
 353, 347-353. Rec. A later and fuller paper is in Proc. Amer. 
 
 Acad., 1878, Vol. XIII., p. 333. 
 Wadsworth, M. E., Notes on the Geology of the Iron and Copper Districts 
 
 of Lake Superior. Cambridge, 1880. 
 Whitney, J. D., " On the Black Oxide of Copper of Lake Superior," Proc. 
 
 Boston Soo. Nat. Hist., January, 1849, p. 103 ; Amer. Jour. Sci., ii., 
 
 VIII. 373. 
 Metallic Wealth in the United States, p. 345. Rec. 
 Whittlesey, C, "On Electrical Deposition," A. A. A. S., XXIV. 60. 
 Wright, C. E., and Lawson, C. D., Mineral Statistics of Michigan. An- 
 nual. 
 
172 
 
 KEMP'S ORE DEPOSITS. 
 
 inches and several feet. They lie between chert seams and are 
 associated with clay and sand. The ore is thought by Nicholson 
 to have been deposited in cavities formed by dolomitization, much 
 
 ^ 2nd._MagDesian Limeston* 
 Roof 
 
 Limestone 
 
 ,> Chert seams 
 
 Sulphuret ore 
 
 ^^^ Fioor 
 
 2nd. Magnesian Lrmestooa 
 
 Fig. 39, — Cross section in the St. Genevieve copper mine, illustrating the 
 relations of the ore. After F. Nicholson, M. E, X., p. 450. 
 
 as is advocated by Schmidt for the lead and zinc deposits of south- 
 west Missouri, and as is described under Example 25. For ten 
 years the mines have not been operated.' 
 
 Limestone 
 
 Fig. 40. — Section at the St. Genevieve mine, illustrating the intimate re- 
 lations of ore and chert. After F. Nicholson, M. E., X., p. 451. 
 
 2.04.18. Example 20. Arizona Copper. Bodies of oxidized 
 copper ores in Carboniferous limestones, associated with eruptive 
 rocks. In addition to these, which are the most important, are 
 
 ' F. Nicholson, "Review of the St. Genevieve Copper District," M. E., 
 X. 444:. B. F. Shumard, " Observations on the Geology of the County of 
 St. Genevieve, Missouri," Trans. St. Louis Acad. Sci., Vol. I., p. 40 ; ab- 
 stract in Amer. Jour. Sci., ii., XXVIII. 126. 
 
COPPER. 
 
 173 
 
 veins in eruptive rocks, or in sandstones, or ore bodies of still 
 different character as set forth under the several sub-examples. 
 The copper districts are nearly all in the southeastern part of the 
 territory, but the Black range is near the center. 
 
 2.04.19. Example 20a. Morenci. The Morenci district, known 
 also as the Clifton or Copper Mountain, lies in a basin, six to ten 
 miles across, whose high surrounding hills consist of limestone. 
 
 Fia. 41, — Geological map of the Morenci or Clifton copper district of 
 Arizona. After A. F. Wendt, M. E. 
 
 probably Lower Carboniferous, which rests on sandstone, and this on 
 granite. The principal mines are grouped about the town of Morenci. 
 Clifton is seven miles distant at the point where the smelter of the 
 Arizona Copper Company is located. In the basin is a mass of por- 
 phyry, containing frequent great inclusions of limestone. Felsite or 
 porphyry dikes are also abundant in the surrounding sedimentary 
 and granite rocks. Several miles to the east there is an outflow 
 of late trachyte and evidence of recent volcanic action. From this 
 it appears that eruptive phenomena are abundant and widespread. 
 
174 KEMP'S ORE DEPOSITS. 
 
 2.04.20. The ores are classified by Henrich as follows : 
 
 1. Contact deposits. These occur in a zone of decomposed and 
 
 teHOFELtOW H LV 
 
 Fig. 42. — Vertical section of Longfellow Hill, Clifton district, Arizona. 
 After Wendt, M. E., XV. 53.; 
 
 Fig. Ad.Sorizontal sections of Longfellow ore body. After Wendt. 
 
 kaolinized porphyry, between a bluish, fine-grained limestone, and 
 solid porphyry. Many ore bodies, and probably the largest, are 
 
COPPER. 
 
 175 
 
 directly on the limestone, while others are surrounded by the de- 
 composed porphyry. As included masses of limestone, with as- 
 sociated ore, are found in the decomposed porphyry, it is probable 
 that these ore bodies may have originally replaced such. The 
 ores are malachite, azurite, cuprite with some metallic cojaper 
 and melaconite, in a gangue principally of limonite. Wad is 
 also frequent. Much clay of a residual character occurs with the 
 ores. 
 
 2. Deposits in limestone. These are closely associated with 
 
 ^^* *"*:** **%» 
 
 Fig. 44. — Geological section of the Metcalf mine, Clifton district, Arizona. 
 
 After Wendt. 
 
 the first class, and have apparently formed as outlying bodies in 
 the limestone, as they are connected by ore channels with the 
 principal lines of circulation along the contact. They appear 
 to contain more wad and lime than the typical contact de- 
 posits. 
 
 3. Deposits in porphyry. These form sheets and pockets in 
 porphyry, or impregnate the solid rock itself. They are oxidized 
 at the surface, but pass in depth into chalcocite. The principal 
 gangue is kaolinized porphyry. 
 
 According to Wendt, the Coronado vein fills a longitudinal 
 fissure in a quartz porphyry dike. It afforded chalcocite above, 
 
176 
 
 KEMP'S ORE DEPOSITS. 
 
 but passed into chalcopyrite below^. Wendt also mentions a 
 group of veins in granite that likewise afforded chalcocite.' 
 
 2.04.21. Example 20b. The Bisbee district, called also the 
 Warren district, is situated in the Mule Pass Mountains in 
 southern Arizona, near the Mexican line. The range runs east and 
 west and consists of beds of Lower Carboniferous limestone, dip- 
 ping away from a central mass of porphyritic rock. The ores are 
 found in the canons on the south side, which have been formed 
 by erosion, along the contact of the limestone and porphyry. 
 They are of the same oxidized character as at Morenci, and in the 
 
 H 'Ar-x 
 
 < X + y + 
 
 ERUPTIVE ROCK •*> 
 
 » -(.J, ERUPTIVE ROCK X , 
 
 Fig. 45. — Section of Copper Queen ore. body Bisbee district, Arizona. 
 After A. F. Wendt, M. E., XV, 52. 
 
 important mines occur in the limestone. The ore-bearing solutions 
 seem to have spread out chiefly along the bedding planes and to 
 have replaced the limestone at a distance from the contact. The 
 ore bodies leave great chambers when excavated and partake of 
 the nature of bedded veins. Empty caves occur associated with 
 
 1 J. Douglass, " Copper Resources of the United States,'" M. E., Sep- 
 tember, 1890. Reo. " Arizona Copper and Copper Mines," Engineering 
 and Mining Journal, Aug. 13, 1881, p. 103. " Clifton Copper Mines of Ari- 
 zona," Ibid., Feb. 21, 1880, p. 183. C. Henrich, " The Copper Ore Deposits 
 near Morenci, Ariz.," Ibid., March 26, 1887, pp. 202, 219. Reo. ■ A. Wendt, 
 " Copper Ores of the Southwest," M. E., XV., p. 23. Rec. 
 
i 
 ■ r 
 
 Jl. ' -: i 
 
 ?r 
 
 "5) 
 o 
 
 ^ 
 
 o; 
 
 
 
178 KEMPS ORE DEPOSITS. 
 
 them, doubtless formed, as at Eureka, Nev. (Example 36), by 
 surface waters and having no genetic connection with the ore. 
 Evidences of hydrothermal action along the contact are abundant. 
 The Copper Queen and the Arizona Prince are the principal mines. 
 There are minor deposits in the porphyry of oxidized ores above, 
 changing to chalcocite and this to chalcopyrite in depth. ^ 
 
 2.04.22. Example 20c. Globe District. As in the other dis- 
 tricts, the most productive mines are in limestone near the contact 
 with eruptive rocks. 
 
 1. Contact deposits in limestone. At the Globe mines the 
 Carboniferous limestone abuts against a great dike of diorite, 
 while trachyte and granite are near. Along the contact there is 
 abundant evidence of thermal action in the kaolinized rock. The 
 great bodies of oxidized ores are found on this contact and extend 
 out into the limestone. The one on the Globe claim is described 
 by Wendt as resembling a great chimney. 
 
 2. A fissure vein in sandstone, containing arsenical and anti- 
 monial copper ores and known as the Old Dominion, was formerly 
 worked. 
 
 3. Fissure veins in talcose slate and gneiss, and filled by a 
 quartz gangue with bunches of malachite and azurite (New York 
 and Chicago mines), and now no longer worked. 
 
 4. Numerous small veinlets forming a stockwork, in gneiss 
 near a dike of diorite, which is crossed by a dike of trachyte. 
 These are known as the Black Copper Group. The ores are too 
 low grade for profitable exploitation. Of greater interest are the 
 bodies of chrysocolla, found in the wash, down the hill from the 
 outcrop of the veins, and evidently due to the superficial drainage 
 of the stockworks. Similar bodies of ore, though not chrysocolla, 
 were found at Rio Tinto, in Spain. ^ 
 
 2.04.23. Example 20cZ. Santa Rita District. Although in New 
 
 1 J. Douglass, " Copper Resources of the United States," M. E., Sep- 
 tember, 1890. Rec. A. Wendt, " Copper Ores of the Southwest," M. E., 
 XV., p. 52. Rec. 
 
 ' J. Douglass, " Copper Resources of the United States," M. E. , Sep- 
 tember, 1890. Rec. " The Globe District," Engineering and Mining 
 Journal, April 9, 1881, p. S43. W. E. Newberry, " Notes on the Produc- 
 tion of Copper in Arizona,'' School of Mines Quarterly, VI. 370. A. Trip- 
 pel, " Occurrence of Gold and Silver in Oxidized Copper Ores in Arizona," 
 Engineering and Mining Journal, June 16, 1883, p. 485. A. Wendt, " Cop- 
 per Ores of the Southwest," M. E., XV., p. 60. 
 
COPPER. 179 
 
 Mexico, this district has much in common with those already 
 mentioned. A great dike of felsite cuts limestones, and along the 
 contact, as well as in the felsite itself, copper ores are found. 
 
 1. Contact deposits in limestone. These afforded the usual ox- 
 idized ores, hut were not found to extend to any great depth, and 
 while for a time productive, they were soon exhausted. 
 
 2. Deposits in felsite. These consisted of pellets and sheets of 
 native copper in the dike itself, which were oxidized to cuprite 
 near the surface. (Cf. Lake Superior amygdaloids. Example 13.) 
 They were worked by the Mexicans in the early part of the pres- 
 ent century.' 
 
 2.04.24. Example 20e. Black Range District. The mines of 
 this region differ from those described above, and in some respects 
 resemble the pyrite beds of the Alleghanies. (Example 19.) The 
 ore occurs in one or more great fissure veins, along the contact of 
 vertical slates with a great dike of porphyrite. The veins run com- 
 pletely into the porphyrite and into the slate, and afford oxidized 
 ores above, changing into chalcopyrite below. They contain con- 
 siderable silver and gold, as well as arsenic and antimony. The 
 principal mines are the Hampton and Eureka. They are situated 
 in the valley of the Verde River, twenty miles east of Prescott.^ 
 
 2.04.25. Example 20/. Copper Basin. Beds of closely text- 
 ured conglomerate and sandstone, resting on granite and gneiss, 
 and having a cement of copper carbonates. Copper Basin lies 
 about twenty miles southwest of Prescott, and is formed by a de- 
 pression in greatly decomposed granite, which is traversed by 
 numerous small veinlets of copper ores. The granite is pierced by 
 j)orphyry dikes, and covered by the sedimentary conglomerates 
 and sandstones into which its copper is thought by Blake to have 
 partially leached and precipitated as a cement. Reference, by 
 way of comparison, may be made to the Lake Superior conglomer- 
 ates, in which, in part, the native copper serves as a cement.^ 
 
 1 A. F. Wendt, "Copper Ores of the Southwest," M. E., XV. 27. 
 Wislizenus, " On the Santa Eita Mines : Memoir of a Tour in Northern 
 Mexico, 1846-47," p. 47 ; Amer. Jour. Sci., ii., VI. 385, 1848. 
 
 2 J. F. Blandy, "The Mining Region around Prescott, Ariz.," Jf. E., 
 XI. 386. G. K. Gilbert, "On the General Geology of the Black Mountain 
 District," Wheeler's Survey, III., p. 35. A. R. Marvine, " Brief Details of 
 the Verde Valley," Wheeler's Survey, III., p. 209. A. F. Wendt, " Copper 
 Ores of the Southwest," M. E., XV. 63. Rec. 
 
 » W. P. Blake, "The Copper Deposits of Copper Basin, Arizona, and 
 Their Origin," M. E., XVII. 479. 
 
180 KEMP'S ORE DEPOSITS. 
 
 2.04.26. There are numerous other copper districts in Arizona 
 of minor importance or entirely undeveloped, but the examples 
 above cited probably illustrate the occurrences quite fully. Those 
 not referred to above are of sporadic development. Mention 
 should also be made of the mines in Lower California, opposite 
 Guaymas, a brief description of which will be found in "Wendt's 
 paper.' Much copper is now met in depth at Leadville, Colo. 
 
 2.04.2V. Example 20^. Crismon-Mammoth, Utah. In the 
 Tintic district, Juab County, Utah, are three great ore belts, in 
 vertically dipping dolomitic limestone, as more fully set forth 
 under "Silver" (Example 35a). One of these, the Crismon-Mam-" 
 moth, contains ores that bear silver, gold, and copper in propor- 
 tions of about equal value. They have been a very difficult 
 mixture to treat successfully. Of late considerable copper has 
 been produced, placing the ore deposits among those deserving 
 mention. The Crismon-Mammoth vein or belt covers a maxi- 
 mum width of 10 feet, and runs 500 feet on the strike, dipping 75° 
 Tvest. The ores seem to have been deposited along the bedding 
 planes, though often cutting across them. The productive por- 
 -tions are found in richer chutes or chimneys, amid much low-grade 
 material and gangue, and are of all shapes and sizes, from 25 feet 
 in diameter, down. The Copperopolis is thought to be on the same 
 belt, and is a neighboring location of similar geological structure 
 and ores.^ 
 
 2.04.28. Sunrise, Wyoming. Oxidixed ores have been ex- 
 ploited to some extent at the Sunrise mines, in the Laramie range, 
 Wyoming, but were never of much importance. 
 
 2.04.29. Example 21. Copper ores in Triassic or Permian 
 sandstone. They occur as oxidized ores, with native silver, and 
 chalcocite in contact deposits in Triassic and Permian sandstones 
 at their junction with diabase or gneiss, or as disseminated masses 
 replacing organic remains. Copper ores are very common 
 throughout the estuary Triassic rocks of the Atlantic coast, and 
 although formerly much mined, they are now proved valueless, and 
 of scientific interest only. 
 
 2.04.30. Example 21a. Contact deposits in sandstone at its 
 
 1 See also M. E. Saladin, "Note sur les Mines de Cuivre du Boles 
 (Basse Californie)," Bull, de la Societe de Vlndustrie Minirale, 3 Serie, 
 VI. 5, 283. 
 
 2 O. J. Hollister, "Gold and Silver Mining in Utah," M. E., XVI., 
 p 10. D. B. Huntley, Tenth Census, Vol. XIII., p. 456. 
 
COPPER 
 
 181 
 
 junction with diabase. These include the New Jersey ores, vigor- 
 ously worked before the Revolution. They consist of the carbon- 
 ates, of cuprite and native copper, disseminated through sand- 
 stone near the trap. The Schuyler mines, near Arlington, IST. J., 
 and several other openings near New Brunswick, N. J., are best 
 known. These Triassic diabases often sliow chalcopyrite, and it 
 is probable that the copper came from this or from copper in the 
 augite of the rock, in accordance with Sandberger's investigations. 
 The deposits are unreliable, and except at a very early period 
 have never been an important source of ore. 
 
 2.04.31. Example 215. Contact deposits in sandstones at the 
 
 Fig. 47. — Cross section of the Schuyler Copper mine, New Jersey, 
 trap; b, sandstone; c, shales; the black shading, copper ores. 
 After N. H. Darton, U. S. Geol. Survey, Bull. 67, p. 57. 
 
 a, 
 
 junction with gneiss. A number of deposits were formerly 
 worked of this character, especially at Bristol, Conn., and at the 
 Perkiomen mine, Pennsylvania. The mine at Bristol, Conn., is a 
 well-marked contact deposit, on the line between the Triassic 
 sandstone and the schistose rocks. The contact runs northeast and 
 southwest, has suffered great decomposition from mineral solutions, 
 and has been largely kaolinized. A broadband of this decomposed 
 material, 30 to 120 feet wide, lies next the sandstone and contains 
 disseminated ore. Then follow micaceous and hornblende slates, 
 often with horses of gneiss. The slates are much broken by 
 movements that have formed cavities for the ores. It is reason- 
 able to connect the stimulation of the ore currents with the 
 neighboring trap outbreaks. Unusually fine crystals of chalco- 
 
182 KEMP'S ORE DEPOSITS. 
 
 cite and barite have made the mine famous the world over. While 
 at one time a source of copper, for many years it has been unpro- 
 ductive.' 
 
 2.04.32. Example 21c. Chalcocite and copper carbonates re- 
 placing vegetable remains, etc., in the Permian or Triassic sand- 
 stones of Texas, New Mexico, and Utah. In the Permian of 
 iiorthei-n central Texas are three separate copper-bearing zones, 
 forming three lines of outcrop that extend in a general north- 
 easterly direction over a range of about three counties. The ore 
 is largely chalcocite in beds of shale, and often replacing frag- 
 ments of wood. It may be available in time.^ 
 
 At various places in Utah and New Mexico (Abiquiu, N. M., 
 Silver Reef, Utah) the sandstones, as reported by Newberry and 
 others, have copper ores disseminated through them and deposited 
 on fossils, at times with associated silver (Utah). The copper, 
 "whether coming from the waters along the shore line or from sub- 
 terranean currents, was precipitated by the organic matter. (See 
 also under "Silver," in Utah.) These deposits are not yet sources 
 of copper.^ 
 
 ' L. C. Beck, " Notice of the Native Copper Ore*, Copper, etc., near 
 New Brunswick, N. J.," Amer. Jour. Sci., i., XXXVI. 107. G. H. Cook, Geol. 
 ofN. J., 1868, p. 675; also L. C. Beck, Ibid., 218-334. J. G. Percival, Rep. 
 on Geol. of Conn., p. 77. C. A. Shaefler, "Native Silver in New Jersey 
 Copper Ore," Engineering and Mining Journal, February, 1882, p. 90. C. 
 Shepard, Geol. of Conn., 1837, p. 47. B. Silliman and J. D. Whitney, 
 "Notice of the Geological Position and Character of the Copper Mine at 
 Bristol, Conn.," Amer. Jour. Sci., ii., XX. 361. J. D. Whitney, Metallic 
 Wealth. RtfC. 
 
 * W. F. Cummins, "Report on the Permian of Texas and its Over- 
 lying Beds," First Ann. Rep. Texas Geol. Survey, p. 196. J. F. Furman, 
 " Geology oE the Copper Region of Northern Texas and Indian Territory," 
 Trans. N. Y. Acad. Sci., 1881-83, p. 15. 
 
 * F. M. F. Cazin, "The Origin of the Copper and SUver Ores in Tri- 
 assic Sand Rock," Engineering and Mining Journal, April 80, 1880 ; Dec. 
 11, 1880, p. 331. "Tlie Nacemiento Copper Deposits,'' Ibid., Aug. 22, 
 1885, p. 124. A. W. JdcksoQ, Sep. Director of the Mint. 1880, p. 334. 
 J. S. Newberry, "Copper in Utah, Triassic Sandstones," Engineering 
 and Mining Journal, Vol. XXXI., p. 5. Also Oct. 23, 1880, p. 269; 
 Jan. 1, 1881, p. 4. See also Tenth Census, Vol. XIII., Precious Metals, 
 pp. 40, 478. C. M. Rolker, "The Silver Sandstone District of Utah," 
 M. E., IX. 21. R. P. Roth well, Quoted in Tenth Census, Vol. XIII., p. 
 478. B. Silliman, " The Mineral Regions of Southern New Mexico," M. E., 
 XVI. 437. 
 
COPPER. . 183 
 
 2.04.33. Copper production in 1882 and 1890, in tons of 2000 
 pounds each. 
 
 1883. 1890. 
 
 LakeSuperior 28,578 50,373 
 
 Montana 4,529 56,490 
 
 Arizona 8,993 17,398 
 
 Colorado 747 441 
 
 New Mexico 434 485 
 
 California 413 11 
 
 Utah 303 503 
 
 Elsewhere , 1,413 3,906 
 
 45,408 139,546 
 
 The figures indicate in general a vast increase in production, 
 and, above all, the advance of Montana. For detailed statistics 
 the volume on " Mineral Industry " issued by the Scientific Pub- 
 lishing Company (New York, 1894) is most available. 
 
CHAPTER V. 
 
 LEAD ALONE. 
 
 2.05.01. The deposits of lead are treated in three different 
 classes, according as they produce or have produced lead alone, 
 lead and zinc, or lead and silver. Of late years the lead-silver ores 
 have been the great source of the metal. Only the southeast 
 Missouri region is of much importance among the others, although 
 considerable lead is also obtained in association with zinc. 
 
 LEAD SEPaES. 
 
 Pb. S. 
 
 Galena, PbS 86.6 13.4 
 
 Cerussite, PbCOj 77.5 
 
 Anglcsite, PbSO^ 67. 7 
 
 Pyromornhite, PbjPsOs + l/SPb.ClB 75.36 
 
 Earthy mixtures of these last three aad limonite. 
 
 2.05.02. Example 22. Atlantic border. Veins of galena in 
 the Arcliean rocks of the States along the Atlantic border; also 
 others into Paleozoic strata, as described in the sub-examples. 
 
 2.05.03. Example 22a. Veins in gneiss and crystalline lime- 
 stone, sometimes with a barite or calcite gangue. These deposits 
 were vigorously exploited forty years ago or more, but have since 
 been of small importance other than scientific. They may be 
 described best by districts, as they hardly deserve a greater prom- 
 inence. 
 
 2.05.04. (1) St. Lawrence County, New York. Veins with 
 galena in a gangue of calcite in Arcliean gneiss. Those near 
 Rossie are perhaps best known, especially for their unusually in- 
 teresting calcite crystals. There are numbers of veins in the dis- 
 trict which are notable in that the galena is without zinc or iron 
 associates. The lead carries a very small amount of silver, not 
 enough to separate. Hornblende and mica schists occur in the 
 same region and the Potsdam sandstone is not far removed. A few 
 
LEAD ALONE. 185 
 
 minor veins cut the Trenton limestone near Lowville, Lewis 
 County, sometimes with fluorite for a gangue.' 
 
 2.05.05. (2) Massachusetts, Connecticut, and eastern New 
 York. Veins of galena with more or less chalcopyrite and pyrite 
 in a quartz gangue in gneiss, slates, limestones, or mica schists. 
 The mines near Northampton, Mass., were formerly well known, 
 although never productive of a great deal of metal ; but as there 
 is a large, prominent vein, it attracted attention. There are nu- 
 merous others in the same region. Veins also occur at Middle- 
 town, Conn., -where much silver is said to be found in the galena. 
 More recently {circa 1873) at Newburyport, Mass., argentiferous 
 galena attracted attention, but was not of any importance. Other 
 veins are known in Lubeck, Me., and in various parts of New 
 Hampshire and Vermont. For a time small lodes in the slates of 
 Columbia County, New York, were unsuccessfully exploited, of 
 which the Ancram mine is of historic interest. Although these 
 galena veins are numerous, they are not to be taken too seri- 
 ously.^ 
 
 2.05.06. (3) Southeastern Pennsylvania. Veins on the con- 
 tact of Archean gneiss and Triassic sandstone and diabase. These 
 were referred to under Example 21 5. As noted by Whitne}', the 
 copper is especially strong in the sandstone, and the lead in the 
 gneiss. Trap dikes are abundant, and the eruptive phenomena in 
 connection with them doubtless occasioned the activity of circula- 
 tion which filled the veins. The Wheatley mine is best known. 
 It has afforded a great variety of lead minerals, especially pyro- 
 morphite. They have not been worked in years.^ 
 
 2.05.07. (4) Davison County, North Carolina. Veins in tal- 
 cose slate were formerly exploited, but are now little known. 
 
 ' L. C. Beck, Mineralogy of New York, p. 45. E. Emmons, "Geology 
 of the Second District," N. Y. Geol. Survey, 1843. G. Hadley, "Crystal- 
 lized Carbonate ot Lead at Rossie," Anier. Jour. Sci., ii., II. 117. F. L. Na- 
 son, 'Calcite from Rossie," Bull. 4, N Y. State Museum, 1888, J. D. 
 Whitney, Metallic Wealth. Rec. 
 
 ^ C. A. Lee, "Notice of the Ancram Lead Mine," Amer. Jour. Sci., 
 i., VIII. 247. A. Nash, "Notice of the Lead Mines and Veins in Hampshire 
 County, Massachusetts," Amer. Jour. Sci., i., XII. 388. R. H. Richards, 
 "The Newburyport Silver Mines," M. E., III. 443. J. D. Whitney, Me- 
 tallic Wealth. 
 
 « H. D. Rogers, Oeol. of Perm,., II. 701 ; also Amer. Jour. Sci., ii., 
 XVI. 423. J. D. Whitney, Metallic Wealth, p. 396. 
 
186 KEMP'S ORE DEPOSITS. 
 
 except as having furnislied beautiful crystals of oxidized lead 
 minerals.^ 
 
 2.05.08. Example 22b. Sullivan and Ulster Counties, New 
 York. Veins along a line of displacement on the contact between 
 the Hudson River slates and the sandstones of the Medina stage 
 (Shawangunk grit), carrying galena and chalcopyrite in a quartz 
 gangue ; or else gash veins filled with the same in the grit. These 
 mines formerly produced considerable lead and copper, but are 
 now best known for the excellent quartz crystals which they have 
 furnished to all the mineralogical collections of this and other 
 lands.^ 
 
 2.05.09. Example 23. Southeast Missouri. Galena accom 
 panied by nickeliferous pyrite, disseminated through beds of the 
 Third or Lower Magnesian limestone of the Missouri geologists, 
 which is doubtless Cambrian in age. The mines are at Bonne 
 Terre, Mine La Motte, and Doe Run, twenty-five miles west of the 
 Mississippi River and forty to one hundred miles south of St. Louis. 
 The strata lie almost horizontal, and are known to carry lead 
 through over 200 feet in thickness. The productive places fade 
 out into barren rock and appear to be local enrichments of the 
 limestone, of which the galena forms an integral part. At Bonne 
 Terre they are of enormous size, one working running 3000 feet, and 
 being 100 to 200 feet broad and 25 to 60 feet high. No zinc, how- 
 ever, occurs with the lead, and the silver contents are very small, 
 being about four ounces to the ton of lead. _A.t Mine La Motte 
 some copper is found, and considerable nickel and cobalt. The 
 rare mineral siegenite, a variety of linnaeite, impregnates a sand- 
 stone supposed to be the equivalent of the Potsdam. Pyrite accom- 
 panies the galena both at Mine La Motte and at the other mines, and 
 carries the nickel and cobalt, which is obtained as a by-product in the 
 lead smelting. All the ore bodies are crossed by small faults, ad- 
 joining which the rock is invariably barren. Knobs of Archean 
 granite, containing diabase dikes, crop out near the mines both at 
 Mine La Motte and at Doe Run. But the dikes never penetrate 
 the limestone, and were evidently intruded before it was deposited. 
 
 ' J. C. Booth, " Analyses ot Various Ores of Lead, etc., from King's 
 Mine, Davison County, North Carolina," Amer. Jour. Sci., i., XLI. 348. W. 
 C. Kerr, Oeol. of North Carolina, p. 289. 
 
 2 J. D. Whitney, Metallic Wealth. W. W. Mather, New York State 
 Surrey, Report on First District, 358. 
 
LEAD ALONE. 187 
 
 The ore must have been deposited with the limestone or it must 
 have been introduced since the latter was formed, and by the per- 
 colation of ore-bearing solutions through the rock, with no marked 
 fissure vein development. The first view has been advanced by J. 
 F. Kemp (1887), it being thought that decaying marine vegetation 
 had precipitated the ores from solution in sea-water, as is outlined 
 for another region under Example 24, but this explanation has 
 been practically disproved. W. P. Jenney has considered the ore 
 to have come in ascending solutions through the small fault fis- 
 sures referred to above, and from these to have spread outward, 
 replacing the limestone (privately communicated). Places where 
 several fissures cross are said to be specially favorable. It is a 
 curious fact, however, that as the ore bodies are followed up to the 
 faults they invariably become lean or run out. Their place of 
 formation has apparently some connection, as recent explorations 
 seem to indicate, with low folds at right angles to the faults. The 
 ore bodies favor the anticlinal bends. 
 
 This whole region of Cambrian and Lower Silurian rocks, over 
 nearly 3000 square miles, contains lead, and within a year or so past 
 some new mines, not yet under way (1892), have been started. 
 These disseminated deposits are in no way to be confused with 
 the mines of the Upper Mississippi in Wisconsin and Iowa. They 
 are now large producers of lead and the only mines worked in the 
 United States for lead alone. The ore affords an average of about 
 eight per cent, galena. Except at Mine La Motte, lead was also 
 obtained at this region, previously to 1865, from small gash veins 
 like those of Example 24, but the workings were never in any de- 
 gree commensurate with the present mines of disseminated ore. 
 The history of Mine La Motte dates back to the early part of the 
 eighteenth century, and it is said to have furnished lead for bullets 
 used in the Revolution.' 
 
 2.05.10. The great increase in lead production in the United 
 States came about 1880, with the opening of the Leadville ore 
 
 1 G. C. Broadhead, " The Southeastern Missouri Lead District," M. E., 
 V. 100. Rec. J. R. Gage, " On the Occurrence of Lead Ores in Missouri," 
 M. E., III. 116. Rec. Geol Survey of Missouri, 1873-74, pp. 30, 603. J. 
 F. Kemp, "Notes on the Ore Deposits, etc., in Southeastern Missouri," 
 School of Mines Quarterly, October, 1887. Rec. 
 
 Several other papers have been published on the metallurgical treat- 
 ment and methods of ore dressing in the Trans. Inst, of Mining Engineers 
 and the School of Mines Quai terly. 
 
188 KEMPS ORE DEPOSITS. 
 
 bodies. From 1877 until 1881 Eureka, Nev., was an important 
 source, but since then it has greatly declined. Utah has preserved 
 a fairly uniform production since the early seventies. Lead from 
 all sources is here mentioned, although lead-silver ores are sub- 
 sequently treated. The amounts are in tons of 2000 pounds. For 
 detailed statistics see the volume on " Mineral Industry." (New 
 York : Scientific Publishing Company, 1893.) 
 
 1880. 1890. 
 
 Missouri, Kansas, Wisconsin, Illinois 37,690 55,000 
 
 Colorado 35,674 60,000 
 
 Nevada 16,659 2,500 
 
 Utah 15,000 24,000 
 
 Idaho, Montana 34,000 
 
 Elsewhere 3,803 15,994 
 
 97,835 181,494 
 
 From 80 to 85^ of the total product is from lead-silver ores. 
 
 Note. — "The Economic Gleology of Lead " is the title of a series of 
 papers by Prof. H. A. Wheeler in the Colliery Engineer, Scranton, 
 Penn. , during 1893. 
 
CHAPTER VI, 
 
 LEAD AND ZINC. 
 
 2.06.01. Example 24. The Upper Mississippi Valley. Gash 
 veins and horizontal cavities (flats), limited to the Galena and 
 Trenton limestones of the Upper Mississippi Valley, and contain- 
 ing galena, . zinchlende, and pyrite (or marcasite), with calcite, 
 barite, and residual clay. The deposits are found in southwest 
 Wisconsin, eastern Iowa, and northwestern Illinois. The greater 
 portion of the productive territory lies in Wisconsin, and covers 
 an area which would be included in a circle of sixty miles' radius, 
 whose limits would pass a few miles into Illinois and Iowa. A low 
 north and south geanticline runs through central Wisconsin dat- 
 ing back to Archean times and called by Chamberlin " Wisconsin 
 Island." On its western slope the Cambrian and Lower Silurian 
 rocks are laid down, and these in the western limit of the lead dis- 
 trict pass in the adjoining States under the Upper Silurian. They 
 are folded also in low east and west folds, but in the aggregate 
 the whole series dips very gradually westward. The chief east 
 and west fold forms the south bank of the Wisconsin River, and 
 may have been the cause that deflected it from a southerly 
 course. The easterly part of the lead region is 350 feet higher 
 than the western, and the northern is 500 feet above the southern. 
 The general slope is thus southwesterly. 
 
 2.06.02. The Galena limestone is a dolomite reaching 250 feet 
 in thickness. On the hilltops left by erosion Maquekota (Hudson 
 River) shales are seen. The Galena has shaly streaks, which have 
 largely furnished the residual clay of the cavities. There are also 
 cherty layers and sandy spots. Under the Galena lies the Tren- 
 ton, from 40 to 100 feet thick, and made up of an upper blue por- 
 tion, which is a pure carbonate of lime, and a lower buff portion 
 that is magnesian. The upper portion of the blue has a band of 
 shale locally called the "Upper Pipe Clay," and the pure, crypto- 
 crystalline limestone under this is called " Glass Rook." The blue 
 
190 
 
 KEMP'S ORE DEPOSITS. 
 
 contains mucli bituminous matter. The buff is locally called 
 " Quarry Rook " and is prolific in fossils. Under the Trenton lies 
 the St. Peter's sandstone, 150 feet below w-hich is the Lower Mag- 
 nesian, 100 to 250 feet, and still lower the Potsdam, averaging 
 VOO to 800 feet. The Potsdam rests on the quartzites and schists 
 of the Archean. The ore beds especially favor the shallow, syn- 
 clinal depressions of the east and west folds. They occur in crev- 
 ices, the great majority of which run east and west. The pro- 
 ductive ground comes in spots which are separated by stretches 
 
 ^~Z^^{ 
 
 '-"^^^^ 
 
 -^Miiii 
 
 ■^—Tlllli'- 
 
 Fig. 48. — 0ash veins, fresli and disintegrated. The heavy black shading 
 indicates galena. After T. C. Chamherliu, Qeol. Wis., Vol. IV., 454. 
 
 of barren ground. The lead ores are chiefly produced by the 
 crevices in the Upper Galena. In the Lower Galena the zinc ores 
 become relatively more abundant, and they are also in the Tren- 
 ton. The ores do not extend in any appreciable amounts either 
 above or below these horizons. The upper deposits favor the ver- 
 tical gash vein form ; the lower tend rather to horizontal open- 
 ings, called flats, which at the ends dip down (pitches) and often 
 connect with a second sheet (flat) lying lower. There are several 
 m.inor varieties of those two main types of cavity, which mainly 
 def)end for their differences on the grade of decomposition, which 
 the walls have undergone, and whether there was an original open- 
 
LEAD AND ZING. 
 
 191 
 
 iug, or only a brecciated and crushed strii). Oliiimberlin cites 
 twelve varieties in all, some of which are based on rather fine dis- 
 tinctions. 
 
 2.06.03. The cavities were referred by J. D. Whitney to 
 joints, formed either by the drying and consolidating of the rock 
 or by gentle oscillations of the inclosing beds. The later work 
 has largely corroborated this, and they are generally thought to 
 be chiefly caused by the cracks and partings formed by the gentle 
 synclinal foldings. Such cavities have usually been enlarged by 
 subsequent alteration of the walls. Whitney also essentially out- 
 lined the explanation of origin, which has been more fully elabo- 
 
 p^ Galena ~l — timrstone i-. ^ 
 
 Fig. 49. — Idealized section of '•flats and pi.tclies,^'' forms of ore bodies in 
 Wisconsin. After T. C. Chambei-lin, Oeol. Wis. , Vol. 1 V. , jO. 458. 
 
 rated by Chamberlin. Both these writers have urged that the 
 ores could not have come from below, for the lower rocks are sub- 
 stantially barren of them. The conclusion therefore follows that 
 they were deposited in the limestones at the time of their forma- 
 tion. The source of the ores is placed in the early Silurian sea, 
 from which it is thought they were precipitated by sulphuretted 
 hydrogen, exhaled by decaying seaweeds, or similar dead organ- 
 isms on the bottom. In carrying the idea further, Chamberlin 
 has endeavored to reproduce the topography of the region in the 
 Lower Silurian times and to indicate the probable oceanic cur- 
 rents. These are conceived to have made an eddy in the lead 
 district and to have collected there masses of seaweed, etc., re- 
 sembling the Sargasso Sea. While interesting, this must be con- 
 sidered very hypothetical. When the sulphides became precipi- 
 
192 KEMPS ORE DEPOSITS. 
 
 tated they were doubtless finely disseminated in the rock and 
 were gradually segregated in the crevices. The sulphurous exhala- 
 tions from the bituminous limestones may have aided in their 
 second precipitation. The paragenesis of the minerals shows the 
 following succession : (1) Pyrite, (2) Galena, (3) Pyrite; or (1) 
 Pyrlte, (2) Blende, (3) Galena, (4) Pyrite; or (4) Calcite. The 
 ores, especially of zinc, are often oxidized, and afford considerable 
 calamine and smithsonite. Some oxidized copper ores are pro- 
 duced at Mineral Point, formed by the alteration of chalcopyrite. 
 In the early mines lead alone was sought, but of late years the 
 zinc has been produced in greater quantities and is more valuable 
 than the lead. 
 
 Dr. W. P. Jenney, whose work in the region of southwest Mis- 
 souri is later referred to (2.06.07), has also written of these mines, 
 and his views are quite different from those of any of the writers 
 mentioned above. His investigations cover all the lead and 
 zinc regions of the entire Mississippi Valley. The east and 
 west fissures, already mentioned as crevices, are regarded as faulting 
 planes. They are usually not far from the vertical, but in a few 
 instances dip 35° to 45°. The smaller north and south series are 
 considered to be due to the same cause, but to an earlier period of 
 disturbance, as they are faulted by the east and west set. The 
 latter exhibit but little vertical displacement, although some con- 
 siderable horizontal. The ore is principally in and along the east 
 and west fissures, but these seem to be locally enriched at their 
 intersections with the north and south series. The deposits are 
 described as runs ; that is, lateral enrichments along a fissure. 
 The ores are thought to have come up from below through the 
 chief fissures, and in this respect Dr. Jenney's views mark a 
 return to the earlier ones of Percival. The solutions are said to 
 have favored particular beds for the following reasons. The beds 
 were cellular from long exposure to atmospheric agents, or they 
 were chemically (being dolomitic) and physically of a nature to 
 occasion it, or they were soft and permeable shaly beds.i (See 
 also under 2.06.07.) 
 
 * Wisconsin. 
 J. A. Allen, " Description of Fossil Bones of Wolf and Deer from Lead 
 Veins," Amer. Jour. Sci., in., II. 47. T. C. Chamberlain, Wis. Geol. Sur- 
 vey, Vol. IV., 1882, p. 367. Rec. E. Daniels, " Geolog-y of the Lead Mines 
 of Wisconsin," A. A. A. S., VII. 290; Engineering and Mining Journal, 
 July 6, 13, 20, 27, Aug. 8, 10, 24, Oct. 5, 1878 ; Wis. Geol. Survey, 1854. 
 
LEAD AND ZINO. 193 
 
 Especial attention was direeted in the summer of 1893 to these 
 and the other lead and zinc deposits of the Mississippi Valley. 
 Ill addition to the paper of W. P. Jenney, earlier cited, W. P. 
 Blake presented two.' Blake brings out the fact that PerciTal, the 
 early State geologist of Wisconsin, had advocated the existence of 
 faults, and that the later work is a confirmation of these, the ear- 
 liest of all views. Although Percival's report is cited on a previ- 
 ous page, his name is not bo generally associated with the geology 
 of the Wisconsin deposits as those of his successors. The diffi- 
 culties that have been met in detecting these geological dis- 
 turbances, notwithstanding that the mines have been long and vig- 
 orously worked, indicate what obscure phenomena they are. 
 Blake, however, cites a case in the Helena mine, near Shullsburg, 
 where mineralization occurs near a pair of faults. Blake also lays 
 stress upon the presence of thin seams of a rich bituminous shale 
 in layers usually about as thick as cardboard, which are present in 
 a richly fossiliferous limestone at the top of the Trenton, just be- 
 neath the ore-bearing "Galena" dolomite. 'So doubt these richly 
 bituminous layers (locally called " oil-rock") are genetically con- 
 nected with the precipitation of the ores as Blake mentions. 
 It should be added that the region is unglaciated, and has, there- 
 fore, been long exposed to atmospheric agents. In the general dis- 
 cussion which followed the papers of Jenney and Blake great dif- 
 erences of views were developed, and it must be admitted 
 that to-day there is as little unanimity of opinion regard- 
 ing the origin of these ores as in the past. The method of origin, 
 whether from circulations, permeating the lower Silurian lime- 
 stones themselves, and leaching them of disseminated galena and 
 blende, and concentrating the ores in cavities, or from uprising 
 solutions along fissures, has an important practical bearing as re- 
 gards the future of the country. The latter view gives greater 
 hope of lower lying productive horizons, but the old question raised 
 by Percival, answered in the negative by Whitney and Chamberlin, 
 and somewhat favorably regarded by Jenney and Blake, as to 
 whether there are lower lying ore bodies in the Lower Magnesian 
 limestone, is not yet solved by a deep shaft or boring. 
 
 1 W. P. Blake, "Tlie Mineral Deposits of Soutliwest Wisconsin," 
 Trans. Amer. Inst. Min. Engineers, Chicago Meeting, 1893 ; Amer. 
 Geol. , XII. 337 , 1893. ' ' Wisconsin Lead and Zinc Deposits, ' ' Bull. Oeol. 
 Soc. Amer. V. 25, 1898. Attention shotild also be called to a previous 
 paper, ' ' Progress of Geological Surveys in the State of Wisconsin ; A 
 Review and Bibliography, ' ' Trans, Wis. Acad. Sci., LX. 335. 
 
194 KEMP'S ORE DEPOSITS. 
 
 2.06.04. Example 24a. Washington County, Missouri. Gash 
 veins in the Lower Magnesian limestones of eastern Missouri in 
 the same region as the disseminated ores of Example 23, and con- 
 taining galena, barite (locally called "tiff"), calcite, and residual 
 clay. The cavities are described by Whitney as resembling in all 
 respects the gash veins farther north, which, however, lie in rocks 
 higher in the geological series. These mines were the earliest 
 worked, but have been given up since the price of lead has been 
 at present figures (1875 and subsequently). The ore was obtained 
 from pockets, cave.3, irregular cavities, and from the overlying 
 residual clays. This whole region has been exposed and above 
 water since the close of Carboniferous times and has suffered 
 enormous surface decay (see R. Pumpelly, Tenth Census, Vol. 
 XV., p. 12, and Geol. Soc. Amer., Vol. II., p. 20), which has left a 
 mantle of residual clay spread widely over its extent. In this, 
 more or less float mineral occurred. The mines were located in 
 Washington, Franklin, Jefferson, and St. Francois counties.' 
 
 2.06.05. Example 24S. Livingston County, Kentucky. Veins 
 in limestone of the St. Louis stage of the Lower Carboniferous, 
 containing galena in a gangue of fluorite, calcite, and clay. The 
 
 James Hall, "Notes on the Geology of the Western States," Amer. Jour. 
 Sci., 1., XLII. 51. J. T. Hodge, " On the "Wisconsin and Missouri Lead Re- 
 gion," Amer. Jour. Sci., i., XLHI. 35. R. D. Irving, "Mineral Resources 
 of Wisconsin," M. E., VIII. 478. E. James, "Remarks on the Limestones 
 of the Mississippi Valley Lead Miues," Phil. Aoad. Sci., V., Part I., p. 51. 
 J. Murrish, Report on the lead regions, 1871, as commissioner for their 
 survey. D. D. Owen, "Report on the Lead Region," U. S. Senate Docu- 
 ments, 1844. J. G. Percival, Wis. Geol. Survey, 1856. Squier and Davis, 
 Historical account, Smithsonian Contributions, Vol. I., p. 208. M. Strong, 
 Wis. Geol. Survey, 1877, 1. 637 ; II. 645, 689. J. D. Whitney, iris. Geol. 
 Survey, 1861-63, 1. 231. Rec. Metallic Wealth, p. 408, 1856. " On the Oc- 
 currence of Bones and Teeth in the Lead-bearing Crevices," A. A. A. S., 
 1859. 
 
 Illinois. 
 J. Shaw, Geol. Survey of Illinois, 1873, Vol. II., p. 840. J. D. Whit- 
 ney, Geol. Survey of Illinois, 1866, Vol. I. 153. 
 
 Iowa. 
 
 C. A. White, Iowa Geol. Survey, 1870, Vol. II., p. 339. J. D. Whit- 
 ney, Iowa Geol. Survey, 1858, Vol. I., p. 433. 
 
 1 Compare the older references under Example 33, and the following: 
 A. Litton, Second Ann. Rep. Missouri Geol. Survey, 1854. J. D. Whitney, 
 Metallic Wealth, p. 419. 
 
LEAD AND ZING. 195 
 
 ore bodies have never been well described and no very accurate 
 diagnosis can be given. They are found in Livingston, Crittenden, 
 and Cald-well counties, Kentucky, in that portion of the State 
 lying south of the Ohio River and east of the Cumberland. While 
 limestone always forms one wall, a sandstone of geological rela- 
 tions not well determined forms the other. The veins run from 
 two to seven feet wide and in instances are richer in their upper 
 portions than in the lower. As yet they are of greater scientific 
 than practical importance. Some galena occurs also in irregular 
 cracks in the limestone. As a possible indication of a stimulating 
 cause for the formation of the veins, the interesting dike of mica- 
 peridotite may be cited, which has been described by J. S. Diller.^ 
 The dike occurs in the same fissure with a vein of fluorspar.^ 
 
 2.06.06. Example 25. Southwest Missouri. Zincblende and 
 very subordinate galena with their oxidized products, associated 
 with chert, residual clay, calcite, a little pyrite and bitumen, in 
 cavities of irregular shape and in shattered portions of Subcarbon- 
 iferous limestone. Across Missouri, from a point south of St. 
 Louis, and including the country as far to the northwest as 
 Sedalia and Glasgow, a broad belt, called the Ozark uplift, extends 
 southwesterly into Arkansas. It has formed a great plateau in 
 central and southern Missouri and consists largely of Silurian 
 rocks. These have a fringe of Devonian on the edges and dip un- 
 der the Lower Carboniferous. The plateau reaches 1500 feet above 
 the sea in Wright County, but on the limit is succeeded by lower 
 country. To the southwest it drops somewhat, with Lower Car- 
 boniferous strata outcropping, which in Kansas are overlain by the 
 coal measures. The surface then rises again in the prairies. At 
 the edge of the plateau is a trough, in whose bottom the Lower 
 Carboniferous strata are cut by the Spring River, which flows 
 southwesterly from Missouri across the western State line into 
 Kansas and has a general direction parallel to the western limits 
 of the uplift. It receives tributary streams on each bank, which 
 cut the strata in strongly marked valleys and afford good ex- 
 posures. Those on the east bank, from south to north, are Shoal 
 
 ' " Mica-Perldotite from Kentucky,'' Amer. Jour. Sei., October, 1892. 
 
 * S. F. Emmons, "Fluorspar Deposits of Southern Illinois," M. E., 
 February, 1893. C. J. Norwood, " Report on the Lead Region of Living- 
 ston, Crittenden, and Caldwell Counlies," Kentucky Oeol. Survey, 1875, 
 New Series, Vol. I., p. 449. 
 
196 KEMPS ORE! DEPOSITS. 
 
 Creek, Short Creek, Turkey Creek, and Center Creek, while from 
 the west come the Brush, Shawnee, and Cow creeks, all in Kansas. 
 Along the first mentioned creeks the principal mining towns are 
 situated, but others are found on the minor streams. They extend 
 through an area fifteen miles broad from east to west and twenty- 
 five miles from north to south. Newton and Jasper are the most 
 productive counties in Missouri, while Cherokee County, in Kansas, 
 also contains notable mines. Undeveloped districts are recorded in 
 Arkansas, but apparently at a lower geological horizon. The ore 
 occurs in the Keokuk or Archimedes limestone of the Lower Car- 
 boniferous. A generalized section of the rocks, according to F. L. 
 Clerc, is as follows. On the higher prairie, some 15 feet of 
 clay or gravel ; 10 feet of flint or chert beds ; 40 ^feet of lime- 
 stone with thin beds of chert ; 60 feet of alternating layers of 
 limestone and chert; 100 feet and more of chert, sometimes chalky 
 with occasional beds of limestone ; 225 feet in total. In basins 
 and extensive pockets in these rocks, deposits of slates with small 
 coal seams are found, of undetermined geological relations. The 
 large bed of limestone of the section affords a datum of reference 
 in relation to which the ores may be described. A few minor, 
 shallow deposits occur in the flints over it. In the limestone the 
 ores are associated with a gangue of dolomitic clay and residual 
 flint. They occupy irregular cavities or openings, locally known 
 as circles, spar openings, and runs. (Clerc.) Below the limestone 
 the ore is found in " sheets, bands, seams, and pockets," and filling in 
 the interstices of a breccia of chert, which has been formed by the 
 breaking down of the chert layers on the solution and removal of 
 the interbedded limestones. There are districts where the over- 
 lying bed of limestone has also disappeared, and they then lack 
 it for a capping. The deposits extend to considerable depths be- 
 low the position of the limestone. The present mines have not 
 demonstrated as yet their limit of depth. At times the ore is 
 associated with a later formed quartz rock that has coated and 
 filled the cavities of the breccia. 
 
 2.06.07. The removal of the interbedded layers of limestone 
 and the caving in of the associated cherts have been the principal 
 causes of the formation of cavities. Adolph Schmidt referred the 
 shrinkage to the dolomitization of pure lime carbonate, an idea 
 that has had extended adoption, and has also had an important 
 part in causing the general porosit}'. Schmidt traced five periods 
 in the geological history of the ore bodies: 1. Period of deposition 
 
LEAD AND ZINO. 
 
 197 
 
 of the rocks. 2. Period of dolomitization of certain strata and of 
 principal ore deposition. 3. Period of dissolution of part of the 
 limestone, of breaking down of chert, and of continued but di- 
 minishing ore deposition. 4. Period of regeneration, secondary- 
 deposition of carbonate of lime and quartz, and continued ore de- 
 position. 5. Period of oxidation. 
 
 Schmidt's work was done in 1871-72. Since then the increased 
 
 / / I' • / ■ /••'"'/''///''' ' / ■' Pi'obable flint floor of 
 '■J J v'^' J~J\J v' -J^'^'J-jJ^ y vV ^VVv/v-'v'V^A--^-'^-'^-^ --' ore.deposit. 
 
 TvPTOAL ZINC-BLENDE ORE-BOOy NEAR WeBB CitY, Mo. VERTICAL SECTION. 
 -^ ^ubcarboniferoua Limestone 
 
 ^^^inc-blende ope-bodiee 
 •^-•^•••' l^l'"* '•""='< ^^•2!^& Flint rock 
 
 — ^ ^ — ^K« Galenite in fissures & beddin^ptanes in limestone 
 
 Fig. 43. — Vertical section of a typical zincblende ore body, near Webb 
 City, Mo. After C. Henrich, M. E., June, 1892. 
 
 development of the mines has afforded greater opportunities for 
 observation. Haworth, in 1884, referred, with much reason, the 
 shattering of the chert in certain areas to oscillations of the strata, 
 and Clerc, in 1887, emphasized particularly the dissolving action of 
 water. It is a hard problem to discover the original source of the 
 metals. The earlier writers said nothing of this subject, or else, 
 as in Haworth's paper, discussed a possible precipitation from the 
 ocean or, as in Clerc's, referred them to the pockets of slate and 
 coal. In 1893, at the Chicago meeting of the American Institute 
 
198 KEMP'S ORE DKPOSITS. 
 
 of Mining Engineers, W. P. Jenney presented an abstract of the 
 results of his work while detailed by the U. S. Geological Survey 
 to study these ore deposits. As will appear in the abstract of the 
 paper given below, the ores are supposed to have come up through 
 fissures of displacement, and hence from below. These con- 
 clusions have been con- troverted by others, on account of 
 the difficulty in proving the ex- istence of faults when evi- 
 dence of displacement is so obscure. In Jenney's paper 
 all the lead or lead and zinc regions of the Mississippi Valley 
 are considered together. They are described as occurring along 
 three lines of upheaval. The region of Wisconsin and Iowa 
 is on the flanks of the Archean " Wisconsin Island " of Chamber- 
 lin, referred to above under 3.06.01. The southeast and southwest 
 Missouri regions are on the Ozark uplift, while a minor argentif- 
 erous galena district is on the line of the Ouachita uplift of Ar- 
 kansas and Indian Territory. The formation of the ore bodies in 
 the first three of these is regarded as having been in general the 
 same. They are thought to have originated from uprising solu- 
 tions, which came through certain principal fissures, and spread 
 laterally into strata favorable to precipitation. In southwest Mis- 
 souri this was the Cherokee limestone of the Lower Carboniferous. 
 In its unaltered state it is an extremely pure carbonate of lime. It 
 lias a maximum thickness, where not eroded, of 165 to 200 feet, 
 and contains many interbedded layers of chert. Much organic 
 matter, and moi'e or less bitumen, are also at times present. The 
 limestone seems to have been raised above the ocean level at the 
 close of the Lower Carboniferous and to have remained for a long 
 period exposed to the atmospheric agents. Much caving in of 
 unsupported layers of chert and much attendant brecciation re- 
 sulted. The general stratum became quite open and cellular in 
 certain portions. At a later period, supposed from several indica- 
 tions to be at the close of the Cretaceous, dynamic disturbance 
 occurred, which along certain lines produced fissures, sometimes 
 parallel, sometimes intersecting. Solutions arose through these 
 which dolomitized much of the remaining limestone and caused 
 additional porosity. Zinc and lead ores were afforded, and where 
 the conditions were favorable they spread laterally from the fis- 
 sures and deposited the sulphides in the cellular rock or replaced 
 the limestone itself. The intersection of crossing fissures is a fre- 
 quent point of deposition, and at times parallel master fissures 
 have given a wide area of impregnation. This form of ore '^"- 
 
LEAD AND ZING. 199 
 
 posit is called a run. The runs are from 5 to 50 feet in height, 
 100 to 300 feet long, and 10 to 50 feet across. At Webb City 
 they are even larger. As a general thing the ore is in the inter- 
 stices of the brecciated chert, but it is also in limestone and dolo- 
 mite, and associated with a silicified form of the insoluble residue 
 left by the solution of the limestone, which Dr. Jenney calls 
 " cherokite." All the ores require concentration. Galena usually 
 occurs near the surface, while blende is more abundant in depth. 
 Cadmium is at times present in the blende in notable amount. 
 
 2.06.08. Some interesting alterations of the minerals have oc- 
 curred, which have changed the blende to smithsonite and cala- 
 mine. In one case a secondary precipitation of zinc sulphide has 
 occurred as a white amorphous powder which is of very recent 
 date. With the original precipitation of the blende the asphaltic 
 material may have had something to do. In the matter of produc- 
 tion Dr. Jenney fixes the ratio of the blende, galena, and pyrite 
 at about 1000 : 80 : 0.5} 
 
 2.06.09. Other zinc and lead deposits are known in central 
 Missouri generally resembling the above quite strongly, but of 
 less economic importance. Some, however, are described by 
 Schmidt as conical stockworks. They sometimes are found in 
 Lower Silurian strata. 
 
 1 G. C. Broadhead, "Geological History of the Ozark Uplift," Amer. 
 Geol, III. 6. H. M. Chance, "The Rush Creek (Arkansas) Zioc District," 
 Trans. Amer. Inst. Min. Eng., Wa.shington meeting, 1890. F. L. Clerc, 
 Geological description of the mines in a statistical pamphlet on the Lead 
 and Zinc Ores of Southwest Missouri Mines, p. 4, published by J. M. Wil- 
 son, Carthage, Mo., 1887. Eec. See also Engineering and Mining Jour- 
 nal, June 4, 1887, p. H97. " Zinc in the United States," Mineral Resources, 
 188y, p. 368. Engineering and Mining Journal, Nov. 3, 1888, p. 389 ; March 
 8, 1890, p. 386. E. Haworth, A Contribution to the Geology of the Lead 
 and Zinc Mining District of Cherokee County, Kansas, Oskaloosa, Iowa, 
 1884. C. Henrich, " Zincblende Mines and Mining near Webb City, Mo.," 
 M. E., February, 1893 ; Engineering and Mining Journal, June 4, 1893. 
 R. W. Raymond, "Note on the Zinc Deposits of Southern Missouri," M. 
 E., VIII. 165 ; Engineering and Mining Journal, Oct. 4, 1879. J. D. Rob- 
 ertson, "A New Variety of Zinc Sulphide from Cherokee County, Kansas,'' 
 Amer. Jour. Sci., iii., XL., p. 160. A. Schmidt and A. Leonhard, Missouri 
 Geol. Survey, 1874. A. Schmidt, "Forms and Origin of the Lead and Zinc 
 Deposits of Southwest Missouri," Trans. St. Louis Acad. Sci., III. 246; 
 Amer. Jour. Sci., iii., X., p. 300. Die Blei und Zink Erzlagerstdtten von 
 SiXdwest Missouri, Heidelberg, Germany, 1876. W, H. Seamen, "Zinc 
 iferous Clays of Southwest Missouii,' Amer. Jour. Sci., iii., XXXIX., p. 38. 
 
!iOO 
 
 KEMP'S ORE DEPOSITS. 
 
 All the Missouri deposits will furnish the subject of a forth- 
 coming report by Arthur Winslow, late State geologist, which will 
 be issued by the State survey. Preliminary papers, cited below by 
 Mr. Winslow, indicate that he does not regard the derivation of the 
 ores from below as proved, and the full statement of his views will 
 be awaited with interest. 
 
 ENLARGED SECTION SHOWING RELATION OF ZINC-ORE 
 TO THE. -LIMESTONES AND CLAY. 
 
 Tig. 51. — Geological section of the Bertha zinc mines, Wythe County, Va. 
 After W. H. Case, Trans. Am. Inst. Min. Eng., August, 1893. 
 
 2.06.10. Both the mines of Example 25 and those of Example 
 24 were originally worked for lead, and the zinc minerals were re- 
 garded as a nuisance ; of late years the zinc has been much more 
 of an object than the lead. The deposits in southwest Virginia 
 (Example 26) also produce lead, but are best known for zinc. 
 
 ^ C. R. Boyd, Resources of Southwest Virginia, p. 71; "Mineral 
 Wealth of Southwest Virginia," M. E., V. 81 ; Ibid., VIII. 340. Eec. H. 
 Credner, Zeitschr. fur die gosammten Naturwissenschaften, ISTO, Vol. 
 XXXIV., p. 21. F. P. Dewey, "Note on the Falling Cliff Zinc Mine," 
 M. E.,X. 111. A. V. Groddeck, Typus Austin, Lehre von den Lagerstat- 
 ten der Erze., p. 103. 
 
 2 Dr. Jenney's paper appeared in the Trans. Amer. Inst. Min. Eng., 
 Chicago meeting, 1893, and was entitled ' ' The Lead and Zinc Deposits 
 of the Mississippi VaUey. ' ' It prompted an important discussion. 
 Arthur Winslow has contributed the following : ' ' Notes on the Lead 
 and Zinc Deposits of the Mississippi Valley and the origin of the Ores, ' ' 
 Jour, of Geology, I. 612, 1893; and a brief account in "The Geology and 
 Mineral Products of Missouri, " pamphlet, distributed at the World's 
 Fair, Chicago, 1893. His full report is in press (July, 1894). 
 
LEAD AND ZINC. 
 
 201 
 
 3.06.11. Example 26. 
 Wythe County, Va. Veins 
 or beds of oxidized ores, 
 changing to blende below, 
 in crystalline limestone or 
 dolomite, which lies just 
 above the Calciferous, but 
 is as yet not sharply deter- 
 mined stratigraphically. 
 A' so residual deposits of 
 oxidized ores resting on the 
 limestone, in clays which 
 have resulted from its decay. 
 The ore-bearing terrane is 
 known over a considerable 
 extent of country, running 
 from near Roanoke, one 
 hundred miles westward. 
 The largest mines are in 
 Wythe County, and of 
 these the Bertha is best 
 known. The Bertha ores 
 are calamine and smith- 
 sonite, both crystallized and 
 earthy or ochreous. They 
 lie upon a limestone which 
 is of very irregular surface, 
 being so deeply pitted by 
 superficial decay that it pro- 
 jects in knobs and pillars, 
 and sinks in intervening 
 depressions. These are 
 shown very graphically in 
 Fig. 53, p. 203, where they 
 are left in relief by the 
 stripping. They are man- 
 tled and rounded ofE by the 
 overlying residual clay, 
 which may be 50 to 75 feet 
 deep. The ore lies in sheets 
 and balls or as a powdery 
 
 fe 
 
 
 qs 
 
 «a 
 
 &! 
 
 s 
 
 O 
 
 ALTOONA COAL-MINE* 
 
 4 
 
 s 
 
 § 
 
 g 
 fi- 
 
 fe^ 
 
 fe 
 
 iow*wo>Mai(Do 
 
 
 » " o a o S 
 > M 5 P D 
 
 J I 53 g* » S 
 
 N' & W. Tlv ft. 
 PEAK CREEK 
 
 DRAPER MOUNTAIN 
 
 DtUeEft VAU'EV 
 
 ® 
 
 NEW RIVER 
 
 N. A W. R. R. N. C. DIV. 
 
 BERTHA ZINC-MINES 
 
 ROARING TAUe. MOUNTAIN 
 
302 KEMP'S ORE DEPOSITS. 
 
 mass upon or near the limestone In the clay, and is won either by 
 stripping this, or by shafts and drifts. (See Fig. 51.) Accord- 
 ing to Boyd, in one section there are 486 feet of strata impreg- 
 nated with zinc and lead sulphides, with some pyrite. At the 
 Wythe Company^s mines both the oxidized ores and the unchanged 
 sulphides in the underlying limestone are exploited. More or 
 less limonite is obtained from all these surface workings, and is 
 sent to neighboring blast furnaces. 
 
 Near Bonsacks the gossan of the ore was exposed but not recog- 
 nized for a long time, in a cut of the Norfolk and Western E. E. 
 The mine yielded rich earthy oxidized ores which, however, passed 
 in depth into a very intimate and rebellious mixture of zinc-blende 
 and pyrite. These deposits extend over a wide stretch of country, 
 running from near Eoanoke, one hundred miles westward.^ 
 
 Eelated deposits occur in northeastern Tennessee, between 
 Knoxville and Bristol, and have furnislied more or less ore, chiefly 
 calamine. They are not large. 
 
 2.06.12. Blende is a frequent associate of galena in the Eocky 
 Mountains, but it has been only recently worked for any zinc 
 product, and then largely as a by-product in extracting silver. 
 (See 3.07.10.) 
 
 1 C. B. Boyd, " Resources of Southwest Virginia, " p. 71. "Mineral 
 Wealth of Southwest Virginia, ' ' Trans. Amer. Inst. Min. Eng., V. 81 ; 
 Ibid., VIII. 840. ' ' The Wythe Lead and Zinc Mines, Va. , ' ' Engineering 
 and Mining Journal, June 17 and 34, 1893. W. H. Case, " The Bertha 
 Zinc Mines at Bertha, Va. , ' ' Trans. Amer. Inst. Min. Eng., Chicago 
 Meeting, Aug., 1893. H. Credner, Zeitsch. furdie gesammten Naturwis- 
 senschaften, 1870, XXXIV. p. 24. F. P. Dewey, "Note on the Falling 
 Cliff Zinc Mine (Bertha Company)," Trans. Amer. Inst. Min. Eng., X. 
 111. A. V. Groddeck, Typus Austin. Lehre von den Lagerstotten der 
 Erze, p. 103. 
 
CHAPTER VII. 
 
 ZINC ALONE, OR WITH METALS OTHER THAN LEAD. 
 
 2.07.01. Zinc ores commonly occur in association with lead, but 
 there are one or two exceptional deposits in this country which are 
 without lead and which have no parallel in other parts of the world. 
 The minerals containing zinc at Franklin Furnace and Ogdens- 
 burg, N. J., are known elsewhere only as rarities, although they 
 are found in vast amounts in New Jersey.^ 
 
 ZINC SERIES. 
 
 Zn. S. Fe. SiO^. Mn. 
 
 Sphalerite (commonly called blende) ZnS 67 33 
 
 Zincite, ZnO 80.3 
 
 Franklinite,(Fe.Zn.Mn)0,(Fe.Mn)203 (variable) 5.54 51.8 7.5 
 
 Willemite, 2ZaO.Si02 58.5 27.1 
 
 Calamine, SZnO.SiO^.HaO 54.2 25.0 
 
 Smithsonlte, ZnOCOj 51.9 
 
 2.07.02. Example 27. Saucon Valley, Pennsylvania. Zinc- 
 blende and its oxidation products, calamine and smithsonite, fill- 
 ing innumerable cracks and fissures in a disturbed, magnesian lime- 
 stone, thought to belong to the Chazy stage. The ore bodies 
 occur in the Saucon Valley near the town of Friedensville, about 
 four miles south of Bethlehem. The limestone is inclosed between 
 two northerly spurs of the South Mountain, and has apparently 
 been tilted and shattered by the upheaval of the latter. The 
 shattering and disturbances decrease as the South Mountain is left 
 and the dijj decreases. There are three principal mines, the 
 Ueberroth, the Hartman, and the Saucon, the first named being in 
 the portion which is tilted nearly to a vertical dip and is much dis- 
 turbed, while the next is where the dip has gradually decreased to 
 35°. The mines are on a belt some three quarters of a mile long. 
 At the Ueberroth an enormous quantity of calamine was found on 
 
 1 F. L. Clerc, "Zinc in the United States," Minercl Resources, 1883, 
 p. 358. 
 
ZINC ALONE. 205 
 
 the surface, but it passed in depth into blende and was clearly an 
 oxidation product. In the others the blende came nearer the sur- 
 face. The ore follows the bedding planes and the joints normal to 
 these throughout a zone varying from 10 to 40 feet across and fills 
 the cracks. At their intersection the largest masses are found. 
 Six larger parallel fissures were especially marked at the Ueberroth. 
 This mine jDroved in development to be very wet, and a famous 
 pumping engine, the largest of its day, was built to keep it dry. 
 The Hartman and Saucon are less wet. A little pyrite occurs with 
 the blende, and thin, powdery coatings of greenockite sometimes 
 appear on its surface, but it is entirely free from lead and a very 
 high grade spelter is made from it. The mines were strong pro- 
 ducers from 1853 to 1876, but little has been done since. It is re- 
 ported (1891) that the great pumping engine has been started, and 
 they may once more furnish considerable quantities of ore. 
 
 2.07.03. The mines wei"e evidently filled by circulations from 
 below that brought the zinc ore to its present resting place in the 
 shattered and broken belt. Drinker considers it to have been de- 
 rived from a disseminated condition in the limestone.' 
 
 2.07.04. Example 28. Franklin Furnace and Sterling, N. J. 
 A bed consisting of franklinite, willemite, zincite, etc., in crystal- 
 line limestone, in many respects analogous to the magnetite of Ex- 
 ample 13. The franklinite and zincite beds are in a belt of white, 
 crystalline limestone which runs southwesterly from Orange County, 
 New York, across northwestern New Jersey. It was considered 
 metamorphosed Lower Silurian by H. D. Rogers, but its associa- 
 tion with Archean gneiss is so close that it has with some reason 
 been regarded as of the same age with the gneiss. Beyond the 
 gneiss to the west a blue limestone supposed to be Lower Silurian 
 outcrops, and the same rock appears again to the southeast. F. L. 
 Nason, of the New Jersey Survey, has recently argued, after careful 
 and praiseworthy field work, and after discovering in unmetamor- 
 phosed portions some fossils which belong to the Olenellusfaunaof 
 the Cambrian, that the blue and white limestones are of the same 
 age, and that the latter owes its character to a great dike of granite. 
 
 1 F. L. Clerc, Mineral Resources, 1883, 361. Eec. H. S. Drinker, 
 "On the Mines and Works of the Lehigh Zinc Company," M. E., I. 67. 
 C. E. Hall, in Rep. D3, Second Geol. Survey Penn., p. 239. Die Gruben 
 und Werke der Lehigh Zink Oesellschaft in Pennsylvanien, B. und H. 
 Zeit., 1873, p. 51. 
 
206 
 
 KEMPS ORE DEPOSITS. 
 
 which appears at various points. The granite is not always con- 
 tinuous, and is often in isolated masses or horses, as in the Trotter 
 mine. There is also in some portions of the belt a curious scapo- 
 lite rock, regarded as igneous. It is not unlikely that the great 
 dikes may have been a factor in the formation of the ore, although 
 this is not demonstrated. At Franklin Furnace the crystalline 
 limestone forms a low hill (Mine Hill) east of the upper waters of 
 the AVallkill, and again at Ogdensburg, two miles south, another 
 (Sterling Hill), on the west bank. There is a valley and unex- 
 posed strip between, so that the unbroken continuity without a 
 possible intervening fault cannot be established. The bed at 
 Franklin outcrops on the west side of the hill. It begins on the 
 north just across the Hamburg road and runs south 30° west as a 
 
 Fig. 54.— Cross Section at Franklin Furnace, Sf. J., corresponding to 
 
 A A- of Map (Fig. 55), andfotir times the scale of Map. At the 
 
 left is blue limestone and quartzite. After J. F. Kemp, 
 
 Trans. N. Y. Acad, of Sciences, XIII. 86, 1893. 
 
 continuous bed for about 2500 feet. This portion is called the 
 Front vein. It contains on the north the old Hamburg mine, 
 then the Trotter mine, and in the southern portion belongs to the 
 New Jersey Zinc and Iron Company. It runs from 8 to 30 feet 
 broad at the outcrop, but swells below. It dips southeast 40 to 60° 
 into the hill, and is interbedded in the limestone. In the Trotter 
 mine a wedge or horse of hornblende, augite, plagioclase, and 
 various other silicates enters the bed a short distance. In this 
 horse some of the most interesting minerals have been found, such 
 as fluorite, rhodonite, blende (var. cleiophane), smaltite (var. 
 chloanthite), axinite, etc. At the end of the Front vein — or, more 
 properly, bed — a branch or bend strikes off at an angle of 30 to 40° 
 to the east. This more easterly branch, which is called the Buck- 
 wheat mine, outcrops on the surface some 500 feet, and then, after 
 being cut by a trap dike 32 feet wide, pitches down at an angle of 
 37° and passes under the limestone. The portion of the mine north- 
 east of the dike furnishes the most and best ore. The surface out- 
 
ZINO ALONE. 207 
 
 crop of the Buckwheat was 25 to 30 feet across, but it swelled be- 
 low to 52 feet, and in the second level, about 200 feet from the 
 surface, it was penetrated by a cross-cut 125 feet without finding 
 the wall. The character of the ore varies ; for while it is excellent 
 at the point of the cross-cut, at 125 feet nearer the intersection with 
 the front bed it becomes lean, while preserving its width lower. 
 Beyond the dike the bed is likewise broad, and is mined out for 40 
 to 50 feet across. The workings are now some distance down on 
 the pitch. The imjjression made by the arch of the roof and 
 by the curving beds is that this is the crest of an anticline 
 whose axis pitches north 27°, and whose central portion is formed 
 by the franklinite bed being doubled up together on itself bf. 
 fore the two parts diverge in depth. Its western portion probably 
 is continuous in a synclinal trough with the front bed, and its 
 eastern portion dips east at some unknown angle. If this is true, 
 it would doubtless be struck by drilling in the surface to the east- 
 ward. Mining has generally been followed along the entire out- 
 crojD except at the junction of the two branches. At present the 
 most active work is being done on the front bed at the Trotter 
 mine and on the rear bed of the Buckwheat, the latter being much 
 the larger. 
 
 2.07.05. The ore consists of franklinite in black crystals 
 usually rounded and irregular, but at times affording quite a per- 
 fect octahedron combined with the rhombic dodecahedron and set 
 in a matrix of zincite, willemite, and calcite. The richest ore lacks 
 the calcite and consists of the other three in varying proportions. 
 This best ore is in largest amount in the Buckwheat mine, beyond 
 the trap dike which cuts it. The limestone containing the ore has 
 a notable percentage of manganese replacing the calcium, and 
 where it is exposed to the atmosphere it weathers a characteristic 
 brown. An analysis of a sample occurring with the ore at Sterling 
 Hill afforded F. C. Van Dyck : 
 
 CaCOa 82.2,8 
 
 M11CO3 16.57 
 
 FeoOa 0.50 
 
 SiOj 0.30 
 
 H2O 1.0 
 
 100.50 
 
 The percentage of manganese is veiy high for a limestone. 
 
 2.07.06. The Sterling Hill outcrop is less extensive. It begins on 
 
208 KEMPS ORE DEPOSITS. 
 
 the north with the New Jersey Zinc and Iron Company's property 
 and runs south 30° west for 1100 feet. It then branches or bends 
 around to the west and runs north 60° west for 300 feet, bend- 
 ing again to north 30° east, and pitches beneath the surface. 
 Thus the general relations between the front and back beds 
 are somewhat the same as at Mine Hill, and the dip and pitch 
 are similar. The principal workings are on the Front vein, where 
 there are two veins (beds), according to the older descriptions, one 
 rich in franklinite and the other in zinoite. It is doubtful if there 
 really are two distinct beds, but probably one portion is richer in 
 zincite than the other. The part mined is from two to ten feet. 
 The footwall is corrugated and causes many pinches and swells, 
 whose troughs pitch north. The limestone between the front and 
 back outcrop is charged with franklinite and various silicates (jef- 
 fersonite, augite, garnets, etc.), and has been mined out in large 
 open cuts now abandoned. A deposit of calamine was found in 
 the interval about 1876, and has furnished many fine museum 
 specimens. 
 
 2.07.07. It is not clear that the Sterling Hill and Mine Hill 
 deposits were once continuous. The bed at Mine Hill runs in the 
 front portion close to the contact of the white limestone and the 
 gneiss. The Sterling Hill bed is much farther away from the 
 gneiss, and this would indicate that it is at a higher horizon. The 
 evidence, too, of a pitching syncline is strong, but a pitching S-fold 
 is not as clear. A faulting of the Archean rocks in an east and 
 west line across their strike, and a subsequent tilting so as to give 
 them a northerly pitch, is a very widespread phenomenon in the 
 Highlands, and lends weight in this instance to the idea that a fault 
 intervenes between the two hills. Such faulting is shown even in 
 New Yorl: City. 
 
 2.07.08. The origin of these beds is very obscure. They are so 
 unique in their mineralogical composition that very little direct 
 aid is furnished by deposits elsewhere. At Mine Hill, below the 
 fork of the franklinite bed, there was formerly a large lense of 
 magnetite that has now been mined out. It was in the white 
 limestone. There are many points of analogy between the frank- 
 linite beds and extended magnetite deposits. They are both min- 
 erals of the spinel group, and the spinels are a common result of 
 metamorphic action. The presence of zincite and willemite com- 
 plicates matters, however, and while an original ferruginous de- 
 posit might be conceived with a large percentage of manganese 
 
ZINC ALONE. 
 
 209 
 
 yet sucli abundance of zinc is beyond previous experience. It is, 
 however, suggestive that no inconsiderable amount of zinc is found 
 in the Low Moor (Va.) limonites, as shown by the flue dust (see 
 E. C. Means, " The Dust of the Furnaces at Low Moor, Va.," Buf- 
 falo meeting Amer. Inst. Min. Eng., October, 1888), and this 
 in the course of a protracted blast may amount to many tons, 
 but it does not approach the Franklin Furnace ores. None the 
 less, in the absence of a better explanation, the franklinite bed 
 may be thought of as perhaps an original manganese, zinc, iron de- 
 posit in limestone, much as many Siluro-Cambrian limonite beds 
 are seen to-day, and that in the general metamorphism of the re- 
 gion it became changed to its present condition. Minerals of the 
 spinel group occur all thi'ough this limestone belt, and in Orange 
 County, New York, to the north, there is an old and prolific source 
 of them. 
 
 2.07.09. If it is possible to demonstrate the connection between 
 the white limestone and a granite dike, as Mr. Nason argues, this 
 may have been an important factor in the ore formation. It is 
 very reasonable that the igneous intrusion should start ore-bearing 
 currents along a certain stratum in the limestone, which would re- 
 place it with ore. Subsequent folding and metamorphism must 
 then have changed these ores, whatever they were, to the present 
 unusual minerals.^ 
 
 Figures 55 and 56.— Geological Maps of Mine Hill and Sterling Hill, 
 
 showing the geological relations of the ore-bodies. After J. F. 
 
 Kemp, Trans. N. Y. Acad, of Sciences, XIII. 
 
 81 and 85, 1893. 
 
 This view of the method of origin has been advocated by J. P. 
 Kemp in the paper cited below, and more careful search, as well 
 
210 
 
 KEMP'S ORE DEPOSITS. 
 
 as the sinking of the new shaft on the strike of the back vein at 
 Mine Hill, have served to bring to light more intrusions of gran- 
 ite than were previously known. Chondrodite, fluorite and other 
 contact minerals occurred near them. Nason has also shown by an 
 interesting series of analyses that the limestone next the granites 
 tends to be pure CaC03, shading gradually at a distance to 
 dolomitic varieties. Victor Monheim, in discussing the vein 
 of willemite worked in the forties at Stolberg, near Aachen, 
 has urged that at temperatures sufficiently high the anhy- 
 drous silicate of zinc may separate directly from solutions, 
 while at lower temperatures the hydrous salt results. His experi- 
 ments and conclusions give support to the view that the igneous^ 
 
 FiGUBES 57 and 58. — Stereograms of the ore-bodies at Mine Hill and 
 
 Sterling Mil. After J. F. Kemp, Trans. N. Y. Acad. 
 
 of Sciences, XIII. 83 and 89, 1893. 
 
 plutonic intrusions have played an important r61e in the ore depo- 
 sition. (See V. Monheim, YerTi. d. Naturldst Ver. der p7'eus. 
 Rheinlande u. Wes fphalen Y. 162, 1848; VI. 1, 1849.) Were this 
 true we would not be compelled to assume an original bed of blende 
 from which these oxidized compounds have been derived. It is a 
 general experience, however, that hydrated oxidized ores of zinc 
 have passed in depth into blende, and this fact, in connection with 
 
 ip. Alger, "On the Zinc Mines of Franklin, Sussex Co., N. J. ," 
 Amer. Jour. Sci. i., XLVIII. 252, 1845, Rec. J. Beco. De I'Etat actual, 
 des Industries du Zinc, etc., aux Etats Unis d'Amerique, Revue TJniver- 
 selle des Mines, 1877, II. 139. W. P. Blake, in paper on ' ' Zinc Ore De- 
 posits of South.western New Mexico, ' ' Trans. Amer. Inst. Mia. Eng., Feb. , 
 1894, gives notes on the ' ' New Jersey Ore Bodies. " N. L. Britton, 
 Annual Report of the State Oeologist, N. J., 1886, p. 89. An excellent 
 
ZING ALONE. 311 
 
 the almost entire absence of blende in these mines, adds to their 
 puzzling character. Were they, however, at one time a thor- 
 oughly oxidized gossan containing the three metals specially prom- 
 inent, the intrusions of granite are probably responsible for the 
 change to their present combinations. 
 
 2.07.10. Blende is known in numerous places in the Kocky 
 Mountains, and is often argentiferous. When mixed with lead- 
 silver ores it has generally proved a drawback and has raised the 
 
 cross-section of Mine Hill is given. Gr. H. Cook, ' ' On the probable age 
 of the White Limestone at the Sussex and Franklin Zinc Mines, " Amer. 
 Jour. Sci., ii., XXXII. 208. Geology of New Jersey, 669, 1868, with map. 
 Rec. H. Credner, " On the Franklinite 'BediS," Berg-u. Hiltt. Zeilung, 
 1866, 29 ; 1871, 369. Bee. E. F. Durre, ' ' MetaUurgisohe Notizen 
 aus New Jersey und dem Lehigh Thai," Zeitsch. des Vereins deutscher 
 Ingenieure, 1894, p. 184. B. K. Emerson, "On the Dykes of Micaceous 
 Diabase, penetrating the bed of Zinc Ore at Franklin Furnace, Susses 
 Co. , N. J. , " Amer. Jour. Scl, May, 1882 , 376. Aug. F. Foerste, ' 'New 
 fossil localities in the early Paleozoics of Penn. , N. J. and Vt. , ' ' etc. , 
 Amer. Jour. Sci., iii. , XL VI. , 345. Discusses the local stratigraphy with 
 a map. P. Groth, "Die Zinkerzlagerstatten von New Jersey. Zelt- 
 Bchrift fur Praktische Geologie, May, 1894, p. 230. W. H. Keating and 
 L. Vanusem, "Geology and Mineralogy of Franklin in Sussex Co., 
 N. J.," Jour. Phil. Acad. Nat. Sci., II. 277, 1822. Rec. J. F. Kemp, 
 "The Ore Deposits at Franklin Furnace and Ogdensburgh, N. J.," 
 Trans. N. Y. Acad. So!., XIII. 76-98, 1893. Gives a full bibliography 
 and annotated list of minerals. Rec. F. L. Nason , ' ' Annual Report 
 of the State Geologist of New Jersey -1890, " p. 25. Amer. Geol, YU. 
 241;VIIL 166; XIL 154. Atner. Jour. Sci., iii., XXXIX., 407—1890. 
 "The Franklinite Deposits of Mine HiU, Sussex County, N. J. ," Trans. 
 Amer. Inst. Min. Eng., Feb., 1894. E]tg. and Mia. Jour., May 3, 1894, p. 
 197. Rec. ' 'Chemical Composition of some of the White Limestone in 
 Sussex Co., N. J.," Amer. GeoL, March, 1894, p. 154. T. Nuttall, "Geo- 
 logical and Mineralogical Remarks on the Minerals of Paterson and on 
 the Valley of Sparta," New York Medical and Physical Journal, April, 
 May and June, 1822. Amer. Jour. Sc!., i., V. 239, 1822. Jos. C. Piatt, 
 Jr. , " The Franklinite and Zinc Litigation concerning the Deposits of 
 Mine HiU at Franklin Furnace, Sussex Co. , N. J. , Trans. Amer. Inst. 
 Min. Eng., V. 580, 1876-77. H. D. Rogers, "Geology of New Jersey, 
 1840, 63-71, with a list cf Minerals by Dr. S. Fowler. ' ' Rec. G. C. 
 Stone, "Analyses of Franklinite and some Associated Minerals (2anals. 
 Zinoite, 4 of Franklinite, 5 of Willemite, 1 of Tephroite)," School of 
 Mines Quarterly, VIII. 148, 1887. G. Troost, "Observations on the 
 Zinc Ores of Franklin and Sterling, Sussex Co. , N. J. , " Jour. Phil. 
 Acad. Nat. Sci., IV. 220, 1824. J. D. Whitney, "Metallic Wealth of the 
 United States, p. 348, 1854. 
 
212 KEMP'S ORE DEPOSITS. 
 
 smelting charges. Recently works have been erected at Canon City, 
 Col., for the treatment of such ores, and very considerable quanti- 
 ties of blende are there turned into zinc-white. While the local 
 demand for this pigment is not so heavy in the West as in the 
 East, any process which frees the lead-silver or copper-silver ores 
 of the objectionable zinc will operate favorably on many mines 
 now handicapped. This has already proved to be the case with 
 the refractory sulphides met in depth at Leadville. 
 
 Deposits of oxidized ores in southwestern New Mexico, 
 near the town of Hanover, have recently been mined to a 
 notable extent. The smithsonite and calamine, as well as the 
 blende, which is met in the same vicinity, are unmixed with 
 galena, but the blende often contains intermingled pyrites, 
 and the oxidized products are at times stained with manganese. 
 The ores occupy irregular caverns and seams in Paleozoic or 
 Archean limestone, in close geological association with intru- 
 sive granite, contact zones and iron ores. Prom Blake's descrip- 
 tion the contact zones offer close mineralogical parallels with those 
 in the great limestone belt of northwestern New Jersey and New 
 York, and it is quite probable that scapolite will be found mixed 
 with the other silicates of which he makes mention. A lenticular 
 shape is often notable in the masses of blende. As remarked by 
 Blake, the deposits show some interesting points of resemblance to 
 those of New Jersey, but further metamorphism would be needed 
 to change them to the anhydrous condition of the latter. We can 
 scarcely avoid, however, attributing a strong genetic influence in 
 both cases to the igneous intrusions. The richest carbonates and 
 calamine have been shipped to the Bast, but with the unavoidably 
 high freights only the purest and best surface ores are available. 
 (W. P. Blake, Zinc-ore Deposits of Southwestern New Mexico, 
 Trans. Amer. Inst. Min. Eng., Feb., 1894.) Large deposits of 
 hematite and magnetite have been worked to some extent in the 
 same region, as a flux for lead-silver smelters, but their remoteness 
 militates against their use as au iron ore. 
 
 2.07.11. A large amount of zinc ore is turned directly into zinc 
 white and employed as a pigment. For this reason later statistics 
 of the metal do not indicate all the ore mined. The accompany- 
 ing figures are short tons. For detailed statistics see the volume on 
 "Mineral Industry" of the Engineering and Mining Journal, 
 1894. 
 
Zma ALONE. 213 
 
 1882. 1890. 
 
 Dlinois 18,201 26,243 
 
 Kansas 7,366 15,199 
 
 Missouri 2,500 13,127 
 
 Eastern and Southern States 5,698 9,114 
 
 33,765 63,683 
 
 These amounts are from the Mineral Resources of the United 
 States, 1889-90, p. 89. 
 
CHAPTER VIII. 
 
 LEAD AND SILVER. 
 
 2.08.01. There are two general methods of extracting silver 
 from its ores, the one indirectly, by smelting with and for lead ; 
 the other by amalgamation, chlorination, or some such process. 
 Hence under silver there are two classes of mines — lead-silver and 
 high-grade silver ores. Both have almost always varying amounts 
 of gold. The lead -silver mines furnish also, as noted above, by 
 far the greater portion of the lead produced in the United States. 
 Ores adapted to lead-silver metallurgical treatment foi'm, in gen- 
 eral, the oxidized alteration products of the upper parts (above 
 permanent water level) of deposits of galena and pyrites. They 
 may be well-marked fissure veins, chimneys, chambers, or contact 
 deposits. Ores which of themselves are adapted to other pro- 
 cesses are often worked in with the lead ores, and unchanged sul- 
 phides are artificially oxidized by roasting preparatory to smelt- 
 ing. The localities are taken up geographically from east to 
 west. 
 
 2.08.02. Lead-Silver Deposits in the Rocky Mountain 
 Region and the Black Hills. — The mines are described in order 
 from south to north, beginning with New Mexico. 
 
 NEW MEXICO. 
 
 2.08.03. Example 29. The Kelley Lode. Oxidized lead ores, 
 with some blende, calamine, etc., forming a contact deposit be- 
 tween slates and porphyry. The ore body is in the Magdalena 
 Mountains, thirtj' miles west of Socorro, and has supplied the 
 Billings smelter at that point. Numerous other ore bodies along 
 the contact between sedimentary and eruptive rocks occur in the 
 same region. 
 
 2.08.04. Lake Valley. Farther south in Dofla Afla County the 
 mines of Lake Valley are and have been worked upon deposits 
 very closely analogous to those of Leadville, which furnish the 
 
LEAD AND SILVER. 
 
 215 
 
 principal type. They contain less lead, hardly enough in fact to 
 be classed as lead-silver ores, according to the recent valuable paper 
 of Ellis Clark, although earlier descriptions place greater emphasis 
 on the presence of carbonates of this metal. According to Clark the 
 geological section involved includes quartzite and limestone, consid- 
 ered Silurian, 600 feet; Lower Carboniferous, black shale, 100 feet; 
 green shale, 60 feet; nodular limestone, 48 feet; blue limestone, 34 
 feet; crinoidal limestone, 125 feet, and overlying limestone, 50 feet; 
 about 1000 feet in all. These are penetrated by four distinct erup- 
 tions of igneous rocks, hornblende-andesite, rhyolite, obsidian and 
 porphyrite. The obsidian is comparatively unimportant, and of the 
 
 Fig. 5^.— Geological cross-section at Lake Valley, New Mexico, toshotothe 
 
 relations of the ore. The Hack mass is ore; the dark hachures 
 
 in the lower left-hand corner are black shale. After Ellis 
 
 Clark, Trans. Amer. Inst. Min. Eng., Feb., 1894. 
 
 others the porphyrite is most intimately associated with the ore. The 
 ore-bodies are always connected with the blue limestone, and lie along 
 the contact of this, either with the porphyrite or the overlying 
 crinoidal limestone. They are in the nature of large chutes or 
 elongated contact deposits, very similar, as the figure will indicate, 
 to those at Leadville. 
 
 The ores are of several varieties but the general components, in 
 addition to the silver, are silica, oxides of iron and manganese, 
 limestone, some galena at times, and some zinc. 
 
 The varying percentages of the silica and bases afford 
 basic, neutral and siliceous ores. In the bonanza called the 
 Bridal Chamber, great masse_8 of horn- silver were found. Many 
 ores, and interesting minerals, such as vanadinite, descloizite, etc., 
 have made the district well known to collectors. Clark favors the 
 view that the leaching of the porphyrite (which is argentiferous) 
 during its exposure and erosion, by descending surface waters, has 
 
216 KEMP'S ORE DEPOSITS. 
 
 been the source of the ore. An earlier view attributed it to 
 uprising currents.^ 
 
 COLOEADO. 
 
 2.08.05. Example 30. Leadville. Bodies of oxidized lead- 
 silver ores, passing in depth into sulphides, deposited in much 
 faulted Carboniferous limestone, in connection with dikes and 
 sheets of porphyry. Leadville is situated in a valley which is 
 formed by the head waters of the Arkansas River. The valley 
 runs north and south, being confined below by the closing in of 
 the hills at the town of Granite. It is about twenty miles Isng 
 and sixteen broad, and even to superficial observation is seen to be 
 the dried bottom of a former lake. The mountains on the east 
 form the Mosquito range, a part of the great Park range, while 
 those on the west are the Sawatch, and constitute the Continental 
 Divide at this point. Leadville itself is on the easterly side, upon 
 some foothills of the Mosquito range. The eastern slope of the 
 Mosquito range rises quite gradually from the South Park to a 
 general height of 13,000 feet. The range then forms a very ab- 
 rupt crest, with steep slopes looking westward, which are due to a 
 series of north and south faults whose easterly sides have been 
 heaved upward as much as 7500 feet. The faults pass into anti- 
 clines along their strike. The Mosquito range consists of crystal- 
 line Archean rocks, foliated granites, gneisses, and arnphibolites, 
 and of over 5000 feet of Paleozoic sediments and igneous rocks. 
 The former inch de Cambrian quartzite, 150 to 200 feet; Silurian 
 white limestone, 160 feet, and quartzite, 40 feet ; Carboniferous 
 blue limestone, 200 feet (the chief ore-bearing stratum) ; Weber 
 shales and sandstones, 2000 feet; and Upper Carboniferous lime- 
 stones, 1000 to 1500 feet. The igneous rocks are generally por- 
 phyries. The sedimentary rocks were laid down in Paleozoic time 
 on the shores of the Archean Sawatch Island, and were penetrated 
 by the igneous rocks, probably at the close of the Cretaceous. 
 They were all upheaved, folded, and faulted in the general eleva- 
 tion of the Rocky Mountains, about the beginning of the Tertiary 
 period. The intrusion of the igneous rocks was the prime mover 
 
 IB. Clark, "The Silver Mines of Lake VaUey, IST. M.," Tram. 
 Amer. Inst. Min. Eng., Feb., 1894. Rep. of Director of the Mint, 1882, Lake 
 VaUey, p. 341, Kelley Lode, p. 376. B. Silliman, "Mineral Regions of 
 New Mexico," Trans. Amer. Inst. Min. Eng., X. 224. 
 
LEAD AND SILVER. 317 
 
 in starting ore deposition, and the solutions favored the under side 
 of the sheets, along their contacts with the blue Carboniferous 
 limestone. 
 
 2.08.06. The early history of Leadville will be subsequently 
 referred to in speaking of auriferous gravels. The lead-silver 
 ores first became prominent in 1877, although discovered in 1874, 
 and by 1880 the development was enormous. The region grew at 
 once to be the largest single producer of these ores, and has re- 
 mained such ever since. The mines are situated east of the city 
 on the three low hills. Fryer, Carbonate, and Iron, but recently a 
 deep shaft in the city itself has found the extension of the ore 
 chutes and opened up great future supplies. The ores have chiefly 
 come in the past from the upper oxidized portions of the deposits. 
 Of late years, however, the older and deeper workings have been 
 showing the unchanged sulphurets. The ores are chiefly earthy 
 carbonate of lead, with chloride of silver, in a clayey or siliceous 
 mass of hydrated oxides of iron and manganese. In the Robert 
 E. Lee mine silver chloi'ide occurred without lead. Some zinc is 
 also found, and a long list of rare minerals. Where the ore is in 
 a hard, siliceous, limonite gangue it is called hard carbonate, but 
 where it is sandy and incoherent it forms a soft carbonate, or 
 sand carbonate. All the mines produce small amounts of gold, 
 which in one case (the Printer Boy) has been of more importance 
 than the silver. A few ore bodies are found at other horizons 
 than the Carboniferous. They also run in instances as much as 
 100 feet from the contact, and may likewise be found in the por- 
 phyry, doubtless replacing included limestone. They were all 
 deposited as sulphides, and, according to Emmons, when the rocks 
 were at least 10,000 feet below the surface. 
 
 2.08.07. In the valuable monograph on the region, which is 
 now a classic on the subject and which is cited below, Emmons 
 endeavors to prove the following points : 
 
 I. That the ores were deposited from aqueous solution. 
 
 II. That they were originally deposited mainly in the form of 
 sulphides. 
 
 III. That the process of deposition involved a metasomatic 
 interchange with the material of the rock in which they were de- 
 posited. 
 
 IV. That the mineral solutions or ore currents were concen- 
 trated along natural water channels, and followed, by preference, 
 the bedding planes at a certain geological horizon, but that they 
 
LEAD AND SILVER. 219 
 
 also penetrated the adjoining rocks through cross joints and cleav- 
 age cracks. 
 
 These additional points are also advanced : 
 
 I. That the solutions came from above. 
 
 II. That they were derived mainly from the neighboring 
 eruptive rocks. 
 
 2.08.08. The first four points are doubtless correct, and No. 
 III. is an important application of the theory of replacement, fre- 
 quently referred to in the introduction. The last two propositions 
 merit less confidence. Seven additional years of mining have 
 brought many new facts to light and have led others (A. A. Blow 
 in particular, whose valuable paper is cited below) to refer the 
 ores to upward rising currents. Emmons foresaw this possibility 
 and mentioned it on p. 584 of his monograph. The amount of the 
 adjacent, igneous rocks is quite insufficient to afford the ore. In 
 alteration the galena has passed through an intermediate stage of 
 sulphate before changing to carbonate. These mines have been 
 important not alone in their own metallic products, but in fur- 
 nishing the smelters with oxidized lead ores they have sup- 
 plied a means of reduction for many other more refractory ones, 
 "which could be conveniently beneficiated through the medium of 
 lead.^ Much copper occurs with the sulphides now met in depth. 
 
 2.08.09. Example 30a. Ten Mile, Summit County. Bodies 
 
 ' F. M. Amelung, "The Geology of the Leadville Ore District," Engi- 
 neering and Mining Journal, April 16, 1880, p. 35. " On the Origin of the 
 Ore," Ibid., Dec. 20, 1879. A. A. Blow, "The Geology and Ore Deposits 
 of Iron Hill, Leadville, Colo.," M. E., June, 1889. Rec. Ann. Rep. Colo. 
 School of Mine.'!, 1887, p. 63. S. F. Emmons, " Geology and Mining lodua- 
 try of Leadville," Monograph 13, U. S. Geol. Survey. Rec. Second Ann. 
 Rep. Director of U. S. Geol. Survey. Rec. Tenth Census, Vol. XIII., p. 
 76. F. T. Freeland, "The Sulphide Deposits of South Iron Hill, Lead- 
 ville," M. E., XIV. 181. C. Henrich, " The Character of the Leadville Ore 
 Deposits," Engineering and Mining Journal, Deo. 37, 1879, p. 470. "Ori- 
 gin of the Leadville Deposits," Engineering and Mining Journal, May 
 13, 1888, p. 33. "On the Evening Star Mine," Ibid., May 7, 1881, p. 361. 
 "Leadville Geology," Ibid., June 3 and 10, 1883 ; Historical, May 30, April 
 6, 13, 30, 37, 1878 ; also many other allusions, 1879-81. R. W. Raymond, 
 Rep. on the Little Pittsburg Mine, Engineering and Mining Journal, June 
 28, 1879. L. D. Rickelts, The Ores of Leadville, Princeton, 1883. C. M. 
 Rolker, "Notes on Leadville Ore Deposits," M. E., XIV. 273, 949. F. L. 
 Vinton, " Leadville and the Iron Mine," Engineering and Mining Journal, 
 Feb. 15, 1879, p. 110 ; also Juno 38, p. 465. 
 
220 KEMP'S ORE DEPOSITS. 
 
 of argentiferous galena, pyrite, and blende, in beds of Upper Car- 
 boniferous limestone, on their contact with overlying, micaceous 
 sandstones, or with sheets and dikes of porphyry. The Carbonif- 
 erous limestones that contain the ores at Leadville extend both 
 north and south, and their equivalents occur also on the west 
 flank of the Sawatch range. Ten Mile is another productive por- 
 tion, north of Leadville and at a higher altitude. The strata are 
 enormously disturbed, and pierced even more than at Leadville 
 by sheets and dikes of porphyry. The ores are less oxidized and 
 more rebellious. The Robinson is the principal mine.^ 
 
 2.08.10. Example 30b. Monarch District, Chaffee County. 
 Oxidized lead-silver ores in limestone. The belt of limestones 
 south from Leadville contains some notable ore bodies in Chaffee 
 County. The Monarch district is the most important. It is situ- 
 ated at the head waters of a branch of the South Arkansas River. 
 The ore lies in limestones whose age is not yet accurately deter- 
 mined. The Madonna mine is the best known and has shipped 
 much ore to Pueblo.^ 
 
 2.08.11. Example 30c. Eagle River, Eagle County. Galena 
 and its alteration product, anglesite, in Carboniferous limestone, 
 on the contact between it and quartzite or porphyry. The mines 
 lie in the valley of Eagle River, on the western slope of the Con- 
 tinental Divide. The galena has changed to the sulphate, instead 
 of carbonate, probably having been less completely oxidized than 
 at Leadville, and marking the intermediate stage in the process. 
 The wall rocks lie quite undisturbed, having a low dip of 15° 
 north, and not being faulted. Lying lower than the lead-silver 
 deposits, and in Cambrian quartzite, on the contact with an 
 overlying sandstone are found chutes carrying gold in talcose 
 clay.^ 
 
 2.08.12. Example 30d. Aspen, Pitkin County. Bodies of 
 
 • S. F. Emmons, Tenth Census, Vol. XIII., p. 73 ; also a forthcoming 
 monograph of the U. S. Geol. Surve3'. 
 
 ' S. F. Emmons, Tenth Census, Vol. XIII., p. 79. Eep. Director of 
 the Mint, 1884, p. 191. 
 
 » S. F. Emmons, " Notes on Some Colorado Ore Deposits," Colo. Sci. 
 Soc, Vol. II., Part II., p. 100. E. E. Olcott, "Battle Mountain Mining 
 District, Eagle County, Colorado," Engineering and Mining Journal, 
 June 11, 1887, pp. 417, 436; Ibid., May 21, 1893, p. 545. G. C. Tilden, 
 "Mining Notes from Eagle County," Ann. Rep. Colo. State School of 
 Mines, 1886, p. 129. 
 
s 
 
 i 
 
 a 
 e 
 
 s 
 
 
 B^ 
 
 fcl 
 
 
 Is 3" 
 
 ?s. 
 
 lO 
 
 ^ 
 
 ai 
 
 , 
 
 « 
 
 ^ 
 
 oa 
 
 
 00 
 
 5 
 
 1-H 
 
 o 
 
 
 
 l-H 
 
 •§ 
 
 
 S^ 
 
 05 
 
 
 <5 
 
223 
 
 KEMPS ORE DEPOSITS. 
 
 lead-silver ores, largely oxidized, occurring with much barite, 
 chiefly along the contact between extensively faulted, Lower Car- 
 boniferous, blue limestone and a brown, dolomitized, underlying 
 portion of the same; but also in fissures and less regular deposits 
 in these and older limestones and quartzite. Aspen is on the west- 
 ern slope of the Continental Divide, in the valley of the Roaring 
 Fork, just at the point where it crosses the contact of crystal- 
 line Archean gneisses and Paleozoic sediments. The stream cuts 
 them at right angles to the strike. Aspen Mountain lies on the 
 south side and Smuggler Mountain on the north. The limestone 
 belt continues north and south, and is prospected over a stretch of 
 nearly forty miles. At Aspen there is evidence of a faulted, syn- 
 
 ARCH^AN 
 
 - Cavon nf RnarinaJforJc 
 
 iWAi\WO\'V^WO??y^ DRIFT AND DEBRIS 
 0. (, o Pr «^ O tfAMETAMOHPHOSED 
 
 CAMBRIAN SILURIAN CARBONIFEROUS 
 
 CARBONIFEROUS AND SILURIAN 
 Middle and lower CARSOnlFB 
 
 Fig. 63. — Geological section at Aspen, Colo. After A. Lakes, Ann. Bep. 
 Colo. School of Mines, 1886. 
 
 clinal fold, with m.any minor disturbances. The westerly dipping 
 rocks by the faulting are repeated to the west and are pierced by 
 a great granite intrusion and much porphyry. Still farther west 
 the Red Jura-Trias sandstones are in great force. The faulted 
 repetitions of the Paleozoic rocks are eroded into a narrow ridge, 
 between Castle Creek and the Roaring Fork, just below the town. 
 Over beyond Aspen Mountain, and to the south, lies Tourtelotte 
 Park, in a small synclinal basin of the limestones, and eight or 
 ten miles farther is Ashcroft. The dips in Tourtelotte Park are 
 low, but they increase going down the mountain toward Aspen, 
 and are steepest of all at its foot, where the strata at 60° run un- 
 der the stream gravels and glacial deposits. The geology when 
 closely viewed is very complicated, and involves the following 
 sections according to D. W. Brunton. (See papers of W. E. New- 
 beri-y and S. F. Emmons, cited on page 219. 
 
LEAD AND SILVER. 223 
 
 BeU if TON. 
 
 Archean. 
 
 1. Cambrian quartzite, 400 feet. 
 
 2. Silurian quartzite and limestone, 460 feet. 
 
 3. Lower Carboniferous dolomite, 225 feet. 
 
 4. Lower Carboniferous blue limestone, 110 feet. 
 
 5. Middle Carboniferous (Weber) shales, 50 to 450 feet. 
 
 6. Intruded diorite, maximum 400 feet. 
 
 1. Middle Carboniferous limestone, 10 to 160 feet. 
 8. Jura-Trias sandstone. 
 
 Emmons. 
 Archean. 
 
 1. White quartzite of Upper Cambrian, 200 feet. 
 
 2. Silurian limestone and sandstone, 340 feet. 
 
 3. Lower Carboniferous brown and blue limestone, 240 feet. 
 
 4. Middle Carboniferous clays (Weber shales), 425 feet. 
 
 6. Middle Carboniferous green and red sandstone, of the 
 Weber grits, with thin limestone. 
 6. Jura-Trias sandstone. 
 
 2.08.13. Two other sections by different writers (Lakes and 
 Henrich) have been published; but as fossils are almost unknown, 
 the strata can be divided more or less at will. The blue lime- 
 stone is certainly Lower Carboniferous, for fossils gathered by 
 J. F. Kemp from the same horizon on Lime Creek, twenty-iive 
 miles north, where they are plentiful, were pronounced by authori- 
 ties in the East to be such. 
 
 • 2.08.14. On Smuggler Mountain the same section is shown, 
 but it is not broken by igneous rocks; and although there is a 
 faulting along planes striking parallel with the beds and cutting 
 the dip at a sharp angle, the geology is less complicated. 
 
 2.08.15. On Aspen Mountain the ore bodies favor the contact 
 between the blue limestone and the brown dolomite. The former 
 is a very pure limestone, while the latter contains from 20 to 28^ 
 magnesium carbonate. The ore replaces and impregnates the blue 
 limestone, often with very little change in its appearance, but it 
 fills the numerous cracks in the more broken dolomite, coating 
 larger and smaller blocks. The ore occurs also in minor fissures. 
 On Smuggler Mountain the ore especially follows the fissure veins. 
 
224 KEMP'S ORE DEPOSITS. 
 
 To the north the mines at Woody are on a great fissure, according 
 to W. E. Newberry (private communication), which carries ore 
 where not filled hy a porphyry dike. They ai'e of recent develop- 
 ment, but promise to be rich. Although further systematic study 
 is needed, it is quite clear that the ore bodies of Aspen Mountain 
 have originated by replacement of the blue limestone and by coat- 
 ing the fragments of brown dolomite. The solutions doubtless 
 came up along the fault fissures and selected the contact for the 
 chief point of deposition. The United States Geological Survey 
 has had a party in the region.' 
 
 2.08.16. Example 30e. Rico, Dolores County. Contact de- 
 posits of lead-silver ores, in Carboniferous limestones, along intru- 
 sive porphyries. Considerable base bullion has been shipped. 
 There are coals in the vicinity, but the operation of the smelter 
 has been somewhat intermittent. The Newman Hill mines are 
 mentioned under " Silver." " 
 
 Note.— Example 30/" will be found after Example 31, which 
 has been inserted for geographical reasons. 
 
 2.08.17. Example 31. Red Mountain, Ouray County. Oxi- 
 dized lead-silver ores passing in depth into sulphides, in large and 
 small cavities, in knobs of silicified andesite. The cavities have 
 a close resemblance to caves, but differ from ordinary caves in not 
 being in limestone. They permeate the mountain in an irregular 
 way, and mark the courses of old hot spring conduits. The ande- 
 site is generally altered to a mass of quartz, but the process is 
 thought by Mr. Emmons to have taken place at a considerable 
 depth, and that the quartz is a residual deposit left by the re- 
 moval of more soluble elements of the andesite. T. B. Comstock 
 regards them as hot spring deposits.^ 
 
 1 D. W. Bruaton, "Aspen Mountain: Its Ores and Mode of Occur- 
 rence," Engineering and Mining Journal, July 14 and 21, 1888, pp. 22, 42. 
 S. F. Emmons, "Preliminary Notes on Aspen," Proc. Colo. Sci. Soc, Vol. 
 11., Part III., p. 251. Eec. C. Henrich, "Notes on the Geology and on 
 Some of the Mines o£ Aspen Mountain," M. E., XVII. 156. A. Lakes, 
 " Geology of the Aspen Mining Region,'' Ann. Rep. Colo. School of Mines, 
 1886. W. E. Newberry, " Notes on the Geology of the Aspen Mining Dis. 
 trict," M. E., June, 1889. Rec. L. D. Silver, "Geology of the Aspen 
 (Colo.) Ore Deposits," Engineering and Mining Journal, March 17 and 24, 
 1888. 
 
 * M. C. Ihlseng, "Review of the Mining Regions of the San Juan,'' 
 Ann. Rep. Colo. School of Mines, 1885, p. 43. 
 
 ' T. B. Comstock, "Hot Spring Deposits in Red Mountain, Colorado." 
 
LEAD AND SILVER. 225 
 
 SOUTH DAKOTA. 
 
 2.08.18. Example 30/ Galena (town), in the Black Hills. 
 Contact deposits of galena, in part altered to carbonate, in Car- 
 boniferous limestone along intruded porphyries. The ore occurs 
 in the Carboniferous limestone, which overlies the Potsdam sand- 
 stone near Deadwood, in the northerly flank of the Black Hills. 
 The principal localities are the towns of Galena and Carbonate. 
 Sheets and dikes of igneous rocks penetrate the limestones and 
 have occasioned the ore deposits. Several smelters have had some- 
 what desultory campaigns.^ 
 
 MONTANA IDAHO. 
 
 2.08.19. Example 32. Glendale, Beaver Head County. Ore 
 bodies of argentiferous galena, zincblende, copper and iron pyrites, 
 and their oxidation products, occurring parallel with the stratifica- 
 tion planes of a blue-gray limestone, of age not yet determined. 
 These deposits constitute the Heola mines, and are in the south- 
 western part of the State. They oifer some parallel features with 
 those of southeastern Missouri. (Example 23.) They differ from 
 Example 30 in not being associated, so far as known, with igneous 
 rocks.^ 
 
 2.08.20. Example 32a. "Wood River, Idaho. Bodies of ar- 
 gentiferous galena and alteration products, irregularly distributed 
 in limestone, of age as yet undetermined. Southwestern Idaho is 
 largely formed of granite, southeastern is covered by the immense 
 fissure outpourings of basalt along the Snake River. North of 
 these, and on the flanks of the granite, are slates and limestones, 
 especially on the Wood River. The latter contain the lead-silver 
 ores. They are not in immediate association with igneous rocks, 
 and from published descriptions appear to be somewhat irregu- 
 
 M. E., XVIII. 361. S. F. Emmons, "Notes on Some Colorado Ore De- 
 posits," Proc. Colo. Sci. Soc, Vol. II., Partll., p. 97. M. C. Ihlseng, "Re- 
 view of the Mining Interests of the San Juan Region," Ann. Rep. Colo. 
 School of Mines, 1885, p. 46. T. E. Schwartz, "The Ore Deposits of Red 
 Mountain, Colorado," M. E., June, 1889 ; Proc. Colo. Sci. Soc, Vol. III., 
 Part I., p. 77. 
 
 1 F. R. Carpenter, " Ore Deposits of the Black Hills of Dakota," M. E., 
 1879, New York meeting. See also report by Dr. Carpenter on the geol- 
 ogy etc. , of the Black Hills, to the trustees of the Dakota School of Mines, 
 1888, p. 134. S. F. Emmons, Tenth Census, Vol. XIII., p. 91. 
 
 2 S. F. Emmons, Tenth Census, Vol. XIII., p. 97. 
 
226 KEMP'S ORE DEPOSITS. 
 
 larly distributed, although possibly connected with fissures. The 
 structural relations with Example 23 may again be referred to. 
 The neighboring slates and granite contain gold and silver veins, 
 which are taken up later on. Several small smelters have been 
 erected in the region, and have been intermittently operated. 
 The country is really in the northern end of the Great Basin.^ 
 
 2.08.21. Example 33. Wickes, Jefferson County, Mont. Fis- 
 sure veins near the contact of granite and liparite, but cutting 
 both rocks and carrying in a gangue of quartz the ores, galena, 
 zincblende, copper and iron pyrites, and mispickel. The liparite 
 is said by Lindgren to be Cretaceous or Tertiary. Wickes is just 
 south of Helena, and was one of the first places in the West to 
 establish successful concentration. There are two companies, the 
 Helena and the Gregory, both large producers. 
 
 2.08.22. Example 34. Coeur d'Alene, Idaho. Galena and 
 very subordinate alteration products, in a mineralized zone having 
 a well-marked quartzite footwall and an impregnated, brecciated 
 hanging of the same rock. The ore is in large chutes, which fill 
 innumerable small fractures in the rock. The mines are in Ward- 
 ner Canon, in the Bitter Root ^Mountains, northern Idaho. The 
 rocks are quartzite and thin beds of schists, much folded along 
 east and west axes. In this way they became faulted and shat- 
 tered, and in the principal mineral belt afforded an opportunity for 
 the ore to deposit. The gangue is siderite. The mines are ex- 
 tremely productive and are the chief sources of ore supply for 
 lead smelters in Montana and on the Pacific coast. '^ 
 
 THE REGION OF THE GREAT BASIX. 
 
 2.08.23. Example 35. Bingham and Big and Little Cotton- 
 wood Canons, Utah. Bed veins, often of great size, containing 
 oxidized lead-silver ores above and galena and pyrite below the 
 water level, in Carboniferous limestones, or underlying quartzite, 
 or on the contact between the two. The mines are situated in the 
 Oquirrh and Wasatch Mountains, southwest and southeast of Salt 
 Lake City, in caBions well up toward the summits. The region is 
 
 1 G. F. Becker, Tenth Census, Vol. XIII., p. 55. Engineering and 
 Mining Journal, July 3, 1887, p. 2. iJep. Director of the Mint, IHHi, p. 198. 
 
 ^ J. E. Clayton, "The Coeur d'Alene Silver-lead Mines," Engineering 
 ui,d il uimj Journal, Feb. 11, 1888, p. 108. 
 
o 
 
 ^ 
 
 1*3 
 
 
 
 
 
 
 
 
 
 
 
 ~: 
 
 fO 
 
 ^j 
 
 7^ 
 
 
 'ii 
 
 
 
 
 
 ^ 
 
 
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 ~ S* 
 
 s 
 
 'S? 
 
 i:) 
 
 ■w 
 
 
 
 
 
 
 
 
 
 CO 
 
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 a 
 
 
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 o 
 
228 KEMPS ORE DEPOSITS. 
 
 mucli disturbed, and there are great faults and porphyry dikes and 
 knobs of granite associated with ih,e sedimentary rocks. The ores 
 occur in belts, extending considerable distances, and these in places 
 have the rich chutes or chimneys of oxidized products. In Bing- 
 ham Cafion an immense bed of auriferous quartz is found, overly- 
 ing the lead zone and next the hanging. Some jieculiarity about 
 the gold prevents its easy treatment, but much of the rock is very 
 low grade. Other fissure veins in the massive rock of the region 
 are known, but are of less importance. The general geological 
 relations suggest the deposits mentioned under Example 30 and 
 subtypes. The mines were the occasion of the first development 
 of the lead-silver smelters in the West, and have made Salt Lake 
 City an important center of the industry. The Telegraph group, 
 the Emma, Flagstaff, and others were famous mines in their day. 
 As will appear, nearly all the Utah mines are productive of lead- 
 silver ores. 
 
 2.08.24. Example 35a. Tooele County. Bedded veins in 
 limestone, or between it an 1 quartzite, and containing lead-silver 
 ores with oohers, in rich chutes. The deposits occur in the west 
 side of the Oquirrh range, in Ophir and Dry canons, over the di- 
 vide from Bingham. The principal mine is the Honorine. Fis- 
 sure veins also occur in the region, but are of less importance. 
 The Deep Creek district, near the Nevada line, is mentioned under 
 2.11.04.1 
 
 2.08.25. Example 35b. Tintic District. Ore beds or belts, three 
 in number, and one to three miles long, generally parallel with 
 the stratification of vertical blue limestones, but sometimes run- 
 ning across them. The ore-bearing zone is from 300 to 600 feet 
 wide in at least one belt, and bears in places rich chutes of car- 
 bonate ore. The Crismon-Mammoth has been referred to under 
 
 1 W. P. Blake, " Brief Description, of the Emma Mine,'' Amer. Jour. 
 Sci., ii., II. 216. C. E. Fenner, "The Telegraph Mine," School of Mines 
 Quarterly, Julj-, 1893. O. J. Hollister, " Gold and Silver Mioing in Utah," 
 M. E.,XV1. 8. Rec. D. B. Huntley, Tenth Cen.sus, Yo\. XIII., p. 407. 
 G. Lavagnino, "The Old Telegraph Mine," M. E., 2VI. 25. " Little Cotton- 
 wood and Bingham, Utah," Engineering and Mining Journal, Aug. 14, 
 1880, p. 106 ; also July 19, 1889. J. S. Newberry, School of Mines Quarterly, 
 1884, p. 329. R. W. Raymond, Mineral Resources West of the Rocky Moun- 
 tains, 1868-76, and J. R. Brown, Ibid., 1867-68. Ann. Reps, of Director of 
 the Mint. B. SiUiman, "Geological and Mineralogical Notes on Some 
 Mining Districts of Utah,'' Amer. Jour. Sci., iii., III. 195. 
 
LEAD AND SILVER. 329 
 
 " Copper " (Example 20h), as it contains much copper. The ore is 
 thought by HoUister to have replaced the limestone.' 
 
 Passing mention should also be made that lead-silver ores occur 
 in Summit County, at the Crescent and other mines. 
 
 2.08.26. Example 30ejf. Horn Silver Mine, Beaver County. 
 A great contact fissure between a rhyolite hanging wall and a 
 limestone footwall, and carrying, at the Horn Silver mine, oxi- 
 dized lead-silver ores, chiefly anglesite, with considerable barite, 
 and with many other rarer minerals. The town of Frisco, con- 
 taining the mine, is at the southern end of the Grampian Moun- 
 tains. The great fissure is known for two miles, but is proved 
 valuable only between the lines of the Horn Silver mine. It 
 strikes north and south and dips 70° east. In the neighborhood 
 of the vein the rhyolite is largely altered to residual clay. The 
 mine is very dry and the entire region lacks good water. The 
 Tein in general varies from 20 to 60 feet, but has pinched twice in 
 going down, and of late years has largely ceased producing, al- 
 though there may yet be much ore below. The ores are smelted 
 near Salt Lake, and the base bullion is refined at Chicago. Some 
 free milling ore has been afforded.^ 
 
 2.08.27. Example 33a. Carbonate Mine, Beaver County. A 
 fissure vein in hornblende andesite, filled with rounded fragments 
 of wall rock, which are cemented by residual clay and galena. 
 Some oxidized products occur near the surface. The mines are two 
 and a half miles northeast of Frisco, but are in a different eruptive 
 rock from that forming the walls of the Horn Silver. The literature 
 is the same as for Example 30^/, especially Hooker, 1. c. p. 470. 
 
 2.08.28. Example 325. Cave Mine, Beaver County. Cham- 
 bers irregularly distributed in the limestone, and more or less 
 filled with limonite and oxidized lead-silver ores. Small leaders 
 of ores, which mark old conduits, connect the chambers. Up to 
 1880 five large and fifteen small chambers had been found. They 
 are of very irregular shape, and have a vacant space of from one 
 to ten feet between the ore and the roof. This deposit was the 
 typical one cited by Newberry as illustrating the chamber or cave 
 
 1 D. B. Huntley, as above (footnote, p. 194) ; also O. J. HoUister, as 
 above, under Example 85a. J. S. Newberry, Engineering and Mining 
 Journal, Sept. 13 and 20, 1879. 
 
 2 O. J. HoUister, "Gold and Silver Mining in Utah," M. E., XVI. 3. 
 R»'C. W. A. Hoolier, Report quoted in Ihe Tenth Census, Vol. Xlli., p. 464 
 
230 KEMP'S ORE DEPOSITS. 
 
 form of deposit. According to this view, the chambers were 
 formed before the ore was brought in. It is also possible that the 
 ore bodies have been deposited by replacement of the limestone 
 with sulphides, as is known abundantly elsewhere, and that the 
 alteration of these to oxides has occasioned the apparent caves. 
 The products of the mine afford but 5 to 1% lead, but are valuable 
 as an iron flux to the neighboring smelters. The mines are in the 
 Granite range, seven miles southeast of Miiford.' 
 
 Note. — Although the larger part of the Utah mines are for 
 lead and silver, several others of great importance will be taken 
 up under " Silver " itself. 
 
 NEVADA. 
 
 2.08.29. Example 36. Eureka. Bodies of oxidized lead-sil- 
 Ter ores in much faulted and fractured Cambrian limestone, 
 Tvith great outbreaks of eruptive rocks near. The Eureka geo- 
 logical section is one of the most interesting in the entire country, 
 and involves some 30,000 feet of Paleozoic strata, divided as fol- 
 lows : Cambrian quartzite, limestone, and shale, 7700 feet ; Silu- 
 rian limestone and quartzite, 5000 feet ; Devonian limestone and 
 shale, 8000 feet ; Carboniferous quartzite, limestone, and conglom- 
 erate, 9300 feet. These have afforded some extremely valuable 
 materials for comparative studies with homotaxial strata in the 
 East. The ore occurs especially in what is called the Prosjsect 
 Mountain limestone of the Cambrian, one smaller deposit being 
 also known in Silurian quartzite. The limestone has been crushed 
 and shattered along a great fault, and through its substance 
 ore solutions have circulated, replacing it in part with large 
 bodies of sulphides which have afterward become oxidized to 
 a depth of 1000 feet. The ore bodies were puzzling as regards 
 their classification, and a famous mining suit, with many interpre- 
 tations from various experts, resulted. The alteration of the ore 
 has caused shrinkage and the formation of apparent caves over it. 
 But there are many empty caves, formed by surface waters long 
 after the ore was deposited, and Mr. Curtis very clearly shows 
 that the ore bodies originated by replacement. All are connected 
 
 1 O. J. HolUster, "Gold and Silver Mining iu Utah," M. E., 1887. 
 D. B. Huntley, Tenth Census, Vol. XIII., p. 474. J. S. Newberry, School 
 of Mines Quarterly, March, 1880. Reprint, p. 9. Cf. also J. P. Kimball, 
 "The Silver Mines of Santa Eulalia, Chihuahua," Amer. Jour. Sci.,ii., 
 XLIX. 161. 
 
LEAD AND SILVER. 
 
 231 
 
 with more or less strongly marked fissures which formed the con- 
 duits. Mr. Curtis made a careful series of assays of the neigh- 
 boring igneous rocks to find some indication of the source of the 
 ore. A quartz porphyry gave significant results and to this the 
 metals are referred, but the portions of the mass at a great 
 
 Fio. 64. — Section at Eureka, Nev. Reproduced in line work after colored 
 plate by J. S. Curtis, Monograph VI., U. S. Oeol. Survey. 
 
 depth are considered to have furnished them. " Eureka was one of 
 the first jDlaces in this country where the hypothesis of replace- 
 ment was applied to ores in limestone. The district is now far 
 less productive than it was ten or fifteen years ago.' 
 
 1 G. F. Becker, Tenth Census, Vol. XIII., p. 32. Rec. W. P. Blake, 
 " The Ore Deposits of the Eureka District, Nevada," M. E., VI. 554. J. S. 
 Curtis, "Silver-lead Ore Deposits of Eureka, Nev.," Monograph VII., 
 
233 KEMP'S ORE DEPOSITS. 
 
 ARIZONA CALIFOENIA. 
 
 2.08.30. Some $98,000 worth of lead ores were shipped from 
 Arizona in 1889, chiefly from Cochise County (Tombstone region) 
 and Pima County (Tucson region). They will he mentioned un- 
 der "Silver." Insignificant amounts are also afforded by Cali- 
 fornia (about $2000 in 1889), mostly from Inyo County. (See 
 Eleventh Census, Bull. No. 80, June 18, 1891.) 
 
 v. S. Geol. Survey. A. Hague, " Geology of the Eureka District," Mon- 
 ograph XX., U. S. Geol. Survey. Abstract in Third Ann. Rep. Director 
 U. S. Oeol. Survey. W. S. Keyes, "Eureka Lode of Eureka, Nev.," 
 M. E., VI. 344. J. S. Newberry, School of Mines Quarterly, March, 1880. 
 R. W. Raymond, "The Eureka^Richmond Case," M. E., VI. 371. C. D. 
 Walcott, " Paleontology of the Eureka District," Monograph VIIL, U. S, 
 Oeol, Survey, 
 
CHAPTER IX. 
 
 SILVER AND GOLD.— INTRODUCTORY : EASTERN SILVER MINES 
 
 AND THE ROCKY MOUNTAIN REGION OF NEW MEXICO 
 
 AND COLORADO. 
 
 2.09.01. The two " precious " metals are so generally associ- 
 ated that they cannot be separately treated. While endeavoring to 
 preserve the distinctive impression given by examples, it is practi- 
 cally impossible to set forth all the vt-'idely varying phenomena of 
 the silver-gold veins of the West in any other than an approxi- 
 mate way. Hence geographical considerations are placed iirst, and 
 where markedly similar ore bodies in different States are to be 
 grouped together cross references are given. The following gen- 
 eral examples have been made because their individual features 
 are based on those geological relations which are most vitally con- 
 cerned with questions of origin. 
 
 2.09.02. Example 37. Veins containing the precious metals 
 usually with pyrite, galena, chalcopyrite, and less common sul 
 phides, sulpharsenides, sulphantimonides, etc., in igneous rocks. 
 No special subdivision is made on the character of the gangue, 
 which may be quartz, calcite, barite, fluorite, etc., one or all. The 
 first named is commonest. A great and well-defined original fis- 
 sure is not necessarily assumed, but some crack, or joint, or crushed 
 strip must have directed the ore-bearing solutions, which may have 
 then replaced the walls in large measure. For other structural 
 features see the discussion of veins (1.05.01) ; compare also Ex- 
 ample 17, Butte, Mont. 
 
 Example 37a. Replacements more or less complete of igneous 
 dikes, which have usually been described as porphyry. Compare 
 Example l7a under "Copper" (Gilpin County, Colorado), and 
 Example 20c? (Santa Rita, N. M.). Ore and gangue (where the 
 matrix is not the dike rock) as in Example 37. 
 
 Example 38. Contact de2:)osits between two kinds of igneous 
 rock or between two different flows. Ore and gangue as in Ex- 
 ample 37. 
 
234 KEMP'S VBE DEPOSITS. 
 
 Example 39. Agglomerates of rounded, eruptive boulders, 
 bombs, etc., in abandoned volcanic necks or conduits, and coated 
 with ores. The mines of Custer County, Colorado, are the only 
 examples of ore deposits of this kind yet identified. 
 
 Example 40. Contact deposits between igneous and sedimen- 
 tary rocks. No subdivisions are made on the kind of rocks. Ore 
 and gangue as in Example 37. Compare also Example 20, " Ari- 
 zona Copper ; " Example 21a, " Triassie Copper;" Example 30, 
 " Leadville ; " and Example 30^, " Horn Silver Mine." 
 
 Example 41. Veins in sedimentary rocks, generally cutting the 
 bedding, but at times parallel with it. Lateral enlargements are 
 frequent. The ore body may be largely due to replacement. Ore 
 and gangue as in Example 37. 
 
 Example 42. Veins cutting both sedimentary and igneous 
 rocks, and therefore due to disturbances after the intrusion of the 
 latter. Ore and gangue as in Example 37. 
 
 No special examples are made for metamorphic rocks. 
 
 2.09.03. Silver minerals. 
 
 Ag. S. As. Sb. CI. 
 
 Native silver 100. 
 
 Argenite (silver glance), AgjS 87.1 12.9 
 
 Prousite (light ruby silver), 3AgjS.As2S8 . . 65.5 19.4 15.1 
 
 Pyrargerite(darkruby silver), SAgaS.SbaSj. 59.8 17.7 22.5 
 
 Stephanite (brittle silver), SAgsS.SbjSs 68 . 5 16 . 2 15 . 8 
 
 Cerargerite (horn silver), AgCl 75.3 24.7 
 
 Silver also occurs with galena (Cf. "Lead") and with tetrahe- 
 drite (Cf. " Copper "). Gold occurs combined with tellurium in a 
 few rare tellurides, mechanically mingled with pyrites, and as the 
 uncombined native metal. From a metallurgical point of view the 
 ores of the precious metals are divided into two classes. 1. Those 
 whose amount of precious metal amalgamates readily with mer- 
 cury, and is thus obtained with comparative ease — the free milling 
 ores. 2. Those which require roasting or some previous treatment 
 before amalgamation, chlorination, or similar process, or which 
 must be smelted primarily for lead or copper, from which the 
 precious metals are afterward extracted — the rebellious ores. In 
 the subsequent description the endeavor has been made to work 
 from the distinctively silver mines to those of gold where geo- 
 graphically possible.^ 
 
 1 Ann. Reps. Directors of the Mint. Eec. W. P. Blake, " The Vari- 
 
SILVER AND GOLD. 235 
 
 2.09.04. Example 22a. Atlantic Border. Already mentioned 
 (2.05.02), the region is only of historical interest as affording sil- 
 ver, although lately some attention has been directed to Sullivan, 
 Me., where the veins have pyrite and probably stephanite, in a 
 quartz gangue, in slates, associated with granite knobs and trap 
 dikes which are of later age than the veins. Some silver is gener- 
 ally found in the galena of the Eastern States, but the ores have 
 never yet proved abundant enough to be important.' 
 
 Mention m^ay also be made at this point of the argentiferous 
 galena veins along the Ouachita uplift of Arkansas. A few are 
 known, usually with Trenton shales or slates for walls. They are 
 low gi'ade, and though once the basis of a small excitement, their 
 production has never been serious. Additional reference to the 
 region will be found under "Antimony." Some mines of the lat- 
 ter metal are stated by W. P. Jenney to show low-grade, argentif- 
 erous ores in depth.' 
 
 2.09.05. Example 42. Silver Islet, Lake Superior. A fissure 
 vein carrying native silver, argentite, tetrahedrite, galena, blende, 
 and some nickel and cobalt compounds in a gangue of calcite, in 
 flags and shales of the Animikie (Cambrian) system, and cutting 
 a large trap dike, within which alone the vein is productive. 
 Silver Islet is or was originally little more than a bare rock some 
 
 ous Forms in which Gold Occurs in Nature," Rep, Director of the Mint, 
 1884, p. 573. Rec. Brown, Raymond, and others, 1868 to 1876, ' ' Mineral 
 Resources West of the Rocky Mountains." Annual. T. C. Chamberlain, 
 "On the Geological Distribution of Argentiferous Galena," Oeol. of Wis., 
 Vol. rv. Clarence King, "Production of the Precious Metals in the 
 United States," Second Ann. Rep. Director U. S. Oeol. Survey, p. 333. A. 
 G. Lock, Gold, 1882. Mineral Resources of the U. S.; annual publication of 
 the Geological Survey. R. I. Murohison, "General View of the Conditions 
 under which Gold is Distributed," Quar. Jour. Geol. Soc, VII. 134. Also 
 in Siluria and Amer. Jour. Sci., ii., XVIII. 301. J. S. Newberry, " On the 
 Genesis and Distribution of Gold," School of Mines Quarterly, III., No. 1, 
 and Engineering and Mining Journal, Dec. 24 and 31, 1881, pp. 416, 437. 
 R. Pearce, "On the Ores of Gold," etc., Colo. Sci. Soc, III., p. 237. J. A. 
 Phillips, Ore Deposits, 1884. The Mining and Metallurgy of Gold and 
 Silver, 1867. Tenth Census Report on the Precious Metals. 
 
 1 0. W. Kempton, "Sketches of the New Mining District at Sullivan, 
 Me.," M. E., VII. 349. M. E. Wadsworth, "Theories of Ore Deposits," 
 Proc. Boston Soc. Nat. Hist, 1884, p. 305. Engineering and Mining Jour- 
 nal, May 17, 1884. Bull. Mus. Comp. Zool, 3, Vol. VII., 181. 
 
 ' T. B. Comstock, Ann. Rep. Geol. Survey of Arkansas, 1888, Vol. I., 
 "Gold and Silver." 
 
236 KEMP'S ORE DEPOSITS. 
 
 90 feet square, lying off the north shore of Lake Superior just out- 
 side of Thunder Bay, and within the Canadian boundaries. The 
 native silver was detected outcropping beneath the water. The 
 vein was productive to a depth of 800 or 1000 feet, but below this 
 it yielded little. The trap dike has usually been called diorite, 
 but is determined to be norite by Wadsworth {Bull. 2, 3finn. 
 Geol. Survey, p. 92), and gabbro by Irving {Monograph V., U. 
 S. Geol. Survey, p. 378). Some $3,000,000 were obtained from 
 the mine, yet the expenses were so great in keeping up the surface 
 works against winter gales and ice that but little profit was 
 realized. The vein has been traced 9000 feet but is nowhere else 
 productive. Considerable graphite has been found in the work- 
 ings, and some curious pockets of gas.^ 
 
 2.09.06. Example 42. Thunder Bay, Canada. The mainland 
 near Silver Islet contains many similar veins. They have fur- 
 nished considerable silver as argentite in a gangue of quartz, barite, 
 caloite, and fluorite, and associated with zincblende, galena, and 
 pyrite.^ 
 
 THE REGION OF THE ROCKY MOUNTAINS AND BLACK HILLS. 
 
 NEW MEXICO. 
 
 2.09.07. Geology. — The general topography and geology of 
 New Mexico were outlined in the introduction. Much remains to 
 be done in developing its geology. The eastern part belongs to 
 the prairie region and is very dry. A few rivers, notably the 
 Pecos and the Rio Grande, afford water for irrigation, the former 
 of which is now being utilized on a grand scale, and for the latter 
 plans have been prepared. In the central portion many subordi- 
 
 ' R. Bell, Engineering and Mining Journal, Jan. 8 and 15, 1887. See 
 also May 14, 1887. W. M. Courtis, "On Silver Islet," Engineering and 
 Mining Journal, Dec. 21, 1873, and M. E., Y. 474. E. D. Ingall, Ann. Rep. 
 Can. Geol. Survey, 1887-88, Part II., p. 14. F.A.Lowe, "The Silver 
 Islet Mine and its Present Development," Engineering and Mining Jour- 
 nal, Dec. 16, 1883, p. 321. T. MacFarlane, " Silver Islet," M. E., VIII. 236. 
 Oeol, of Canada, 1863, 717. Canadian Naturalist, Vol. IV. , p. 37. McDer- 
 mott, Engineering and Mining Journal, Vol. XXIII., Nos. 4 and 5. 
 
 2 R. Bell, "Silver Mines of Thunder Bay," Engineering and Mining 
 Journal, Jan. 8 and 15, 1887. E. D. Ingall, Ann. Rep. Can. Survey, 1887- 
 88, Part II., p. IH. Rec. See also Engineering and Mining Journal, 
 May 14, 1887 ; Feb. 18, 1888, p. 133 ; May 36, 1888, p. 383. 
 
SILVER AND GOLD. 237 
 
 nate north and south ranges of mountains are found, which are 
 less elevated than those of Colorado. The Colorado ranges vir- 
 tually die out at the northern boundary. The northwestern por- 
 tion comes in the great Colorado Plateau, and has been quite 
 fully described by Captain Button {Eighth Ann. Rep. Director 
 TJ. S. Geol. Survey). In numerous localities throughout the 
 Territory volcanic action has been rife and in places is but re- 
 cently extinct. The eastern part is largely Cretaceous, and also 
 the northwestern plateau, which contains much valuable coal. The 
 mountain ranges often have nuclei of Archean ci-ystalline rocks, 
 with successive strata of Carboniferous, Permian, Triassic, Juras- 
 sic, and Cretaceous on the flanks. The mining regions are in 
 these ranges of mountains.^ 
 
 2.09.08. The southwestern county is Grant, whose lead-silver 
 deposits have been briefly referred to. North of Silver City are 
 quartz veins of gold and silver ores, in diabase and quartz por- 
 phyry (Example 37), and again, west of Silver City, are ferru- 
 ginous deposits with chlorides and sulphides of silver in limestone. 
 In the Burro Mountains are silver ores in limestones, apparently 
 Lower Silurian. The Santa Rita Mountains contain, in addition 
 to the copper (Example 20d), silver and gold in quartz veins in 
 
 1 W. P. Blake, Proc. Bost. Soc. Nat. Hist., 18o9, Vol. VII., p. 64 
 " Geology of the Rocky Mountains in the Vicinity of Santa Fe,"^. A. A. S., 
 1859. A. R. Conkllng, "Report on Certain Foothills in Northern New 
 Mexico," Wheeler's Survey, Rep. of Chief of U. S. Engineers, 1877, II. 1298. 
 E. D. Cope, " Report on the Geology of a Part of New Mexico,"' Wheeler's 
 Survey, 1875; Appendix Gl. C. E. Button, "Mount Taylor andtheZuni 
 Plateau," Sixth Ann. Rep. U. S. Geol. Survey, pp. 111-305. S. F. Emmons, 
 Tenth Census, Vol. XIII. 100. O. Loew, "Report on the Geology and 
 Mineralogy of Colorado and New Mexico," Wheeler's Survey, 1875 ; Ap- 
 pendix G2, p. 27. J. Marcou, " The Mesozoic Series of New Mexico," 
 Amer. Geol, IV. 155, 216. R. E. Owen and E. J. Cox, "Report on the 
 Mines of New Mexico," Washington, 1865, 60 pp., Amer. Jour. Sci., ii., 
 XL. 391. G. F. Runton, " On the Volcanic Rocks of New Mexico," Quar. 
 Jour. Geol. Soc., Vol. VI., p. 351, 1850. B. Silliman, Jr., "The Mineral 
 Regions of Southern New Mexico," M. E., X. 434. F. Springer, "Occur- 
 rence of the Lower Burlington Limestone in New Mexico," Amer. Jour. 
 Sci., iii., XXVII. 97. J. J. Stevenson, "Geological Examinations in 
 Southern Cjlorado and Northern New Mexico,'' Wheeler's Survey, 1881. 
 " Geology of Galisteo Creek," Amer. Jour. Sci., iii., XVIII. 471. " On Ihe 
 Laramie Group of Southern New Mexico," Am^r. Jour. Sci., iii., XXII. 
 870. 
 
238 KEMP'S ORE DEPOSITS. 
 
 eruptive rooks (Examijle SY). Lake Valley, in Dona Ana County, 
 has been mentioned (2.08.04). In Lincoln County gold ores are 
 reported from the AVhite Oak district. The principal mines of 
 Socorro County have been mentioned (Example 29), and the cop- 
 per in Permian sandstone under Exampile 21e. There are other 
 silver-bearing lodes in the Socorro Mountains near the town of 
 Socorro. Henrich has described (1. e.) a curious deposit of quartz 
 carrying gold and silver (the Slayback Lode) on the contact be- 
 tween the older bedded eruptions and a later siliceous dike in the 
 Mogollon range (Example 38). In Santa Fe County are impor- 
 tant placer mines (Example 44) and thin veins of galena in rhyo- 
 lite. In Bernalillo County are placers on the slopes of the Sandia 
 Mountains. In Colfax County, in the Rocky Mountains, are other 
 placers, and reported gold and silver mines.J 
 
 COLORADO. 
 
 2.09.09. Geology. — The eastern portion contains prairies and is 
 a region lacking water. It consist of Quaternary and Creta- 
 ceous rocks. The plains rise in the foothills, which are chiefly up- 
 turned Jura-Triassic and Cretaceous strata. The Paleozoic is rela- 
 tively limited, although known. It rests on the crystalline rocks 
 of the Archean. There are some minor uplifts, running out at right 
 angles to the Front range, that divide the foothill country into 
 basins, and are especially important in connection with coal. 
 Next come the easterly ranges of the Rooky Mountains, in linear 
 north and south succession. They consist largely of dome-shaped 
 23eaks of granite, with great local developments of volcanic rocks. 
 To the west follow the several parks, largely consisting of 
 Mesozoic strata. They are bounded by ranges again on the west, 
 some of which, like the Mosquito range (see under Example 30), 
 mark great lines of post-Cretaceous upheaval, and are accompanied 
 by immense igneous intrusions. On the east and west flanks of 
 the Sawatch range (the granitic Continental Divide) are Paleoznic 
 
 1 W. P. Blake, "Gold in New Mexico," Proc. Bast. Soc. yat. Hist., 
 VII., p. 16, July, 1859. "Observations on the Geolog-y, etc., near Santa 
 Fe," A. A. A. S., X. 1859. S. F Emmons, Tenth Census, XIII., p. 101. 
 C. Henrich, "The Slayback Lode, New Mexico," Engineering and Mining 
 Journal, July 13, 1889, p. 27. E. E. Owen and E. T. Cox, iJep. on the 
 Mines of New Mexico, Washingi^on, 1865. Rep. Director of. the Mint, 1882, 
 )>. 339. B. Silliman, "Mineral Resources of Southern NewMexico," 21. E., 
 X. 434. Engineering and Mining Journal, Oct. 14 and 21, 1882, pp. 199, 212. 
 
SILVER AND GOLD. 33f 
 
 strata in considerable thickness, but to the west they dip under 
 the vastly greater development of Mesozoic terranes which shade 
 out into the Colorado Plateau. In northern, central, and south- 
 western Colorado are vast developments of igneous rocks that 
 have attended the geological disturbances.^ 
 
 2.09.10. The San Juan region includes several counties in 
 southwestern Colorado, in whole or in part, viz. : Ouray, Hinsdale, 
 San Juan, Dolores, and La Plata. The chain of the San Juan 
 Mountains consists of great successive outflows of eruptive rocks, 
 porphyry, diabase, diorite, basalt, etc., which cover up the Archae- 
 an and later sedimentary terranes, except in a few scattered ex- 
 
 ^ G. L. Canaon, "Quaternary of the Denver Basin," Proc. Colo. Sci. 
 Sac, III. 48. See also III. 200. W. Cross, "The Denver Tertiary Forma- 
 tion," Amer. Jour. Sci., iii., XXXVII. 361. G. H. Eldredge, "On the 
 Country about Denver, Colo.," Proc. Colo. Sci. Soc, III. 86. See also 140. 
 S. F. Emmons, " Orographic Movements in the Rocky Mountains," Oeol. 
 Soc. of America, I. 245-286. F. M. Endlich, " On the Eruptive Rocks of 
 Colorado," Tenth Ann. Rep., Hayden's Survey. H. Gannett, " Report on 
 the Arable and Pasture Lands of Colorado," Hayden's Surrey, 1876, p. 313. 
 H. C. Freeman, " The La Platte Mountains," 3L E., XIII. 681. G. K. Gil- 
 bert, "Colorado Plateau Province as a Field for Geological Study," Amer. 
 Jour. Sci., iii., XII. 16,85. J. D. Hague, Fortieth Parallel Survey, Vol. 
 III., p. 475. F. V. Hayden, Reports of Hayden's Survey, 1873, 1874, p. 40 ; 
 1875, p. 33 ; 1876, pp. 5, 70. R. C. Hills, " Preliminary Notes on the Erup- 
 tions of the Spanish Peaks," Proc. Colo. Sci. Soc, III. 24, p. 224. "Tiie 
 Recently Discovered Tertiary Beds of the Huerfano River Basin," Proc. 
 Colo. Sci. Soc, III., pp. 148, 217. " Jura-Trias of Soutiieastern Colorado," 
 Amer. Jour. Sci., iii., XXIII., p. 243. A. Lakes, " Extinct Volcanoes in 
 Colorado,'' Amer. GeoZ., January, 1890, p. 38. OacarLoew, " Report on the 
 Minerals of Colorado and New Mexico," Wheeler's Survey, 1875, p. 97. 
 " Eruptive Rocks of Colorado, " Wheeler's Survey, 1873. C. A. H. McCauley , 
 "On the San Juan Region," Rep. Chief of U. S. Engineers, 1878, III., p. 
 1753. C. S. Palmer, "On the Eruptive Rocks of Boulder County," 'tc, 
 Proc Colo. Sci. Soc, III., p. 230. A. C. Peale, " Oa the Age of the 
 Rocky Mountains in Colorado," Amer. Jour. Sci., iii., XIII., p. 172 ; Reply 
 to the above by J. J. Stevenson, Amer. Jour. Sci., iii, XIII. 297. S. H. 
 Scudder, "The Tertiary Lake Basin at Florissant," Hayden's Survey, 1878, 
 p. 371 ; see also 1877. J. A. Smith, Catalogue of the Principal Minerals 
 of Colorado, Central City, 1870. J. J. Stevenson, "Notes on the Laramie 
 Group of Southern Colorado," Amer. Jour. Sci., iii., XVIII, 129. "The 
 Mesozoic Rocks of Southern Colorado," Amer. Geol, III., p. 391. P. H. 
 Van Diest, "Colorado Volcanic Cones,'' P?-oc. Colo. Sci. (Soc, III., p. 19. 
 C. A. White, "On Northwestern Colorado," Ninth Ann. Rep. Director 
 U. 8. Geol. Survey, 683-710. 
 
240 KEMPS ORE DEPOSITS. 
 
 posures. Considerable masses of rocks formed of fragmental 
 ejectamenta are also known. All these are crossed by immense 
 vertical veins, largely with quartz gangue, and containing argen- 
 tiferous minerals of the usual species, galena, tetrahedrite, pyrar- 
 gerite, and native silver, as well as bismuth compounds. Gold 
 has been quite subordinate, although late developments near Ouray 
 have shown some peculiar and interesting deposits. R. C. Hills, 
 in the Proc. Colo. Sci. Soc, 1883, traced three systems of veins. 
 (1) Silver-bearing, narrow (six inches to three feet), nearly verti- 
 cal veins, with base metal ores and no selvage. (2) Large, strong, 
 gold-bearing veins dipping 60° with selvages and intersecting (1). 
 (3) Like (1), but larger and more persistent, and carrying occa- 
 sionally bismuth and antimonial ores with gold and little or no 
 silver. T. B. Comstock {M. E., XV. 218) has classified the veins 
 in three radiating systems. (1) The northwest, with tetrahedrite 
 (freibergite). (2) The east and west, with bismuth and less often 
 nickel and molybdenum. (3) The northeast, with tellurides and 
 antimony and sulphur compounds of the precious metals. Quite 
 recently a series of small caves near Ouray, in quartzite overlaid 
 by bituminous shales, have been found to contain native gold, agd 
 have excited great interest-.-" -St-iis thought by Endlich that they 
 represent inclusions of shale, now dissolved away, and that the 
 gold was precipitated on the walls. If this view is correct, they 
 mark one of the very few illustrations of chamber deposits which 
 are known. More extended mining work has proved them to be 
 in all cases connected with a supply fissure from which small lead- 
 ers guide the miners to the chambers. 
 
 Placer gold mines (Examj)le 44) are quite extensively worked 
 in San Miguel County. J. B. Farish has recently described the 
 veins at Xewman Hill, near Rico, in a valuable paper cited below. 
 The lowest formation exposed is magnesian limestone, supposed 
 to be Carboniferous. It contains large ore bodies of low grade, 
 and is also, strangely enough, heavily charged with carbonic acid 
 gas. Above this for 500 feet are alternating sandstones and 
 shales, and then a narrow stratum of limestone 18 to 30 inches 
 thick. This is followed by about 500 feet additional of shales and 
 sandstone, regarded as Carboniferous. Fifty feet above the low- 
 est limestone a laccolite of porphyrite has been intruded. Two 
 sets of fissures are present — one nearly vertical and striking north- 
 east, the second dipping 30 to 45° northeast and striking north- 
 west. The former are the richest, are banded (see Fig. 5) and per- 
 
SILVER AND GOLD. 241 
 
 sistent, being worked in one case for 4000 feet. The flatter fissures 
 are less rich. The principal ore bodies, however, occur as hori- 
 zontal enlargements of both these sets of veins. Just over the 
 thin bed of limestone mentioned above the ores have spread out 
 into sheets from 20 to 40 feet wide and from a few inches to three 
 feet thick. They consist of solid masses of the common sulphides, 
 galena, pyrite, gray copper, etc., and are very rich. Above them 
 the fissures apparently cease, or at least are tight. Two hundred 
 feet down from them the vein filling becomes nearly barren, glassy 
 quartz. These are most remarkable ore bodies, and would appear 
 to have been formed by uprising solutions, which met the tight place 
 ai.d spread sidewise, depositing their minerals; but as Mr. Farish 
 advances no explanation, it is hardly justifiable for others, less 
 familiar than himself with the phenomena, to do so. 
 
 The lead-silver ores of Red Mountain and Rico have already 
 been mentioned (2.08.17). Silverton and Ouray are the principal 
 towns of the San Juan.' 
 
 2.09.11. The new mining region of Creede, now decided to be 
 in Saguache County, should be mentioned in this connection. It 
 
 ' T. B. Comstock, " The Geology and Vein Structure of Southwestern 
 Colorado," M. E., Vol. XV., 218 ; also XI. 165, and Engineering and Min- 
 ing Journal, numerous papers in 1885. "Hot Spring Formation in the 
 Eed Mountain District, Colorado," M. E., XVII. 361. Rec. S. F. Em- 
 mons, "On the San Juan District," Engineering and Mining Journal, 
 June 9, 1883, p. 333. " Structural Relations of Ore Deposits," M. E., XVI. 
 804. Rec. Tenth Census, Vol. XIll., p. 60. F. M. Endlich, " Origin of 
 the Gold Deposits near Ouray," Engineering and Mining Journal, Oct. 19, 
 1889. "Sin Juan District," Hayden's Survey, 1874, p. 239. Ibid., 1875, 
 Bull. in.;Amer. Jour. Set., lii., X. 58. J. B. Farish, "On the Ore De- 
 posits of Newman Hill, near Rico, Colo.," Colo. Sci. Soc, April 4, 1893. 
 Rec. R. C. Hills, Proc. Colo. Sci. Soc, 1883. Rec. W. H. Holmes, " La 
 Plata District," Hayden's Survey, 1875 ; Amer. Jour. Sci., iii., XIV. 430. 
 M. C. Ihlseng, " Review of the Mining Interests of the San Juan Region," 
 Hep. Colo. State School of Mines, 1885, p. 37. G. E. Kedzie, " The Bedded 
 Ore Deposits of Red Mountain Mining District, Ouray County, Colorado,"' 
 JIf. J7. , XV. 570. Rec. G. A. Koenig and M. Stocker, "Lustrous Coil and 
 Native Silver in a Vein in Porphyry, Ouray County, Colorado," M. E., 
 IX. 650. T. E. Schwartz, "The Ore Deposits of Red Mountain, Ouray 
 County, Colorado," M. E., 1889. J. J. Stevenson, "On the San Juan," 
 Wheeler's Survey, III., p. 376. " The San Juan Region," Engineering and 
 Mining Journal, Aug. 37, 1881, p. 136 ; Sept. 24, 1881, p. 301 ; July 17, 
 1880 ; Dec. 30, 1879 ; and many other references in 1879 and 1880. P. H. 
 Van Diest, "On the San Juan District," Proc. Colo. Sci., January, 1886. 
 
SILVER AND GOLD. 
 
 243 
 
 is situated near the junction of Saguache, Ouray, and Hinsdale 
 counties, and some ten or twelve miles from Wagon "Wheel GajD. 
 There is a great develoiDment of igneous rocks as well as of Car- 
 boniferous limestone, but the veins as yet developed are in the 
 form'^. They appear to be fissure veins and have quartz, in large 
 
 Fig. 66. — Geological cross sections of strata and veins at Newman Hill, 
 
 near Rico, Colo. After J. B. Farish, Proa. Colo. Sci. Soc. , April 
 
 4, 1893, See also Figures 5 and 6. 
 
 part amethyst, with some manganese minerals as a gangue, and, 
 "with these, oxidized silver ores. The mines are on two moun- 
 tains, Bachelor and Campbell, which are on opposite sides of Wil- 
 low Creek Caflon.' 
 
 1 E. B. Kirby, " The Ore Deposits of Creede and Their Possibilities," 
 Engineering and Mining Journal, March 19, 1892, p. 335. Rec. T. R. 
 MacMechen, "The Ore Deposits of Creede," Engineering and Mining 
 Journal, March 13, 1893, p. 301. Rec. 
 
j.*^- '*>>pPR^-i^J-^| 
 
 
 
 s 
 
 fel 
 
 I; 
 
 O 
 
 d 
 
 l-H 
 
 ^ 
 
 o 
 
 e 
 
 ^1. , -. -^JCJ. 
 
SILVER AND GOLD, 245 
 
 2.09.12. The Gunnison region lies on the 'western slope of the 
 Continental Divide and embraces both mountains and plateaus. 
 West of the main and older range are the later Elk Mountains, in 
 which several mining districts are located. Aspen has already- 
 been mentioned, and the long series of ore bodies in the Carbonif- 
 erous limestones. The other principal districts are Independence, 
 Ruby, Gothic, Pitkin, and Tin Cup. The ores at Independence 
 are sulphides with silver, in the Archean granite rocks. In the Tin 
 Cup district the Gold Cup mine is in a black limestone and con- 
 tains argentiferous cerussite and copper oxide. In the Ruby dis- 
 trict the ores are in the Cretaceous rocks, and in the Forest Queen 
 they are ruby silver and arsenopyrite, partly replacing a porphyry 
 dike. On Copper Creek, near Gothic, a series of nearly vertical 
 fissures traverse eruptive diorite. They contain sulphide of silver 
 and native silver. The Sylvanite is one of the principal mines.^ 
 
 2.09.13. Eagle County. The lead-silver mines of Red Cliff 
 have ah-eady been mentioned (Example 30c), and also the under- 
 lying gold deposits. The Homestake mine, northwest of Lead- 
 ville, over toward Red Cliif, is on a vein of galena in granite, and 
 was one of the first openings made in the region.^ 
 
 2.09.14. Summit County. The Ten Mile district, which is the 
 principal one, has been mentioned under Example 30rt. The Pride 
 of the West mine, on Jacque Mountain, is peculiar, being on a 
 quartz porphyry dike which is partly replaced by ferruginous quartz 
 and barite. Lake County, containing Leadville, has been treated 
 under Example 30. Mention should also be made of the placer 
 deposits in California Gulch, which first attracted prospectors to 
 the region in 1860. In its eastern part Summit County borders on 
 Clear Creek County, and at Argentine are some veins related to 
 those of the latter. They are high up on Mount McClellan, and 
 are remarkable for the veins of ice that are found in them.' 
 
 1 F. Amelung, " Sheep Mountain Mines, Gunnison County," Engineer- 
 ing and Mining Journal, Aug. 28, 1886, p. 149. F. M. Chadwick, "The 
 Tin Cup Mines, Gunnison County, Colorado," Engineering and Mining 
 Journal, Jan. 1, 1881, p. 4, See also Example \2d for iron mine?. 
 
 2 Guiterman, "On the Gold Deposits of Red Cliff," Proc. Colo.Sci. Soc, 
 1890. " On the Battle Mountain Quartzite Mines," Mining Industry, Den- 
 ver, Jan. 10, 1890, p. 28. E. E. Olcott, "Battle Mountain Mining District, 
 Eagle County," Engineering and Mining Journal, June 11 and 18, 1887, 
 pp. 417, 436 ; May 21, 1892. G. C. Tilden, " Mining Notes from Eagle 
 County," Ann. Reii. Colo. State School of Mines, 1886, p. 129. 
 
 " E. L. Berthoud, " Oa Rifts of Ice in the Rocks near the Summit of 
 Mount McClellan," etc., Amer. Jour. Sci., in., II. 108. 
 
246 KEMP'S ORE DEPOSITS. 
 
 2.09.15. Park County, which lies east of Lake County and 
 embraces the South Park, has some mines on the eastern slope of 
 the Mosquito range, and in the Colorado range, to the northwest. 
 The latter are similar in their contents to the Georgetown silver 
 ores, mentioned under Clear Creek County, but the former are 
 bodies of argentiferous galena and its alteration pi-oducts in lime- 
 stone and quartzite. Pyrite is also abundant, and at times a gangue 
 of barite appears. The mines are in the sedimentary series, resting 
 on the granite of the Mosquito range, and are pierced by por- 
 phyry instrusions, as at Leadville. The placer deposits at Fair- 
 play deserve mention, as it was from these that the prospectors 
 spread over the divide to the site of Leadville in I860.' 
 
 2.09.16. ChaflEee County, on the south, contains the iron mines 
 referred to under Example I2d. There are some other gold-bearing 
 veins near Granite and Buena Vista. The lead-silver deposits of 
 the Monarch district are mentioned under Example 305. In 
 Huerfano County, in the Spanish Peaks, veins of galena, gray 
 copper, etc., are worked to some extent.^ 
 
 2.09.17. Rio Grande County. In the Summit district are a 
 number of rich gold mines, of which the Little Annie is the best 
 known. The gold occurs in the native state, in quartz on the con- 
 tact between a rhyolite and trachyte breccia and andesite. The de- 
 posits are thought by R. C. Hills to be due to a silicification of the 
 rhyolite along those lines, probably by the sulphuric acid, which 
 brought the gold. Then the rocks were folded. Oxidation and 
 impoverishment of the upper parts followed, forming bonanzas 
 below. The paper has a very important bearing on the formation 
 of many replacements.' 
 
 2.09.18. Conejos County. Some deposits of ruby silver ores 
 have recently been developed in this county, near the town of 
 Platoro. The county lies near the middle of the southern tier. 
 
 2.09.19. Custer County affords some of the most interesting 
 deposits in the West. Rosita and Silver Cliff are the principal 
 towns and are situated in the Wet Mountain Valley, between the 
 Colorado range on the north and the Sangre de Cristo on the 
 
 1 J. L. Jernegan, "Whale Lode of Park County," M. E., III. 352. 
 
 = R. C. Hills, " On the Eruption of the Spanish Peaks," Proc. Colo. 
 Scd. Sac, III., pp. 24, 234. 
 
 8 R. C. Hills, Proc. Colo. Sci. Soc, March, 1883. Abstract by S. F. 
 Emmons in the Engineering and Mining Journal, June 9, 1883, p. 333. 
 
SILVER AND GOLD. 247 
 
 south. At Silver Cliff an outbreak of pinkish rhyolite occurs, im- 
 pregnated with silver chloride. It affords a free-milling although 
 low-grade ore. This forms a unique deposit. There is a great 
 thickness of tuffs beneath it, as shown in the Geyser mine, and 
 some remarkable forms of spherulitic crystallizations. 
 
 2.09.20. Example 39. Bull Domingo and Bassick. The first 
 named is two miles north of Silver Cliff, and the latter seven miles 
 east, near Roslta. The Bull Domingo is in Arcliean, hornblende 
 gneiss, and consists of what appear to be pebbles or boulders of the 
 wall rock, which are coated with argentiferous galena and an out- 
 er shell of quartz. The ore body is 40 to 60 feet across. The 
 Bassick is in andesite, and likewise consists of what appear to be 
 boulders and pebbles of the country rock, coated by concentric 
 shells of rich ores, and in an elliptical chimney 20 to 100 feet across. 
 The first coat is a mixture of lead, antimony, and zinc sulphides, 
 and is always present. A second, somewhat similar, but of lighter 
 color and richer in lead and the precious metals, is sometimes seen. 
 A third is chiefly zincblende, rich in silver and gold, and is the 
 largest of all. A fourth, of chalcopyrite, sometimes occurs, and 
 lastly a fifth, of pyrite. Various other minerals are found, and, 
 curiously enough, carbonized wood on the outer limits. Both 
 these deposits have been thought to be the tubes of geysers, in 
 which boulders have been tossed about, rounded, and finally ce- 
 mented together. Mr. Emmons has argued against this view, and 
 in a forthcoming monograph will present the results of extended 
 study. A brief account of these results has, however, been pub- 
 lished by Dr. Whitman Cross. The region is shown to be one 
 containing numerous, although not always large, volcanic out- 
 breaks. One of them furnished the sheet of rhyolite at Silver 
 Cliff, while others had for their conduits the chimneys of the Bull 
 Domingo and the Bassick. The ore bodies thus occur in volcanic 
 necks, and make a new form for the science. 
 
 2.09.21. Humboldt-Pocahontas. These mines are near Rosita 
 on fissure veins in andesite, but of a different flow and kind from 
 the walls of the Bassick. They are filled with gray copper and 
 chalcopyrite, in a barite gangue. Other mines of less importance 
 occur in the district, but the three above cited are given prom- 
 inence because of their own intrinsic interest and because they 
 have often been referred to in discussions about the origin of ores.^ 
 
 1 E. N. Clark, " Humboldt-Pocahontas Vein," M. £., VII. 21. "Sil- 
 
248 KEMFS ORE DEPOSITS. 
 
 2.09.22, Gilpin County has already been mentioned undei 
 " Copper " (2.04.08). The general geology of the veins is much like 
 that of Clear Creek, although the ores are quite different. R. 
 Pearce has shown the existence of bismuth in the ore, and gives 
 reasons for believing that the gold is in combination with it. 
 Clear Creek County contains veins on a great series of jointing 
 planes in gneiss (granite), and in large part replacements of the 
 wall. Others are replacements of porphyry dikes or of pegmatite 
 segregations. The ores are chiefly galena, tetrahedrite, zincblende, 
 and pyrite, and the gangue is the wall rock. The curious decrease 
 of value in depth of a series of parallel veins in Mount Marshall was 
 referred to (1.05.05). Georgetown is the principal town and mining 
 center. Others of importance are Idaho Spi'ings and Silver Plume.^ 
 
 2.09.23. Boulder County contains veinsalong joints or faulting 
 planes in gneiss, or granite, or associated with porphyry dikes, or 
 pegmatite segregations, and carrying tellurides of the precious 
 metals more or less as impregnations of the country rock. The 
 prevalent country rock is called by Emmons a granite-gneiss. 
 Van Diest distinguishes four successive terranes of massive and 
 schistose rooks along three principal axes and two side ones, and 
 states that the mines are on the sides of the folds. The country 
 is very generally pierced by porphyry dikes, with which the ore 
 bodies are often associated. A large number of species of tellu- 
 ride minerals have been determined from the region, especially by 
 the late Dr. Genth of Philadelphia. The mines afford very rich 
 ores, somewhat irregularly distributed.^ 
 
 ver Cliff, Colorado," Engineering and Mining Journal, Nov. 2, 1878, p. 
 314. W. Cross, " Geology of the Eosita Hills," Proc. Colo. Sci. Soc, 1890, 
 p. 269. Eec. S. F. Emmonp, "The Genesis of Certain Ore Deposits," 
 M. E.,XV.U6. TenthCensus,\'o\. XIII., p. 80. L. C. Graybill, " On the 
 Peculiar Features of the Bassick Mine," M. E., XI., p. 110 ; Engineering 
 and Mining Journal, Oot. 28, 18S2, p. 226. Eec. O. Loewand A. E. Conk- 
 ling, "Eosita and Vicinity," Wheeler's Survey, 1876, p. 48. See also Ste- 
 venson in the Eeport for 1873. 
 
 1 S. F. Emmons, Tenth Census, Vol. XIII., p. 70. Eec. F. M. Eod- 
 lich, Hayden's Survey, 1873, p. 298 ; 1876, p. 117. P. Eraser, Hayden's 
 Survey, 1869, p. 301. J. D. Hague, Fortieth Parallel Survey, Vol. III., p. 
 589. Eec. E. Pearce, Proc. CoZo. Sci. Soc, Vol. III., pp. Tl, 210. "The 
 Association of Gold with Other Metals," M. E., 1890. J. J. Stevenson, 
 Wheeler's Survey, Yo\. III., p. 351. F. L. Vintoa, "The Georgetown (Colo.) 
 Mines," Engineering and Mining Journal, Sept. 13, 1879, p. 184. 
 
 2 A. A. Eilers, " A New Occurrence of the Telluride of Gold and Sil- 
 
SILVER AND GOLD. 349 
 
 2.09.24. El Paso County. Within the last three or fonryearsa 
 rich gold district has been opened in the hills west of Pike's Peak. 
 The country is rugged and elevated, and although more or less pros- 
 pected in former years, it has only in very recent times been shown 
 to be an actual producer. A number of minor hills have been 
 formed by trachytic outbreaks, or by these and the red granite of 
 Pike's Peak. The trachytic sheets (they may prove andesites or 
 rhyolites) are cut, as is also the granite, by dikes of typical phono- 
 lite, with nepheline, nosean and other characteristic minerals of 
 this rock. Along the sides of the dikes ore bodies have been 
 formed as well as in fissures. Decomposed country rock (granite, 
 trachyte and phonolite) is often mingled with the ore, and in some 
 veins is found red auriferous jasper. The walls of the veins, 
 whether along the dikes or the fissures, exhibit the results of f uma- 
 role action and purple fluorite is a common veinstone. The origi- 
 nal ore seems to have been a telluride of gold (probably sylvanite, 
 according to Eichard Pearce, or calaverite or krennite, according 
 to Blake), but it has been largely oxidized to the native metal. 
 The trachytic country rock is thickly charged with pyrites.^ 
 
 2.09.25. The resources of the remaining counties of Colorado 
 are chiefly in coal. 
 
 ver," M. E., Vol I, p. 16. S. F. Emmons, Tenth Cmsus,Yol. XIII. , p. 
 64. J. B. Farish, "Interesting Vein Phenomena in Boulder County, 
 Colorado, " il/. £., September, 1890. F. A. Gtenth, "On Tellurides," 
 Amer. Jour. Sci., ii., XLV., p. 805, and other papers in the same jour- 
 nal. C. S. Palmer, ' 'Eruptive Bocks of Boulder and Adjoining Coun- 
 ties," Proc. Colo. Sci. Soc, Vol. III., p. 230. P. H. Van Diest, "The 
 Mineral Eesources of Boulder County," Ann. Rep. Colo. State School of 
 Mines, 1886, p. 25. 
 
 1 "W. P. Blake, "The Gold of Cripple Creek," Engineering and Min- 
 ing Journal, Jan. 13, 1894. Whitman Cross, of the U. S. Greologioal 
 Survey, has in preparation one of the survey atlas sheets of this district. 
 H. L. MoCarn, "Notes on the Geology of the Gold Field of Cripple 
 Creek, Colo.," Science, Jan. 19, 1894, p. 31. R. Pearce, "The Mode of 
 Occurrence of Gold in the Ores of the Cripple Creek District, ' ' Froc. 
 Colo. Sci. Soc, Jan. 8, 1894; Eikj. and Min. Jour., March 24, 1894. E. 
 Skewes and H. J. Eder, "The Victor Mine, Cripple Creek, Colo.," En- 
 gineering and Mining Journal, Aug. 19, 1893 , p. 193. 
 
 NoTB. — Important discoveries of gold have been lately reported near 
 Leadville, Colo. The veins appear to be of the same geological charac- 
 ter as those which have yielded silver-lead, but lie further east. 
 
CHAPTER X. 
 
 SILVER AND GOLD, CONTINUED.— ROCKY MOUNTAIN REGION, 
 WYOMING, THE BLACK HILLS, MONTANA, AND IDAHO. 
 
 WYOMING. 
 
 2.10.01. Geology. — The southeastern part of Wyoming is 
 in the Prairie region, the southwestern in the Plateau. The 
 Rocky Mountains shade out more or less on leaving Colorado, 
 hut are again strongly developed in northern Wyoming. The 
 northwestern portion contains the great volcanic district of the 
 National Park, and the northeastern, a part of the Black Hills. 
 The Cretaceous and Tertiary strata chiefly form the plains and 
 plateaus. Granite and gneiss constitute the central portion of 
 some of the greater ranges. Paleozoic rocks are very subordinate. 
 The resources in precious metals are small, consisting chiefly of 
 gold in quartz veins in the gneisses, schists, and granites of Sweet- 
 water County. The great mineral wealth of the State is in coal. 
 The iron mines have already been mentioned (2.03.09), and the 
 copper (2.04.27).' 
 
 THE BLACK HILLS. 
 
 2.10.02. Geology. — The Black Hills lie mostly in South Da- 
 kota. They consist of a somewhat elliptical core of granite 
 and metamorphic rocks, with a north and south axis, and on 
 these are laid down successive strata of Cambrian, Carbonifer- 
 
 1 H. M. Chance, " Resources of the Black Hills and Big Horn Coun- 
 try, Wyoming," 31. K, XIX., p. 49. T. B. Comstock, "On the Geology 
 of Western Wyoming," Amer. Jour. Sei., iii., VI. 426. S. F. Emmons, 
 Tenth Census, Vol. XIIL, p. 86. F. M. Endlich, "The Sweetwater Dis- 
 trict," Hayden's Survey, 1877, p. 5 ; " Wind River Range Gold Washings," 
 p. 64. A. Hague, "Geological History of the Yellowstone National Park," 
 M. K, XVI. 783. See also F. V. Hayden, Amer. Jour. Sci., iii.. III. 105, 
 161. F. V. Hayden, Rep. for 1870-73, p. 13; also Amer. Jour. Sci., ii., 
 XXXI. 229. A. C. Peale, "Report on the Geology of the Green River Dis- 
 trict," Hayden's Survey, 1877, p. 511. Raymond's Statistics West of the 
 Eochy Movntains. W. C. Knight, BnU. 14 ^yyo. Exp't. Station, Oot.'^^. 
 
SILVER AND GOLD, CONTINUED. 
 
 251 
 
 OU8, Jura-Trias, and Cretaceous rocks. There are some igneous 
 intrusions. The principal product of the Black Hills is gold. 
 The lead-silver deposits have already been described (2.08.18), and 
 the tin, mica, etc., will be mentioned later.' 
 
 2.10.03. The gold occurs in placers of Quaternary and recent 
 age, as well as in Potsdam sandstones, which are old shore beaches 
 now hardened to rock ; in pyritous beds in schistose rocks, and in 
 segregated quartz veins. The Quaternary and recent placers are 
 the usual gravels, which are more fully described under " Cali- 
 fornia." The Potsdam sandstone is an extremely interesting de- 
 posit. It has resulted from the wearing action of the waves of 
 the Potsdam ocean on the Archean schists. Tlie Potsdam also 
 carries other deposits in the vicinity of porphyry sheets and dikes, 
 
 Fig. 68.— Geological section of the Black Hills. After Henry Newton 
 
 Report on the BlacJe Hills, p. 206. 
 
 1. Schists. 2. Granite. 3. Potsdam sandstone. 4. Carboniferous. 5, 6. Jura-Trias. 
 
 7. Cretaceous. 
 
 which consist of auriferous pyrite, sometimes oxidized. This has 
 replaced the original calcareous cement of the quartzite. The 
 pyritous beds are in a great impregnation zone 2000 feet broad 
 (Carpenter), of slates and schists, with portions especially rich in 
 auriferous pyrites. They occur near the town of Lead City, not 
 far from Dead wood, in the northern hills. The deposits present 
 many analogies with Example 16, and also are like fahlbands 
 (1.06.10). The ore is not high grade, running $3 to $4 per ton, 
 but it is treated at great profit by mining it in enormous quanti- 
 ties. There are also many so-called segregated quartz veins in the 
 
 1 F. R. Carpenter, "Ore Deposits in the Black Hills," M. E., XVII. 
 370. Prelim. Rep. on the Geol. of the Black Hills, Rapid City, So. Dak., 
 1888. W. O. Crosby, "Geology of the Black Hills," Bost. Soc. Nat. Hist., 
 XXIII., p. 89. Newton and Jenney, Report on the Black Hills, Washing- 
 ton, 1880. C. R. Van Hise, " The Pre-Cambrian Rocks of the Black Hills," 
 Bull. Geol. Soc. Amer., I. 203-244. N. H. Winohell, " Report on the Black 
 Hills," Rep. Chief of U. S. Engineers, 1874, Part II., p. 680. 
 
252 KEMP'S ohj'J deposits. 
 
 schists and slates. These are lenticular masses of limited extent, 
 horizontally and below, somewhat like a magnetite lens (Example 
 12) in shape, and carrying a small amount of gold with little or 
 no pyrites.^ 
 
 MONTANA. 
 
 2.10.04. Geology. — The eastern part of the State belongs to 
 the Prairie region, which is, however, in portions greatly scarred 
 by erosion, forming the so-called Bad Lands. The approaches to 
 the Rocky Mountains are not abrupt and sudden as in Colorado, 
 but are marked by numbers of outlying ranges of both eruptive 
 and sedimentary rocks. The chain of the Rookies takes a north- 
 westerly trend in Wyoming, and so continues across Montana. It 
 is rather the jjrolongation of the Wasatch than of the Colorado 
 Mountains, whose strike is for the Black Hills. The character of 
 the ranges is also very different. They are less elevated and have 
 broad and well-watered valleys between, that admit of considera- 
 ble agriculture. Geologically the country is in marked contrast 
 with Colorado. While in the latter the Paleozoic is feebly de- 
 veloped, in the former it reaches great thickness. In the eastern 
 ranges W. M. Davis gives Lower Cambrian 10,000 to 15,000 feet; 
 Silurian and Devonian, not yet recognized ; Carboniferous lime- 
 stones, 3500 feet; Trias, not definitely recognized; Jurassic 
 and Cretaceous sandstones, shales, and thin limestones, 15,000 
 feet. This more closely resembles the Wasatch and Great Basin 
 sections (see 2.08.29, and 2.11.01). Much granite of a basic or 
 dioritic character is present (Example IV), and great develop- 
 ments of eruptive rocks of extremely interesting character. Xo 
 more interesting field for geological work awaits the investigator.^ 
 
 1 A. J. Bowie, "Notes on Gold Mill Construction," il/. E., X. 1881. 
 W. B. Devereux, "The Occurrence of Gold in the Potsdam Formation," 
 M. E., 465 ; Engineering and Mining Journal, Dec. 23, 1882, p. 3S4. H. 
 O. Hofman, "Gold Mining in the Black Hills," M. E., XVII. 498 ; also in 
 preliminary report cited under Carpenter, under Geology. 
 
 ^ S. Calvin, "Iron Butte: Some Preliminary Notes," Amer. GeoL, 
 IV. 95. G. E. Culver, " A Little Known Region of Northwestern Mon- 
 tana," Wis. Acad., Dec. 30, 1891. W. M. Davis, "The Relation of the 
 Coal of Montana to the Older Rocks," Tenth Census, Vol. XV., p. 697. 
 Rec. J. Eccles, "On the Mode of Occurrence of Some of Ihe Volcanic 
 Rocks of Montana," Quar. Jour. Geol. Scl, XXXVII. 399. G. H. El- 
 dridge, "Montana Coal Fields," Tenth Census, Vol. XV., p. 739. S. F. 
 Emmons, Tenth Census, Vol. XIII., 97. Rec. Hayden's Survey, Ann. 
 
SILVER AND GOLD, CONTINUED. 253 
 
 2.10.05. Montana took the lead of all the States .in 1887 in 
 the production of silver, was second in gold, and first in the total 
 production of the two. It is now second. In its mineral wealth 
 it yields to no other State in the Union. The mining districts are 
 mostly in the western central and western portions. Develop- 
 ments have progressed so rapidly that all the desirahle data are 
 not available. 
 
 2.10.06. Madison County. Veins in gneiss containing galena 
 and pyrite in a quartz gangue. Virginia City is the principal 
 town, and the veins are north of it in the northern part of the 
 countj'.^ 
 
 2.10.07. Beaverhead County. Near Bannack City quartz veins 
 with auriferous pyrite on the contact between the limestone and 
 so-called granite.' At Glendale, in the northern part of the 
 county, are the Hecla mines, referred to under " Lead-silver " 
 (Example 32). Auriferous quartz veins are reported farther 
 north. ^ 
 
 2.10.08. Jefferson County. This county contains ore bodies 
 chiefly aui-iferous quartz, in gneiss, porphyry, or limestone. The 
 
 Rep., 1871-72. W. S. Keyes, in Brown's first report on mineral resources, 
 etc., last part, Amer. Jour. Sci., II. 46, 431. Rec. W. Lindgren, "Eruptive 
 Rocks," Tenth Census, Vol. XV., p. 719, forming Appendix B of Davis's 
 flrstpaper. SeealsoProc. Cat. Acad. Sci., SeconASeries, Vol. III., p. 39. J. 
 S. Newberry, "Notes on the Surface Geology of the Country bordering on 
 the Northern Pacific Railroad," Annals N. Y. Acad. Set, Vol. III. 243 ; 
 Amer. Jour. Sci., iii., XXX. 337. " The Great Falls Coal Fields," in Geol. 
 Notes, School of Mines Quarterly, VIII. 327. F. Rutley, "Microscopic 
 Character of the Vitreous Rocks of Montana," Quar. Jour. Geol. Sci., 
 XXXVII. 391. See Eccles, above. W. H. Weed, "The Cinnabar and 
 Bozeman Coal Fields of Montana," Bull. Geol. Soc. Amer., II. 349-364. 
 Engineering and Mining Journal, May 14 and 21, 1892. "Montana Coal 
 Fields," Bull. Geol. Soc. Amer., III. 301-330. C. A. "White, " Existence of 
 a Deposit in Northwestern Montana and Northeastern Dakota that is Pos- 
 sibly Equivalent with the Green River Group,'' Amer. Jour. Sci., iii., 
 XXV. 411. R. P. Whitfield, "List of Fossils from Central Montana," 
 Tenth Census, Vol. XV., p. 713 ; Appendix A to Davis's paper. J. E. 
 Wolff, " Notes on the Petrography of the Crazy Mountains," etc., North- 
 ern Trans. Survey. " Geology of the Crazy Mountains," Bull. Geol. Soc. 
 Amer., III. 445. H. Wood, "Flathead Coal Basio," Engineering and 
 Mining Journal, July 16, 1893, p. 57. H. R. Wood, "Mineral Zones in 
 Montana," Engineering and Mining Journal, Sept. 34, 1892, p. 292. 
 
 1 S. F. Emmons, Tenth Census, Vol. XIII., p. 97. 
 
 = Ibid. 
 
254 
 
 KEMP'S ORE DEPOSITS. 
 
 lead-silver mines near Wiokes have been referred to. (Example 
 33.) Red Mountain lies at the head of a valley like Wiokes and 
 contains many narrow argentiferous veins. A concentrator was 
 at work on them in 1892.' 
 
 2.10.09. Silver Bow County. The copper mines and the gen- 
 eral geology of the Butte City region were referred to under 
 "Copper" (Example 17). In the basic granite, and north of the 
 copper zone, is a belt carrying sulphides of silver, lead, zinc, and 
 iron in a siliceous gangue, but abundantly associated with manga- 
 nese compounds of various sorts, especially rhodochrosite. 
 
 No manganese is known in the copper belt, nor any copper in 
 the silver belt — most striking phenomena in veins in the same wall 
 
 
 
 
 
 /O'.of^co 
 
 5 6 7 
 
 69 —Cross section of vein at the Alice mine, Butte, Mont. The 
 of vein is 40 feet. After W. P. Blake, M. E., XVI., p. 72. 
 
 t. Granite country. 2. Softened granite with small veins. 3. Cay wall with 
 [granite. 4. Quartz, broken and seamed. 5. Clay anddecomposed^ranite. 6. 
 and manganese spar — "curly ore." 7. Quartz and ore — " hard vein." 8. Soft 
 with veinlets. 9. Dark colored, hard granite of the hanging-wall countrj'. 
 
 Fig 
 
 decom- 
 Quartz 
 granite 
 
 rock. The line of outcrop has a cresoentic sweep, and it was 
 therefore called by J. E. Clayton the Rainbow Lode. It includes 
 from west to northeast six claims, all but two of which are con- 
 trolled by the Alice Company. There are as many as four dis- 
 tinct veins present in the Magna Charta. All the mines show 
 that the ore and gangue have replaced the granite along a shat- 
 tered strip, for cross sections exhibit alternations of quartz with 
 ore, rhodochrosite, crushed wall rock, residual clay, occasional 
 horses of granite, etc. In the more siliceous granite west of the 
 butte is another silver belt with the same ores as in the Rainbovv' 
 
 1 S. F. Emmons, Tenth Census, Vol. XIII , p. 97. J. S. Newberry, 
 'On R^•d Mountain," Annals N. Y. Acad. Sci., III., p. 351. 
 
SILVER AND GOLD, CONTINUED. 235 
 
 Lode and likewise having manganese minerals associated. The Blue- 
 bird is the principal mine. The manganif erous outcrop was a notable 
 feature in the landscape, and exhibited a broad, rusty-black belt, 
 not rich at the surface, but only showing the silver in depth. Like the 
 veins in the basic granite, these were also formed by replacement of 
 the rock along a shattered strip. Placer mines were early worked near 
 Butte and led to the location of the deep mines. They are still pro- 
 ductive and are again referred to under "Auriferous Gravels."' 
 
 2.10.10. Deer Lodge County. Placer deposits are numerous 
 along the Deer Lodge River, and auriferous quartz veins are 
 known, but the greatest mine is the Granite Slountain, a source 
 of very handsome returns. This is in the southern part of the 
 covmty, nea..- Phillipsburg, and is a fissure vein in granite, prin- 
 cipally with silver ores, although affording considerable gold. On 
 the same vein is the Bimetallic. Farther west sedimentary rocks 
 come in, much metamorphosed by contact with the later irrup- 
 tive granite. On the edge of the county, and not far from the 
 Drumlummon group of veins, later mentioned, are the veins of the 
 Bald Butte Company, in slates and intrusive diorite. A number 
 of other veins are in the same general region.' 
 
 2.10.11. Lewis and Clarke County. The placer mines, near 
 Helena (in Last Chance and Prickly Pear gulches), were the first 
 in the county to attract attention. They were found by the 
 prospectors, who spread through the Rocky Mountains as the Cali- 
 fornia gold diggings gave out. Since then many auriferous quartz 
 veins in granite and slates have been developed. Some twenty 
 
 1 W. P. Blake, "Silver Mining and Milling at Butte, Mont.," ilf. E., 
 XVI. 38. "Rainbow Lode, Butte, Mont.," M. E., XVI. 65. Rec. S. F. 
 Emmons, " Notes on the Geolog-y of Butte, Mont.," M. E., XVI. 49. Rec. 
 Richard Pearce, "The Associations of Minerals in the Gagnon Vein, Butte 
 City," M. E., XVI. 63. E. D. Peters, Mineral Resources of U. S., 1883-84, 
 p. 374. E. G. Salisbury, " Pl.iccr Mining in Montana," Engineering and 
 Mining Journal, Sept. 8, 1887, p. 167. Rec. " Silver Mines of Butte, 
 Mont.," Ibid., April 18, 1885, p. 261. AVilliams and Peters on Butte, Mont., 
 Engineering and Mining Journal, March 38, 1885, p. 308. 
 
 2 H. M. Beadle, " The Coaditioa of the Mining Industry in Montana 
 in 1898," Engineering and Mining Journal, Feb. 11, 1893, p. 123. G. W. 
 Goodale and W. A. Ackers, "Concentration, etc.. with Notes on the Geol- 
 ogy of the Flint Creek Mining District," 31. E. , 1890. Rec. "The Granite 
 Mountain Mine,'' Engineering and Milling Journal, Dec. 10, 1887 ; Nov. 
 33, 1889. E. G. Spilsbury, " Placer Mining in Montana," Ibid., Sept. 3, 
 1887, p. 167. 
 
356 KEMPS ORE DEPOSITS. 
 
 miles north of Helena, in the town of Marysville, is the Drum- 
 lummon group of veins, which carry refractory silver and gold 
 ores, in a quartz gangue, on the contact between a granite knob 
 and the surrounding metamorphic schists. There are also other 
 veins in the granite. Dikes of intrusive rocks occur associated 
 with the ore bodies.^ 
 
 2.10.12. Missoula County. In the northwestern corner of the 
 State is a region of very recent development, and more especially 
 since the Northern Pacific Railroad has been built through it. At 
 Iron Mountain and elsewhere mining districts are growing up, but 
 available descriptions have not yet been received. (See paper by 
 G. E. Culver, cited under 2.10.04.) In Meagher County, in the 
 central part of the State, there are a number of mining districts 
 in the Little Belt Mountains. Neihart is the location of some 
 rich silver mines, and is now connected with Great Falls by rail. 
 Other camps are as yet too remote for profitable working. 
 
 IDAHO. 
 
 2.10.13. Geology. — The southern part of the State extends 
 into the alkaline deserts of the Great Basin and is dry and barren. 
 North of this is the Snake River Valley, which is filled by a great 
 flood of recent basalt which stretches from the "Wyoming line 
 nearly across the State. North of the Snake River a large area 
 of granite appears in the western portion and contains many 
 mines. Extensive deposits of gravel also occur. Metamorphic 
 rocks and Paleozoic strata largely constitute the northern portion 
 of the State, and are penetrated by many igneous intrusions. The 
 eastern part lies on the western slopes of the Bitter Root Moun- 
 tains, whose general geology was outlined under Montana. The 
 geology of Idaho has been but slightly studied, and the few re- 
 liable records have resulted from the scattered itineraries of Hay- 
 den's survey, isolated mining reports, and the collections of the 
 Tenth Census.^ 
 
 "^ J. E. Clayton, '• The Drumlummon Group of Veins," etc.. Engineer- 
 ing and Mining Journal, Aug. 4 and 11, 1888, pp. 85, 106. S. F. Emmons, 
 Tenth Census, Vol. XIII., p. 97. 
 
 2 G. F. Becker, Tenth Census, Vol. Xin., 52. F. H. Bradley, Hayden's 
 Survey, 1873, p. 208. F. V. Hayden, Ann. Rep., 1871, pp. 1, 147 ; 1872, p. 
 20. J. S. Newberry, "Notes on the Gi;ology and Botany along the North- 
 ern Pacific Railroad," Annals N. Y. Acad. Sci., III. 353. Eaymond's Re- 
 ports on Mineral Resoures West of the Rocky Mountains. O. St. John, 
 Hayden's Survey, 1877, p. 323 ; 1878, p. 175. 
 
SILVER AND GOLD, OONTTNUED. 257 
 
 2.10.14. Custer Comity lies soutli of Lumhi and contains 
 several well-known mines. The Ramshorn is in metamorphic 
 slates on a fissure vein that has rich chutes of high-grade silver 
 ores in a siderite gangue. The Custer and the Charles Dickens 
 are farther west, near Bonanza City, and afford both silver and 
 gold in quartz gangue from veins in porphyry. Smelting ores oc- 
 cur in the region and have been used in some operations based on 
 this treatment. In Boise and western Alturas counties a granite 
 area forms the greater part of the surface, and in it are numerous 
 productive veins. In the former they are chiefly gold quartz ex- 
 cept in the Banner district, where silver predominates. 
 
 The placer deposits of Boise County, which were developed in 
 1863, were very rich, but are now less productive than in former 
 years. In Alturas County gold quartz veins occur, and also 
 others carrying silver, and the county is a strong producer. The 
 Wood River mines in slates and limestones, southeast of the 
 granite, have already been referred to under Example 32a. Owyhee 
 County is in the southwestern corner of the State. It is probable 
 that the granite of the two last mentioned counties extends under 
 overlying drift and comes up again near Silver City (Becker). 
 Southwest of it quartz porphyry and metamorphic rocks are found, 
 with dikes of basalt. Gold quartz and high-grade silver ores are 
 present. The Poorihan Lode is famous for ruby silver ores. W. 
 P. Blake mentions seeing a piece from this mine at the Paris Ex- 
 position which weighed about 200 pounds.' It was awarded a gold 
 medal. The crystal from which it was broken weighed 500 
 pounds.' In Cassia and Oneida, two other counties in the southern 
 part, placers are being or have been worked, and in Bear Lake 
 County, in the southeast corner, salt and sulphur deposits are re- 
 corded.' 
 
 1 Amer. Jour. Sci., ii., XLV. 97. 
 
 ' Eaymond's Reports on Mineral Resources West of the Roehy Moun- 
 tains, 1868, p. 533. 
 
 " G. F. Becker, Tenth Census, Vol. XIII., p. 59. Raymond's Reports 
 on Mineral Resources West of the Rocky Mountains, Rep. Director of the 
 Mint, 1883, p. 237. 
 
CHAPTER XL 
 
 SILVER AND GOLD, CONTINUED.— THE REGION OF THE GREAT 
 BASIN, IN UTAH, ARIZONA, AND NEVADA. 
 
 T7TAH. 
 
 2.11.01. Geology. — The eastern half of Utah, terminating 
 with the western front of the Wasatch, is in the Colorado Pla- 
 teau, but the western is within the limits of the Great Basin. 
 The plateau portion consists largely of Mesozoic strata, quite 
 horizontal and more or less carved by erosion. The east and west 
 arch of the Uintah Mountains, in the northern part, has upheaved 
 them, so that where the Green River has cut a channel across, the 
 Paleozoic is exposed in great strength. The Wasatch range rises 
 with a gradual ascent from the east, and then terminates with a 
 great fault line having a steep westerly front. This line of weak- 
 ness was developed in the Archean and has been a scene of move- 
 ment even to recent times. It is a very important structural feat- 
 ure. West of the Wasatch, which is a fine example of block tilt- 
 ing in mountain-making, the mountains belong to the Basin ranges, 
 which are more typically developed in Nevada. The Wasatch 
 section was shown by the Fortieth Parallel Survey to involve 
 12,000 to 14,000 feet of the Upper Archean and nearly 30,000 feet 
 of the Paleozoic. In southern Utali the Triassic rocks are im- 
 portant and contain some rich mines.^ 
 
 1 Or. F. Becker, Tenth Census, Vol. XIH., 38. C. E. Dutton, Bep. on 
 the High Plateaus of Utah, Washington, 1880. A. G«ikie, "Archean 
 Rocks of the Wasatch Mountains," Amer. Jour 8ei., hi., XIX. 363. G. K. 
 Gilbert, " Cent ribu' ions t") the History cf Lalie Bonneville,'' Seconc? Ann. 
 Rep. Director U. S. Geol. Survey, 169-300, and Monograph II. "The An- 
 cient Outlet of Great Salt Lakp," Amer. Jour. Sci., iii., XV. 256, XIX. 341; 
 see also A. C. Peale, Ibid , XV. 439. The Henry Mountains,'WashiBgton, 
 1877. Hague, Kinp-, and Emmons, Fortieth Parallel Survey, Vols. I. and 
 II. O. C. Marsh, '-On the Geology of the Eastern Uintah Mountains," 
 Amir. Jour. Sci., iii., I. 191. B. Silliman, ''Geological and Mineralogical 
 No.es on Some of the Mining Districts of Utah Territory," ^mer. Jour. 
 
SILVER AND GOLD, CONTINUED. 259 
 
 2.11.02. The greater number of the Utah mines are for lead- 
 silver ores and have been mentioned under " Lead Silver." The 
 northwestern county, Box Elder, is in the alkaline desert region 
 of the Great Basin. The mining districts occur in the central 
 part of the State, in the Wasatch and Oquirrh mountains, and are 
 also found in the extreme southwest. 
 
 2.11.03. Ontario Mine. Nearly east of Salt Lake City, in 
 Summit County, is the Ontario mine, a vein from four to twenty- 
 three feet wide (averaging eight feet), in quartzite, but extremely 
 persistent, being opened continuously for 6000 feet. In the lower 
 working a jjorphyry dike has come in as one of the walls. It is 
 extensively altered by fumarole action to clay. The best parts of 
 the mine have quartzite walls. The ores consist of galena, gray 
 copper, silver glance, blende, etc. Other somewhat similar ore 
 bodies are known in the same region but are less developed.^ 
 
 2.11.04. The lead-silver veins of Bingham Canon, in Salt 
 Lake County, have already been mentioned. Reference may 
 again be made to the great bed-veins of gold quartz associated 
 with them. Ophir Canon and Dry Canon, in Tooele County, 
 and the Tintic district, in Juab County, have also been described. 
 In addition to the smelting ores, others have been treated by 
 milling. Quite recently interest has been directed to the mines 
 of the Deep Creek district, on the extreme western border of 
 Utah, in the Ibapah range. Limestones regarded by Blake as 
 Carboniferous, and other sedimentary rocks, have been broken 
 through by great outflows of granite, andesite, hypersthene-ande- 
 site, etc. The ore bodies appear to be contact deposits in lim.e- 
 stone near igneous rocks, and carry much free gold.^ 
 
 In Beaver County the interesting deposits of the Horn Silver, 
 the Carbonate, and the Cave ore bodies have been mentioned 
 
 Sci., iii., III. 195. Wheeler, Gilbert, Lockwood and others on Western 
 Utah, Wheeler's Survey, Rep. Prog. 1869-71-78. Idem, Final Reports, 
 Vol. III. 
 
 ' T. J. Almy, "History of the Ontario Mine, Park City, Utah," 
 M. E., XVI. 35. " The Ontario Mine," Engineering and Mining Journal, 
 May 38, 1881, p. 865. D. B. Huntley, Tenth Ceiswt, Vol. XIII., p. 438. 
 
 2 W. P. Blake, "Age of the Limestone Strata at Deep Creek, Utah, 
 and the Occurrence of Gold," etc., Amer. Geol, January, 1893, p. 47. Engi- 
 neering and Mining Journal, Feb. 33, 1893, p. 353. S. F. Emmons, For- 
 tieth Parallel Survey, Vol. II. J. F. Kemp, " Petrographical Notes on a 
 Suite of Rocks collected by E. E. Olcott, " N. Y. Acnd. Set., May, 1893. 
 W. H. Dodds, "Granite Mountain Mine," Collier ij Engl urn; Dec, 1893. 
 
260 
 
 KEMP'S ORE DEPOSITS. 
 
 under Examples 30ff, 33a, and 32b. The great iron mines of Iron 
 County will be found under Example 14. In Piute County, near 
 the town of Marysvale, around Mount Baldy, are a number of 
 mines with lead-silver or milling ores in quartz porphyry (copper 
 belt), or between limestone and quartzite (Deer Trail, Greeneyed 
 Monster, etc.). Selenide of mercury is found in the Lucky Boy.' 
 
 2.11.05. Example 41. Silver Reef, Utah. Native silver, cerar- 
 gerite, and argentite, impregnating Triassic sandstones, and often 
 replacing organic remains. These deposits were earlier referred 
 to under Example 21, p. 80. They were discovered in 1877. At 
 Silver Reef there are two silver-bearing strata or reefs, w'ith beds 
 of shale between. Above the water line the ore is horn silver ; 
 below, it is argentite. At times it replaces plant remains ; at other 
 times no visible presence of ore can be noted, although the rock 
 
 Ore-*- 
 
 Fig. 70. — Two sections of the argentiferous sandstone at Silver Reef, 
 Utah. After C. M. Rolker, M. E., IX., p. 31. 
 
 may afford $30 to the ton. The silver always occurs along certain 
 ore channels, distributed through parts of the sandstone. The 
 origin of the deposits has given occasion to a vigorous discussion. 
 J. S. Newberry holds that the silver was deposited in and with 
 the sandstone from the Triassic sea, although it may have been 
 concentrated since in the ore channels. F. M. F. Cazin holds that 
 the organic remains were deposited in and with the sandstone, and 
 that these were the immediate precipitating agents of the ores. 
 R. P. Roth well explained them much as does Rolker, below. C. M. 
 Rolker, who was for some years in charge of several of the mines, 
 has also written about them, and is probably nearest to the truth. 
 Rolker argues that the impregnation was subsequent to the forma- 
 tion of the sandstone, and was caused by the igneous outbreaks in 
 the neighborhood, and probably runs along old lines of partial 
 -.veakening or crushing that afterward healed up. Eruptive rocks 
 
 Ore 
 
 1 G.J, Brush, "On the Onof rite, etc.," ^mer. Jour. Set., iii., XXI. 313. 
 
SILVER AND GOLD, CONTINUED. 261 
 
 are known in the neighborhood of the ores both in Utah and in the 
 Nacemiento copper district of New Mexico. From what we know 
 of ore deposits in general this seems most probable.^ 
 
 AKIZONA. 
 
 2.11.06. G-eology. — Arizona lies partly in the plateau region 
 and partly in the Great Basin. The Basin ranges converge with 
 the Rocky Mountains, which, however, are chiefly in New Mexico. 
 The uplands of the ranges are well watered and covered with 
 timber, but the low-lying portion of the Great Basin is an arid 
 desert, and in southwestern Arizona is the hottest jsart of the United 
 States. Cretaceous and Jura-Trias largely form the plateau 
 region. Running southeast to northwest is the great development 
 of Carboniferous limestone so often referred to under " Copper," 
 and underlying this are found Archean granites, gneisses, etc. A 
 great series of ore deposits is ranged along this contact. In the 
 southwest are mountains of granites and metamorphic rocks. The 
 Territory also contains vast flows of igneous rocks, and in the pla- 
 teau country between the converging ranges some 20,000 or 23,000 
 square miles are covered by them. The Grand Canon of the Colo- 
 rado has laid bare a magnificent geological section of many thou- 
 sand feet, from the Archean to the Tertiary.* 
 
 1 F.M.F.Cazin, "TheOrig'iQof the Copper aod Silver Ores in Triassic 
 Sandrock," Engineering and Mining Journal, Dec. 11, 1880, p. 381 ; April 
 30, 1881, p 800. " The Silver SandstoDe Formation of Silver Reef," Ibid., 
 May 22, 1880, p. 851 , Jan. 10, 17, 24, 1880, pp. 25, 48, 79 (Rothwell). A. N. 
 Jackson, " Silver ia Sedimentary Sandstone," Rep. Director of Mint, 1882, 
 p. 384, reprinted from Cal. Acad. Sci. J. S. Newberry, "Report on the 
 Properties of the Stormout Silver Mining Company," etc.. Engineering 
 and Mining Journal, Oct. 38, 1880, p. 269. "The Silver R-ef Mines," 
 Ibid., Jan. 1, 1881, p. 4. C. M. Rolker, " The Silver Sandstone District of 
 Utah," M. E., IX. 21. 
 
 ' "Central Arizona," Engineering and Mining Journal, April 23. 
 1881, p. 285. "Colorado River of the West," review of Ives Expedition, 
 Amer. Jour. Sci., ii., XXXIII. 387. G. F. Becker, Tenth Census, Vol. 
 XIII., p. 44. C. E. Dutton, " The Physical Geology of the Grand Canon 
 District," abstract of Monograph II., Second Ann. Rejj. Director U. S. 
 Geol. Survey, 49-161 ; see also the monograph. Patrick Hamilton, The 
 Resources of Arizona, A. L. Bancroft & Co., San Francisco, 1884. B. Silli- 
 man, "Report on Mining Districts of Arizona, near the Rio Colorado," En- 
 gineering and Mining Journal, Aug. 11, 1877, p. Ill ; taken from Amer. 
 Jour. Sci., ii. XLI. 289. C. D. Walcott, " P.^rmiin an.l Ot er Paleozoic 
 
363 KEMP'S ORE DEPOSITS. 
 
 2.11.07. Apache County is in the northeastern comer. In the 
 southern part of the county gold and silver ores, in veins in lime- 
 stone, associated with copper ores, are reported, and some small 
 placers. 
 
 2.11.08. Yavapai County. Gold and silver ores, in quartz veins, 
 in granite and metamorphic rocks. The Black Range copper dis- 
 trict has already been referred to under Example 20e. 
 
 Mohave County. Silver sulphides, arsenides, etc., and alteration 
 products in veins in granite, at times showing a gneissoid structure. 
 Only the richest can now be worked. 
 
 Yuma County. Quartz veins, with silver ores and lead miner- 
 als in metamorphosed rocks (gneiss, slate, etc.), or in granite. 
 
 Maricopa County contains both Paleozoic aud Archean expos- 
 ures. The ore deposits lie mostly along the contact of the two, in 
 granite or highly metamorphosed strata. They are usually quartz 
 veins, with silver ores and copper, lead, and zinc minerals. The 
 Globe district, extending also into Pinal County, is the principal 
 ■one. Mention has already been made of it under " Copper," Ex- 
 ample 20c. 
 
 Pinal County adjoins Maricopa on the south and contains a 
 number of important mines. They produce mostly silver ores, 
 with lead and copper associates, and some blende. The gangue 
 minerals are quartz, calcite, etc., occasionally manganese com- 
 pounds, and sometimes, in the granites, barite. Limestone, slate, 
 sandstone, and quartzite, as well as granite, diabase, and diorite, 
 occur as wall rock. 
 
 2.11.00. Silver King Mine. A central mass or chimney of 
 quartz, with innumerable radiating veinlets of the same, carrying 
 rich silver ores and native silver, in a great dike of feldspar por- 
 phyry, with associated granite, syenite (Blake), porphyry, gneiss, 
 and slates, all of Archean age. The veinlets ramify through the 
 strongly altered porphyry, and form a stockwork, which furnishes 
 the principal ores. In the region are also Paleozoic strata, whose 
 upper limestone beds are referred by Blake to the Carboniferous. 
 The minerals at the mine are native silver, stromeyerite, argen- 
 tite, sphalerite, galenite, tetrahedrite, bornite, chalcopyrite, pyrite, 
 quartz, calcite, siderite, and, as an abundant gangue, barite. 
 
 Groups of the Kanab Vallej', Arizona,'' Amer. Jour. Sci., in., XX. 321. 
 " Pre-Carboniferous Slrata iathe Grand Canon of the Coloi-ado, Arizona," 
 Amer. Jour. Sei., December, 1883, 437. Wheeler's Survey, Vol. III., and 
 Supplement. 
 
SILVER AND GOLD, CONTINUED. 2C3 
 
 trraham County contains the Clifton copper district, referred 
 to under Example 20a. 
 
 Cochise County is the southeastern county, and contains the 
 Tombstone district, the most productive of the precious metals in 
 the Territory. 
 
 2.11.10. Tombstone. A great porphyry dike up to 70 feet 
 wide, cutting folded Paleozoic strata, and itself extensively faulted 
 and altered, and carrying above the water line in numerous verti- 
 cal joints, or partings, quartz with free gold, horn silver, and a lit- 
 tle pyrite, galenite, and lead carbonate. Curiously enough, in the 
 porphyry itself, and far from the quartz veins, flakes and scales of 
 free gold have been found, evidently introduced in solution. Ore 
 also occurs along the side of the dike. There are also other fis- 
 sures parallel with this principal dike, and still another series 
 crossing these and the axis of the great anticline of the district. 
 Connected with these fissure veins are bedded deposits in the 
 limestone, along the bedding planes or dropping from one to an- 
 other, appearing to have originated by replacement. Blake offers 
 two explanations of the first-mentioned dike deposit — either that 
 the dike itself held the precious metals, or that they came from the 
 pyrite of the adjoining strata. Several other mining districts of 
 less note occur in the county. The important copper deposits of the 
 Bisbee region have already been mentioned under Example 20/! 
 
 2.11.11. Pima County is the central county of the southern 
 tier and has Tucson as its principal city. There are numbers of 
 mines of the precious metals, and a few less important copper de- 
 posits. 
 
 Yuma County, in the southwestern corner, has some mines 
 along the Colorado River, on quartz veins in metamorphosed rocks, 
 containing silver and lead minerals.^ 
 
 1 G. F. Becker, Tenth Census,Yo\. XIIL, p. 44. G. H. Birnie, " Castle 
 Dome District," Wheeler's Survey, 1876, p. 6. W. P. Blake, " The Geology 
 of Tombstone, Ariz.," M. E., X. 334, Engineering and Mining Jour- 
 nal, June 34, 1882, p. 328 ; The Silver King Mine, a short monograph, 
 New Haven, March, 1883. Rec. See also Engineering and Mining Jour- 
 nal, April 28, 1883, p. 238. J. F. Blandy, "The Mining Region around 
 Prescott, Ariz.," M. E., XI. 286, Engineering and Mining Journal, July 
 21, 1883. " On Tombstone, Ariz.," Ibid., May 7, 1881, p. 316 ; March 18, 
 1882, p. 145. "Silver in Arizona," General Review, Engineering and Min- 
 ing Journal, Sept. 21 and 25, 1880, pp. 172, 203. " Central Arizona," Ibid., 
 April 33, 1881, p. 285. O. Loew, "Hualapais District," Wheeler's Survey, 
 
264 KEMP'S ORE DEPOSITS. 
 
 NEVADA. 
 
 2.11.12. Geology. — Nevada lies almost entirely in the Great 
 Basin, only the western portion being in the Sierras. The surface 
 is thus largely formed by the dried basins of former great lakes, 
 principally Lakes Lahontan and Bonneville. A large number of 
 ranges extend north and south through the State, known collec- 
 tively as the Basin ranges. They have been formed by block tilt- 
 ing on a grand scale and present enormously disturbed strata. 
 The geological sections exposed are of surpassing interest (cf. Ex- 
 ample 36), and show Archean and Paleozoic in great thickness. In 
 these mountains are found the mining districts, while between 
 them lie the alkaline plains.' 
 
 2.11.13. Lincoln County is in the southeastern corner and con- 
 tains a number of small mining districts. The ores are in general 
 silver-lead ores in limestone, or veins with sulphuret ores in quartz- 
 ite and granite. Pioche is one of the principal towns, near which 
 is found the once famous and now reopened Raymond & Ely 
 mine. A strong fissure cuts Cambrian quartzite and overlying 
 limestone, where the latter has not been eroded, and is occupied, 
 by a great porphyry dike. Along the contact between the por- 
 phyry and the wall rock the chutes of ore have been found. Mr. 
 Ernest Wiltsee, at the Montreal meeting of the American Insti- 
 tute of Mining Engineers, February, 1893, described and figured 
 the Half Moon mine, on this same great fissure, where the quartz- 
 
 1876, p. 55. B. Silliman, "Report on the Mining District of Arizona near 
 the Rio Colorado," ATner. Jour. Sci., ii., XLI. 289 ; see also Engineering 
 and Mining Journal, Aug. 11, 1877, p. 111. Raymond's Reports, and 
 those of the Diroctor of the Mint. 
 
 1 J. Blake, "The Great Basin," Proc. Cal. Acad. Sci., IV. 275, Amer. 
 Jour. Sci., iii., VI. 59. W. P. Blalie, " On the Geology and Mines of Ne- 
 vada " (Washue silver region), Quar. Jour. Geol. Sci., Vol. XX., p. 317. 
 H. G. Claik, "Aurora, Nev.: a Little of its History, Past and Present," 
 School of Mines Quarterly, III. 133. G. K. Gilbert, "A Theory of the 
 Earthquakes of the Great Basia, with a Practical Application," Amer. 
 Jour. Sci., iii., XXVII. 49. I. C. Russell, "Geology End History of Lake 
 Lahontan, a Quaternary Lake of NorthwesternNevada," Monograph XL, 
 U. S Oeol. Survey ; also Third Ann. Rep. Director U. S. Geol. Survey, 
 195. C. D. Walcott, " Paleontology of the Eureka District," Mononraph 
 VIIL, U. S. Geol. Survey. Gilbert, Wheeler, Lockwood, and others, 
 "Eastera Nevada: Notes on its Economic Geology," Wheeler's Survey, 
 Rep. Prog., 1869, 71, 72 ; also Vol. III. and Supplement. For further lit- 
 erature, see under Example 36. 
 
SILVER AND GOLD, CONTINUED. 365 
 
 ite still retained a limestone cap. The ore-bearing solutions, on 
 reaching a shaly streak containing a limestone layer, departed 
 from the fissure and followed under the limestone, so as to form a 
 lateral enlargement, much like those described and figured from 
 Newman Hill, Colorado, under 2.09.10. The Pahranagat and Tern 
 Pahute districts, still farther south, have had some prominence, 
 but the whole region is so far from the lines of transportation that 
 the conditions are hard ones.' 
 
 2.11.14. Ney County, next west, has an important mining 
 center, in its northern portion, around the town of Belmont. 
 Quartzite and slates rest on granites in the order named, and in 
 them are veins with quartz gangue and silver chlorides, affording 
 very rich ores. Southeast of Belmont is Tybo.^ 
 
 2.11.15. "White Pine County lies to the northeast, and contains 
 the White Pine district. The principal town is Hamilton, about 
 110 miles south of Elko, on the Central Pacific. The Humboldt 
 range is prolonged southward in some broken hills, consisting 
 chiefly of folded Devonian limestone. At Hamilton these are 
 bent into a prominent anticline, and this has a strong fissure cross- 
 ing the axis. The geological section is Devonian limestone, thin 
 calcareous shale, thin siliceous limestone, argillaceous shale, prob- 
 ably Carboniferous sandstone, and Carboniferous limestone. The 
 ore bodies occur, according to Arnold Hague, in four forms, all in 
 the Devonian limestone: (1) in fissures crossing the anticlinal axis; 
 (2) in contact deposits between the limestones and shales; (3) in beds 
 or chambers in the limestone parallel to the stratification; (4) in ir- 
 regular vertical and oblique seams across the bedding. The ore is 
 chiefly chloride of silver in quartz gangue. It is thought by Mr. 
 Hague to have probably come up through the main cross fissure, 
 and, meeting the impervious shale, to have spread through the 
 limestone in this way.' 
 
 Egan Caflon is in the northern part of the county and shows a 
 geological section of granite, quartzite, and slate in the order 
 named. In slates, and perhaps extending into the quartzite, is a 
 quartz vein five to eight feet wide carrying gold and silver ores. 
 
 1 E. P. Howell, Wheeler's Survey, III. 257. Gr. M. Wheeler, Report, 
 Wheeler's Survey, 1869, p. 14. 
 
 2 S. F. Emmons, Survey of the Fortieth Parallel, Vol. III., p. 393. G. 
 K. Gilbert, "On Belmont and Neighborhood," Wlieeler's Survey, III. 36. 
 
 " J. E. Clayton, "Section of the Roclts at Hamilton, Nev.," Cal. 
 Acad. Sci. A. Hague, Fortieth Parallel Survey, Vol. III., p. 409. 
 
266 KEMP'S ORE DEPOSITS. 
 
 Eureka County is the next county west of White Pine. The 
 deposits at Eureka have already been described under " Lead-sil- 
 ver " (Example 36). 
 
 2.11.16. Lander County lies next west of Eureka. The Toy- 
 abe range runs through it from north to south and in its southern 
 portion, in Ney County, contains the Belmont deposits. (See above, 
 2.11.14.) At Austin, which is 80 or 90 miles south of the Central 
 Pacific Railroad, now connected with it by a branch, are the mines 
 of the Reese River district, named from the principal stream near 
 by. From Mount Prometheus, which consists of biotite- granite 
 or granitite, and which is pierced by a great dike of rhyolite, a 
 western granite spur runs out known as Lander Hill. The ore 
 bodies are in this hill, and are narrow fissure veins with a general 
 northwest and southeast trend, carrying rich ruby silver ores, with 
 gray copper, galena, and blende, in a quartz gangue with associated 
 rhodochrosite and calcite. They are also often faulted. At times 
 they show excellent banded structure. Antimony has recently 
 been found in this region.' (See under " Antimony.") 
 
 2.11.1V. Elko County lies north of White Pine and Eureka 
 counties and contains the Tuscarora mining district. The depos- 
 its are high-grade silver ores in veins, in a decomposed hornblende 
 andesite.^ 
 
 Humboldt County is the middle county of the northern tier, 
 and contains a number of mining districts, which produce both sil- 
 ver and gold from quartz veins in the Mesozoic slate. Small 
 amounts of the precious metals come also from Washoe County, in 
 the northwest corner of the State.' 
 
 Churchill County adjoins Lander on the west and possesses a 
 few silver mines. 
 
 Esmeralda County, in the southwest, has a considerable num- 
 ber of rich silver and gold mines, which produce high-grade ores 
 from veins, with a quartz gangue in metamorphic rocks, slates, 
 schists, etc. (See also under " Xickel.") 
 
 2.11.18. Storey and Lyon are two small counties in the west- 
 ern central portion of the State, but the former contains the most 
 important and interesting ore deposit in Nevada, if indeed it is not 
 the largest and richest single vein yet discovered. 
 
 1 S. F. Emmons, Fortieth Parallel Survey, Vol. III., p. 349. 
 
 2 G. F. Becker, Tenth Census, Vol. XHI., p. 34. 
 
 3 Ibid., p. 33. 
 
SILVER AND GOLD, CONTINUED. 
 
 367 
 
 2.11.19. Comstock Lode. A great fissure vein, four miles 
 long, forked into two branches above, along a line of faulting in 
 eruptive rocks of the Tertiary age and chiefly andesites. In the 
 central j)art of the vein the displacement has been about 3000 
 feet, shading out, however, at the ends. The ores are high-grade 
 silver ores in quartz, and occur in great bodies, called " bonanzas," 
 along the east vein. Over $325,000,000 in gold and silver has 
 been extracted, in the ratio of two of the former to three of the 
 
 ^lA 
 
 CIT Y 
 
 TlanX of 
 W Davidson 
 
 yxxxv'<;x'' 
 
 yXXXX >''xX^ 
 
 <xyxyx " '<'«'^^,„,^ ,„ 
 
 xXXxyVX* X X c,>^^fe^G; 
 
 XXXXX XX" X "^ o 
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 »xxyvxxxyx* X >» 
 nXxxxxvxxX>^ 'o 
 <xxxxyxxxxxx>y 
 x>'xx.xxxxxxxyyx y 
 x>|x xxxx XX xyx>^ '>< X 
 Jjy^2j?^x>xxxxyxx X 
 
 <yXK GRANULAR XXXX^'^^ *1 "e 
 
 )fXx .,, XXXXX XX X XX x^ "^ X 
 
 ■^ X XxX PIOR'TEXXX XX> X^ *^ ^ 
 
 «XX JJx >?>"<^xxxyxxxxx>' x'" X ^,^, 
 
 «XXXXXy^>'?JXX><XXXXXXX*XV X X^^ 
 
 xxxxxxxx v5<v yxxxxxxyx%^ J^'''' 
 
 X^^JXXXX^^XXXKXXXXXXV^V;,''^. 
 
 'y XX ""^ X >< X y i ^"^ ^ X ^ X X X XV XX V ^5^ ^ ^ 
 
 ,XXXyy>^J<y y ^yy^ XvXxXXX X^.V x^ ^ 
 xXXXyyv^XXK v'^'"''^X'^XvyyXX x^A X 
 
 +4V 
 
 l^M 
 
 
 ^t+%-:4-r;!-4^ 
 
 4,^4 -f 
 
 4'4'4 4 + 
 
 Fig. 71. — Section of Comstock Lode on line of Sutra Tunnel. After O. F. 
 
 Becker, Monograph III., U. S. Geol. Survey. The colors of the 
 
 original are h-re indicated by line-work. 
 
 latter. The vein lies on the easterly slope of a northeasterly spur 
 of the Sierras. West of it is Mount Davidson. The outcroppings 
 lie on the flank of the latter, about 6500 feet above the sea and 
 1500 feet below the summit. The general strike of the vein is 
 east of south and it dips east. Views regarding the geology of 
 the Comstock have changed in the course of years, as they have 
 been influenced by the successive writings of Von Richthofen, 
 King, Church, Becker, and Hague and Iddings, the points in es- 
 pecial conti'oversy being the determinations of the rock species. 
 2.11.20. It may be remarked that the whole scheme of the 
 
268 KEMP'S ORE DEPOSITS. 
 
 classification of our volcanic (eifusive) rocks rests largely on Von 
 Richthofen's early studies, and that perhaps the most important 
 generalization of late years is due to the work of Hague and Id- 
 dings on the same. Von Richthofen (1885) described the ore body 
 as filling a fissure on the contact of a so-called syenite and an 
 eruptive rock that he called "propylite." The ore and gangue 
 are thought to have been brought up from below by solfataric ac- 
 tion, in which fluorine, chlorine, and sulphur were the principal 
 dissolving agents. Clarence King (1867-68, published in 1870) 
 bi-ings out forcibly the fact that the footwall of the vein approxi- 
 mates closely the natural continuation of Mount Davidson, and 
 contends that the vein filled a fissure between the syenite of which 
 Mount Davidson consists and the late Tertiary eruptive rocks 
 poured out against its flanks. He traced the geological succession 
 of these and explained the filling of the vein by solfataric action, 
 attendant on a thin dike of andesite, which forced its way into the 
 contact. J. A. Church (1877) thought that the diorite (called sy- 
 enite above) of Mount Davidson had been 2:ioured out originally in 
 thin horizontal sheets, which were folded in east and west folds. 
 Tliis was to account for the bedding of the rocks of the lode as 
 now seen. On the diorite was poured out next the jjropylite, 
 likewise in successive horizontal sheets. Then they were all 
 tilted along north and south axes, and eruptions of andesite jiene- 
 trated between their sheets in very large amount. Further move- 
 ments forced the convexities of the first-formed folds against the 
 andesites and crowded their substance sidewise, to some extent, 
 into the synclinals. This movement slightly parted the beds, af- 
 fording watercourses through which rose siliceous waters. These 
 dissolved away the neighboring beds, leaving extensive quartz 
 bodies in their places. They also removed the andesite caps. No 
 ore was formed as yet. Now followed great trachyte erujDtions 
 on the east, and they loaded the hanging wall of the lode so 
 heavily as to cause a downward movement of it on the foot, 
 making a new series of openings, and into these poured the ore- 
 bearing solutions which brought the jjrecious metals. Xo one 
 who has intelligently followed this explanation will doubt that 
 Mr. Church has shown great ingenuity, and yet few would be in- 
 clined to have very much confidence in this long, unnatural hy- 
 pothesis when a simple course will lead to the same results. At 
 the time of Mr. Church's visit the workings were becoming very 
 deep and the great heat which has been since such an obstacle was 
 
SILVER AND GOLD, CONTINUED. 269 
 
 manifesting itself. Flooded drifts, it was thought, had been 
 observed to grow hotter, and from this the hypothesis of kaolin- 
 ization was conceived. It was that the kaolinization of the feld- 
 spar in the deeply buried rock occasioned the heat of the lode. 
 
 2.11.21. G. F. Becker (18Y9-82) comments on the excessive 
 alteration which the rocks have undergone, as it figures largely in 
 his hypothesis of origin. He then traces the results of faulting, 
 and shows that under conditions like those present the surface 
 would tend to assume a logarithmic curve, which coincides sur- 
 prisingly well with the present outline of the country. After 
 describing the lode itself, the origin of its metalliferous contents 
 is traced as follows. Waters under hydrostatic pressure from the 
 heights to the west are supposed to have percolated toward the 
 lode, passing through deeply buried regions of heat. They were 
 probably diverted from rising directly through the lode by an 
 impervious clay seam, and were thus forced to soak through the 
 diabase hanging, relieving it in passage of the metals, which were 
 afterward deposited in the higher portions of the lode. The 
 metals them.selves were probably largely derived from the augite 
 of the rock. Mr. Becker had as an associate Dr. Carl Barus, who 
 studied the heat phenomena (especially the hypothesis of kaolini- 
 zation) and the electrical manifestations of the lode. The i-esult 
 of Dr. Barus's careful experiments threw great doubt on kaolini- 
 zation as a source of heat. The electrical experiments were not 
 satisfactory. They were carried on also at Eureka, Nev., but no 
 very definite results were reached. 
 
 2.11.22. The correct determination of the eruptive rocks 
 neighboring to the Comstock has been of great importance, not 
 alone because of their scientific interest, but as bearing on the fact 
 as to whether the lode itself was a contact fissure between two 
 different rocks, or whether it was simply a fissure vein. It is 
 worthy of note that in connection with it Von Richthofen de- 
 veloped one of the first important attempts to classify the vol- 
 canic rocks, and that Hague and Iddings have finally urged that 
 the peculiar crystalline structures of all eruptive rocks depend 
 primarily on the heat and pressure (i.e., depth below the surface) 
 under Avhich they have solidified, destroying thus the time ele- 
 ment in classification. This is, to be sure, an old idea, but it gains 
 its best confirmation from the Comstock. Von Richthofen, in his 
 report to the Sutro Tunnel Company, and in his later memoir on 
 "The Natural System of the Volcanic Rocks" {Cal. Acad. Sci., 
 
270 KEMPS ORE DEPOSITS. 
 
 ISe"? ; also Zeitschrift d. d. geol. Gesell., 1868, 663), distinguished 
 in the Washoe district syenite, metamorphie rocks, quartz-por- 
 phyry, propylite, sanidine-trachyte, and very. subordinate andesite. 
 Mr. King referred much of the propylite of Von Riohthofen to 
 andesite, but retained the propylite as a distinct species, although 
 remarking the close affinities of the two. The quartz-porphyry he 
 called quartz-propylite. In other respects no changes are intro- 
 duced. Zirkel [Fortieth Parallel Survey, Vol. VI.) determined 
 the syenite as granular diorite, and while accepting hornblende- 
 propylite and quartz-propylite as separate species, the greater part 
 of the quartzose rock he called dacite. He introduced for the 
 first time augite-andesite, rhyolite, and basalt. Mr. Church paid 
 less attention to lithology, and used the terms of his predecessors 
 somewhat loosely. Mr. Becker makes the following classifica- 
 tion : granular diorite, porphyritic diorite, micaceous diorite- 
 porphyry, quartz-porphyry, earlier diabase, later diabase, earlier 
 hornblende-andesite, augite-andesite, later hornblende-andesite, 
 and basalt. In this it will be seen that several new varieties are 
 introduced, but the main mass of Mount Davidson was still con- 
 sidered diorite, and the vein was thought to lie between this and 
 some of the other species mentioned, especially diabase. In 1885, 
 Arnold Hague and J. P. Iddings completed new microscopical 
 studies upon the materials collected by Mr. Becker, and the re- 
 sults were published as Bulletin 17 of the United States Geologi- 
 cal Survey (" On the Development of Crystallization in the 
 Igneous Rocks of Washoe," etc.). These two writers had had 
 more to do with the eruptive rocks of the Great Basin "and the 
 Pacific slope than any other geologists, and hence brought to the 
 review an exceptional experience. Xowhere else in the world are 
 such exposures and thorough sections afforded, alike in depth and 
 in horizontal extent. They proved that the diabase and augite- 
 andesite shade into each other, the differences in crystallization 
 being due to depth ; that the hornblende of the so-called diorite 
 was largely secondary from original augite, being derived by 
 paramorphic change (uralitization), and that the diorite was a 
 structural variety of the diabase ; that the porphyritic diorites 
 shade into the earlier hornblende-andesites and are structural 
 varieties of them ; that the mica-diorites and hornblende-andesite 
 are identical in the same way ; that the assumed Pre-Tertiary age 
 of the quartz -porphyry was unwarranted, and that it was partly 
 dacite and partly rhyolite, the two shading into each other ; that the 
 
SILVER AND GOLD, CONTINUED. 271 
 
 younger diabase, so called, of the sub-surface dike was identical with 
 the rook elsewhere occurring on the surface and called basalt, and 
 was really a basalt, owing its holocrystalline character to its depth ; 
 and finally, — the most important conclusion of all in this connec- 
 tion, although the other conclusions are among the most important 
 advances made in late years, — •" that the Comstock Lode occupies 
 a line of faulting in rock of Tertiary age, and cannot be con- 
 sidered as a contact vein between two different rock masses." 
 The crystalline structure of the Washoe rocks has been subse- 
 quently treated by Mr. Becker. ("The Washoe Rocks," Bull. 
 Cal. Acad. ScL, Vol. II., p. 93, January, 1887 ; "Texture of Mas- 
 sive Rocks," Amer. Jour. Sci., ii., Vol. XXXIIL, p. 50, 1887.) 
 The various structures — granular, porphyritic, and glassy — are re- 
 ferred more to differences in composition and fluidity than to cir- 
 cumstances of solidification.^ 
 
 1 G. F. Becker, " Geology of the Comstock Lode and the Washoe Dis- 
 trict," Monograph III., V. S. Oeol. Survey. Rec. See also Engineering 
 and Mining Journal, March 1, 1884, p. 163 ; Second Ann. Rej). Director 
 U. 8. Geol. Survey. Rec. J. A. Church, The Comstock Lode : Its Forma- 
 tion and History. New York, John Wiley & Sons. Reviewed in Engi- 
 neering and Mining Journal, Feb. 31, 1880, p. 397. See also shorter papers 
 in the Engineering and Mining Journal, Dec. 38, 1878, p. 456 ; July 19, 
 1879, p. 85 ; Dec. 13, 1885, p. 397 ; Jan. 23, 1886, p. 52. " On the Chacges 
 in the Comstock Vein," Engineering and Mining Journal, Dec. 18, 1886, 
 p. 434 ; " The Discovery of the Comstock Lode," Ibid., Deo. 5 and 19, 1891, 
 and other papers in 1892 by Dan Dequille. Hague and Iddings, " On the 
 Development of Crystallization in the Igneous Rocks of Washoe, Nev.," 
 etc.. Bull. 17, U. S. Geol. Survey. See also Bull. 6, Cal. Acad. Sci., and 
 Engineering and Mining Journal, Dec. 11, 1886, p. 415. 
 
CHAPTER XII. 
 
 THE PACIFIC SLOPE : WASHINGTON, OREGON, AND CALIFORNIA, 
 
 ■WASHINGTON. 
 
 2.12.01. Geology. — Little is available in the way of systematic 
 descriptions of the geology of Washington, and an attractive field 
 remains to be developed. The rocks of the Rocky Mountains 
 extend across the panhandle of Idaho and show in northeastern 
 Washington, affording considerable amounts of ores. They are 
 prevailingly granite and gneiss, which have escaped being covered 
 by the enormous volcanic outbreaks of Tertiary and later time. 
 West of the granites a great plateau country of somewhat diversi- 
 fied surface is met. It seems to have been an ancient lake basin, 
 but is now covered by igneous rocks and deposits of volcanic tuff. 
 Still farther west the Cascade chain forms the central divide of 
 the State. The rocks are granites, flanked by Paleozoic, Mesozoic, 
 and metamorphic strata, much like the Sierras of California. 
 They were upheaved in large part before the Cretaceous, and since 
 then other movements have occurred. There are vast develop- 
 ments of igneous rocks, forming, as at Mount Tacoma (Rainier), 
 some of the highest American peaks. West of the Cascade range 
 is a great valley formerly marking a drainage system, but now 
 covered partly by glacial drift and partly by the waters of Puget 
 Sound. The glacial deposits are enormous, and render the prob- 
 lem of working out the geology very difficult. Some glaciers re- 
 main on the heights even to the present day. West of the Puget 
 Sound Basin is the northerly extension of the Coast range, locally 
 called the Olympics, and largely Cretaceous and Tertiary strata.^ 
 
 1 G. F. Becker, Tenth, Census, Vol. XIH., p. 37. G. A. Bethune, First 
 Ann. Rep. State Geologist, 1891. A. Bowman, " Mining Developments on 
 the Northwest Pacific Coast and their Wider Bearing," 3J. E., XV. 707. 
 J. MacFarlane, Geol. Raihray Guide, second edition, p. 262 ; notes by 
 Punipelly, Willis, and others. Rec. J. 8. Newberrj', "Geology and Bot- 
 
THE PACIFIC SLOPE. 273 
 
 2.12.02. Good descriptions of the ore deposits of Washington 
 are greatly needed. The First Annual Report of the State Geolo- 
 gist has little of scientific value, and the other accounts ai-e ancient 
 history. There are gold placers in Yakima, Stevens, and Kittitas 
 counties, largely worked hy Chinese. But in Okanogan and Ste^ 
 vens counties, in the northeast, the developments of deep mining 
 for silver ores, although recent, are considerable. The veins are 
 largely in metamorphic rocks and contain the usual sulphides in 
 quartz gangue.' 
 
 OREGON. 
 
 2.12.03. Geology. — Northeastern and northern central Oregon 
 are formed by a prolongation southward of the igneous plateaus 
 of "Washington. Slates and granite appear in Baker County on 
 the east, in the Blue Mountains, and the geology seems to resem- 
 ble the Sierras. All southeastern Oregon belongs in the Great 
 Basin, which comes north from Nevada, but is better watered 
 than the southern portion. It is traversed by several subordinate 
 ranges of the block-tilted basin type. Of these the Stein Moun- 
 tains are the most prominent. The general surface is formed by 
 Quaternary lake deposits and great outbreaks of igneous rocks. 
 West of the basin and the plateau the Cascade range traverses the 
 State, and is cut by the Columbia River on the north and the Kla- 
 math on the south. The range consists of granite and metamor- 
 phic rocks, etc., the latter chiefly Mesozoic. In northern Oregon 
 a broad valley intervenes between the Cascade and the Coast 
 ranges, but in the southern part the two ranges run together, and 
 their distinction has been only partly worked out. (See J3uU. 33, 
 
 U. S. Oeol. Survey.) In the Coast range Cretaceous and Tertiary 
 strata predominate.^ 
 
 any of the Northern Pacific Railroad," Trans. N. Y. Acad. Sci., III., 1884, 
 p. 253. C. A. White, "Puget Group of Washington," Amer. Jour. Soi., 
 iii., XXXVI. ?t43. B. Willis, " Our Grandest Mountain and Deepest For- 
 est," School of Mines Quarterly, VIII. 153. "Report on the Coal Fields 
 of Washington Territory," Tenih Census, Vol. XV., p. 759. " Changes of 
 River Courses in Washington Territory due to Glaciation," Bull. 40, U. S. 
 Oeol. Survey. 
 
 1 G. A. Bethune, First Ann. Rep. State Geol., 1891. C. B. Fenner, 
 " The Monte Crihto District, Snohomish County," School of Mines Quar- 
 terly, November, 1893. "The Mines of Kittitas County," Engineering 
 and Mining Journal, Deo. 34, 1893, p. 608. 
 
 2 G. F. Becker, Tenth Census, Vol. XIII., p. 37. T. Condon, " On 
 
274 KEMF8 ORE DEPOSITS. 
 
 2.12.04. Oregon is an important producer of gold both from 
 placers and from veins. Baker County, on the east, presents the 
 characteristic placers and gold quartz of the California Sierras, and 
 is the most productive section of the State. Grant and Josephine 
 counties also have placers, and smaller amounts come from a few 
 others. In the extreme southeast, near the California line, is 
 Curry County, containing : 
 
 2.12.05. Example 44a. Port Orford. Auriferous beach sands 
 at the foot of gravel cliffs, and shifting with the winds and tides. 
 At Port Orford the ocean has access to great sea cliffs of gravel 
 which it breaks down by the force of the waves. A sorting ac- 
 tion ensues, performed by the undertow and the littoral cun-ent. 
 The heavier gold dust is concentrated and gathered up by the 
 miners at low tide. Some submarine work has also been at- 
 tempted. The product is not great, and the deposit is chiefly in- 
 teresting in its scientific bearing. It runs along into California as 
 well. Auriferous sands occur at Yakutat Bay, Alaska. (See J. 
 Stanley-Browne, JVat. Geog. Mag., Yol. III., 1891.) The gold of 
 the Potsdam sandstones of the Black Hills has been concentrated in 
 a similar way in early geologic time, and the magnetite sands which 
 were referred to under 2.03.13 furnish something of a parallel.^ 
 
 Some Puints Connected with the Igneous Eruptions along the Cascade 
 Mountains of Oregon,'' Amer. Jour. Sci., iii. XVIII. 406. J. S. Diller, 
 " Notes on the Geology of Northern California," Bull. 33, U. S. Geol. Sur- 
 vey. J. C. Fremont, " Observations on the Rocky Mountains and Orpgon," 
 Amer. Jour. Sci. , ii. , I'll. 193. George Gibbs, ' ' Notes on the Geology of the 
 Country East of the Cascade Mountains, Oregon,'' Amer. Jour. Sci , ii., 
 XX. 275. J. Leconte, " On the Great Lava Flood of the West, and on the 
 Structure and Age of the Cascade Mountains," Amer. Jour. Sci., iii., 
 VIII. 167, 259. CKing, Fortieth Parallel Surveij,Yo\. I. J. MacFarlane, 
 Geol. Railu-ay Guide, p. 316. J. S. Xewberry, Pacific R. R. Reports, Vol. 
 VI , pp. 1-73. I. C. Russell, "A Geological Reconnaissance in Southern 
 Oregon," Fourth Ann. Rep. Director U. S. Geol. Survey, pp. 435^63. 
 
 '■ G. F. Becker, Tenth Census, Vol. XIII., p. 27, general account of 
 Oregon. "W. P. Blake, "Gold and Platinum from Cape Blanco (Port Or- 
 ford)," Amer. Jour. Sci., ii., XVIII. 156. " Remarks on the Extent of the 
 Gold Regions of California and Oregon," etc., Amer. Jour. Sci., ii., XX. 
 72. A. W. Chase, " The Auriferous Gravel Deposits of Gold Bluffs, Cali- 
 fornia," Cal. Acad. Sci., 1874 ; Amer. Jour. Sci., iii , VII. 367. " Dredging 
 for Gold," Engineering and Mining Journal, June 23, 1833, p. 860. B. 
 Silliman, " Cherokee Gold Washings,'' Amer. Jour. Sci., iii., VI. 132. W. 
 P. Watts, " Sands in Santa Cruz County, California," Rep. Cal. State Min- 
 eralogist, 1890, p. 633. 
 
THE PACIFIC SLOPE. 275 
 
 CALIFOEXIA. 
 
 2.12.06. Geology. — The topography and geology of northern 
 California have been but recently made clear. Diller considers 
 that the southern end of the Cascade range is Mount Shasta ; 
 that the Sierras proper terminate near the north fork of the 
 Feather River, but the line is continued about fifty miles farther 
 north, in the Lassens Peak volcanic ridge, and that all else west 
 and south of Mount Shasta belong to the Coast range. Central 
 California, as is well known, has the Sierras on the east, the great 
 Sacramento Valley in the middle, with the Coast range on the 
 west. The arid regions of the Great Basin just touch the north- 
 eastern corner, but on the southern extremity they swing around 
 and form a large part of the State. The Great Basin portion is 
 formed by Quaternary lake deposits. The Sierras consist of cen- 
 tral granite and gneiss, with great developments of slates and 
 eruptives on their flanks. The excessive metamorphism has large- 
 ly destroyed the fossils, but enough have been found to prove that 
 while in large part Jurassic, yet Carboniferous and Cretaceous 
 representatives are also present. The western slopes have the 
 mantles of gravel, which have furnished so much gold, and with 
 these are large outflows of basalt. The upheaval of the Sierras 
 occurred before the middle Cretaceous time. The Coast range con- 
 sists of rocks of late Cretaceous and early Tertiary age, extending 
 into the Miocene. They were upheaved in post-Miocene time. 
 Great outbreaks of andesite also occurred, and later basalts. The 
 principal product of California is gold, but recently a district 
 which furnishes considerable silver has been developed. This 
 will flrst be described, in order to lead up to gold. The copper 
 and iron resources have already been mentioned, and the mercury, 
 antimony, and chromium deposits remain for description after the 
 precious metals.^ 
 
 ' G. F. Becker, " Notes on the Early Cretaceous of California," Amer. 
 Jour. Sci., ill., II. 301. "Antiquities from under Tuolumne Table Moun- 
 tain, California," O. S. A., II. 189. "Cretaceous Metamorphic Rocks of 
 California," Amer. Jour. Sci., iii., XXXI. 348. "Structure of a Portion 
 of the Sierra Nevada of Calitornia," O. S. A., II. 50. "Notes on the 
 Stratigraphy of California," Bull. 19, U. S. Oeol. Survey. W. P. Blake, 
 "Notes on California," Amer. Jour. Sci., ii., XVIII. 441. W. H. Brewer 
 epitomizes Whitney's report, Amer. Jour. Sci., ii., XLI. 331; also 351. J. 
 D. Dana, "Notes on Upper California," Amer. Jour. Sci., ii., VII. 376. 
 J. S. Diller, " Geology of the Lassen Peak District," EigJith Ann. Sep. Di- 
 
276 
 
 KEMP'S ORE DEPOSITS. 
 
 2.12.0Y. Calico District. Deposits of 
 silver chloride in fissure veins, small frac- 
 tures and pockets in liparites and tuf aceous 
 sandstones, probably of the Pliocene series. 
 They occur in southwestern California, in 
 that portion of the State belonging rather 
 to the Great Basin than to the Pacific 
 slope. An immense outbreak of liparite 
 has formed a series of elevations, and the 
 attendant tufas are extensively developed. 
 
 
 Cj 
 
 rector U. S. Geol. Survey, pp. 401, 435. "On 
 the Cretaceous Rocks of Northern California," 
 Amer. Jour. Sci., iii., XL. 476. " On the Geol- 
 ogy of Northern California," Proc.Phil. Sac. of 
 Wash., Jan. 16, 1886; Abstract, Amer. Jour. 
 Sci., iii., XXXIII. 152. " Geology of the Tay- 
 lorville Region, Plumas County," Bull. Geol. 
 Soc. Amer., III. 369. G. K. Gilbert, "The Re- 
 cency of Certain Volcanoes of the Western 
 United States," A. A. A. S., XXIII. 39. A. 
 Hyatt, " Jura and Trias of Taylorville, Cali- 
 fornia," Bull. Geol. Soc. Amer. , III. 895. Will- 
 iam Irelan, State Mineralogist, .Anm.J?ep., 1886, 
 and following, especially 1890, geology by 
 counties. J. Leconte, " Post-tertiary Ele- 
 vation of the Sierra Nevadas, shown by the 
 River Beds," Amer. Jour. Sci., iii., XXXII. 167. 
 "Old River Beds of California," Ibid., iii., 
 XIX. 190 ; iii , XXXVIII. 261. " Extinct Vol- 
 canoes about Lake Mono, and their Relations 
 to the Glacial Drift," Ibid., iii., XVIII. 85. 
 Jules Marcou, " Report on the Geology of a 
 Portion of Southern California," Wheeler's Sitr- 
 vey, Ann. Rep. ,1816, Afli.,Tp 158. J. E. Mills, 
 "Stratigraphy and Succession of the Rocks of 
 the Sierra Nevada of California," Bull. Geol. 
 Soc. Amer., III. 413. E. Reyer, Theoretische 
 Geologic, p. 537, 1888. I. C. Russell, " The 
 Quaternary History of Mono Valley, Cali- 
 fornia," Eighth Ann. Rep. Director U. S. Geol. 
 Survey, pp. 267-400. H. W. Turner, "The 
 Geology of Mount Diablo, with the Chemistry 
 of the Rocks, by W. H. Melville," G. S. A.,IL 
 
THE PACIFIC SLOPE. 
 
 277 
 
 The ore is thought by Lindgren to liave come in heated solution 
 from below and to have tilled the tissures and overflowed, forming 
 the surface deposits in tlie tufas. (Cf. Silver Cliff, Colorado.) 
 There are deposits of gold ores in the same region.' 
 
 2.12.08. Example 44. Auriferous Gravels. (1) River grav- 
 els, oy placers in the beds of I'unning streams. These have been 
 often referred to in other (States, but the type is placed in Cali- 
 
 r~ 
 
 
 H: 
 
 "Hfc 
 
 
 Fio. 73, — Vieii^ of the Unian digginga, Columbia Hill, Nevada- County, 
 California. From a x'hotograph. 
 
 fornia, as they are there best known. They were the first gravels 
 washed in 1840, and, although sulistantially exhausted by 18CC, 
 iroductive. Eastward from the great Sacraiiiento 
 
 ■were very pr 
 
 383. J. A. Veatch, " Notes on a Visit to the Mud VolcaDoes of the Col- 
 orado Desert," etc., Amer. Jour. Sci., ii., XXVI. 288. J. D. Whitney and 
 others, reports o( the California Geological Surve}-, issued at Cambridge, 
 Mass. L. G. Yates, "Notes on the Geology and Scenery of the Islands 
 forming the Southern Line of the Santa Barbara Channel," ^4. G., V. 43. 
 1 W. Lindgrea, "The Silver Mines of Calico Dlstnut, California," 
 M. E., XV. 717. 
 
srs 
 
 KEMP'S ORE DEPOSITS. 
 
 Valley ibe surface rises with a quite gentle gradient to the sum- 
 mit of the Sierras. Tlie country consists chiefly of metaniorphio 
 rocks, which have 3-ieliled a very few well-determined fossils of 
 almost the entire Paleozoic and Mesozoic eras; but the identity of 
 
 
 Flo. li. — Vieir nf the Timbnctoo digciings, Yuba County, California. 
 From n photograph. 
 
 the strata iu all the stretch is difficult to make out, because where 
 the fossils were originally present they are almost entirelv de- 
 stroyed by metaniorjihism. Down the slopes of the range the 
 modern streams have flowed and cut deep canons in which gravels 
 have gathereil. Out in the more open country the gravels have 
 also accumulated and ha\c furnished some productive bars. The 
 
THE PACIFIC SLOPE. 279 
 
 gold has been derived principally from the quartz veins of the 
 slates, which are later described, and has been mechanically con- 
 centrated in the streams. Before coming to its final rest it may 
 have lodged in the high or deep gravels, of which mention will 
 next be made. 
 
 It is accompanied by magnetite as a general thing, by zircon, 
 garnet, and rarely by other heavy metals, such as platinum and 
 iridosmine. The greatest amount is usually near the bed rock, 
 and when this is at all porous the gold may work into it to a small 
 distance from the top. The gold is usually in flattened pellets of 
 all sizes, from the finest dust to nuggets of considerable weight. 
 They show evidence of being water worn. The interesting phe- 
 nomena connected with the possible circulation of the precious 
 metal in solution through the gravels are discussed under the deep 
 gravels. Important deposits of the same general character as these 
 have also been dug over near Santa Fe, N. M. ; in California 
 Gulch, near Leadville, Colo.; at Fairplay, Colo.; in San Miguel 
 Coimty, Colorado ; in the Sweetwater district, Wyoming ; near 
 Butte, Mont. ; in Last Chance and Prickly Pear gulches, near 
 Helena, Mont.; in the Black Hills; in southern Idaho, especially 
 along the Snake River ; and at various points in "Washington and 
 Oregon. Placers of this type have also been found on the slopes 
 of the Green Mountains and in the Southern States, but they never 
 have proved of serious importance. 
 
 2.12.09. (2) High or Deep Gravels. With the exhaustion of 
 the river gravels the gold seekers of California were driven to 
 prosjsect on the higher slopes, where auriferous gravels much less 
 accessible had been long noted. Increasing observation and de- 
 velopment have shown that these are the relics of former and 
 very extensive drainage systems, which was more or less parallel 
 with the present streams, but of greater volume. The beds lie in 
 deep gulches in the slates, and are capped in most cases by basal- 
 tic lava flows or by consolidated volcanic tuffs, called cement. 
 They extend some 250 miles along the Sierras and up to 5000 feet 
 above the sea. They have at times great thickness, reaching 600 
 feet at Columbia Hill, but drop elsewhere to 1 or 2 feet. They vary 
 from a maximum widthin workable material of 1000 feet to a mini- 
 mum of 150. The inclosing slates on the sides of the old river 
 valley are called " the rims," and on them are sometimes found 
 other gravels. In some districts channels, belonging to two or 
 three periods of flow, have been traced. They tend to follow the 
 
280 
 
 KEMP'S ORE DEPOSITS. 
 
 softer strata, breaking at times across the harder rocks. The 
 channel filling consists of gravel, sand, and clays, volcanic tuffs, 
 and firm basalt. With these are great quantities of silicified 
 trees, and even standing trunks project through some beds. The 
 gravel is oftenest formed of white quartz boulders, but may con- 
 tain all the metamorphic rocks of the neighborhood, and even 
 boulders brought fi-om a great distance. The gravel at times is 
 cemented together by siliceous and calcareous matter, and then 
 requires blasting ; but loose gravel also occurs. The clays are 
 locally called "pipe clays," and are often interbedded with sand 
 layers. They are blue when unoxidized, giving rise to the term 
 " blue lead," but red oxidized clays are not infrequent. The clays 
 
 Fia. 75. — Generalized section of a deep gravel bed, with technical terms. 
 After R. E. Browne, Rep. Cal. State Mineralogist, 1890, 2>- 437. 
 
 contain many leaf impressions of species thought by Lesquereux to 
 be late Tertiary. The gravels also contain bones of extinct verte- 
 brates, and have affoi-ded some authentic human remains and 
 stone implements of good workmanship. The volcanic tuffs have 
 been strong factors in modifying the original drainage lines. 
 They have flowed into the ancient valleys in a state of mud and 
 have then consolidated. 
 
 2.12.10. The richest gravels are those nearest the bed rock. 
 In these the distribution of the gold is governed more or less by 
 the character of the ancient channels. It favors the inside of 
 bends and the tops of steeper runs. The gradients of the old 
 channels were fairly high, often running 100 to 200 feet per mile. 
 Gold has also been found by assay in pyrite that has been formed 
 in the gravels since their deposition, and from this it is evident 
 that the precious metal does circulate in solution with sulphate of 
 
THE PACIFIC SLOPE. 
 
 381 
 
 iron, but on this slender foundation some quite unwarranted 
 chemical hypotheses for the origin of nuggets have been based. 
 Substantially all the gold has been derived by the mechanical 
 degradation of the quartz veins in the slate. 
 
 2.12.11. The depths to which the modern streams have cut out 
 their channels below the old drainage lines have received con- 
 siderable attention. Whitney avers that no disturbance has taken 
 place since the old gravels were laid down, but Leconte thinks 
 that there has been a tilting or elevation of the higher parts of 
 the range, all moving as a block. Becker has recently shown in the 
 
 I 2 3 ♦ S 6 7 e 9 10 II 12 13 14- 15 16 17 la 19 20 21 IZ 23 24- 25 26 27 
 
 Fig. 76. — Section of Forest Hill Divide, Placer County, California, to il- 
 lustrate the relations of old and modern lines of drainage. After 
 R. E. Browne, Rep. Cal. State Mineralogist, 1890, p. 444. 
 
 high portions a great series of small north and south faults with 
 uniform downthrow on the western side or upthrow on the east- 
 ern. (See paper below, cited from Geological Society of America.) 
 This is of varied intensity in different portions and is limited to 
 the strip just west of the summit. It occurred in the Pliocene 
 and increased the gradient of the streams where the present deep 
 caQons occur, but had no effect near the plains, where the old and 
 new channels are nearljr on the same level. 
 
 2.12.12. After the formation of the deep gravels and after the 
 volcanic flows, glaciation took place in great extent over the 
 mountain sides, but it was doubtless later in time than the glacial 
 period of the East. References to the similar great development 
 of the ice in Washington have already been made. Many hypoth- 
 eses were early advanced to explain the deep gravels. They 
 
2S2 KEMP'S ORE DEPOSITS. 
 
 have been referred to the ocean, to ocean currents, and to glaciers ; 
 but it is now well established that they are river gravels, formed 
 when the rainfall was probably in excess of what it is to-day, and 
 when the attitude of the land toward the ocean may have been 
 different.' 
 
 2.12.13. The II. S. Geological Survey has been directing its 
 attention in recent years to the geology of the gold belt in the 
 Sierras in connection with the issue of atlas sheets, based on topo- 
 graphic and geologic surveys. Several of these are practically 
 complete, and they and the auxiliary papers which have resulted 
 from the work have served to throw a flood of light upon the ob- 
 scure problems of the geology of the Sierras. At the same time, 
 as cited under subsequent paragraphs, other local workers have been 
 active. The geological relations of the gravels as well as the solid 
 strata have been made clear in greater detail than ever before. 
 Waldemar Lindgren has discussed the geological history of the 
 
 1 G. F. Becker, "Notes on the Stratigraphy of California," Bull. 19, 
 U S. Geo!. Survey. " Structure of the Sierra Nevadas," G. S. A., 11. 43. 
 W. P. Blake, " The Various Forms in which Gold Occurs," Rep. Director 
 of the Mint, 1884, p. 573. A. J. Bowie, Jr., "Hydraulic Miniog Iq Cali- 
 fornia," M. E., VI. 37. E. E. Browne, "The Ancient Eiver Beds of the 
 Forest Hill Divide," Rep. Cal. State Mineralogist, 1890, p. 435. Rec. T. 
 Egleston, "Formation of Gold Nuggets and Placer Deposits," M. E., IX. 
 63. "Working Placer Deposits in the United States," School of Mines 
 Quarterly, VII., p. 101. J. H. Hammond, "Auriferous Gravels of Cali- 
 fornia,'' Rep. Director of the Mint, 1881, p. 616. Eec. Rep. Cal. State 
 Mineralogist, 1889, p. 105. H. G. Hanks, "Placer Gold," Rep. Director 
 of the Mint, 1882, p. 728. H. G. Hanks and William Irelan, Rep. Cal. State 
 Mineralogist, Annual. T. S. Hunt, " On a Recent Formation of Quartz, 
 and on Silicification in California," Engineering and Mining Journal, May 
 29, 1880, 869. J. Leconte, " The Old River Beds of California," Amer. 
 Jour. Sci., iii., XIX. 80, p. 176. J. J. McGillivray, "The Old River Beds 
 of the Sierra Nevada of California," iJep. Director of the Mint, 1881, p. 
 630. E. I. Murchison, " Siluria," etc. Contains a sketch of the distribu- 
 tion of gold over the earth. J. S. Newberrj-, " On the Genesis and Distri- 
 bution of Gold," School of Mines Quarterly, Vol. III.; Engineering and 
 Mining Journal, Dec. 24 and 31, 1881. J. A. Phillips, " Notes on the 
 Chemical Geology of the California Gold Fields," Philos. Mag., Vol. 
 XXXVI., p. 321 ; Proc. Roy. Soc, XVI. 394 ; Amer. Jour. Sci., ii., XL VII. 
 134. B. Silliman, "On the Deep Placers of the South and Middle Yuba, 
 Nevada County, California," Amer. Jour. Sci., ii., XL. 1. J. D. Whitney, 
 " Auriferous Gravels of the Sierras," Cambridge, 1880. " Climatic Changes 
 in Later Geological Times," Cambridge. 
 
THE PACIFIC SLOPE. 283 
 
 American and Yuba rivers in his valuable paper entitled, "Two 
 Neocene Kivers of California" {Bull. Geol. Soc. of America, IV., 
 257-298, 1893). The conclusion is that the old divide in general 
 coincided with the present one, but that the slope of the Sierra 
 has been considerably increased since the time when the Neocene 
 {i. e., Miocene and Pliocene) ante-volcanic rivers flowed over its 
 surface. " It finally appears probable . . . that the surface of 
 the Sierra Nevada has been deformed during this uplift, and that 
 the most noticeable deformation has been caused by a subsidence 
 of the portion adjoining the great valley, relatively to the middle 
 part of the range." J. S. Diller has also discussed the same sub- 
 ject, and for a wider range of country (Kevolution in the Topog- 
 raphy of the Pacific Coast since the Auriferous Gravel Period, 
 Journal of Geology, II., 32, 1894). Mr. Diller shows that the 
 western side of the present Sierras formed in tne Eocene or Tejon 
 times a gently-sloping base-level of erosion, with quiet streams and 
 extensive superficial deposits of a residual character. The Sierras 
 were from 4000 to 7000 feet below their present altitude. With the 
 Miocene came a period of upheaval, of increased gradients and 
 rapid denudation of the soft surface materials. The old auriferous 
 gravels were thus formed in the stream channels while the lighter 
 materials floated out to sea. The course of development is graph- 
 ically traced out by Mr. Diller in accordance with our modern 
 knowledge of stream-erosion and transportation. For Southern 
 California Dr. A. C. Lawson has described a somewhat similar de- 
 velopment in later geological time (The Post-Pliocene Diastroph- 
 ism of the Coast of Southern California, Bull, of the Dept. of 
 Geol., Univ. of Calif., I., 115, Dec, 1893), but as the region is not 
 one of auriferous gravels, it is only cited here as of interesting 
 correlative character. H. W. Turner has lately reviewed the whole 
 stratigraphy of the region south of the fortieth parallel, has cor- 
 related the new formational names adopted in the survey atlas 
 sheets, has added many valuable notes on the petrography of the 
 igneous rocks, and has outlined the sti'atigraphical relations of the 
 gravels ("Geographical Notes on the Sierra Nevada," Amer. Geol- 
 ogist , XIU ., ^2^ &n(i 221 , 1894). Mr. Turner distinguishes two 
 series of Neocene river gravels (p. 241). 1st. The older gravels 
 composed chiefly of white quartz pebbles and frequently capped by 
 rhyolitic flows. These may be characterized in a broad way as the 
 gravels formed before the volcanic period. 2d. A later series, con- 
 taining volcanic pebbles chiefly of andesite and later in age than 
 
284 KEMP'S ORE DEPOSITS. 
 
 the rhyolitic flows. These may be called the gravels of the vol- 
 canic period. Such gravels are often capped by andesite-tufE." 
 Included fossil leaves indicate that the older gravels are Miocene, 
 the later Pliocene. The Pliocene river gravels merge into shore 
 gravels of the same age in Amador and Calaveras Counties. The 
 pebbles in the shore gravels are quartzite, mica-schist, quartz-por- 
 phyrite, granitoid rocks, andesite, and rhyolite, the last named 
 being at times very abundant and characteristic. They appear to 
 have been deposited along the shores of the great gulf which filled 
 the central valley of California in these times. They now range 
 as a general thing 500 to 700 feet above the sea. Later than the 
 Pliocene gravels are the Pleistocene, both shore and river deposits. 
 The former occur in the depressions between the Neocene and 
 older hills and at u lower altitude, by one to several hundred feet. 
 They seem to consist of the harder pebbles of the Pliocene gravels, 
 the softer ones having been destroyed by abrasion. The Pleisto- 
 cene river gravels lie usually less than 100 feet above the present 
 streams, and also in remnants of the channels left behind by old 
 changes of course. They and the shore deposits of this time are 
 often highly auriferous. Several lake-bottoms of this period have 
 been recognized where for some reason, such as the damming of a 
 stream by a volcanic flow, or a probable orographic upheaval, the 
 waters were set back. These lakes have left benches which mark 
 their old shore lines. Finally, we have the recent stream gravels 
 and alluvium. These papers show that the geological relations are 
 more complex than was earlier known, but in their practical bear- 
 ings the gravels can perhaps hardly be better grouped than into 
 the Kiver gravels or placers, in the beds of running streams, and 
 the High or Deep gravels, according to the old nomenclature. 
 
 2.12,14. Example 45. Gold Quartz Veins. Veins of gold- 
 bearing quartz, usually described as segregated veins, in slates 
 and other metamorphic rocks, and more or less parallel with the 
 bedding. The quartz contains auriferous pyrite, free gold, 
 arsenopyrite, chalcopyrite, tetrahedrite, galena, and blende, but 
 pyrites is far the most abundant. Som-e tellurides have been 
 noted by Silliman at Carson Hill, Calaveras County. The veins 
 approximate at times a lenticular shape, which is less marked in 
 California than in some other regions, and which shows analogies 
 of shape with pyrites lenses (Example 16) and magnetite lenses 
 (Example 12). In such cases the fissure-vein character is some- 
 
THE PACIFIC SLOPE. 285 
 
 what obscure. In California the veins occupy undoubted fissures 
 in the slates. The largest and best known is the so-called Mother 
 Lode, which is a lineal succession of innumerable larger and 
 smaller quartz veins that run parallel with the strike, but which 
 cut the steep dip of the slates at an angle of 10°. It was doubt- 
 less formed by faulting in steeply dipping strata. The wall rocks 
 of the California veins are serpentine, diabase, diorite, and granite, 
 as well as slate, for all these enter into the western slopes of the 
 Sierras. The serpentine is probably a metamorphosed igneous 
 rook, while the diabase and diorite form great dikes. Considerable 
 calcite, dolomite, and ankerite occur with the quartz, and very 
 often it is penetrated by seams of a green chloritic silicate, which 
 is provisionally called mariposite, as it is probably not a definite 
 mineral, but rather an infiltration of decomposition products. The 
 quartz veins vary somewhat in appearance, being at times milk 
 white and massive (locally called " hungry," from its general bar- 
 renness), at times greasy and darker, and again manifesting other 
 differences, which are difficult to describe, although more or less 
 evident in specimens. The richer quartz in many mines is some- 
 what banded, and is called ribbon quartz. The quartz has been 
 studied in thin sections, especially in rich specimens, by W. M. 
 Courtis, who shows that fluid or gaseous inclusions of what is 
 probably carbonic acid are abundant. In rich specimens the cavi- 
 ties»tend to be more numerous than in poor, but more data are 
 needed to form the basis of any reliable deductions. Some quartz 
 showed evidence of dynamic disturbances. The walls of the veins 
 are themselves impregnated with the precious metal and the at- 
 tendant sulphides. The rich portions of the veins occur in chutes 
 to a large degree. 
 
 2.13.15. The great Mother Lode is the largest group of veins 
 in California. It extends 112 miles in a general northwest direc- 
 tion. Beginning in Mariposa County, in the south, it crosses 
 Tuolumne, Calaveras, Amador, and El Dorado counties in succes- 
 sion. It is not strictly continuous nor is' it one single lode, but 
 rather a succession of related ones, which branch, pinch out, run 
 off in stringers, and are thus complex in their general grouping. 
 Over 500 patented locations have been made on it. Whitney has 
 thought it may have originated from the silicification of beds of 
 dolomite, but others regard it, with greater reason, as a great 
 series of veins along a fissured strip. The veins are often left in 
 strong relief by the erosion of the wall rock, and thus are called 
 
286 KEMPS ORE DEPOSITS. 
 
 ledges, or reefs. Some discussion has arisen over the condition of 
 the gold in the pyrite, but in most cases it is the native metal 
 mechanically mixed, and not as an isomorphous sulphide. It has 
 been detected in the metallic state, in a thin section of a pyrite 
 crystal from Douglass Island, Alaska, as later set forth (2.13.04), 
 and the fact that it remains as the metal when the pyrite is dis- 
 solved in nitric acid makes this undoubtedly the general condition. 
 The association of gold with bismuth, which has been shown by 
 K Pearce to occur in the sulphurets of Gilpin County, Colorado 
 (referred to on p. 212), and the difficulty experienced in amalga- 
 mating some ores, indicate the possibility of other combinations. 
 When crystallized, gold has shown, in one specimen and another, 
 nearly all the holohedral forms of the isometric system, but the 
 octahedron and rhombic dodecahedron are commonest. The veins 
 are younger than any of the igneous dikes with them. They may 
 have been filled, as thought by Whitney, during the metamor- 
 phism of the rocks attendant upon their upheaval in post-Jurassic 
 time. Certain it is that a very extensive circulation of siliceous 
 solutions was in progress. For the gold in the similar veins of 
 Australia a precipitation by organic matter has been urged. (See 
 William Nicholas, "The Origin of Gold in Certain Victorian 
 Reefs," Engineerhig and Mining Journal, Dec. 15, 188,3.) In 
 the development of explanations of origin, hoAvever, a wide field 
 for study yet remains.^ 
 
 1 M. Attwood, "On the Wall Rocks of California Gold Quartz and the 
 Source of the Gold," iSep. Cal. Mineralogist, 18f8, p. 771 (tliought to be 
 due to igneous injection in diabase). W. P. Biake, "On the Parallelism 
 between the Deposits of Auriferous Drift of the Appalachian Gold Field 
 and those of California," Amer. Jour. Sci., ii., XXVI. 128. "Remarks 
 on the Extent of the Gold Region of Californi-i and Oregon," etc.. Ibid. 
 ii., XX. 72. "The Carboniferous Age of a Portion of the Gold-bearing 
 Rocks of California," Ibid., ii., XLV. 264. W. H. Brewer, reply to above, 
 Ibid., ii., XLV. 397. A. Bowman, " Gei logy of the Sierra Nevada in Re- 
 la! ion 1o Vein Mining,"' Jlfm. Resources West Rocky Mountains, 1875, p. 
 441. W. H. Brewer, " On the Age of the Gold bearing Rocks of the Pacifio 
 Coast," Amer. Jour. Sci., ii., XLII. 114. F. O. Corning, "The Gold Quartz 
 Mines of Grass Valley, California," Engineering and Mining Journal, 
 Dec. 11, 1886, p. 418. W. M. Courtis, "Gold Quartz," M. E., 1889, Ottawa 
 meetmg. H. W. Fairbanks, " Geology of the Mother Lode," Tenth Ann. 
 Rep. Cal. Mineralogist ; also in briefer form in Amer. Geol., April, 1891, 
 p. 201. Rec. "On the Pre-Cretaceous Rocks of the California Coast 
 Ranges," Amer. Oeol., March, 1892, February, 1893. J. H. Hammond, 
 
THE PAOmO SLOPE. 287 
 
 2.13.16. In rare instances the gold is associated with some otlier 
 gangue tlian quartz. Thus in Vol. XIII., p. 24, of the Tenth 
 Census, G. F. Becker records gold in calcite, in the Mad Ox mine 
 of Shasta County, where the hanging wall is a siliceous limestone. 
 J. S. Diller has cited a similar case from Minersville, Trinity County. 
 The gold occurred in veinlets of calcite in a dark, carbonaceous 
 shale [Amer. Jour. Sci., Feb., 1890, p. 160). Waldemar Liud- 
 gren* has described an instance of gold with some silver occurring 
 in seams of barite, which were themselves in a kaolinized zone in 
 diabase and diabase-porphyrite. In the kaolin 0.34^ Ba SO^ was 
 determined by analysis. It may have been derived from the feld- 
 spar of the original diabase. "W". F. Hillebrand^ has lately shown 
 the wide distribution of both barium and strontium. Through 
 the kindness of Mr. Leo von Eosenberg, the writer (J, F. Kemp) 
 has had the opportunity to examine a suite of ores from the Shaw 
 mine, El Dorado County, which have been donated to the School of 
 Mines. The same had been previously examined by H. W. Turner, 
 of the U. S. Geol. Survey, by whom the determinations were 
 originally made. The mine is based on a dike of porphyrite, sixty 
 or seventy feet thick and charged with pyrites. It is auriferous 
 throughout, but richest next the walls. The gold in the native 
 form occurs in veinlets of albite, which ramify through the por- 
 
 " Mining' of Gold Ores in California," Tenth Ann. Rep. State Mineralogist, 
 p, 8.58. Eec. P. Laur, " Du Gisempnt et de I'Exploration de I'Or en Cali- 
 fornie," Ann. des Mines, Vol. III., 1863, p. 412. G. W. Maynard, "Re- 
 marks on Gold Specimens from California," M. E., VI. 451. J. S. New- 
 berry, " On the Genesis and Distribution of Gold," School of Mines Quar- 
 terly, III., p. 16. A. Eemond, "Mining Statistics," No. 1, Cal. Geol. 
 Survey (tabular statement of quartz mining and mills between the Merced 
 and Stanislaus rivers). J. A. Phillips, "Mining and Metallurgy of Gold 
 and Silver," Wiley, N. Y.; also treatise on Ore Deposits, p. 534. Rec. 
 C. M. Rolker, " The Late Operations in the Mariposa Estate," M. E., VI. 
 145. B. Silliman, "Notice of a Peculiar Mode of Occurrence of Gold and 
 Silver in the Foothills of the Sierra Nevada, California," Amer. Jour. Sci., 
 ii., XLV. 93; Cal. Acad. Sci., Vol. III., p. 333. H. M. Turner, review of 
 recent papers by H. W. Fairbanks and others on California geology, in 
 Amer. Geol, June, 1893. Rec. J. D. Whitney, Cal. Geol. Survey, Geol- 
 ogy, Vol. I., p. 313. J. S. Wilson, "On the Gold Regions of California," 
 Quar. Jour. Geol. Sci., Vol. X., p. 808, 1854. 
 
 iW. Lindgren, "The Gold Deposit at Pine Hill, Calif.," Amer. 
 Jour. Sci., Aug., 1893, p. 91. 
 
 2 W. F. Hillebrand, ' 'The widespread Occurrence of Barium and 
 Strontium in Rocks," Jour. Amer. Chem. Soc, Feb. , 1894, p. 81. 
 
288 KEMP '3 ORE DEPOHITS. 
 
 phyrite. An analysis by Mr. Hillebrand established the identity 
 of the albite.' T. A. Eickard'' has called attention to the especial 
 richness of gold at the intersection of small quartz veins in Tuol- 
 umne and Calaveras Counties, California, and to the occurrence of 
 a particularly rich pocket in the Rathgeb mine, San Andreas, 
 where a small vein was faulted a few inches, and where the gold 
 was associated with pitch-blende or uranite, and uranium 
 ochre.' 
 
 2.13.17. The recent work of T. A. Rickard,* both descriptive 
 and theoretical, on the remarkable saddle-shaped auriferous quartz 
 deposits of Bendigo (or Sandhurst), Victoria, which are locally 
 called "saddles," has led to an extended and interesting discussion 
 regarding the origin of auriferous quartz, and the source of the 
 gold. All must agree in attributing the origin of the quartz to 
 more or less heated solutions penetrating along fault-cracks, planes 
 of schistosity or bedding planes, but whether the gold comes up 
 from below, or from the adjacent walls, is the old point of differ- 
 ence between the lateral-secretionists and the infiltration-ascen- 
 sionists. Mr. Eickard, in the case in point, attributes it to gold 
 deposited from the ocean in the original marine sediments of the 
 walls, and instances the salts of iodine in sea-water as the original 
 solvent, subsequently the release of iodine contained in the brines 
 which soaked the sediments, and in the fucoids, etc., likewise in 
 the sediments, facilitated the migrations of the gold to the veins. 
 This emphasizing of iodine is somewhat new, and while not to be 
 denied on theoretical grounds, yet the question ultimately becomes 
 the point of difference between the two views noted above. In 
 the discussion of the paper Philip Argall gives a very complete 
 review of the experiments and observations, hitherto recorded, re- 
 garding the chemistry of gold in nature. 
 
 1 Since the above was written Mr. Turner has published the results 
 of his examination of this ore , as weU as many additional important 
 notes on the associates of the gold. (H. W. Turner, "Notes on theGrold 
 Ores of California," Amer. Jour. ScL, June, 1894, p. 467.) Mr. Turner 
 also cites gold in quartz in rhyolite , and gold with, cinnabar. 
 
 ^ T. A. Rickard , ' ' Certain dissimilar Occurrences of Gold-bearing 
 Quartz," Proc. Colo. Sci. Soc, Sept. , 1893, pp. 6-9. 
 
 ' Henry Lewis has given a very complete review of the associates 
 and occurrence of gold in the Mineralogical Magazine, X. , 241, London, 
 1893. 
 
 4 T. A. Rickard, "The Bendigo Gold Field, " Trans. Amer. Inst. Min. 
 Eng., XX., 463, Oct., 1891 ; XXI., 686, 1892. "Origin of the Gkild-bear- 
 
THE PAGIFIG SLOPE. 289 
 
 2.13.18. The stratigraphy of the auriferous strata in the 
 Sierras was briefly referred to above as involving Paleozoic and 
 Mesozoic strata. It would be impossible and undesirable to give 
 in this place any complete bibliography of the subject, but in the 
 papers of Diller,* J. P. Smith^ and Turner', cited below, quite full 
 references are to be found to earlier work. In the atlas sheets of 
 the U. S. Geol. Survey local names are given to the various forma- 
 tions, which are classified on the physical basis as outlined in the 
 introduction (l.Ol.Ol), but as regards geological time, strata have 
 been identified as follows: Pre-Silurian crystalline schists; Silurian 
 quartzite and slate, with included lenses of limestone; Devonian 
 coralline limestone; probably both Lower and Upper Carboniferous 
 argillite, quartzite, mica-schist, and metamorphosed tuffs; various 
 Triassic and Jura-trias sediments more or less metamorphosed; 
 Jurassic slates; Cretaceous (Chico) sandstone; Tertiary and Qua- 
 ternary sandstone, sands, gravels and clays. (See paper of H. W. 
 Turner, cited below, pp. 328-249. Also Diller op. cit.) 
 
 In the auriferous belt, .J. P. Smith has admitted the presence 
 of Silurian, Carboniferous, Triassic and Jurassic strata, but rejects 
 Cretaceous. 
 
 Our knowledge has also increased of late regarding the intru- 
 sions of granite and the relations of the various sedimentary forma- 
 tions to the old basement upon which they were laid down. The 
 work of H. W. Fairbanks, often cited in the text, and that of 
 the U. S. geologists, Becker, Diller, Turner and Lindgren, have 
 been bringing out forcibly the intrusive nature and Mesozoic age 
 of much of the granite of the Sierras and of the Coast Range. 
 Most recently among the Canadians Gr. M. Dawson has traced sim- 
 ilar effects to the north, and A. C. Lawson * from an extended 
 survey of the western coast and search in the literature of Mexico, 
 Central and even South America, forcibly portrays the advance of 
 
 ing Quartz of the Bendigo Reefs, Australia," Idem, Aug., 1893; and 
 discussion of same. 
 
 1 J. S. Diller and Charles Schuchert , ' ' Discovery of Devonian Rocks 
 in Calif.," Amer. Jour. Sci., June, 1894,416. 
 
 2 J. P. Smith, "Age of the Auriferous Slates of the Sierra 'Ne- 
 yaAa," Bull. Geol. Sac. Amer., V., 343,1894. 
 
 » H. W. Turner, "Greological Notes on the Sierra Nevada," Amer. 
 Geol, April and May, 1894, 338-297. 
 
 * A. C. Lawson, ' ' The Cordilleran Mesozoic Revolution, ' ' Journal 
 of Geology,!., 579, 1898. 
 
290 KEMP'S ORE DEPOSITS. 
 
 the great granitic "batholites" (t. e., plutonic masses) toward the 
 surface, the fusing into their magmas of the overlying strata, 
 and the metamorphic effects. All these cannot but be strong fac- 
 tors to consider in connection with the ore bodies, and as time goes 
 on this connection will probably be shown. 
 
 In regard to the other forms of igneous rocks involved in the 
 gold belt and often greatly metamorphosed, we are advancing rap- 
 idly in knowledge. These were referred to earlier under 3.13.13, 
 but in his review of the igneous rocks Mr. Turner {Amer. Geol., 
 May, 1894, pp. 297-316) cites nearly the entire series of plutonic 
 and effusive types. In many instances the more basic members 
 have passed, under the influence of dynamo-metamorphism, into 
 amphibolites and talcose rocks, but in other cases the dikes and 
 sheets are still little if at all changed. Great areas are formed of 
 them or involve them, and lead to the inference that they have not 
 been without their influence in stimulating ore-bearing circulations. 
 
CHAPTER XIII. 
 
 GOLD ELSEWHERE IN THE UNITED STATES AND IN CANADA. 
 
 2.13.01. Example 45a!. Southern States. (1) Gold quartz 
 veins (segregated veins) in metamorphic slates, talcose schists, 
 etc., of late Archean or early Paleozoic age, with numerous as- 
 sociated trap (diabase) dikes. (2) Beds of auriferous slates, gneiss, 
 feldspathic and hydromica schists, and even limestone. The 
 general geology of the southern Atlantic States has been outlined 
 in the introduction. Reference may again be made to the Coastal 
 Plain of Quaternary, Tertiary, and ^Mesozoic rocks, and to the 
 Archean strip back of this. In the latter are found the gold de- 
 posits. At times they resemble the Western quartz veins, but they 
 are also extremely diverse in character, and involve almost every 
 sort of rock. Gold has even been found in a trap dike by Genth. 
 It is generally in pyrite, and the rock, where productive, is heavily 
 charged with this mineral. The trajj dikes have also exerted an 
 important influence, and in some localities, as at the Haile mines, 
 South Carolina, the rock is rich only near them. They have 
 probably stimulated the ore-bearing solutions. The belt of aurif- 
 erous rocks begins in Maryland, although gold is known in the 
 States farther north. It runs with varying width into Alabama, 
 where it terminates. It reaches a maximum of VO miles in Korth 
 Carolina. The country rock in these unglaciated regions is often 
 covered to a great depth by the residual clays and other products 
 of its alteration which are as much as 100 feet in places. This 
 substance is sometimes called laterite. Where the original rocks 
 have been auriferous they have furnished loose material for panning 
 and washing, which is essentially different from the Western 
 placers. It gradually works down hill, and has been called by 
 Kerr "frost drift." The ores of the Southern States are gen- 
 
292 KEMP'S ORE DEPOSITS. 
 
 erally low grade, and need careful management to be made profit- 
 able.^ 
 
 2.13.03. Example 455. In the fundamental complex (3.C3.17) 
 north of the iron region at Ishpeming gold occurs at the Ropes mine 
 in reticulations of pyritous quartz and country rock at the contact 
 of a great intrusion of peridotite and greenstone schist. Other lees 
 developed locations are on quartz veins in the schist.^ 
 
 ALASKA. 
 
 2.13.03. Geology. — Our knowledge of the geology of Alaska is 
 very fragmentary, and is chiefly obtained from the reports of ex- 
 ploring expeditions along the coast and up the Yukon River. The 
 Cretaceous and Tertiary rocks of Washington and of British 
 America extend north into the southern portion. Igneous rocks 
 
 1 W. P. Blake, A. Eaton, D. Olmstead, C. U. Shepard, the elder Sllli- 
 man, and others have made many references to gold in the Southern States 
 in the early numbers of the American Journal of Science. H. M. Chance, 
 " Auriferous Gravels of North Carolina," Amer. Philos. Soc., July 15, 1881, 
 p. 477. H. Credner, " Report of Explorations in the Gold Fields of Virginia 
 and North Carolina," Amer. Jour, of Mining, 1868, pp. 361, 877, 398, 407. W. 
 B. Devereux, "Gold and its Associated Minerals at Kings Mountain, North 
 Carolina," Engineering and Mining Journal, Jan. 15, 1881, p. 89. S. F. 
 Emmons, "Notes on the Gold Deposits of Montgomery County, Mary- 
 land," June 11, 1881, p. 397. F. A. Genth, " Contributions to Mineralogy," 
 Amer. Jour. Sci., ii., XXVIII, 246. F. C. Hand, " Southern Gold Fields,'' 
 Engineering and Mining Journal, Dec. 7, 1889, p. 495. G. B. Hanna, 
 " Fineness of Native Gold in the Carolinas and Georgia," Ibid., Sept. 18, 
 1886, p. 201. W. C. Kerr, " Gold Gravels of North Carolina," M. E., VIII. 
 463. " Some Peculiarities in the Occurrence of Gold in North Carolina," 
 M. E., X. 475 ; also Geological Report on North Carolina, 1875. O. M. 
 Lieber, " Ueber das Gold-vorkommen in North Carolina," Gangstudien, 
 Vol. III., p. 353. Lieber states that Whitney's Metallic Wealth was writ- 
 ten to "boom " certain mines ! " Gold in South Carolina," Oangstudien, 
 Vol. III., pp. 353, 481. P. H. Mell, " Auriferous Slate Deposits in South- 
 ern Mining Regions," M. E., IX. 399. W. B. Phillips, "The Lower 
 Gold Belt of Alabama," Bull. No. 3, Geol. Survey Ala., 1893. E. G. 
 Spillsbury, " Gold Mining in South Carolina," J/. E., XII. 99; Engineer- 
 ing and Mining Journal, June 23, 1883, p. 363. A. Thies and W. B. 
 Phillips, "The Thies Process, etc., at the Haile Mine, South Carolina," 
 M. E., September, 1890. A. Thies and A. Mezger, " Geology of the Haile 
 Mine," M. E., September, 1890. 
 
 ^ C. D. Lawton, Rep. Mich. Com. of Mineral Statistics, 1887, p. 167. 
 "The New Michigan Gold Field," Engineering and Mining Journal, Sept. 
 22, 1888, p. 338. M. E. Wadsworth, Am. Rep. Mich. State Geologist, is- 
 sued January, 1893. 
 
GOLD ELSEWHERE IN UNITED STATES AND CANADA. 293 
 
 often pierce them. Tertiary coals are recorded from several local- 
 ities in the ai-chipelago in the southern part. The Aleutian Isl- 
 ands mark a long stretch of volcanic eruptions. W. H. Dall has 
 given a general section of the banks of the Yukon River from 
 the British boundary to the delta. There are, in rough order from 
 east to west, granite, talcose slates, and Azoic rocks, 150 miles ; 
 sandstone and conglomerate, 250 miles ; shales with one small coal 
 seam, 75 miles ; blue slate, conglomerate, eruptive rocks, slate, 
 eruptive rock, blue slate, and black sandstone, 325 miles ; blue 
 sandstone, slate, trap, blue and black slate, volcanic rock, to the 
 northwest mouth. The interior is largely composed of tundras, or 
 great plains of moss and other plants, frozen into perpetual ice at 
 a depth of a foot or so. These hide the geology. Doubtless the 
 slates of the upper waters have supplied the gold, which is rich in 
 some of the river gravels. On the Aleutian Islands some brown 
 Miocene sandstones are seen (Shumagin), and granite and meta- 
 morphic rocks. ^ 
 
 2.13.04. Example 46. Douglass Island. A dike or boss of 
 granite 400 feet wide, piercing slates regarded as Triassic by G. M. 
 Dawson, and impregnated (i.e., the granite) with auriferous pyrites. 
 This enigmatical ore body is thought by Dawson to be the upper 
 part of a granite dike. It consists in great part of a mass of 
 quartz, feldspar, calcite, and pyrite, in which are buried the so- 
 
 1 " Alaska as a Mining Territory," Engineering and Mining Journal, 
 June 37, 1885, p. 444. "Mineral and Asrricultural Wealth of Alaska," En- 
 gineering and Mining Journal, Aug. 24, 1887, p. 134. T. A. Blakn, Rep. 
 on the Geo), of Alaska, Ex. Doc. No. 177, Fortieth Congress, New Serie.o, 
 p. 314, Washington, 1868. W. H. Dall, "Explorations in Alaska,'' ^mer. 
 Jour. Sci., ii., XLV. 96. Rec. "Notes on Alaska and the Vicinity ot 
 Bering Straits," Ibid., in., XXI. 104. " Notes on Alaska Tertiary Deposits, 
 GeologicalSeotionoftheShumaginIslands,"I6id.,!ii., XXIV. 67. "Alaska 
 and its Resources," Washington, 1870. Rec. "Glaciation in Alaska," 
 Bull. Phil. Soc, Vol. VI., p. 33, Washington, 1884. G. H. Dawson, "Re- 
 port on the Yukon District in 1887," Geol. Survey of Canada, 1887-88, 
 Vol. III., Part B, pp. 14B-18B, 154B-156B. H. W. Elliot, "Our Arctic 
 Provinces," p. 163, New York, 1887. E. J. Glave, "Pioneer Packhorses 
 in Alaska," The Century, September and October, 1892. R. G. McConnell, 
 "Glacial Features of Parts of the Yukon and Mackenzie Basins," Geol. 
 Soc. of Amer., L, p. 540. I. C. Russell, " The Surface Geology of Alaska," 
 Geol. Soo. of Amer., I., p. 99. E. R. Skidniore, "Alaska," Rep. Director 
 of the Mint, 1883, p. 17, and 1884, p. 17. J. Stanley-Brown, "Auriferous 
 Sands at Yakutat Bay, Alaska," Nat. Geog. Mag., Vol. III., 1891. 
 
294 KEMP'S ORE DEPOSITS. 
 
 called kernels, which have been shown by F. D. Adams to be mass- 
 es of less altered granite, almost without pyrite. Both varieties 
 show abundant cataclastic or crushed structure, as an evidence of 
 having suffei'ed from dynamic movements. Adams concludes that 
 the mass was originally a hornblende granite that has been sub- 
 jected to solfataric action, which has brought in the gold. The 
 gold in itself is in irregular masses in the pyrite. The Treadwell 
 mine, located here, is very extensive, and the chief source of Alaska 
 bullion.' 
 
 2.13.05. Example 45e. Nova Scotia. The southeastern por- 
 tion of Nova Scotia is composed of Cambrian slates. They stretch 
 from Canso to Yarmouth, and, together with associated granites, 
 cover from 6000 to 7000 square miles. There are two well-marked 
 divisions. The upper, 3000 feet thick, consists of dark pyritous 
 slates, with beds of quartzite and small irregular veins; the lower, 
 8000 feet thick, has quartzites, sandstones, and slates, which in 
 parts contain the veins. The slates are folded along east and 
 west axes. The veins are not large, averaging from 4 to 8 inches, 
 while 20 inches is very exceptional. The gold is both free and 
 associated with the usual sulphides, among them often mispickel. 
 The assays are such that with careful working the mines pay 
 good returns.^ 
 
 1 F. D. Adams, " On the Microscopical Character of the Ore of the 
 Treadwell Mine, Alaska," Amer. Geol., August, 1889, p. 88. G. M. Daw- 
 son, "Notes on the Ore Deposits of the Treadwell Mine, Alaska," Amer. 
 Geol. , August, 1889, p. 84. Mining and Scientific Press, San Francisco, 
 Sept. 27, Oct. 4, 1884. 
 
 2 J. W. Dawson, " On Recent Discoveries of Gold in Nova Scotia," 
 Canadian Naturalist and Oeologist, December, 1861. E. Gilpin, Jr., "The 
 Nova Scotia Gold Mines," M. E., XIV. 674. Eec. H. Y. Hind, "Report 
 on the Mount Uniache, Oldham, and Renfrew Gold Mining District," Hali- 
 fax, 1872 ; Amer. Jour. ScL, iii., IV. 497. D. Honeyman, "On the Geol- 
 ogy of the Gold Fields of Nova Scotia," Quar. Jour. Geol. Sci., Vol. 
 XVIII., p. 842, 1862. T. S. Hunt, "On the Gold Region of Nova Scotia," 
 Can. Geol. Survey, 1868 ; Canadian Naturalist, February, 1868. W. E. 
 Logan, " Notes on the Gold of Eastern Canada," Can. Geol. Survey, 1864. 
 O. C. Marsh, "The Gold of Nova Scotia," Amer. Jour. Sci., ii., XXXH. 
 395. A. Michel and T. S. Hunt, "Report on the Gold Region of Canada," 
 Can. Geol Survey, 1866. H. S. Poole, "The Gold Leads of Nova Scotia," 
 Quar. Jour. Geol. Sci., Vol. XXXVL, p. 307. A. R. C. Selwyn, " On the 
 Gold Fields of Quebec and Nova Scotia," Can. Geol. Survey, 1870-71, pp. 
 252-389. B. Symons, " The Gold Fields of Nova Scotia," Trans. Min. Asso. 
 and Inst. Cornwall, III. 80, 1898. 
 
GOLD ELSEWHERE IN UNITED 8TA TES AND CANADA. 295 
 
 2.13.06. Example 45c?. Gold elsewhere in Canada. At the 
 headwaters of the Chaudi^re River, in eastern Quebec, auriferous 
 gravels have been located, and also quartz veins in the raetaraor- 
 phic rocks. They have been vs^orlfed to a small extent. Gold oc- 
 curs in many places north and west of Lake Superior in the region 
 of the Lake of the Woods. Some small mining has been carried 
 on. An interesting and important vein, carrying auriferous mis- 
 pickel in quartz, occurs in Marmora, Hastings County, just north 
 of Lake Ontario. It is more fully described under " Arsenic," 
 as it is the one American source of that metal. Auriferous gravels 
 occur in British Columbia in not a few places and are being 
 worked. They are also found along the disputed boundary of 
 Alaska, and scattered reports of their existence have reached civ- 
 ilization from the Mackenzie River and the remote Northwest.' 
 
 2.13.07. The following table gives an idea of the relative im- 
 portance of the several States. Full details of the United States 
 and other countries are given in the Annual Reports of the Di- 
 rector of the Mint, the Mineral Mesources of the United States 
 Geological Survey, and the annual statistical number of the En- 
 gineering and Mining Journal. 
 
 1881. 1890. 
 
 Snvur. Gold. Silver. Gold. 
 
 Alaska $15,000 . $9,697 $763,500 
 
 Arizona $7,800,000 1,060,000 1,293,929 1,000,000 
 
 California 750,000 18,300,000 1,168,636 13,500,000 
 
 Colorado 17,160,000 3,300,000 34,307,070 4,150,000 
 
 Dakota 70,000 4,000,000 139.393 8,200,000 
 
 Georgia 125,000 517 100,000 
 
 Idaho 1,300,000 1,700,000 4,788,888 1,850,000 
 
 * " Descriptive Catalogue of ihe Economic Minerals of Canada at the 
 Colonial and Indian Exhibition," London, 1886, p. 54. " The Marmora 
 Gold Mine," Engineering and Mining Journal, Oct. 23, 1880, p. 366. R. 
 Bell, "Mineral Resources of the Hudson Bay Territories," M. E., Febru- 
 ary, 1886. E. Coste, "Report on the Gold Mines of the Lake of the Woods," 
 Rep. Prog. Can. Survey, 1883-84, K, 3-32. W. M. Courtis, "Animikie 
 Rocks and their Vein Phenomena as shown at the Duncan Mine, Lake Su- 
 perior," M. E., XV. 671. R. W. Ells, " Mining Industries of Eastern Que- 
 bec," M. E., October, 1889. T. S. Hunt, "On Gold in the Laurentian 
 Rocks of Canada,'' A. A. A. S., XVIIth meeting. A. Michel and T. S. 
 Hunt, "Report on the Gold Regions of Canada," Can. Oeol. Survey, 1866- 
 68. R. P. Roth well, "The Gold-bearing Mispickel Vein of Marmora, On- 
 tario," M. E., IX. 409. A. Blue, "The Gk)ld-mining Industry in 
 Canada in 1893," Engineering and Mining Journal, June 16, 1894, p. 558. 
 
296 KEMP'S ORE DEPOSITS. 
 
 1881. 1890. 
 
 Silver. Gold, Silver. Gold. 
 
 Montana $3,630,000 $3,330,000 |30,363,686 $3,300,000 
 
 Nevada 7,060,000 3,250,000 5,753,535 2,800,000 
 
 New Mexico 375,000 185,000 1,680,808 850,000 
 
 North Carolina 115,000 7,757 118,500 
 
 Oregon 50,000 1,100,000 96,969 1,100,000 
 
 South Carolina 35,000 517 100,000 
 
 Utah 6,400,000 145,000 9,050,505 680,000 
 
 Washington 120,000 90,505 204,000 
 
 Other States 5,000 20,000 461,574 130,000 
 
 Total $43,000,000 $34,700,000 $70,485,714 $82,845,000 
 
 A glance at the table will indicate where the heaviest pro- 
 ducers and most important districts are situated. In the next few 
 years a heavy falling off in silver and a relative increase in gold 
 seems inevitable. 
 
CHAPTEE XIV. 
 
 THE LESSER METALS: ALUMINIUM, ANTIMONY, ARSENIC, 
 BISMUTH, CHROMIUM, MANGANESE. 
 
 ALUMINIUM. 
 2.14.01. The importance of aluminium grows with improved 
 and cheaper methods of production. Its sources are, or have been, 
 alums, either natural or artificial, corundum, cryolite, kaolin and 
 bauxite. The first of these is formed in nature by the decay of 
 pyrite in shales and slates, and is little if at all used as an ore at 
 present. The second is more valuable as an abrasive, and with the 
 fall in the price of the metal has given way to other and cheaper 
 ores. Still corundum (AljOj) with 53.3 Al, is the richest natural 
 mineral. Cryolite and bauxite are now the staple ores, but in the 
 Grabau process kaolin is employed, although not as yet in any such 
 amount as these other two. The fused cryolite plays the r61e of a 
 bath in which the alumina is dissolved and reduced by electrolysis, 
 so that really bauxite has come to be the principal source. Cryo- 
 lite occurs as an immense bedded deposit in gneiss at Evigtok, on 
 the Arksut Fjord, Greenland. It is mined as an open cut, and 
 being near the water's edge, on a steep cliff, after hand-picking, it 
 is loaded directly upon vessels, which moor to the cliff. The cryo- 
 lite is associated with various related minerals, all rare and mostly 
 limited to this locality, with sulphides of iron, copper and lead, 
 and with siderite. The Pennsylvania Salt Co., of Natrona, Pa., 
 receive by contract two-thirds of the output, the remaining third 
 going to Denmark. The other localities of this mineral at Miask, 
 in the Urals, and near Pike's Peak, Colo., are small and commer- 
 cially unimportant pockets. Cryolite when pure contains 13.02 Al, 
 and of itself is tlius a very low grade ore.' 
 
 1 On the geology of Greenland Cryolite see G. Hagennann, ' ' On 
 some Minerals associated with the Cryolite in Greenland," Ainer. Jour. 
 ScL, ii., XLIL, 93. C. Hart, "On the Cryolite Deposit, " Joaninl of 
 Analytical aad Applied Chemistry, Oct., 1893. G. Lunge, in the treatise 
 entitled ' ' The Manufacture of Sulphuric Acid and Alkali. ' ' J. W. Tay- 
 lor, " Cryolite of Evigtok, " Quar. Jonr. Geol. Sac, XII., 140. See also 
 the ' ' Mineral Industry, ' ' Vols. I. and II. , and a pamphlet published by 
 the Pennsylvania Salt Manufacturing Co. 
 
298 KEMP'S OBE DEPOSITS. 
 
 Bauxite (AI2O3, SH^O) is now the main source of the metal. In 
 the pure condition and of the composition given above it contains 
 AI2O3, 65.55, or Al, 34.94, but various impurities are always with 
 it, of which the commonest are silica, oxide of iron, oxide of man- 
 ganese, carbonates of lime and magnesia, phosphoric acid, and, in 
 the Southern States, small but constant amounts of titanic acid. 
 The merchantable ore ranges from about 40 to over 60^, or even 
 over 70^ AI2O3, but any analysis over 65.55^ AI2O3 indicates a 
 mineral of diflerent composition from AljOs SH^O. There is no 
 doubt that such exist, and in an interesting paper entitled "The 
 Bauxites; A Study of a new Mineralogical Family," M. Francis 
 Laur^ has advocated that there is a whole series of hydrated com- 
 pounds of alumina belonging here, as complex, perhaps, as the 
 anhydrous compounds of this metal. Bauxite is now known to 
 occur in economic quantities in Georgia and Alabama, and in 
 Arkansas. It has been mentioned, however, from numerous other 
 points in States immediately north of these two. The deposits in 
 Georgia and Alabama^ occur along a narrow belt in the Coosa 
 Valley, extending some sixty miles from Adairsville, Ga., to Jack- 
 sonville, Ala. The mineral itself is pisolitic or oolitic in structure, 
 as a general thing, and the individual masses are often in concentric 
 layers, and are held together either by non-oolitic bauxite or by 
 silica. Less often the ore is more massive, and may be in fairly 
 hard lumps or soft and earthy. The surface ore is often pitted and 
 cellular. The general geological relations will be best understood 
 by referring to Figure 4, p. 18. The region is largely formed by 
 Cambrian strata, of which the Connasauga shales are the upper 
 member, and the Eome sandstone, or Weissner qnartzite, is the 
 lower. Above the Cambrian is found the Silurian Knox dolomite, 
 rich in chert. These strata are broken by folds and faults of sev- 
 eral series and formed at different periods. The great overthrust 
 
 ' Trans. Amer. Inst. Min. Eng., Feb., 1894. 
 
 2 C. W. Hayes, ' ' Greologioal Eelations of the Southern Appalachian 
 Batixite Deposits, " Trans. Amer. Inst. Mir).. Eng., Feb., 1894. Reo. 
 H. McCalley, "Alabama Bauxite," Proc. Ala. Indust. and Sci. Soc, 
 1893. "Ba-axite'' in "The 3Iineral Industry," U., 57, 18H. Bee. Also 
 in a forthcoming report of the Ala. Gteol. Sxirvey. E. Nichols, ' ' An 
 Almninimn Ore : Bauxite," Trans. Amer. Inst. Min. Eng., XVI., 905. 
 R. L. Packard, "Altmiinium., " Mineral Resources, 1891, 147. J. W. 
 Spencer, ' ' Greology and Resources of Ten Counties in N. W. Gieorgia, ' ' 
 p. 310, 1893. Rec. 
 
THE LESSER METALS. 
 
 399 
 
 shown in Pig. 4. is of post-Carboniferous time, long after the prin- 
 cipal Appalachian upheaval. 0. W. Hayes has shown that the ore 
 bodies lie along certain of these fault lines, and the association 
 gives us a possible clue to their method of deposition. The ores 
 are always found in the residual alteration products of the Knox 
 dolomite, from which, however, they are quite sharply separable. 
 The accompanying cross-section shows the relations. While more 
 or less irregular in shape they have proved quite persistent, and 
 many years' supply is now in sight. Mr. Hayes suggests that the 
 crushing attendant on the faulting developed great heat, and that 
 atmospheric waters penetrating along these zones became charged 
 with sulphuric acid, derived from decomposing pyrite. The acid 
 would dissolve alumina from the Connasauga shales, possibly form- 
 
 \ DRAINAnF n-Tfu • \^^-, 
 
 Fig. 77. — Cross-section of a Bauxite deposit in Georgia. After C. 
 Willard Hayes, Trans. Amer. Inst. Min. Eng., Feb., 1894. 
 
 ing alums, with some alkali. Calcium carbonate would react on 
 such solutions so as to precipitate hydrate of alumina, and this ris- 
 ing as a flocculent precipitate in springs gave rise to the oolitic 
 and pisolitic deposits, which were afterward, in the decay of the 
 Knox dolomite, involved in its residual products. The explana- 
 tion is reasonable and has great claims to confidence. The same 
 may be applied to the neighboring limonites. 
 
 The deposits in Arkansas have been less fully described as yet. 
 They occur near Little Eock, in Pulaski County, and near Benton, 
 in Saline County, and aggregate about one square mile. The ore is 
 pisolitic, and is interbedded in Tertiary sandstone, but it is only 
 found in the vicinity of intruded syenites. At times the bauxite 
 is high in iron. J. F. Williams rather favored a method of origin 
 from hot springs, regarding this as more tenable than that the ores 
 were derived from the superficial decay of the -syenite. In this re- 
 spect C. W. Hayes is in accord with him. The Arkansas deposits 
 
300 KEMP 'S ORE DEPOSITS. 
 
 have not shipped as much as those in tlie South, owing doubtless 
 to their more remote situation.' Bauxite is employed for many 
 other purposes besides furnishing an ore of aluminium, as this is 
 one of its later adaptations. Great quantities are used to produce 
 alums, and as a refractory material it has long been appreciated. 
 
 In the earlier development of the aluminium industry corun- 
 dum was somewhat sought as an ore. The varieties with vitreous 
 luster and light colors are called sapphire, the duller and more 
 smoky ones, corundum, while the impure kinds, which are mixed 
 more or less with magnetite, hematite, spinel, etc., pass under the 
 name of emery. The last named is of no importance in this con- 
 nection. Some sapphire and corundum have been obtained in 
 Chester County, Penn., but, practically the only source of any mo- 
 ment is in a belt of a curious rock called dunite, which consists of 
 grains of olivine, and which traverses western North Carolina and 
 Georgia. The corundum occurs along the contacts of the dunite 
 and a hornblende gneiss with which it is associated. It lies in 
 scattered lumps distributed through decomposed micaceous mate- 
 rial which is at times so soft as to be washed out in the hydraulic 
 way. The mineral appears to have resulted from some reactionary 
 effects of the two rocks, or of solutions emanating from them, on 
 each other. The gneiss is aluminous, the dunite magnesian.^ 
 
 1 J. C. Branner, "Bauxite in Arkansas," Airier . Oeol., VII., 181, 
 1891. An extended report was annoxmced for Vol. I., 1889, of Dr. 
 Branner's Annual Reports as State Greologist of Arkansas, but it has not 
 yet (1894) been issued. J. Francis Williams, Ann. Rep. Oeol. Siirv. 
 Ark., 1880, II., 134. 
 
 2 T. M. Chatard, Mineral Resources, U. S. Geol. Sun:, 1883-84, 714. 
 Rec. ' ' The Gneiss-Dunyte Contacts of Corundum Hill, N. C. , " etc. , 
 Bull. U. S. Geol. Surv., XLII. 45, 1881. Rec. Short abstract in the 
 Eng. and Min. Journal, July 31, 1888, p. 46. J. P. Cooke, Proc. Amer. 
 Acad., IX. 48, 1874. F. A. Genth, "Corundum, Its Alterations and 
 Associated Minerals, " Amer. Phil. Soc, Sept. 19, 1873; July 17, 1874; 
 Amer. Jour. Sci., iii., VI. 461, 1873. T. S. Hunt, Trans. Roy. Soc. 
 Canada, U. 1884. C. W. Jenks, Quar. Jour. Geol. Soc, XXX. 303, 
 1874. A. A. Julien, Proe. Post. Soc. Xat. Hist, XXH. 131, 1893. W. C. 
 Kerr, ' ' Geol. of North Carolina, Supplement, ' ' 64, 1875. R. W. Ray- 
 mond, "Jenks' Corundum Mine, N. C," Trans. Amer. Inst. Min. Eng., 
 VII., 88, 1878. C. U. Shepard, "On the Corundum Region of N. C. 
 and Ga. , " Amer. Jour. Sci. , iii. , IV. 109, 175, 1873. Rec. C. D. Smith, 
 "Geol. N. C. I., Appendix D.," 91, 1875, II. 43, 1881. J. L. Smith, 
 "Notes on the Corundum of N. C. , Ga. ," etc., Amer. Jour. Set., iii., 
 VI., 180, 1873. Rec. M. E. Wadsworth, Mem. Mm. Comp. ZooL, XL 
 Part I., p. 118, 1884. 
 
THE LESSER METALS. 301 
 
 ANTIMONY. 
 Senarmontite, SbjOj ; Sb. 83.56 ; 0.16.44. 
 
 StibnitG (Antimonite, Antimony Glance), SbjSj ; Sb. Vl.8 ; 
 S. 28.2. 
 
 2.14.02. Antimony occurs in composition with several silver 
 ores, but almost its sole commercial source is stibnite. The oxide, 
 senarmontite, is rarely abundant enough to be an ore. Stibnite was 
 one of the minerals formerly cited as having originated in veins by 
 volatilization from lower sources. But it has probably, in all cases, 
 been derived from solutions of alkaline sulphides. 
 
 2.14.03. Example 47. Veins containing stibnite, usually in 
 quartz gangue. California, Kern County. At San Emigdio a vein 
 of workable size has been found. It has a quartz gangue and is in 
 granite. The vein varies from a few inches to several feet across, 
 and has afforded some metal. Several others are known in San 
 Benito and Inyo counties. 
 
 2.14.04. Nevada, Humboldt County. Stibnite has been known 
 for some years in veins with quartz gangue. The Thies-Hutchens 
 mines, about 15 miles from Lovelock station, were productive in 
 1891. Lander County. The most important of the American 
 mines are the Beulah and Genesee, at Big Creek, near Austin. 
 The vein is reported as showing three feet of nearly pure stibnite. 
 It produced 700 tons of sulphide in 1891, and was operated in 
 1892. 
 
 2.14.05. Arkansas, Sevier County. Stibnite occurs in veins 
 with quartz gangue in southwestern Arkansas. Some attempts 
 have been made to develop them, but the ore is rei^orted to be too 
 remote for profitable working. The veins appear to be generally 
 interbedded in Trenton shales and to lie along anticlinal axes, 
 which trend northeast. They are all controlled by the United 
 Slates Antimony Company of Philadelphia. 
 
 2.14.06. New Brunswick, York County. Veins of quartz or 
 quartz and calcite, carrying stibnite, occur over several square miles. 
 The wall rocks are clay slates and sandstones of Cambro-Silurian 
 age. The mines have been commercially productive. The veins 
 vary from a few inches to six feet. 
 
 2.14.07. Example 48. Utah, Iron County. Disseminations of 
 stibnite in sandstone and conglomerate, following the stratification. 
 In Iron County, southwestern Utah, masses of radiating needles 
 occur in sandstones and between the boulders of an associated 
 conglomerate. Very large individual pieces have been obtained. 
 
303 KEMP'S ORE DEPOSITS. 
 
 but not enough for profitable mining. Blake thinks that the ore 
 has crystallized from descending solutions. Eruptive rocks are 
 present above the sandstones. 
 
 2.14.08. An interesting deposit of senarmontite was worked 
 for a time in Sonera, just south of the Arizona line, but it was 
 soon exhausted.' 
 
 ARSENIC. 
 
 2.14.09. This metal occurs with many silver ores in the West 
 and in arsenopyrite, or mispickel, a not uncommon arseno-sulphide 
 in the gold quartz veins, east and west. At the Gatling mines, in 
 the town of Marmora (more lately called Deloro), in Hastings 
 County, Ontario, auriferous mispickel occurs in great quantity in 
 granite, in veins with quartz gangue. Considerable oxide of arsenic 
 has been obtained in the past from the roasters, but for five years 
 or more the mines have not been productive. For reference to the 
 printed descriptions see under "Gold in Canada" (2.13.0'7). 
 
 BISMUTH. 
 
 2.14.10. Bismuth occurs with certain silver ores in the San 
 Juan district, Colorado, and is referred to in describing the country 
 under "Silver and Gold" (2.09.10). Lane's mine, at Monroe, 
 Conn., has furnished museum specimens of native bismuth in 
 quartz. Some neighboring parts of Connecticut have afforded 
 
 * General references: W. P. Blake, "General Distribution of Ores 
 of Antimony," Mineral Resources of the U. S., 1883-84, p. 641. Arkan- 
 sas : T. B. Comstock, Geological Survey of Arkansas, 1888, I., p. 136. 
 F. P. Dunnington, " Minerals of a Deposit of Antimony Ores in Sevier 
 County, Arkansas," A. A. A. S., 1877. Rec. J. W. Mallet, Chemical 
 News, No. 533. C. E. Waite, " Antimony Deposits of Arkansas," M. E., 
 VII. 43. C. P. Williams, " Notes on the Occurrence of Antimony in Ar- 
 kansas," M. E., III. 150. California : W. P. Blake, "Kera County," U. 8. 
 Pac. R. R. Explorations and Survey, Vol. V., p. 391. H. G. Hanks, Rep. 
 Cal. State Mineralogist, 1884. See also subsequent reports by William 
 Irelau, Jr. Mexico : E. T. Cox, " Discovery of Oxide of Antimony in So- 
 nora," Amer. Jour. Sci., XX. 431. J. Douglass, "The Antimony Deposit of 
 Sonora," Engineering and Mining Journal, May 21, 1881, p. 850. Nevada: 
 Engineering and Mining Journal, 1892, p. 6. New Brunswick : L. W. 
 Bailej', " Discovery of Stibnite in New Brunswick," Amer. Jour. Sci., ii., 
 XXXV. 150, and in Rep. on the Geol. of Neiv Brunswick, 1865 ; also H, Y. 
 Hind, in the same. Utah : D. B. Huntley, Tenth Census, Vol. XIII., 
 p. 463. 
 
THE LESSER METALS. 303 
 
 bismuth minerals, and not a few other places in the country con- 
 tain traces, but the San Juan is the only serious one as yet.^ 
 
 CHROMIUM. 
 
 2.14.11. Chromite, whose theoretical composition is FeO.CraOj, 
 with CrjOj 68^, often has MgO and FejOj replacing its normal 
 oxides. The percentage of CrjO, is thus reduced. It is always 
 found in association with serpentine, which has resulted from the 
 alteration of basic rocks consisting of olivine, hornblende, and 
 pyroxene. These minerals contain the chromic oxide probably as 
 a base in their fresh condition, but lose it on alteration. A chrome 
 spinel, picotite, which is an original mineral in these rocks, likewise 
 affords it. The chromite is scattered through the serpentine, often 
 forming masses of large size. Traces of nickel minerals are fre- 
 quently noted associated with the chromite. 
 
 2.14.12. Example 49. Disseminations of chromite in serpen- 
 tine. Pennsylvania and Maryland. Great areas of this rock are 
 found in southeastern Pennsylvania and in the adjacent parts of 
 Delaware and Maryland. Considerable mining has been done in 
 the past. Woods mine, in Lancaster County, Pennsylvania, has 
 furnished great quantities, and other large producers are situated 
 in the Bare Hills, near Baltimore. This section is now no longer 
 commercially productive. Chromite has also been announced 
 from several places in the South, no one of which has yet sent 
 notable quantities to the market. 
 
 2.14.13. California. As already mentioned under the precious 
 metals, great areas of serpentine occur on the western flanks of 
 the Sierras and in the Coast range. In Del Norte, San Luis Obis- 
 po, Placer, and Shasta counties, California, they furnish commer- 
 cial amounts of chromite. In some places the ore is followed by 
 underground mining, and in others it is gathered as float material. 
 The irregular distribution, always characteristic of the mineral, 
 renders underground work uncertain. Good ore should afford 50^ 
 CrjOj, and in California no ore less than Al% is accepted. It 
 brings in the East |22 to $35 per ton. Considerable quantities 
 are imported.^ 
 
 1 Mineral Resources of the U. S., 1885, p. 899. B. Silliman, " Bismuth- 
 inite from the Granite District, Utah," Amer. Jour. Sci., iii., VI. 133. 
 H. L. Wells, " BismuthosphcErite from Willimantic and Portland, Conn ," 
 Amer. Jour. Sci., iii., XXXIV. 371. 
 
 * F. D. Chester, A7in. Rex). Penn. Survey, 1887, p. 93, describes the 
 
304 KEMPS ORE DEPOSITS. 
 
 COBALT (SEE UNDEE "Nickel"). 
 MANGANESE. 
 
 2.14.14. Ores: Pyrolusite MnOj, Mn. 63.2, braunite, Mn.jOs, 
 Mn 69.68. Some SiOj, which may be chemically combined, is 
 usually present, and small amounts of MgO, CaO, etc. Psilome- 
 lane has no definite composition, but usually contains barium or 
 other impurities. An Arkansas variety has afforded Brackett 
 MnO, 77.85. 
 
 There are various other oxides and hydroxides, which are rare- 
 ly abundant enough to be ores. The carbonate, rhodochrosite, 
 and the silicate, rhodonite, are rather common gangue minerals 
 with ores of the precious metals. Franklinite is also an impoi'tant 
 source (2.07.04). Pyrolusite and psilomelane are the commonest 
 ores the country over, but braunite is the one in the Batesville 
 (Ark.) region. Manganese is widely distributed, and yet is com- 
 mercially important in but few localities. It imitates limonite 
 very closely in its occurrence and is often associated with this ore 
 of iron. To make a manganese ore valuable, at least 40^ metallic 
 manganese should be present, and this is a lower limit than was 
 formerly admissible when the ores were chiefly used in chemical 
 manufactures. Under present conditions, if iron is present, the 
 ore may be suited to spiegel, although even lower in manganese 
 than 40^. Further, there should be low phosphorus ; Penrose 
 says not over 0.2 to 0.25^ in Arkansas, and not over 12^ SiOj. 
 High-grade ores run 50 to 60^ manganese. 
 
 2.14.15. Example 50. Manganese ores, chiefly psilomelane 
 
 serpentine along the State line near Delaware. B. T. Day, Mineral Re- 
 sources of the U. S., 1882, p. 428 ; 1883-84, p. 567 (Eec.) ; 1885, p. 357 ; 1886, 
 p. 176 ; 1887, p. 132. J. Eyerman, " On "Woods Mine, Pennsylvania," Min- 
 eralogy of Penn., Easton, 1889. P. Fraser, "The Northern Serpentine 
 Belt in Chester County, Pennsylvania," M. E., XII. 349. Rep. C3 (Lan- 
 caster County), Penn. Geol. Survey. T. H. Garrett, "Chemical Examina- 
 tion of Minerals associated with Serpentine," Amer. Jour. Sci., ii., XIII. 
 45, and XV. 332. Also F. A. Genth, Amer. Jour. Sci., ii., XLI. 120. E. 
 Goldsmith , " Chromite from Monterey County, California ," Phil. Acad. Sci., 
 1873, p. 365. William Irelan, Jr., Reps. Cal. State Mineralogist, especially 
 1890, pp. 167, 189, 313, 582, 583, 638. G. H. Williams, "The Gabbros and 
 Associated Hornblende Rocks near Baltimore," Bull. 23, U. S. Geol. Sur- 
 vey, pp. 50-59. " The Geology of the Crystalline Rocks near Baltimore," 
 distributed at the Baltimore meeting of the Institute of Mining Engineers, 
 February, 1892. Rec. 
 
THE LESSER METALS. 
 
 305 
 
 and pyrolusite, often in concretionaiy masses, disseminated through 
 residual clay, which with the ores has formed by the alteration of 
 limestones and shales. The deposits are entirely analogous to 
 Examples 2 and 2a, under "Iron." Along the Appalachians 
 the favorite horizon is just over the Cambrian (Potsdam) quartzite. 
 Such is the case at Brandon and South Wallingford, Yt., where 
 the ores occur in a great bed of clay between quartzite and lime- 
 stone. They are referred to under Example 2a, where mention is 
 made of the associated limonites and interesting lignite. They 
 have never been important producers of manganese. Crimora, in 
 
 SECTION NO 
 
 SECTrON NO. ». 
 
 Fig. 78. — Sections of the Crimora manganese mine, Virginia. The trough 
 
 is formed by Potsdam sandstone and is filled with clay carrying 
 
 nodules of ore. After C. E. Hall, M. E., June, 1891. 
 
 Augusta County, Virginia, is the largest mine in the country. The 
 containing clay bed is very thick, as a drill hole of 276 feet failed 
 to strike rook. The ores occur in pockets, which as a maximum 
 are .5 to 6 feet thick and 20 to 30 feet long, and of lenticular 
 sliape. Other irregular stringers and smaller masses run through 
 the clay, which preserves the structure of the original rock. 
 Potsdam quartzite underlies it. Other similar bodies occur at 
 Lyndhurst and elsewhere in the Great Valley of Virginia, but 
 Crimora is now no longer a source of ore. Cartersville, Ga., 
 is second to Crimora in production. The ores again occur in 
 pockets in a stifp clay and are associated with quartzite, which is 
 not sharply identified as yet. It may be Cambrian (Potsdam) or 
 Upper Silurian (Medina). West of Cartersville is the Cave Spring 
 
IDEAL Sections showing the formation of manganese-BEARing 
 CLAY FROM THE DECAY OF THE ST.CLAIR LIMESTONE. 
 
 ^BOONE Chert ^^ MANGANESE-BeARlNfi CLAY I LIlZARO LIMESTONE 
 
 3 St. Clair limestone 
 
 l^Saccharoioal Sandstone 
 
 Fig. 1.— Obiqinal Condition of the Socks. 
 
 Fig. 2.— First Stage op Deoosiposition. 
 
 Fig. 3.— Second Stage of Decomposition'. 
 
 
 Fig. 4, — Third Stage of Decomposition. 
 
 Fig. 79. — Geological sections illustrating the formation of the manganese 
 ores in Arkansas. After R. A. F. Penrose, Oeol. Survey of Ark., 
 1890, Vol. I., p. 177. 264 
 
THE LESSER METALS. 
 
 3or 
 
 region, where the ores occur with Lower Silurian cherts. There 
 are numerous other localities not yet of commercial importance 
 along the Appalachians, in Tennessee and elsewhere. Full de- 
 scriptions will be found in Penrose's report, cited below. 
 
 2.14.16. Batesville, Ark. The ore is braunite, and is found in 
 masses disseminated in a residual clay left by the alteration of a 
 
 Fig. 80.— The Turner mine, Batesville region, Arkansas. After B, A, F, 
 Penrose, Geol. Survey Ark,, 1890, Vol. L,p. 372. 
 
 limestone locally called the St. Clair. It is of geologic age be- 
 tween the Trenton and Niagara periods, and is underlain by 
 another limestone called the Izard, which is later than the Calcif- 
 erous. On the St. Clair a series of cherts called the Boone cherts 
 is found, which is of Subcarboniferous (Mississippian) age. The 
 clays are sometimes in valleys, sometimes on hillsides, according 
 to the unequal decay of the limestone. South of the Bates- 
 ville district are the Boston Mountains, a range of low hills 500 
 
308 KEMPS ORE DEPOSITS. 
 
 feet high, and from these the manganiferous rocks form a low 
 monocline to the north. This district is in northern central Ar- 
 kansas. Southwestern Arkansas contains a second district in 
 which the ore occui's in a great stratum of novaculite of probable 
 Lower Silurian age. The ores are of no practical importance, 
 being too lean and too disseminated. Small amounts of manga- 
 nese ore have been obtained in California, in San Joaquin County, 
 and from Red Rock, in San Francisco harbor. The former, and 
 perhaps others in the State, may prove important hereafter. 
 
 2. 14.17. Quite productive deposits are found in pockets at 
 Markhamville, Kings County, N. B., in Lower Carboniferous lime- 
 stone. Some thousands of tons have been shipped. Other mines 
 are situated at Quaco Head. At Tenny Cape, in the Bay of Mi- 
 nas, Xova Scotia, is another deposit in Lower Carboniferous lime- 
 stone which has furnished several thousand tons of ore. Others 
 less important occur on Cape Breton. 
 
 The production of manganese ores in the United States seems 
 to be falling off. In 188V it reached its maximum, 34,524 long 
 tons. In 1889 it was 23,927 tons, divided as follows : The Vir- 
 ginias, 14,616; Arkansas, 2528; Georgia, 5208; other States, 1575.^ 
 
 ^ "Manganese Mines near Santiago, Cuba," Engineering and Mining 
 Journal, Nov. 24, 1888, p. 439. H. P. Brumell, "Notes on Manganese in 
 Canada," Amer. Geol., August, 1892, p. 80. D. T. Day, Mineral Resources, 
 1882, p. 424; 1883-84, p. 550. F. P. Dunnington, "Oa the Formation of 
 the Deposits of Oxides of Manganese," Amer. Jour. Sci., in., XXXVI. 175. 
 Rec. W. M. Fontaine, "Crimora Manganese Deposits,'' The Virginias, 
 Mirch, 1883, pp. 44-46. Rec. C. E. Hall, "Geological Notes on the Man- 
 ganeseOre Deposits of Crimora, Va.," M. E., June, 1891. E. Halse, " Notes 
 on the Occurrence of Manganese Ore, near Mulege, Baja California, Mex- 
 ico," Trans. N. of Eng. Min. and Mech. Eng., XLI. 302, 1892. H. Hoy, 
 "Ores of Manganese and their Uses," Proc. and Trans. N. S. Inst. Nat. 
 Sci., Halifax, 11., 1864-65, p. 139. " Manganese Mining in Merionethshire, 
 England," Engineering and Mining Journal, Deo. 18, 1886, p. 438. R. A. 
 F. Penrose, Ann. Rep. Ark. Oeol. Survey, 1890, Vol. 1. The best work 
 published. Rec. " Origin of the Manganese Ores ot Northern Arkansas," 
 etc., A. A. A. S., XXXIX. 250. J. D. Weeks, Mineral Resources of the 
 U. S., 1885, p. 303 (Rec) ; 1886, p. 180; 1887, p. 144. D. A. Wells, "On 
 the Distribution of Manganese," A. A. A. S., VI. 375. C. L.- Whittle, 
 " Genesis of the Manganese Deposits at Quaco, N. B.," Proc. Bost. Soc, 
 Nat. Hist, XXV., p. 253. 
 
 Note. — H. S. "Williams has recently stated on paleontologic evi- 
 dence, that the St. Clair limestone of Penrose represents both Lower and 
 Upper Silurian, with an intermediate (Cason) shale of Clinton-Niagara 
 age, which has yielded the manganese nodules. G. S. A. , Aug. , 1894, 
 
CHAPTER XV. 
 
 THE LESSER METALS, CONTINUED— MERCURY, NICKEL AND 
 COBALT, PLATINUM, TIN. 
 
 MERCURY. 
 
 2.15.01. Ores : Cinnabar, HgS. Hg. 86.2, S. 13.8. Metacin- 
 nabarite is a black sulphide of mercury. Native mercury also 
 occurs. 
 
 Mercury deposits are found in workable quantities in the 
 United States only in California, in Oregon, and in one locality 
 in Nevada. In all cases cinnabar is the principal ore. The Cali- 
 fornia deposits are limited to the Coast range and in their forma- 
 tion seem to have followed great basaltic eruptions of post-Plio- 
 cene age. 
 
 2.15.02. Example 50. New Almaden. Cinnabar with sub- 
 ordinate native mercury, in a gangue of crystallized and chalce- 
 donic quartz, calcite, dolomite, and magnesite, forming a stockwork, 
 or " chambered vein," in shattered metamorphic rocks (pseudo- 
 diabase, pseudo-diorite, serpentine, and sandstone). There are 
 two main fissures, making a sort of V, with a wedge of country 
 rock between. The ore bodies are in the fissures and also in the 
 intervening wedge, and have associated with them much attrition 
 clay. A great dike of rhyolite runs nearly parallel to the fissures, 
 and to this Becker attributes the activity of circulations which 
 filled the vein. New Idria is farther south, high up toward the 
 summit of the Coast range. The ore is deposited in shattered 
 metamorphic rocks of Neocomian (Lower Cretaceous) age, and in 
 overlying Chico beds. The ore is accompanied by bitumen. Ba- 
 salt is abundant ten miles away. North of San Francisco other 
 mines have been opened, among which are the Oat Hill, Great 
 Eastern, and Great Western. The mines are in a region pierced 
 by eruptions of basalt and andesite, which doubtless gave impetus 
 
dlO 
 
 KEMP'S ORE DEPOSITS. 
 
 to the ore-bearing solutions. The ores are deposited in hotli meta- 
 raorphic and unaltered sedimentary rocks. 
 
 2!l5.03. Example 50a. Sulphur Bank. This is in the same 
 general region as the last, but from its peculiar character has been 
 one of the best known of ore deposits. A great flow of basalt has 
 come down to the shores of Clear Lake from the west. Waters 
 charged with alkaline (including ammonia) carbonates, chlorides, 
 borates, and sulphides, and with COj, HaS, SOj, and marsh gas, 
 have circulated through it. Sulphur and sulphuric acid have 
 formed at the surface, and the latter has dissolved the bases of 
 the rock, leaving pure white silica behind. Lower down, cinnabar 
 
 
 
 Fig. 81. — Section of the Great Western cinnabar mine. After G. F. 
 Becker, Monograph XIII,, U, S. Geol. Survey, p. 360. 
 
 is found, both in the basalt and in the underlying sedimentary 
 rocks, with other sulphides and chalcedony. Leconte attributed 
 its precipitation to cold surface waters, charged with sulphuric 
 acid, which trickled down and met the hot alkaline solutions. 
 Becker refers the same to the ammonia set free toward the sur- 
 face by diminished heat and pressure. The California cinnabar 
 deposits have been often, but wrongly, referred to vapors of the 
 sulphide volatilized by internal heat and condensed above. 
 
 2.15.04. Example 50S. Steamboat Springs, Nevada. These 
 springs are in Nevada, only six miles from the Comstock Lode. 
 Granite is the principal rock, while on it lie metamorphic rocks 
 of the Jura-Trias, and much andesite and basalt. The hot springs, 
 coming up through small fissures, deposit chalcedony in some 
 
THE LESSER METALS, CONTINUED. 311 
 
 places, carDonates in others, with cinnabar as well as gold. The 
 following minerals have been noted : " Sulphides of arsenic, anti- 
 mony, sulphides or sulphosalts of silver, lead, copper, and zinc, ox- 
 ide, and possibly sulphide of iron; manganese, nickel and cobalt 
 compounds, and a variety of the earthy minerals " (Becker). Becker 
 thinks the source of the cinnabar is in all classes in the underlying 
 granite, and that it has come up in solution with sodium sulphide, 
 and been precipitated toward the surface by the other compounds 
 in the hot alkaline waters, with which it would remain in solution 
 at greater depths, temperatures, and pressures. The Steamboat 
 Springs are often and properly cited as metalliferous veins in ac- 
 tive process of formation.' 
 
 3.15.05. Gr. F. Becker^ has recently given an admirable review 
 of quicksilver deposits, the world over, their mineralogical asso- 
 ciates and probable methods of origin, and the same subject has 
 been treated by A. Sclirauf.' Becker has tabulated the minerals 
 associated with cinnabar from twenty-eight world-wide localities, 
 and has made it evident that silica, either as quartz or in opaline 
 forms, and calcite, are the common gangue associates. Pyrite or 
 marcasite is almost invariably present, and bitumen is very wlde- 
 
 1 W. P. Blake, " Quicksilver Mine at Almaden, Cal.," Amer. Jour, 
 Sci., ii., XVII. 438. G. F. Becker, "Quicksilver Deposits of the Pacific 
 Slope," Monograph XIIL, V. S. Geol. Survey, Chap. 17. Rec. " On New 
 Almaden," Cal. Geol. Survey, I., p. 68. S. D. Christy, " On the Genesis 
 of Cinnabar Deposits," Amer. Jour. Set., June, 1878, p. 453 ; Engineering 
 and Mining Journal, Aug. 3, 1879, p. 65. D. de Cortazar, "General Re- 
 view of Occurrence, etc., of Mercury," Reps, and Awards Group L, Cen- 
 tennial Exposition, p. 196. William Irelan, Ann. Reps. Cal. State Mineral- 
 ogist. Laur, "On Steamboat Springs," Annales des Mines, 1863, 423. 
 J. Leconte and Rising, "Metalliferous Vein Formation at Sulphur Bank," 
 Amer. Jour. Sci., July, 1882 ; Engineering and Mining Journal, Aug. 26, 
 1882, p. 109. J. Leconte, "On Steamboat Springs," Amer. Jour. Set, 
 June, 1883, p. 424. "Genesis of Metalliferous Veins," Amer. Jour. Sci., 
 July, 1883. J. A. Phillips, "On Sulphur Bank, California," Phil. Mag., 
 1871, p. 401 ; Quar. Jour. Geol. Sci., XXXV., 1879, p. 390. Rolland, An- 
 nales des Mines, XIV., 384, 1878. B. Silliman, "Notes on the New Al- 
 maden Quicksilver Mines," Amer. Jour. Sci., ii., XXXVII. 190. Siveking', 
 B. und H. Zeitung, 1876, p. 45. 
 
 ' Or. F. Becker, ' ' Quicksilver Ore Deposits, with Statistical Tables, ' ' 
 Mineral Resources of the United States, 1892. 
 
 "A. Schrauf, "Aphorismen uber Zinuober, " Zeitschrift fur prak- 
 tische Geologie, Jan., 1894, p. 10. 
 
312 EBJMP'S ORE DEPOSITS. 
 
 spread. Various other antimony, arsenic, silver, lead, copper and 
 zinc minerals, as well as gold, are of somewhat irregular occurrence. 
 Becker reaffirms the previously cited theory of origin, that the 
 cinnabar has come up in solution as a double sulphide with the 
 alkaline sulphides, but lays stress upon the precipitating proper- 
 ties of bituminous substances, which reactions were corroborated by 
 experiment. He favors the view that the cinnabar has saturated 
 porous or decomposed rock, rather than that it has actually replaced 
 it by metasomatic processes. The probable source of the ore in 
 deep-seated and widely-distributed granitic rocks, and especially in 
 such portions as overlie the foci of volcanic activity, is reaffirmed, 
 
 NICKEL AND COBALT. 
 
 2.15.06. These two metals almost always occur together. * Their 
 ores embrace the following general classes: 1. Compounds with 
 arsenic and rarely with antimony, or with arsenic (or antimony) 
 and sulphur; 2. Sulphur compounds, including nickeliferous pyr- 
 rhotite and pyrite; 3. Oxidized ores, mostly hydrated silicates re- 
 lated to serpentine.* Although the number of minerals involving 
 nickel and cobalt is quite large, the ores properly speaking are com- 
 paratively few; nickeliferous pyrrhotite is much the most important, 
 especially as concerns this country, but the oxidized ores may yet 
 prove serious. Only the ores (i. e., minerals commercially impor- 
 tant) are mentioned in the table below, 
 
 Niccolite. . . .NiAs, Ni.43.9 As. 56.1 
 
 MiUerite NiS, Ni. 64. 4 S. 35. 6 
 
 Linnaeite . . . . ( CoNi ) 3S4 Co. 31. 34, Ni. 30. 58, Fe. 3. 37 S. 41. 54 
 Pentlaiidite..(NiFe)S, Ni.34.28 re.30.25 S.33.43 
 
 1 Tlie following general papers on nickel and cobalt axe important : 
 F. D. Adams, ' ' On the Igneous Origin of Certain Ore Deposits, ' ' Gen- 
 eral Mining Assoc. Prov. Quebec, Jan. 12, 1894. P. ArgaU, "Nickel: the 
 Occiirrence, Geological Distribution and Genesis of its Ore Deposits, ' ' 
 Proc. Colo. Sci. Soc, Dec. 4, 1893. W. L. Austin, "Nickel, Historical 
 Sketch," Idem, same date. H. B. v. Foullon, "Ueber einige Niokel- 
 BTZYorkoioiiiejx, " Jahrbuch d. k. k. geol. Reichsanstalt, Vienna, XLII., 
 223, 1893. D. Levat, Annnles des Mines, 1892, Part 3. J. H. L. Vogt, 
 " Nikkelf orkomster og Nikkelproduktion ("Occurrence and production of 
 Nickel"), Norwegian Geol. Surrey, Kristiania, 1892. A resumg in G!er- 
 man accompanies the paper. Sulphidische Ausscheidungen von Nickel- 
 sulphiderzen, etc., Zeitsclirlft fur praktische Geologic, April, 1893, 135. 
 
 ^ This is practically the same grouping that is given by J. H. L. 
 Vogt, Zeitschrift fur praktische Geologic, April, 1893, 135. See also P. 
 Aigall, Proc. Colo. Sci. Soc, Deo. 4, 1894. 
 
THE L38SER METALS, CONTINUED. 313 
 
 Gtenthite 3NiO,3Mg0.38 -.OseHsO Ni.33.6 
 
 Garnierite. . .HjO(Ni,Mg)O.Si02 + Aq.Ni.25.0 
 Zaratite NiCos,2Ni(OH)8 + 4H20 Ni.46.8 
 
 To these nickeliferous pyrrhotite and pyrite should be added, 
 the former being the most important of all. 
 
 Niccolite was reported years ago at Tilt Cove, Newfoundland, 
 in some quantity, but elsewhere has not been found in any serious 
 amount in North America. It also, occurs in some of the western 
 openings of the Sudbury district. Millerite furnished a small 
 portion of the nickel at the Gap Mine, Penn., as noted below. 
 Linnaeite, variety siegenite, occurs in a sandstone bed at Mine la 
 Motte in disseminated octahedra, and although small attempts 
 have been made to utilize it, the amounts are, so far as known, not 
 large enough for success. Pentlandite must be mentioned together 
 with nickeliferous pyrrhotite. It has been somewhat of a question 
 among mineralogists in just what relations the nickel occurs in 
 pyrrhotite; whether replacing the iron in PeiSj, or some other vari- 
 ety of re„Sn_|_i, to the extent of a fraction of one per cent, up to 
 five, or whether there is an isomorphous or distinct nickel or iron- 
 nickel sulphide intermingled with the pyrrhotite. As far back as 
 1843 Scheerer identified pentlandite from southern Norway, and 
 several other minerals, such as polydymite, have been less definitely 
 described. More recently it has been shown that the nickel-rich 
 portions of the pyrrhotitic ores are quite feebly magnetic, aud pro- 
 cesses have even been suggested for concentrating the nickel based 
 on this principle.' Pentlandite is non-magnetic, aud possibly this 
 mineral in very fine disseminations may contribute of its richer 
 percentage of nickel to raise the total of the pyrrhotites as mined. 
 Some nickel, however, always remains in the strongly magnetic 
 residues, so that we are not yet justified in abandoning the earlier 
 view that this metal replaces some of the iron of the pyrrhotite. 
 Pyrrhotite is the chief ore at Sudbury, and was the ore at the Gap 
 Mine, Penn., until the workings were dismantled in 1894. In south- 
 east Missouri, but more especially at Mine la Motte, nickeliferous 
 pyrite accompanies the galena (see 3.05.09) and has furnished a 
 considerable amount as a by-product in tlie metallurgy of lead. 
 Of the oxidized ores it is not easy to speak as regards their indi- 
 
 1 See in this connection D. H. Browne, ' ' On the Sudbury Ores, ' ' 
 Engineering and Mining Journal, Dec. 3, 1893. Rec. S. H. Emmens, 
 "The Constitution of Nickeliferous Pyrrhotite," Jour. Amer. Chem. 
 Sac, XIV., No. 10. 
 
314 EEMP'H ORE DEPOSITS. 
 
 vidual importance. The hydrated silicates are of extremely vari- 
 able composition, and while one or two illustrations of the type are 
 selected for the table, no one of them is yet seriously mined in 
 America. 
 
 2.15.07. Example 16c. (See 2.03.16 and 2.04.03.) Pyrrhotite 
 Beds or Veins.' Lenticular masses of pyrrhotite interbedded in 
 gneisses and schists as described for pyrite. They are known at 
 various places in the East. Openings have been made at Lowell, 
 Mass., Chatham and Torrington, Conn., and on the mountain on 
 the east bank of the Hudson called Anthony's Nose. The last is much 
 the largest of those namedj and though never mined for the nickel 
 which is known to be present, it was utilized as a material for sul- 
 phuric acid fumes during the ten years succeeding 1865. The geo- 
 logical relations give it especial interest. The ore body is entirely 
 analogous to the magnetite lenses, which are not rare in the High- 
 lands of the Hudson. It lies in a light-colored gneiss, conforma- 
 bly to the laminations, and must have attained twenty or thirty 
 feet in thickness. It has been mined down 300 or 400 feet, and 
 apparently for 50 feet or more on the strike. About one hundred 
 yards west is found a basic gneiss, consisting of green hornblende 
 and plagioclase, with a little biotite. The wall rock contains 
 quartz, plagioclase and very subordinate hornblende. In the thin 
 section it appears fully as acidic as a quartz-diorite. 
 
 Much hornblende is associated with the pyrrhotite, and occa- 
 sional lumps of magnetite, with which are found titanite and apa- 
 tite. The ore yielded about 28^ sulphur as used for years in the 
 chemical works, and was especially prized because it contained no 
 trace of arsenic. The geological relations give no reason for re- 
 garding the ore body as a basic segregation of a gabbroitic magma, 
 but quite the contrary.'' Several of the magnetite mines in this 
 region, it may be added, are troubled with pyrrhotite in the ore, 
 but whether it is nickeliferous has not been determined. 
 
 1 H. Credner, "Berg- und Huett. Zeit., 1866," p. 17. Dana's Treat- 
 ise on Mineralogy, 6th edition, under Pyrrhotite gives several analy- 
 ses from Putnam Co. , N. Y. J. F. Kemp has a paper in manuscript on 
 the old mine at Anthony's Nose, which will soon appear. 
 
 2 W. H. Hoffman, ' ' The late Discovery of Large Quantities of Mag- 
 netic and Non-magnetic Pyrites in the Croton Magnetic Iron Mines, 
 N. Y.," Trans. Amer. Inst. Min. Eng., June, 1893. J. C. Smock, 
 Bulletin of N. Y. State Museum, Dunderberg Mine, p. 18, Hobby 
 Opening, p. 24. 
 
THE LBS8EB METALS, CONTINUED . 315 
 
 3.15.08. Example 13a. Sudbury, Ont.; Gap Mine, Penn. 
 Bodies of nickeliferous pyrrhotite and chalcopyrite with very 
 subordinate pyiite, in the outer portions of intrusions of basic igne- 
 ous rocks, which may be metamorphosed to amphibolites. Cobalt 
 is present in less amount than nickel and varies much in its rela- 
 tive proportions. Secondary millerite sometimes forms in cracks, 
 as do quartz, siderite and one or two other minerals, but in variety 
 of species ore-bodies of this type are exceptionally barren. The 
 type is of world-wide distribution, as noted by Vogt, and is well 
 known in Norway, Sweden and one or two other European locali- 
 ties. The number of the Example indicates its genetic parallelism 
 with the titaniferous magnetites of 2.03.11. 
 
 2.15.08. The Gap mine in Lancaster County, in southeastern 
 Pennsylvania* was originally opened for copper in the previous 
 century. The copper enterprises were all failures, and not until in 
 the fifties was the presence of nickel recognized. The mine then 
 became the largest single producer of its day and remained active 
 until 1893, since which time it has been abandoned. As shown in 
 the accompanying map and sections a lenticular outcrop or mass 
 of greenish black rock, about 3000 feet in length and 500 feet as a 
 maximum width, is found in the midst of mica schist, and appar- 
 ently conformable to the laminations. It strikes nearly east and 
 west, and is contracted along the section AA, where it was most 
 productive. It seemed to pinch in somewhat in depth, so far as 
 the workings extended (about 350 feet). The ore was chiefly 
 found at the eastern end of the lense, and was much less abundant 
 where followed to the westward on the south side with a drift, as 
 far as is colored black. Prospect holes still further west proved 
 the presence of the amphibolite, but failed to show ore. A dike of 
 olivine-diabase of the familiar Triassic sort common in southeastern 
 Pennsylvania outcrops about 1500 feet southeast, but it is much 
 later in time than the amphibolite, with which and with the ore it 
 has no apparent connection. The ore is pyrrhotite in far the 
 largest amount, but when cut in thin sections along with the con- 
 
 1 P. Fraser, "Report CCC, " Snd Penn. Geol. Survey. (A geological 
 descriptioa and historical sketch are given, and also an outline map in 
 the accompanying atlas, on which the figure here used is based. The 
 description, however, gives the impression that the ore is miUerite, and 
 hardly mentions pyrrhotite, whereas the miUerite is a comparatively 
 rare mineral. ) Joseph Wharton, ' ' Analysis of the Nickel Ore from the 
 Gap Mine, Lancaster County, Pa.," Proc. Phila. Acad. Sci., 1870, p. 6. 
 
THE LESSER METALS, CONTINUED. 317 
 
 taining amphibolite, it is seen under the microscope that a light 
 yellow mineral, presumably pyrite, is mixed all through the bronze- 
 colored pyrrhotite. The ore is richest near the contact and fades 
 into lean disseminations as this is left. The lense consists in far 
 the largest part of green hornblende of the common variety, quite 
 pale in thin section, and with pleochroism from green to yellow. 
 Many specimens are formed of this and nothing else, except scat- 
 tered grains of pyrrhotite. Others show a little plagioclase, 
 and a few flakes of biotite. Recognizable remains of orthorhom- 
 bic pyroxene and olivine were detected despite the general and 
 thorough metamorphism of the rock. No more accurate name can 
 be given it than amphibolite, although there is little doubt that it 
 originally was a very basic gabbro or pyroxenite. The ore contains 
 considerable secondary millerite, which forms crusts on the cracks 
 of pyrrhotite, and often veins and stringers of quartz traverse it. 
 In vuggs in these, beautiful crystals of vivianite are rarely met. 
 The close parallel that the ore-body affords in its geology to several 
 Norwegian mines figured by Vogt in the Zeitschrift filr prakt. 
 Geologie, April, 1893, Plates V. and VI., is very striking. (See 
 especially Meinkjar Grubenfeld, Pig. 3 of Plate VI.) The views of 
 Vogt on the origin of such ore-bodies by differentiation of a basic 
 igneous magma in cooling, and by concentration of the early crys- 
 tallizations at the contacts, according to Soret's principle, were 
 outlined earlier in the discussion of the table of classification of 
 ore deposits. In a metamorphosed rock, such as the Gap amphib- 
 olite, there is a reasonable ground for regarding the ore as a con- 
 tact deposit due to deposition from solutions, but after seeing the 
 larger less metamorphosed but otherwise closely analogous ore-bodies 
 of the Sudbury district, the writer (J. F. Kemp) sees no escape 
 from the conclusion that they and it are original crystallizations 
 from the igneous magma as much as any other component minerals 
 of the intruded mass.* 
 
 2.15.09. The Sudbury nickel mines are of quite recent develop- 
 ment, as they have not yet (1894) been operated ten years. They 
 are situated forty miles north of Georgian Bay, an arm of Lake 
 Huron, and on the eastern portion of the original Huronian belt. 
 The Laurentian granites and gneisses, which to the east form a 
 
 " Literature on the Gap Mine, W. P. Blake, Mineral Resources, 
 1882, p. 399. J. Eyerman, "Mineralogy of Penn.," P. Fraser, Eep. 
 CCC, Second Penn. Geol. Survey, p. 163. J. Wharton, "Analysis of 
 Nickel Ore from the Gap Mine," Proc. Phila. Acad. Sci., 1870, p. 6. 
 
315 
 
 KEMP'S ORE DEPOSITS. 
 
 vast, monotonous stretch of low glaciated hillocks and swamps, ai-e 
 covered near Sudbury, and for a himdi-ed miles west, by a gi'eat area 
 of later Hnronian sediments (graywaclces, quai-fzites, scliists) ;iiid 
 by immense intrusions and dikes, of diorites and more basic I'ocks, 
 at times more or less metamoi'phosed; eruptive breccias anil otlier 
 interesting varieties too numerous to cite in detail are also present. 
 
 Fig. 83. — Yieiv of the Copper Cliff 2Iine, near Siiilbiifii. Ontario 
 mine is in iliurife. TJie riihje at the haikipmi ml is ijranite. 
 From a pliotuijraiiti hij T. G. ^VItitl-. In'.M. 
 
 The 
 
 The geology is vei'y comple.x, and is in large part concealed bv 
 swamps and almost impenetral>le tbickets. It is evident, hiiwever, 
 that several great intrusions of a general dioritic character run 
 iioi'fliea.st and southwest through the Hurouian area. <_)ne on the 
 southeast has along its own southeastern sidesomerich deposits, in- 
 cludiiig the Evans, Copper Cliff, Stobie and Blezard. The Evans 
 
THE LESSER METALS, CONTINUED. 319 
 
 is on a small outlier from the main mass, and the Stobie and 
 Blezard are further in from the actual contact than is the Copper 
 Cliff. Some miles west of the great diorite dike just referred to is 
 the large Murray mine in another intrusion with a stretch of sup- 
 posed Laurentian granite between. Some twenty miles southwest, 
 and in connection with a still different diorite dike are found the 
 Worthington mine and several undeveloped openings in Drury and 
 Denison townships. About the same distance northwest of Sud- 
 bury is a region around Wahnapitae Lake, well thought of, but not 
 yet productive. 
 
 The ore-bodies betray their presence by great outcrops of rusty 
 gossan, consisting of limonite in layers and cellular masses, which 
 has resulted from the decay of the pyrrhotite and clialcopyrite. 
 The interrupted outcrop of this gossan may run for long distances. 
 When it was penetrated in the early prospecting the chalcopyrite 
 lying below attracted attention, and the deposits were regarded as 
 copper mines. Later the presence of the nickel in the pyrrhotite 
 was recognized, and the nickel became the principal object. The 
 two ores are inseparably intermingled and themselves form irregu- 
 lar masses often of great size in the diorite. It is stated by Peters 
 that the early work at the Stobie showed ore over 100 feet across. 
 The diorite is a dense black rock resembling most closely black 
 basalt in its appearance. Quite pure pieces of sulphides of large 
 size are at times obtained, but practically all the ore contains rock 
 up to 30^ or more of its weight, and the sulphides form irregular 
 masses in it. Great heaps of rock too lean to work, but showing 
 bits of sulphides through the pieces, are thrown out on the dumps. 
 The workings are in the form both of open cuts and of shafts, 
 from which the drifts wander out somewhat irregularly in search 
 of the ore-masses. Wliile it is truly said the ores favor the con- 
 tacts this should not be too closely interpreted. The mines and 
 the gossan do lie along the outer portions of the diorite masses, 
 yet as now mined at all the large producers they are entirely in the 
 diorite, and often very considerable distances from the actual con- 
 tact, of which no evidence appears from the workings. Included 
 masses of granite occur with the ore at Copper Cliff, and as a gen- 
 eral thing have a run of chalcopyrite. Some small, secondary and 
 insignificant quartz veins ramify through the diorite, and contain 
 chalcopyrite and some pyrrhotite, both of which are secondary, but 
 they are trifling in amount. On the contrary the masses of the 
 sulphides are irregularly distributed, often as small isolated bits. 
 
320 KEMP S ORE DEPOSITS. 
 
 throughout the fresh, dense diorite, leave one no reasonable alter- 
 native but to conclude that they are as much an original crystalliza- 
 tion from the igneous magma as any other of the minerals in the 
 rock. Evidence of disturbance has been found in the region and 
 apparent fault lines are not lacking, but the great open cuts of the 
 mines show no evidence of them. The method of igneous origin 
 has been somewhat attacked. Posepny, for example, refers to it 
 as something extraordinary when he cites Vogt's work, in his great 
 essay on " Genesis of Ore-Deposits," and controverts it strongly, 
 but it appears to the writer, after having seen the mines, that no 
 process of solution and replacement can be conceived of as intro- 
 ducing these scattered masses of sulphides into dense, undecomposed 
 and apparently unbroken igneous rock which would not strain the 
 faith of a conservative observer to a far greater degree. 
 
 It is an interesting fact that sperrylite, the unique arsenide of 
 platinum, occurs in the Sudbury region, but was not first discov- 
 ered in a nickel mine. Traces are, however, said to occur in the 
 nickel ores. Cobalt is in comparatively small amount, much less 
 than iu some other nickel regions. The ores vary in richness in 
 difEerent mines and in different parts of the same mine. They run 
 from over 1^ to over 5^ nickel, and have a copper percentage some- 
 what under the nickel. The Worthington has yielded a little gers- 
 dorffite (NiAsS), and niccolite (NiAs) in secondary quartz veins, 
 and a vein is reported from Denison township containing both 
 these. A galena vein is reported from the same region, a little mil- 
 lerite is said to have been found in the Copper Cliff mine, and 
 traces of zinc blende have also been noted in some of the ores, but 
 aside from these the mineralogy is limited to the two principal 
 sulphides.'' 
 
 1 On Sudbury see F. D. Adams, ' ' The Igneous Origin of certain Ore 
 Deposits," General Mining Assoc, Prov. Quebec, Jan. 12, 1894. A. E. 
 Barlow, ' ' The Nickel and Copper Deposits of Sudbury, Ont. , ' ' Ottawa 
 Naturalist, June, 1891. R. Bell, Geolog. Survey of Can., 1890-91; F. 5, 
 91. Bull. Geol. Soc. Amer., 11. p. 135. T. G. Bonney, "Notes on a 
 part of the Huronian Series near Sudbury, ' ' Quart. Jour. Geol. Soc. , 
 XLIV. 32, 1888. D. N. Browne, Engineering and Mining Journal, Sept. 
 16 and Deo. 2, 1893. E. R. Bush, ' ' The Sudbury Nickel Region, Idem, 
 March 17, 1894, p. 345. F. W. Clarke and C. Catlett, " Platinif erous 
 Nickel Ore from Canada, " ^mer. .Jour. Sci., iii., XXXVU., 372. J. 
 H. Collins, "Note on the Sudbury Copper Deposits," Quart. Jour. Geol. 
 Sue, XLIV. 834. J. Gramier, "Mines dn Nickel, Cuivre et Platine, 
 du District du Sudbury, ' ' Memoires de la Societie des Ingenieurs Civils. , 
 
thsTlesseb metals, CONTINUKD. 321 
 
 3.15.10. Example 49a. Kiddle's, Douglass County, Oregon. 
 Irregular deposits of hydrated silicates of nickel and magnesia, in 
 serpentine formed by the alteration of peridotites or related rocks, 
 Limonite, chalcedonic quartz and chromite are quite invariable 
 associates, as are clays and other products of alteration. The ore 
 occurs in loose boulders on the surface, and as a coating on the 
 walls of small cracks and veinlets that penetrate the more massive 
 serpentine. The largest deposits of this character so far as yet 
 opened in this country are in the Coast Eange, southwest of 
 Riddle's Station, Douglass County, Oregon, on the Oregon and 
 California Railroad. The mines occur on a steep hillside, in ser- 
 pentine that has resulted from the alteration of the variety of peri- 
 dotite, called harzburgite, i. e., bronzite and olivine. Open cuts, 
 small drifts and test pits have served to show the nickel silicates, 
 richest at the outcrop and fading out into small veinlets and retic- 
 ulations in depth until beyond the zone of snperficial decay they 
 disappear. The openings are still in the condition of prospects, 
 and productive mining is yet to be begun. The nickel has been 
 shown by J. S. Diller to have been derived from the olivine of the 
 rock, as chemical analysis of this mineral indicated 0.2G^ NiO. 
 By the familiar and ready alteration of the olivine the nickel has 
 separated as the silicate and has finally been concentrated suffi- 
 ciently to be noticeable.^ At Webster, in North Carolina, are sur- 
 face deposits of nickel silicate which have attracted attention. 
 They occur in the variety of peridotite, which is chiefly olivine, and 
 is called dunite. The geological relations and origin are practi- 
 cally the same as those in Oregon, just cited. The mines are not 
 yet producers.^ Green crusts of oxidized nickel compounds have 
 been found with the chromite in the town of Texas, Penn., but are 
 
 Paris, March, 1891. W. H. Merritt, Tram. Amer. Inst. Min. Eng., 
 XVn. 395. E. D. Peters, "On Sudbiary Ore Deposits," Trans. Amer. 
 Inst. Min. Eng. , Oct. , 1889 ; Eng. and Min. Jour. , Oct. 36, 1889. Berg, 
 u. Huet. Zeit., L. 149, 1891. 
 
 IF. W. Clarke and J. S. DiUer, "Nickel Ores from Riddle's, 
 Webster and New Caledonia, ' ' Amer. Jour. Soi. , iii. , XXXV. 483. H. 
 B. V. Foullon, "On Riddle's, Jahr d. k. k. Geol. Reichsanstalt, 1893, 
 334. Rec. 
 
 2 Clarke and Diller as cited in preceding reference. S. H. Emmens, 
 ' ' The Nickel Deposits of North Carolina, ' ' Eng. and Min. Jour. , April 
 30, 1893, p. 476. H. Wurtz, ' ' On the Occurrence of Cobalt and Nickel 
 in Q-aston County, North Carolina, "Amer. Assoc. Adv. Sci., XII. 331, 
 Amer. Jour. Sci., ii., XXVII. 34. 
 
332 KEMP'S ORE DEPOSITS. 
 
 of no practical importance. Such superficial discolorations are 
 very common in serpentinous districts, but it is a cnrions fact that 
 they are notably lacking in the dioritic varieties of Example 13a. 
 
 The greatest deposits in serpentinous are found in New Cale- 
 donia, in the South Pacific, vrhere they have been mined for some 
 years past, and have furnished in the last decade the largest part of 
 the world's supply. The ores occur, as is the usual case, associated 
 ■with serpentine, and along the contact of the serpentine with over- 
 lying beds of red clay.' 
 
 2.15.11. Example 23a. Mine la Motte. Considerable pyrite 
 occurs with the lead ores mentioned under Example 23, and is sep- 
 arated in the ore-dressing and treated by itself, as it contains 
 nickel and cobalt. Such pyrite is most abundant at Mine la 
 Motte, and considerable matte is made and shipped abroad. Sieg- 
 enite, a variety of linnaeite, is also found impregnating a bed of 
 Cambrian sandstone that underlies the lead-bearing dolomite. It 
 is not abundant enough to be of practical importance.^ 
 
 2.15.12. Nickel ores have also been reported from Salina County, 
 Arkansas.^ Millerite occurs in a vein with quartz gangue in black 
 shales. It is not practically productive. Nickel is also reported 
 in a rather fine conglomerate from Logan County, Kansas. It oc- 
 curs with manganese and limonite in the cementing material of 
 the rock.* Oxidized nickel ores have also been reported at the Love- 
 lock mines, Churchill County, Nevada, which passed in depth into 
 sulphides. 5 Although they were originally regarded as promising 
 
 • F. Benoit, ' ' Etude snr las Mines de Nickel de la NouveUe Cale- 
 donie, " -B«ZZ. de la Societe de I'Ind. Minerale, VI. 753., 1892. J. G^ar- 
 nier, ' ' Memoire snr les Gisements de Cobalt, de Chrome et de Fer a la 
 Nouvelle Caledonie, " Soc. des Ingenieurs civils., 1887. J. Heard, Jr., 
 "New Caledonia Nickel and Cobalt," Eng. and Min. Jour., August 11, 
 1888, p. 103. D. Levat, Association Francaise pour I' Advancement des 
 Sciences, Paris, 1887. L. Pelaton, "Carte Geologique de la NouveUe 
 Caledonie, ' ' Genie civile, 1891. 
 
 2 J. M. Neill, ' ' Notes on the Treatment of Nickel and Cobalt Mattes 
 at Mine la Motte, " Trans. Amer. last. Mm. Eng., XTTT. 634. For ad- 
 ditional literature see under 2.05.09. 
 
 s Ark. Geol. Survey, 1888, Vol. I. pp. 34, 35. 
 
 * F. P. Dewey, ' ' On the Nickel Ores of Russell Springs, Logan 
 County, Kansas," Trans. Amer. Inst. Min. Eng., XVII. , 636. 
 
 5 A. D. Hodges, ' ' Notes on the Occurrence of Nickel and Cobalt 
 Ores in Nevada," Trans. Amer. Inst. Min. Eng., X. 657. S. B. New- 
 berry, "Nickel Ores from Nevada, " Amer. Jour. Sci., iii., XXVHI. 133. 
 
TEW LESSER METALS,. CONTIN VED. 323 
 
 they have not proved a productive source as yet. Millerite occurs 
 as an interesting mineral in many other places (St. Louis, Mo.; 
 with red hematite in Jefferson County, N. Y., etc.), but is only a 
 rarity. Its interesting position at the former locality, in hair-like 
 tufts in the midst of geodes indicates that nickeliferous solutions 
 must have circulated rather widely in these limestories. In Jefferson 
 County it probably resulted from the decaying pyritous mineral 
 to which Smyth refers the iron ore, as outlined earlier. 
 
 Canada is now the chief producer of nickel (1,336,637 lbs. in 
 1891); New Caledonia follows (885,300 lbs. in 1890). Norway 
 and Sweden come next; while the United States, with the cessa- 
 tion of the Gap mine, are no longer to be reckoned in the list of 
 producers. 
 
 PLATINUM. 
 2.15.12. Some hundreds of ounces of platinum are annually 
 gathered from placer washings in northern California, and two or 
 three times as much more from British Columbia. Much iridium 
 and osmium are associated with it. In October, 1889, F. L. Sperry, 
 the chemist of the Canadian Copper Company, of Sudbury, dis- 
 covered a heavy crystalline powder in the concentrates of a small 
 gold-quartz mine in the district of Algoma. He detected the 
 presence of platinum, and sent the material to Professors "Wells 
 and Penfield of Yale, by whom it was analyzed, and crystallo- 
 graphically determined to be the arsenide of platinum, PtAsj, the 
 first compound of platinum, other than an alloy, detected in 
 nature. It has been appropriately named sperrylite by Wells, and 
 although not at present a source of platinum, it may merit atten- 
 tion, as the price of the metal has recently approximated that of 
 gold. The chief reliance of the world for platinum is Russia, 
 whose deposits are in the Urals. More or less comes also from 
 Colombia, South America, and from placer washings elsewhere. 
 Serpentine is very generally its mother-rock.^ 
 
 ' California : Engineering and Mining Journal, June 29, 1889, 587. 
 B. SilJiman, "Cherokee Gold Washings, California," Amer. Jour. Sci., 
 ill., VI. 133. Canada: F. W. Clarke and Ch. Catlett, " Platiniferous 
 Nickel Ore from Canada," Amer. Jour. Sci., iii., XXXVII. 373. H. L. 
 Wells and S. L. Penfield, " Sperrylite, a New Mineral," Amer. Jour. Sci., 
 ill., XXXVII. 67. Russia: A. Daubree, "On the Platiniferous Rocks of 
 the Urals," Trans. French Acad. Sci, March, 1875 ; Amer. Jour. Sci., iii., 
 IX. 470. General paper by C. Bullman, The Mineral Industry for 1892, 
 p. 373. Rec. 
 
324 KEMP'S ORE DEPOSITS. 
 
 TIN. 
 
 2.15.13. Ores : Cassiterite, SnOj, Sn. 78.67,0. 21.33. The sul- 
 phide stannite is a rather rare mineral. 
 
 Cassiterite occurs in small stringei's and veins on the borders 
 of granite knobs or bosses, either in the granite itself or in the 
 adjacent rocks, in such relations that it is doubtless the result of 
 fumarole action consequent on the intrusion of the granite. It 
 appears that the tin oxide has probably been formed from the 
 fluoride. A favorite rock for the ore is the so-called greisen, a 
 mixture of quartz and muscovite or lithia mica, and probably an 
 
 1»IG. 84. — Horizontal section of the Etta knob. After W. P. Blake, Min- 
 eral Resources, 1884, p. 602. 
 
 o/iginal granite altered by fumarole action. Topaz, tourmaline, 
 and fluorite are found with the cassiterite, indicating fluoric and 
 boracio fumaroles. Cassiterite seems also to crystallize out of a 
 granite magma with the other component minerals. Cassiterite, 
 being a very heavy mineral, accumulates in stream gravels, like 
 placer gold, affording thus the stream tin. When of concentric 
 character it is called wood tin. It is not yet demonstrated that 
 the United States have workable tin mines. 
 
 2.15.14. Example 51. Black Hills. Knobs of granite rock 
 containing cassiterite, disseminated in a mass of albite and mica, 
 and associated with immense crystals of spodumene. Columblte, 
 tantalite, and beryl are also found. There are two granite knobs 
 which are best known, the Etta and the Ingersoll. The former is a 
 conical hill, 250 feet high by 150 feet by 200 feet, piercing mica and 
 garnetiferous slates. Tunnels show it to have a concentric struct- 
 ure — first, a zone of mica ; second, a zone of great spodumene 
 crystals, with an albitio, so-called greisen and cassiterite in the 
 
THE LESSER METALS, CONTINUED. 325 
 
 interstices ; lastly, a mixture of quartz and feldspar as a core. 
 Other tin-bearing granites occur as dikes, or veins, as much as 80 
 feet wide, and bearing the so-called greisen and tin ore in quartz. 
 They are called segregated veins by Carpenter, who doubts their 
 igneous character, probably on good ground. No tin is yet com- 
 mercially produced. The tin deposits extend also into Wyoming.^ 
 
 2.15.15. Tin ores as stream tin have been found in gold wash- 
 ings in Montana and Idaho. Tin is also known in the Temescal 
 Mountains, southern California, and according to Blake is in 
 various small veinlets in a granite region. This locality attracted 
 much interest years ago, but has never yielded any practical re- 
 sults until lately. Operations after being carried on for a time 
 have, however, proved a failure.^ 
 
 2.15.16. Narrow veins carrying cassiterite are being exploited 
 in the granite and schistose rocks of Rockbridge and Nelson 
 counties, Virginia, in North Carolina, and in Alabama. Compa- 
 nies have been formed to work the two former, but as yet without 
 a notable output.' 
 
 2.15.17. Cassiterite has been discovered in narrow veins in mica 
 schists with lepidolite and fluorite at Winslow, Me., and is known 
 at other places in Maine and New Hampshire. A salted tin pros- 
 pect several years ago spread the impression that tin was to be 
 found in southwest Missouri.* 
 
 ' W. P. Blake, Mineral Resources, 1884-85, p. 603. Rec. Amer. Jour. 
 Sci., September, 1883, p. 335 ; Engineering and Mining Journal, Sept. 8, 
 1886. " Tin Ore Deposits of the Black Hills," M. E., XIII. 691. F. R. 
 Carpenter, Prelim. Rep. Dak. School of Mines, 1888 ; also M. E., XVII. 
 570. "Tin in the Black Hills," Engineering and Mining Journal, Nov. 
 38, 1884, p. 353. Mineral Resources of the U. S., annually under "Tin." 
 
 2 W. P. Blake, "Occurrence of Wood Tin in California, Idaho, and 
 Montana," Mining and Scientifio Press, San Francisco, Aug. 5, 1883. H. 
 G. Hanks, Rep. Cal. State Mineralogist, 1884, p. 131. 
 
 ' H. D. Campbell, "Tin Ore, Cassiterite, in the Blue Ridge in Vir- 
 ginia,' The Virginias, October, 1883. A. R. Ledoux, " Tin in North Caro- 
 lina," Engineering and Mining Journal, Dec. 14, 1889, p. 531 ; see also 
 February, 1887, p. 111. McCreath and Piatt, Bull. Iron and Steel Asso., 
 Nov. 7, 1883, p. 209. W. Robertson, London Mining Journal, Oct. 18, 1884. 
 A. Winslow, "Tin Ore in Virginia," Engineering and Mining Journal, 
 November, 1885. Rec. 
 
 * W. P. Blake, Mineral Resources, 1884, p. 588. C. H. Hitchcock, 
 "Discovery of Tia Ore and Emery at Winslow, Me.," Engineering and 
 Mining Journal, Oct. 2, 1880, p. 318. T. S. Hunt, " Remarks on the Oc- 
 currence of Tin Ore at Winslow, Mh.," M. E., I. 573. C. T. Jackson, " Tin 
 Ore at Winslow, Me.," Proc. Bost. Soo Ndt. Hist., XII. 367. 
 
CHAPTER XVI. 
 
 CONCLUDING REMARKS. 
 
 2.16.01. In review of the western border of the country, we 
 note the elevated plateau rising from the Mississippi to the Rocky- 
 Mountain range, which consists of various ranges of general north 
 and south or northwest and southeast trend, with broad valleys 
 between. Next comes the Colorado Plateau, and then the Wa- 
 satch Mountains and the Great Basin, with its various subordinate 
 north and south ranges. These are succeeded by the Sierra Ne- 
 vada, and the great valley of California, the Coast range, and 
 finally the Pacific Ocean. 
 
 From the Archaean to the close of the Carboniferous there 
 Tvere granite islands around which active sedimentation proceeded. 
 At the close of the Carboniferous the elevation of the Wasatch 
 and the region of eastern Nevada occurred. At the close of the 
 Jurassic the elevation of the Sierra Nevada took place. The chief 
 upheaval of the Rocky Mountain system came at the close of the 
 Cretaceous and that of the Coast range at the close of the Miocene 
 Tertiary. Smaller and less important oscillations have occurred 
 before and since. Each elevation was accompanied by foldings, 
 faultings, and extensive outpourings of eruptive rocks. The re- 
 sultant fractures and the solfataric action, occasioned by the 
 dying volcanic activity, constitute the primary cause of the for- 
 mation of the ore deposits, which in some cases lie in ranges along 
 the lines of faulting or of disturbances, and in others are irreg- 
 ularly scattered. We can recognize the Coast range belt with 
 mercury and chromium ; the California gold belt in the western 
 Sierras ; the silver belt of Utah on the western flank of the Wa- 
 satch ; a belt in Arizona from southeast to northwest, along the 
 contact between Paleozoic limestone, mostly Carboniferous, and 
 the Archaean ; and the great stretch of lead-silver mines in the 
 Carboniferous limestones of Colorado. The other areas are scat- 
 
CONGL nniNG B EM A RKS. 32? 
 
 tered, and apparently exhibit no such grand general relations to 
 these geographical and geological phenomena.^ 
 
 2.16.02. In the Mississippi Valley, W. P. Jenney has re- 
 marked the connection of the antimony and silver deposits of Ar- 
 kansas with the Ouachita uplift that traverses that State and In- 
 dian Territory ; also, the location of the Missouri lead and zinc 
 ores along the Ozark uplift ; and he has referred the Wisconsin 
 lead and zinc mines, as well as those in the neighboring part of 
 Iowa and Illinois, to an uplift south of the Arch83an area of Wis- 
 consin. The limitation of the Lake Superior copper deposits to the 
 Keweenawan system may be mentioned, and such parallelism as 
 prevails among the Lake Superior iron ores. In the East the great 
 belt of Clinton Ores ; the long succession of Siluro-Cambrian limo- 
 nites in tJie Great Valley ; the black-band ores and clayironstones 
 of the Carboniferous ; the closely similar geological relations of 
 nontitaniferous, magnetite lenses in the Archaean gneisses ; and 
 the general association of titaniferous magnetites with rocks of the 
 gabbro family the country over — all are striking illustrations of 
 broad, general geological features that may characterize extended 
 areas. To these may be appended the great series of pyritous 
 beds or veins in the slates and schists of the East, the gold belt of 
 the southeastern States, and the small copper deposits associated 
 with the Triassic traps and sandstones. Aside from these, while 
 there are important mines not included in the list, the others do 
 not exhibit the same widespread uniformities of structure or asso- 
 ciations. Yet, from the list cited, it forcibly appears that similar 
 conditions have brought about related ore bodies over great 
 stretches of country ; and while in the opening schemes of clas- 
 sification points of difference were emphasized, in the closing pages 
 points of resemblance may be with equal right brought to the fore- 
 ground. 
 
 2.16.03. A few general conclusions suggest themselves from 
 the preceding pages. 
 
 (1) The extreme irregularity in the shape of metalliferous de- 
 
 1 G. F. Becker, Amer. Jour. ScL, 3d Series, Vol. XXIII., 1884 p. 309. 
 W. P. Blake, Rep. Cal. State Board of Agriculture, 1866. S. F. Emmons, 
 " The Structural Relations of Ore Deposits," M. E., XVI. 804. R. W. Ray- 
 mond, " Geographical Distribution of Mining- Districts in the United 
 States," M. K, I. 33. Fortieth Parallel Survey, Vol. III., Chap. I. " Pre- 
 cious Metals," Tenth Census, Vol. XII. 
 
338 KEMP'S ORW DEPOSITS. 
 
 posits, and from this the unwisdom of the United States law in 
 the West, which is based on well-defined fissure veins. The only 
 practicable method is that a man should own all that is embraced 
 in his property lines, whether the ore body outcrops outside or not. 
 "A square location is the square thing " (Raymond). 
 
 (2) The very general proximity of eruptive rocks in some form 
 to the ore bodies. Except in the case of iron, there are only a 
 few where these are not present, and apparently strong factors in 
 the circulations which formed the ore. The lead and zinc deposits 
 of eastern and western Missouri and the neighboring States, and 
 of New York and Virginia, are almost the only ones, and we are 
 justified in concluding that eruptive rocks are of great importance. 
 
 (3) We know from the investigations of Sandberger and others 
 that the dark silicates of many rocks contain percentages of the 
 common metals. The choice is open whether to refer the ore to 
 original dissemination in these, and derive it by gradual concentra- 
 tion, probably at great depths, or to some indefinite unknown 
 source, which can only be described as " below." 
 
INDEX. 
 
 Abiquiu, N. M., copper ores, 183. 
 Adams, F. D. , on granite at Douglass 
 
 Island, 355. 
 Agglomerates, 334. 
 Alabama, Clinton ore, 105, 106. 
 
 Gold mines, 391. 
 
 Tin, 335. 
 Alaska, geology, 393, 393. 
 Aleutian Islands, 393. 
 Algoma, platinum, 333. 
 Alice mines, Butte, Mont., 354. 
 Allegbany Mountains, geology, 8. 
 Alturas Co., Idabo, 357. 
 Aluminium, 397. 
 Amador Co., Cal., 385. 
 Ancram lead mine, N. T., 185. 
 Antbony's Xose, N. Y., pyrrbotite mine, 
 
 154, 314. 
 Anticlines, 11. 
 
 Cause of cavities, 11. 
 Antimony, 301, 303. 
 
 Nevada, 366. 
 Apacbe Co., Ariz., 363. 
 Appalacbians, general description, 6, 7. 
 
 Topograpby, 6, 7. 
 
 Geology, 7, 8. 
 Argentine, Clear Creek Co., Colo., 845. 
 Arizona copper mines, 173-180. 
 
 Geology. 361. 
 
 Copper deposits, gossan of, 164. 
 
 Lead-silver ores, 333. 
 
 Prince copper mine, Ariz., 178. 
 
 Silver mines, 336. 
 Arkansas, antimony, 301. 
 
 Bauxite, 397, 399. 
 
 Iron ores, 86. 
 
 Manganese, 306-308. 
 
 Nickel, 333. 
 
 Silver mines, 835. 
 Arksut Fjord, Greenland, 397. 
 Arlington, N. J., copper mines, 181. 
 Arnold iron mines, N. Y., 140. 
 Arsenic, 308. 
 
 Ascension by infiltration, 89, 30-38. 
 Asbcroft iron mines, Colo., 144. 
 Asbland mine, Ironwood, Miob., 133. 
 Aspen, Colo., 330-334, 345. 
 
 Iron mines near, 144. 
 Atlantic copper mine, Micb., 169. 
 
 Augusta, Va., manganese, 305. 
 
 Auriferous beacb sands, 374. 
 Gravels, 877-388. 
 
 Austin, Nev., 876. 
 Antimony, 301. 
 
 Bacbelor Mountain, near Creede, Cole 
 343. 
 
 Baker Co., Ore., 373, 374. 
 
 Bald Butte Co.'s mines, Mont., 855. 
 
 Baltimore, Md., cbromite, 303. 
 
 Banded structure of veins, 35. 
 
 Bannack City, Mont., 353. 
 
 Banner district, Boise Co., Idabo, 357. 
 
 Bare Hills, Md., cbromite mine, 303. 
 
 Barton Hill iron mines, N. Y., 139. 
 
 Barus, C, experiments on electrical ac- 
 tivity of veins, 40. 41. 
 Experiments on tbe Comstock Lode, 
 869. 
 
 Bassick mine, Colo., 35, 36, 347. 
 
 Batesville, Ark., manganese, 366, 307, 
 308. 
 
 Bauxite, 397, 398. 
 
 Beacb deposits, 61. 
 
 Bear Lake Co., Idabo, 857. 
 
 Beaver Co., Utab, 859. 
 
 Beaverbead Co., Mont., 853. 
 
 Becker, G. F., precious metals in dia- 
 base, 85. 
 Cited on Steamboat Springs, Nev., 
 
 38. 
 On tbe Comstock Lode, 867-871. 
 On California gravels, 381. 
 On California mercury, 369, 309- 
 
 311. 
 Various metals in granite, 36. 
 
 Beds, in sedimentary rocks, 10. 
 
 Belmont, Nov., 864, 365. 
 
 Belts of ore deposits in tbe West, 336, 
 337. 
 
 Berks Co., Penn., iron mines, 143. 
 
 Bernalillo Co., N. M., 338. 
 
 Bessemer limit of Lake Superior ores, 
 78. 
 
 Betblebem, Penn., zinc mines near, 804. 
 
 Beulab antimony mine, Nev., 301. 
 
 Big Cottonwood Caiion, Utab, 836. 
 
 Big Creek, Nev., .801. 
 
 Bimetallic mine, Butte, Mont., 355. 
 
330 
 
 INDEX. 
 
 Bingham Canon, Utah, 226, 259. 
 
 Cited as illustration of gossan, 39. 
 Birmingham, Ala., 107. 
 Bisbee copper district, Ariz., 276. 
 Bismuth, 302, 303. 
 Bitter Root Mountains, Idaho, 256. 
 Black-band iron ore, 96. 
 Black copper groups of copper mines, 
 
 Arizona, 178. 
 Black Hills, geology, 9. 
 
 Geology and mines, 240-242. 
 
 Gold in Potsdam, 274. 
 
 Placers, 279. 
 
 Tin, 324. 
 Black Range copper mines, Ariz., 179. 
 
 Copper district, 263. 
 Blake, W. P., on the Deep Creek mines, 
 259. 
 
 On lead and zinc in Mississippi 
 Valley, 193. 
 
 On the Silver King mine, Arizona, 
 262. 
 
 On Tombstone, Ariz., 263. 
 
 On Utah antimony, 302. 
 
 Ruby silver ore, Poormau lode, 257. 
 Blende in the Rocky Mountains, 211. 
 Block iron ore, 96. 
 Block Island, R. I., magnetite sands, 
 
 151. 
 Blow, A. A., Illustration of fault by, 
 17. 
 
 Cited on Leadville, Colo., 219. 
 Bluebird mine, Butte, Mont. , 255. 
 Blue lead in California gravels, 280. 
 Bl ue Mountains, Oregon, 273. 
 Bog iron ore, 79. 
 
 At Three Rivers, Quebec, 80. 
 
 Precipitated by algae, 82. 
 Boise Co.. Idaho, 257. 
 Bonanza City, Idaho, 257. 
 Bonanza of ore, 37. 
 Bonne Terre, Mo., lead mines, 186. 
 Bonneville, Lake, 264. 
 Bonsacks, Va., illustration of gossan, 
 39. 
 
 Zinc mines, 200. 
 Boone cherts, Arkansas, 307. 
 Boss of igneous rock defined, 11. 
 Boston Mountains, Ark., 307. 
 Boulder Co., Colo., 248. 
 
 Iron ores, 144. 
 Box Elder Co., Utah, 259. 
 Boyd, C. R. , on zinc in Virginia, 202. 
 Boyertown mines, Penn., 150. 
 Brandon, Vt., manganese, 305. 
 Bristol, Conn., copper mine, 181. 
 British Columbia gold gravels, 295. 
 
 Platinum, 323. 
 Britton, N. L., cited on the geology of 
 the Highlands, N. J. , 151. 
 
 Britton, N. L., on Staten Island bog 
 
 ore, 81. 
 Brooks, T. B., on the Marquette dis- 
 trict, 115, 116. 
 Origin of ores, 120. 
 Browne, D. H., on phosphorus in iron 
 
 mines, 153. 
 Browne, R. E., on California gravels, 
 
 280, 381. 
 Brunton, D. W., cited on Aspen, Colo., 
 
 . 222. 
 Bucks Co., Penn., iron mines, 143. 
 Buckwheat mine, Franklin Furnace, 
 
 N. J., 207. 
 Buena Vista, Colo., 246. 
 Buford Mountain, Mo., 134. 
 Buhrstone ore, 97. 
 Bull Domingo mine, Colo., 36, 247. 
 Burden spathic ore mines, Hudson, 
 
 N. Y., 98. 
 Burro Mountains, N. M., 237. 
 Butte, Mont., 354. 
 
 Copper mines, 137, 143, 162, 163, 
 
 168. 
 Illustrates infiltration by ascension, 
 
 32. 
 Placers near, 379. 
 Cahaba coal field, Ala., 107. 
 Calavaras Co., Cal., 385. 
 Caldwell Co., Ky., lead and zinc mines, 
 
 195 
 Calico district, Cal., 376. 
 California, chromite, 303. 
 Copper mines, 162. 
 
 Literature, 163. 
 Geology, 375, 282, 289. 
 Gulch, near Leadville, Colo., 245, 
 
 279. 
 Kern Co., antimony. 301. 
 Lead-silver ores, 232. 
 Magnetite, 144. 
 Mercury, 309, 310. 
 Platinum, 333. 
 Tin, 325. 
 Gallon scheme of classification of ore 
 
 deposits, 47. 
 Calumet and Hecla copper mines, Mich 
 igan, 169. 
 Iron mine, Colorado, 144. 
 Campbell Mountain, near Creede, Colo., 
 
 243. 
 Campo Seco, Cal., copper mines, 162. 
 Canada, bog ore, 80. 
 Gold, 294, 295. 
 Magnetite ore mines, 140. 
 Canso, N. S., 294. 
 
 Cape Breton, N. S., manganese, 308. 
 Capelton, Quebec, mines of pyrlte, 154; 
 
 chalcopyrite, 160. 
 Carbonate Hill, Leadville, Colo., 217. 
 
INDEX. 
 
 331 
 
 Carbonite mine, Utah, 239. 
 Carpenter, F. R., on the Black Hills, 
 
 S. D., 251. 
 On Black Hills tin, 325. 
 Carson Hill, Calavaras Co., Cal., 284. 
 Cartersville, Ga., manganese, 305. 
 Cascade Mountains, 273. 
 Cascade Range, Cal., 275. 
 Cassia Co., Idaho, 257. 
 Cassiterite, 324. 
 Cave mine, Utah, 329. 
 Caves, origin of, 21. 
 
 As a form of ore body, 57. 
 Cave Spring manganese mines, Georgia, 
 
 305. 
 Cazin, P. M. F., on Silver Reef, Utah, 
 
 250. 
 Cedar Mountain, Mo., 134. 
 Central City, Colo., copper mines, 165. 
 Chaffee Co., Colo., 246. 
 
 Magnetite, 144. 
 Chalcopyrite with pyrite, 160-162. 
 
 Literature, '161. 
 Chamberlin, S. C, on Wisconsin lead 
 
 and zinc mines, 163, 189-191. 
 Chambered vein, 309. 
 Chalcopyrite with nickel ores, 58. 
 Charlemont, Mass., mines of pyrite, 
 
 154. 
 Charles Dickens mine, Idaho, 357. 
 Chateaugay iron mines, N. Y., 138. 
 Chaudiere River, Canada, gold, 395. 
 Chauvenet R,, cited on Colorado iron 
 
 ores, 149. 
 Cherry Valley, Mo., 111. 
 Chester, A. H., on the average yield 
 
 of certain well-known iron ores, 
 
 77. 
 Chicago copper mine, Arizona, 178. 
 Chico beds, California, 309. 
 Chimney of ore, 37. 
 Chisholm, F. F., on Cuban ores, 158. 
 Chromite distribution, 303. 
 Chromium, 303. 
 
 Mines, California, 336. 
 Chugwater Creek, Wyo., iron ores, 
 
 149. 
 Church, J. A., on the Comstock lode, 
 
 367, 368. 
 Churchill Co., Nev., 266. 
 Chute of ore, 37. 
 Cincinnati uplift, 9. 
 Cinnabar, 309. 
 Clark, E., on Lake Valley, N. M., 214, 
 
 215. 
 Clarke, F. W., on the composition of 
 
 the earth, 78. 
 Classification of ore deposits, 43, 67. 
 Classification of ore deposits, underly- 
 ing principles, 43. 
 
 Clay ironstone defined, 95. 
 
 Deposits of, 95-97. 
 Clay selvage, seam, or parting, 37. 
 
 Attrition clay, 37. 
 
 Residual clay, 37. 
 Clayton, J. E., on Butte, Mont., 254. 
 Clayton's law, 37. 
 
 Clear Creek Co., Colo., 245, 246-248. 
 Clear Lake, Cal., mercury, 309. 
 Clerc, F. L., cited on zinc mines of 
 southwestern Missouri, 196-198. 
 Cliff copper mine, Michigan, 169. 
 Clifton, Ariz., copper district, 173. 
 Clinton ore, 102-109. 
 
 Distribution, 103-108. 
 
 Origin, 108. 
 Clinton ores, general relations, 327. 
 Coal measures, classification of in 
 
 Pennsylvania, 96. 
 Coastal Plain, 291. 
 
 Geology, 8. 
 
 Topography, 6. 
 Coast Range belt of mines, 336. 
 
 Chromite, 303. 
 
 Oregon, 39. 
 
 Washington, 373. 
 Cobalt, 304. 
 
 Cochise Co., Ariz., 363. 
 Coeur d'Alene, Idaho, lead silver ores, 
 
 226. 
 Colfax Co., N. M., 338. 
 Colombia, platinum, 333. 
 Colorado, geology, 238. 
 
 Gold at Cripple Creek, 349. 
 
 Iron ores, 88. 
 
 Lead-silver mines, 216-235, 375. 
 
 Magnetite, 144. 
 
 Literature, 144. 
 
 Plateau, 7-9. 
 
 Silver and gold, 339-350. 
 Spathic iron ore, 98. 
 Columbia Co., N. Y., lead mines, 185. 
 Columbia Hill, gravels, California, 379. 
 Comb-in-comb structure in a vein, 35. 
 Comstock lode, Nev., 367-271. 
 Comstock, S. B., on Red Mountain, 
 Colo., 224. 
 
 On vein systems of the San Juan, 
 240. 
 Conejos Co., Colo., 246. 
 Connecticut, bismuth, 303. 
 
 Lead mines, 185. 
 
 Limonite, 89, 94. 
 
 Magnetite sands, 151. 
 
 Roxbury siderite, 100. 
 Contact deposits, 60. 
 Cobalt, ores and general remarks, 
 
 313-314. 
 Coosa coal field, Ala., 107. 
 Copper Basin, Ariz., 179. 
 
332 
 
 INDEX. 
 
 Copper Creek, near Gothic, Colo., 345. 
 Copper Falls copper mine, Michigan, 
 
 169. 
 Copper Mountain, Ariz., copper district, 
 
 373. 
 Copperopolis, Cal., copper mines, 163. 
 Copperopolis copper mine, Utah, 180. 
 Copper ores, analyses of ore minerals, 
 
 160. 
 Copper Queen mine, Arizona, 178. 
 Copper, statistics, 183. 
 Cordillera region, general geology, 386. 
 Cornwall, Penn., iron mines, 143, 145, 
 146. 
 Literature, 145. 
 Corundum, as an ore of aluminium, 
 
 300. 
 Costillo Co., Colo., iron mines, 144. 
 Cotta, B. von, on filling of mineral 
 veins, 38. 
 Schemes of classification of ore de- 
 posits, 44^6. 
 Courtis, W. M., on the microscopic 
 
 structure of gold-quartz, 385. 
 Cranberry magnetite mines. North Car- 
 olina, 143. 
 Crawford Co., Mo., red hematites, 110. 
 Credner, H., on origin of Marquette 
 
 ores, 130. 
 Creede, Colo., 341-343. 
 Crimora, Va., manganese, 305. 
 Cripple Creek, Colo., 349. 
 Crismon-Mammoth copper mine, Utah, 
 
 180, 194, 328. 
 Crittenden Co., Ky., lead and zinc 
 
 veins, 195. 
 Crosby, W. 0., cited on joints, 13. 
 
 On classification of ore deposits, 67. 
 Cross, W., on the mines near Rosita, 
 Colo., 247. 
 Crustification, 65. 
 Cryolite, 300. 
 Cuba iron ores, 157. 
 Cumberland iron mine, Colorado, 144. 
 Curry Co. ore, 274. 
 Curtis, J. S., cited on caves, 21. 
 
 On Eureka, Nev., 197, 830, 331. 
 On growth of aragonite crystals, 34. 
 On replacement, 33. 
 On silver, in quartz porphyry, 25. 
 Custer Co., Colo., 212, 213, 246, 247. 
 
 Idaho, 257. 
 Custer mine, Idaho, 357. 
 Dakyns and Teall, cited on origin of 
 
 magnetite, 158. 
 Dall, W. H., on Alaska, 292. 
 Dana, divisions of geological time, 4. 
 Davison Co., N. C, lead mines, 185. 
 Dawson, G. M., on Douglass Island, 
 293. 
 
 Deadwood, S. D., 351. 
 
 Deep Creek mines, Utah, 259. 
 
 Deep gravels, California, 279. 
 
 Deer Lodge Co. , Mont. , 255. 
 
 Deer Trail mine, Utah, 260. 
 
 De la Biche, electrical activity of veins, 
 
 41. 
 DeLaunay, cited, 66. 
 Delaware, chromite, 303. 
 Del Norte Co., Cal., chromite, 803. 
 Deloro, Can., arsenic mine, 308. 
 Deloro (Marmora), Can., gold mine, 
 
 895. 
 Dent Co., Mo., iron ores. 111. 
 Devereux, W. B., cited on Colorado 
 
 iron ores, 144. 
 Devonian system at Hamilton, Kev., 
 
 365. 
 Diaclases. See under "Joints." 
 Dickerson iron mine, New Jersey, 153. 
 Dike defined, 11. 
 
 Distinction from vein, 11. 
 Cause of earthquakes, 17. 
 Diller, J. S., cited on Kentucky perido- 
 
 tite, 195. 
 On California, 875. 
 On the California gravels, 283. 
 Dillsburg mines, Penn., 150. 
 Doe Run, Mo., lead mines, 186. 
 Dolomitization, 31, 22. 
 Dolores Co., Colo., 239. 
 Dona Ana Co., N. M., 214. 
 Douglass Island, Alaska, 286, 393. 
 Drinker, H. S., cited on the Saucon 
 
 Valley zinc mines, 805. , 
 
 Drumlummon mines, Montana, 255, 
 
 356. 
 Dry Canon, Utah, 838, 259. 
 Ducktown, Tenn., illustration of gos- 
 san, 39. 
 Mines of pyrite and chalcopyrite, 
 
 154, 161. 
 Dutton, Capt. C. E., cited on the geol- 
 ogy of New Mexico, 237. 
 Dyestone iron ore, 103. 
 " Dyestone ranges," 104. 
 Eagle Co., Colo., 245. 
 Eagle River district, Colo., 320. 
 Earth, average composition of crust, 
 
 78. 
 Eastern sandstone, Keweenaw Point, 
 
 Mich., 166. 
 Egan Canon, Nev., 365. 
 El Dorado Co., Cal., 285. 
 Electrical activity of ore bodies, 269; 
 
 of veins, 40. 
 Elk Jlountains, Colo., 245. 
 
 Iron mines, 144. 
 Elko, Nev., 365. 
 Elko Co., Nev., 266. 
 
INDEX. 
 
 333 
 
 El Paso Co., Colo., 349. 
 
 Ely copper mines, Vermont, 135, 160, 
 
 161. 
 Emma mine, Utab, 228. 
 Emmons, E. , Jefferson Co., N. Y., red 
 
 liematites, 113. 
 Emmons, S. F., cited on replacement, 
 
 33. 
 • On Butte, Mont., 164 
 
 On country rock of Boulder Co., 
 Colo., 248. 
 
 On Leadville, Colo., 217-319. 
 
 On Red Mountain, Colo., 224. 
 
 On the mines near Rosita, Colo., 
 247. 
 Endlich, P. M., on gold mines, near 
 
 Ouray, Colo., 340. 
 Enterprise, Miss., spathic ore, 98. 
 Esmeralda Co., Nev., 266. 
 Etta granite knob, with tin ore, 273. 
 Eureka Co., Nev., 266. 
 
 Electrical activity of ore, 369. 
 
 Illustration gossan, 39. 
 
 Lead- silver, 330. 
 Evigtok, Greenland, cryolite, 300. 
 Fahlbands, defined, 63. 
 Fairplay, Colo., 346, 279. 
 Farish, J. B., illustration by, 20. 
 
 On the veins at Newman Hill, near 
 Rico, Colo., 240, 241. 
 Faults, cause of, 13. 
 
 Defined and described, 17-20. 
 
 Hade, 17. 
 
 Norma], 18. 
 
 Reversed, 18. 
 
 Schmidt's law of, 18. 
 
 Step faults, 30. 
 Feather River, Cal.,375. 
 Felch Mountain, area and iron ores, 
 
 Michigan, 118. 
 Fisher Hill iron mines. New York, 139. 
 FlagstafE mine, Utah, 338. 
 Flagstone iron ore, 96. 
 Flaxseed iron ore, 103. 
 Fiotz defined, 43. 
 Floyd Co., Ga., bauxite, 297. 
 Flucan of a vein, 37. 
 Foerste, A. F., on Clinton ore, 108. 
 Folds, various kinds defined, 11. 
 
 Axes of, 11. 
 
 Cause of cavities, 13. 
 
 "Pitch "of, 11. 
 Forest of Dean iron mine. New York, 
 
 141. 
 Forest Queen mine, Ruby district, 
 
 Colo., 245. 
 Formation defined, 5. 
 Fort Laramie, Wyo., iron ore near, 
 
 132. 
 Fossil iron ore, 103. 
 
 Foster and Whitney, cited on Mar- 
 quette district, 115. 
 Foster and Whitney, Marquette dis- 
 trict, origin of its ores, 118. 
 
 On Keweenaw Point copper, 170. 
 Fousnet's series, 58. 
 Franklin copper mines, Michigan, 169. 
 Franklin Co. , Mo. , lead and zinc mines, 
 
 194. 
 Franklin Co. , Va. , magnetite, 143. 
 Franklin, N. J., 141. 
 Franklin Furnace, N. J., 174, 175-179, 
 304, 305-309. 
 
 Iron mines, 143. 
 Frankiinite, 304. 
 
 Eraser, P., on Penn. magnetite, 150. 
 FredHand, F. T., cited on faults, 19. 
 Fremont Co., Colo., magnetite, 144. 
 French Creek mines, Penn., 150. 
 Friedensville zinc mines, Penn,, 204. 
 Frisco, Utah, 339. 
 Fritz Island mine, Penn., 150. 
 Frost Drift, North Carolina, 391. 
 Fryer Hill, Leadville, Colo., 317. 
 Fuchs and De Launay, cited, 66. 
 Fulton, J., on the Menominee district, 
 
 108, 121, 122. 
 Gagnon vein, Butte, Mont., 163. 
 Galena (town), S. D., lead-silver mines, 
 
 335. 
 Gangue, minerals forming, 33. 
 
 Source of, 36. 
 Gap mine of pyrrhotite, Pennsylvania, 
 
 154, 315. 
 Gatling arsenic mines, Deloro, Can., 
 
 303. 
 Genesee antimony mine, Nevada, 301. 
 Genth, F. A., on Boulder Co., Colo., 
 248. 
 
 On gold in Southern States, 391. 
 Geology, modern standpoints, 3. 
 
 Tabulation of geological sub-divis- 
 ions, 4, 5. 
 Georgetown, Colo., 348. 
 Georgia, bauxite, 297. 
 
 Clinton ore, 105. 
 
 Limonite, 93. 
 
 Manganese, 305. 
 Geyser mine, Custer Co., Colo., 347. 
 Gilbert, G. K., cited on joints, 13. 
 
 Illustration loaned by, 15. 
 Gilpin Co., Colo., 248, 286. 
 
 Banded veins, 35, 
 
 Copper mines, 165. 
 Glendale, Mont., 353. 
 
 Lead-silver ores, 325. 
 Glenmore estate, West Virginia, 109. 
 Globe copper district, Arizona, 178, 
 
 263. 
 Gobebic district of Lake Superior, 123. 
 
334 
 
 INDEX. 
 
 Gold, Alaska. 293, 294. 
 
 Black Hills, 251. 
 
 California, 284-286. 
 
 Mineralogical associates, 287. 
 
 In sea beaches, 280. 
 
 Nova Scotia, 294. 
 
 Occurrence and ores, 234. 
 
 Oregon, 274. 
 
 Quartz, 284. 
 
 Quartz veins, 284. 
 
 Southern States, 291. 
 
 Statistics, 295. 
 
 Washington, 273. 
 Gold Cup mine, Tin Cup, Colo., 245. 
 Gossan, 88. 
 
 Gossan lead of Virginia, 85. 
 Gothic, Colo., 245. 
 Gouge of clay in a vein, 37. 
 Graham Co., Ariz., 263. 
 Granby. Mo., zinc and lead mines near, 
 
 '171, 195-199. 
 Grand Cafion of the Colorado, 261. 
 Granite, Chaffee Co., Colo., 246. 
 Granite Mountain mine, Butte, Mont., 
 
 255. 
 Granite in mines of pyrite, Ontario, 156. 
 Grant Co., N. M., 237. 
 Grant Co., Ore., 274. 
 Great Basin, 3-7, 10. 
 
 In California, 275. 
 
 In Oregon, 273. 
 Great Eastern mercury mine, 309. 
 Great Lakes, geology, 8, 9. 
 Great Valley, 8, 327. 
 
 Iron ores, 88. 
 Great Western mercury mine, 309. 
 Green-eyed Monster mine, Utah, 260. 
 Greenland cryolite, 297. 
 Green Mountain placers, 279. 
 Green River, Utah, 224, 258. 
 Greensands, iron ores in, Texas, 87. 
 Greisen with tin ores, 324. 
 Griffin. P. H. on Quebec bog ore, 80. 
 Grimm J., scheme of classification of 
 
 ore deposits, 50. 
 Groddeck, A. v., scheme of classifica- 
 tion of ore deposits, 51. 
 Gulf region, geology. 9. 
 Gunnison Co., Colo., iron mines, 144. 
 Gunnison region, Colorado, 245. 
 Hade of a fault, 17. 
 Hague, A., cited on Wyoming iron ore, 
 144. 
 
 On Hamilton, Nev., 265. 
 Hague, A., and Iddings, J. P., on the 
 
 Comstock lode, 267, 270, 271. 
 Haile gold mine. South Carolina, 291. 
 Hall, C. E., cited on the iron mines of 
 
 the Adirondacks, 140. 
 Hamilton, Nev., 265. 
 
 Hammondville, N. T., iron mines^ 140, 
 Hampton and Eureka copper miueg, 
 
 Arizona, 179. 
 Hancock, Midi., 166. 
 Hanging Rock region, Ky., 85. 
 
 Spathic ores, 97. 
 Hanover, N. M., zinc, 212. 
 Harrington, B. J., cited on the origin 
 
 of magnetite, 153. 
 Hartman zinc mine, Pennsylvania, 204. 
 Hastings Co., Can., 302. 
 Haworth, E., cited on zinc and lead 
 
 ores of southwestern Missouri, 
 
 198. 
 Hayes, C. W., illustration by, 18. 
 
 On southern bauxite, 298. 
 Hecla iron mine, Colorado, 144. 
 Hecla mines, Glendale, Mont., 225. 
 Hecla mines, Montana, 253. 
 Helena, Mont, 255. 
 Hematites, red and specular, table of 
 
 analyses, 136. 
 Henrich, C, cited on Aspen, Colo., 223. 
 On Clifton, Ariz., copper mines, 
 
 174. 
 On the Slayback lode. New Mex- 
 ico, 238. 
 Henry Co., Va., magnetite, 143. 
 Hesse, Germany, bog ore, 82. 
 Hiberuia iron mines. New Jersey, 142. 
 High or deep gravels, California, 279. 
 Hill, R. T., on iron ore in Mexico. 158. 
 Hills, R. C!. , cited on the chemistry of 
 
 replacement, 34. 
 On the Little Annie mine, Colo., 
 
 246. 
 On the vein systems of the San 
 
 Juan, 240. 
 Zone of enrichment in the mines 
 
 of the Summit district, Colo., 
 
 39, 40. 
 Hinsdale Co., 239. 
 Hoefer, H., cited on faults, 19. 
 Hogan Mountain, Mo., 134. 
 Homestake mine, Eagle Co., Colo., 245. 
 Honorine mine, Utah, 228. 
 Horizon defined, 5. 
 Horn Silver mine, Utah, 229, 
 Horses of barren rock in a vein. 36. 
 Hot Springs iron mines, Colorado, 88, 
 
 144. 
 Huerfano Co., Colo., 246. 
 Humboldt Co., Nev., 266. 
 
 Antimony, 301. 
 Humboldt-Pocahontas mine, Custer Co., 
 
 Colo., 247. 
 Humboldt Range, Nev., 265. 
 
 On the iron mines of the Adiron- 
 dacks, 140. 
 Hurd iron mines. New Jersey, 142. 
 
INDEX. 
 
 335 
 
 Hysteromorphic ore bodies, 65. 
 
 Ibapah range, Utab, 259. 
 
 Ice, veins of, on Mount McClellan, 
 
 Colo., 245. 
 Idabo, geology, 356. 
 
 Lead silver ores, 235, 336. 
 
 Tin, 325. 
 Idabo Springs, Colo., 248. 
 Iddings, J. P., on basaltic columns, 13. 
 
 On tbe Comstock lode, 367, 370, 
 271. 
 Idiogenites, 65. 
 
 Igneous roclis, defined and rougbly 
 classified, 6. 
 
 Forms assumed by, 11. 
 Illinois lead and zinc mines, 189. 
 Independence, Colo., 245. 
 lugersoU granitic knob, witb tin ore, 
 
 334. 
 International Geological Congress, 1885, 
 classification recommended by, 
 3,4. 
 Inyo Co., Cal., antimony, 301. 
 Ion defined, 58. 
 Iowa iron ores, 88. 
 lovpa lead and zinc mines, 189, 
 Ireland, bog ore, 83. 
 Iridium, vpitb platinum, 333. 
 Iron Co., Utab, 360. 
 
 Magnetite, 151. 
 
 Literature, 151. 
 Iron hat, 38. 
 
 Iron Hill, Leadville, Colo., 317. 
 Iron in rocks, 78. 
 
 Iron King iron mine, Colorado, 144. 
 Iron Mountain, Colo., 144. 
 Iron Mountain, Missoula Co., Mont., 
 
 256. 
 Iron Mountain, Mo., 134, 153. 
 
 Bibliography, 136, 137. 
 
 Porphyries, 135. 
 Iron ores, bibliography of general pa- 
 pers, 75. 
 
 Brown hematite ore, 79-94. 
 
 General remarks on, 76-79. 
 
 Impurities, 77. 
 Iron ore, magnetite, 137, 153. 
 Iron ore localities: 
 
 Adirondack Mountains, 138, 140. 
 
 Alabama, 93. 
 
 Clinton ore, 103, 106. 
 
 Colorado, 98. 
 
 Connecticut, 89-94, 100. 
 
 Cuba, 1.58. 
 
 Georgia, 93. 
 
 Clinton ore, 105. 
 
 Hesse, Germany, 83. 
 
 Ireland, 82. 
 
 Kentucky, 97. 
 
 Clinton ore, 103. 
 
 Iron ore localities: 
 Maryland, 91. 
 
 Clinton ore, 104. 
 Massachusetts, 89-93, 88. 
 Mexico, 158. 
 Michigan: 
 
 General outline. 111. 
 
 Marquette district, 105.116-119. 
 
 Monominee district, 131, 123. 
 
 Penokee-Gogebic district, 132. 
 Minnesota: 
 
 Vermilion district, 135, 137. 
 
 Mesabi range, 127. 
 Missouri : 
 
 Cambrian, 110. 
 
 Iron Mountain, 134. 
 
 Lower Carboniferous, 109. 
 
 Pilot Knob, 132. 
 Mississippi, 98. 
 Montana, 68. 
 New Jersey, 90. 
 New York, 89, 94. 
 
 Burden mines, 98. 
 
 Clinton ore, 103. 
 
 Jefferson Co., 110. 
 
 Wawarsing, 100. 
 North Carolina, 93, 98. 
 
 Specular, 133. 
 Nova Scotia, Clinton ore, 108. 
 Ohio, 97. 
 
 Clinton ore, 102, 103. 
 Oregon, Port Townsend Bay, Port- 
 land, 83. 
 Pennsylvania, 96. 
 
 Adams Co., 94. 
 
 Franklin Co., 83. 
 
 Huntingdon Co., 83. 
 
 Lehigh Co., 90, 93. 
 
 York Co., 85, 90, 93, 94. 
 
 Clinton ore, 103. 
 
 Mansfield ores, 109. 
 Tennessee, 91. 
 
 Clinton ore, 104. 
 Vermont, 89. 
 Virginia, 89-91. 
 
 Clinton ore, 104. 
 West Virginia, 97. 
 
 Clinton ore, 104. 
 
 Oriskany ore, 109. 
 Wisconsin, Clinton ore, 102. 
 
 Menominee district, 121, 122. 
 
 Penokee-Gogebic district, 122, 
 124. 
 Wyoming, 98. 
 Iron ore, pyrite, 154, 155. 
 
 Red and specular hematite, 103-137 
 Iron ores: 
 
 Siluro-Cambrian limonites. 89-94. 
 Spathic, 95-100. 
 Statistics, 157. 
 
336 
 
 INDEX. 
 
 Iron ores: 
 
 Swedish lakes, 83. 
 Table of and compositions, 76. 
 Irving and Van Hise on the Marquette 
 district, 115, 116. 
 Origin of the ores, 120. 
 Irving, E. D., cited on Silver Islet, 236. 
 On replacement, 33. 
 Penokee-Gogebic district, 124. 
 Ishpeming, Mich., gold, 292. 
 Isle Royale, Lake Superior, 166, 168, 
 
 171. 
 Izard limestone, 307. 
 Jacque Mountain, Summit Co., Colo., 
 
 245. 
 James River, Va., iron ores, 131. 
 Jasper Co., Mo., zinc and lead mines, 
 
 196. 
 Jayville iron mines. New York, 140. 
 Jefferson Co., N. Y. , iron ore, 112. 
 Jefferson Co., Mont., 253. 
 Jefferson Co. , Mo. , lead and zinc mines, 
 
 194. 
 Jenney, W. P., cited on Arkansas sil- 
 ver mines, 235. 
 On lateral enrichments, 37. 
 On lead ores of southeastern Mis- 
 souri, 187. 
 On lead and zinc mines of the Mis- 
 sissippi Valley, 192. 
 On mines of Mississippi Valley, 
 
 327. 
 On the Head Center mine, Tomb- 
 stone, Ariz., 31. 
 On zinc and lead mines of south- 
 western Missouri, 198. 
 Johnson, L. C. , on Louisiana iron ores, 
 
 87. 
 Joints defined, 12. 
 Jones mine, Penn., 150. 
 Joplin, Mo., zinc and lead mines, 171, 
 
 195-199. 
 Josephine Co., Oregon, 274. 
 Juab Co., Utah, 259. 
 Julien, A. A., action of organic acids 
 on rocks, 21. 
 Cited on the origin of magnetite, 
 153. 
 Juragua Hills, Cuba, iron ores, 157. 
 Kaolinization at the Comstock lode, 
 
 269. 
 Kelley lode. New Mexico, 214. 
 Kemp" J. F., scheme for the classifica- 
 tion of ore deposits, 53-55. 
 On Missouri lead deposits, 187. 
 Kennedy, W., on Texas iron ores, 87. 
 Kentucky, lead and zinc ores of Liv- 
 ingston Co., 194. 
 Clinton ore, 103. 
 Limonite or brown hematite orej,85. 
 
 I Kentucky, spathic ores, 97. 
 Kern Co., Cal., antimony, 301. 
 Kerr, W. C, on North Carolina gold, 
 
 291. 
 Keweenaw Point, Mich., copper, 166, 
 
 171. 
 Kimball, J. P., cited on the Burden 
 mines. New York, 98. 
 On Cuban iron ores, 157. 
 On Jefferson Co., N. Y., red hema- 
 tites, 113. 
 On origin of siderite, 101. 
 King, C, on the Comstock lode, 267, 
 
 268. 
 Kinahan, J. H., cited on joints, 13. 
 Kittitas Co. , Washington, gold, 273. 
 Klausen in the Austrian Tyrol, veins 
 illustrating lateral secretion, 31, 
 33. 
 Knob of igneous rock defined, 11. 
 Koehler, G., cited on faults, 19. 
 
 Scheme of classification of ore de- 
 posits, 47. 
 Lahontan Lake, 264. 
 Laccolite defined, 11. 
 Lac la Belle, Keweenaw Point, 169. 
 Lager defined as contrasted with 
 
 " Flotz " and " Gang," 43. 
 Lagoni, cited, 58. 
 
 Lakes, A., cited on Aspen, Colo., 223. 
 Lake Champlain iron region, 138. 
 
 Magnetite sands, 151. 
 Lake Co., Colo., 245. 
 Lake of the Woods, gold district, 295. 
 Lake Superior gold region, 295. 
 Iron ore districts. 111. 
 Mines, 327. 
 Lake Valley, N. M., lead -silver ores, 
 
 214, 215. 
 Lancaster Co., Penn., chromite, 303. 
 Lander Co., Nev. 266. 
 
 Antimony mines, 301. 
 Lane's mine, Monroe, Conn., 302. 
 La Plata Co., Colo., 239. 
 LassensPeak, Cal., 275. 
 Last Chance Gulch, near Helena, Mont., 
 
 245, 255. 279. 
 Lateral enrichments in a vein, 37; se- 
 cretion, 29. 
 Lead City, Black Hills, 251. 
 Leadville, Colo., 185, 216-219. 
 
 Figure of Moyer Fault, 17. 
 Lead minerals, 184. 
 
 Statistics, 188. 
 Leadsilver ores, 214. 
 Lebanon, Penn., 147. 
 Leconte, J., on California gravels, 281. 
 On joints, 13. 
 
 On mercury deposits, California, 
 309. 
 
INDEX. 
 
 337 
 
 Leconte, J., scheme of classification 
 
 of veins, 45. 
 Lehigli Co., Penn., iron mines, magne- 
 tites, 143. 
 Lenses of ore, 63. 
 
 Lesley, J. P., on Cornwall, Penn., 149. 
 Lesser metals, 397-328. 
 Lesquereux, cited on Calif ornia gravels, 
 
 280. 
 Lewis and Clarke Co., Mont., 255. 
 Lewis Mountain, Mo., 234. 
 Lime Creek, Colo., Lower Carbonifer- 
 ous fossils, 233. 
 Limonite, deposits of, 79-95. See also 
 
 under iron ore for geographical 
 
 distribution. 
 Analyses, 95. 
 Lincoln Co., Nev., 264. 
 Lincoln Co., N. M., 238. 
 Lindgren on Wickes, Mont, 226. 
 Lindgren, W., on Calico district, Cal., 
 
 277. 
 On the geology of the California 
 
 gravels, 282. 
 Little Annie mine, Rio Grande Co., 
 
 Colo., 346. 
 Little Belt Mountains, Mont., 356. 
 Little Cottonwood Canon, Utah, 226. 
 Little River iron mines. New York, 
 
 139. 
 Little Rock, Ark., bauxite, 300. 
 Livingston Co., Ky., lead and zinc 
 
 mines, 194. 
 Llano Co. , Texas, copper mines, 166. 
 Lottner-Serlo scheme of classification 
 
 of ore deposits, 47. 
 Louisa Co., Va., mines of pyrite, 154. 
 Louisiana iron ores, 87. 
 Lovelock, Nev., antimony, 301; nickel, 
 
 333. 
 Lowville, Lewis Co., N. Y., lead mine, 
 
 185. 
 Lubeck, Me., lead mine, 185. 
 Lucky Boy mine, 260. 
 LyndUurst, Va., manganese, 305. 
 Lyon Co., Ky., iron ores, 85. 
 Lyon Co., Nev., 266. 
 Lyon Mountain, N.Y., iron ores, 188. 
 Mackenzie River, gold gravels, 295. 
 Madison Co. , Mont. , 253. 
 Magdalena Mountains, N. M., 214. 
 Magna Charta mine, Butte, Mont., 354. 
 Magnet Cove, Ark., magnetite, 87. 
 Magnetite iron ore, 131, 138-154. 
 Analyses, 154. 
 General description, 138. 
 Origin of, 152. 
 
 Origin in igneous magmas, 56. 
 Ore bodies, general relations, 327. 
 Sands, 151. 
 
 Maine tin, 325. 
 Manganese, 366, 304-308. 
 
 Statistics, 308. 
 Mansfield ores, Pennsylvania, 109. 
 Margerie and Heim, cited on faults, 18. 
 Maricopa Co., Ariz., 262. 
 Mariposa Co., Cal., 285. 
 Mariposite, 285. 
 
 Markhamville, N. B., manganese, 308. 
 Marmora, Can., arsenic mine, 302. 
 
 Gold mines, 295. 
 Marquette district. 111. 
 Marshall tunnel, Georgetown, Colo., 
 
 38. 
 Maryland, chromite, 303. 
 
 Clinton ore, 104. , 
 
 Gold mines, 291. 
 
 Limonite, 91. 
 MarysviJle, Utah, 260. 
 Marysville, Mont., 222, 256. 
 Massachusetts, lead mines, 185. 
 
 Limonite, 89-93. 
 
 Spathic ore at Gay Head, 98. 
 McGee, W. J., Appomattox and Colum- 
 bia formations, 5. 
 
 On joints, 13. 
 Meagher Co., Mont., 256. 
 Melaconite, Keweenaw Point, 170. 
 Mendota mines, Keweenaw Point, 170. 
 Menominee district. Lake Superior, 
 
 131. 
 Mercury, 269, 309-311. 
 
 Mines, California, 326. 
 Mercury, mineralogical associates, 311. 
 Mesaba Mountain mine, 129. 
 Mesabi range, Minnesota, 127, 139. 
 Metacinnabarite, 309. 
 Metamorphic rocks, defined and roughly 
 
 classified, 6. 
 Michigan, copper, 166. 
 
 Gold, 292. 
 
 Marquette district, 116-119. 
 
 Menominee, 107, 108, 131, 132. 
 
 Penokee-Gogebic, 122. 
 Middletown, Conn., lead mine, 185. 
 Milan, N. H., mines of pyrite, 154. 
 
 Chalcopyrite, 160. 
 Mine la Motte, Mo , anticlines, 60. 
 
 Lead mines, 186, 187. 
 
 Nickel, 333. 
 Mineral Point, Wis., copper ores, 193. 
 Mineville, N. Y., iron mines, 122, 139, 
 
 140. 
 Mine waters with dissolved metals, 40. 
 Minnesota copper mines, 171. 
 
 Mesabi range, 127. 
 
 Vermilion district, 125, 137. 
 Missabe. See Mesabi. 
 Mississippi, spathic ores at Enterprise 
 97. 
 
338 
 
 INDEX. 
 
 Mississippi Valley, geology, 9. 
 Lead and zinc mines, 189. 
 Relations of ore bodies, 337. 
 Missoula Co., Mont., 256. 
 Missouri, Cambrian bed hematite in 
 Crawford, Dent and Phelps 
 Counties, 110. 
 Copper at St. Genevieve, 171. 
 Iron Mountain, 134. 
 Lead mines of southeastern Mis- 
 souri, 186. 
 Limonite, 86. 
 Lower Carboniferous red hematite, 
 
 99. 
 Pilot Knob, 133. 
 Red hematites, 110. 
 Tin, 325. 
 
 Zinc and lead in the southwest, 195. 
 Mitchell Co., N. C, iron mines, 143. 
 Mohave Co., Ariz., 262. 
 Moisie, Can., magnetite sands of, 151. 
 Monarch district, Chaffee Co., Colo., 
 
 330, 246. 
 Monheim, V., on the origin of willem- 
 
 ite, 310, 
 Monocline defined, 11. 
 Montana, Butte, 137, 163, 163. 
 Montana, geology of, 352. 
 
 Lead-silver ores, 225, 326. 
 
 Silver and gold mines, 332, 253- 
 
 256. 
 Spathic iron ore at Sand Coulee, 
 
 98. 
 Tin. 325. 
 Montville, N. J., 141. 
 Moore, P. N. , on Missouri limonite, 86. 
 Morenci, Ariz., copper district, 173. 
 Moricke, on gold in Chilian volcanic 
 
 rocks, 25. 
 Mosquito range, Colo., 216. 
 In Park Co., Colo., 346. 
 Mother lode, Cal., 285. 
 Mount Baldy, Utah, 260. 
 Mount Davidson, Nev., 367. 
 Mount Hope, K. J., 141. 
 Mount Marshall, near Georgetown. 
 
 Colo., 348. 
 Mount McClellan, Clear Creek Co., 
 
 Colo., 345. 
 Mount Prometheus, Nev., 266. 
 Mount Shasta, Cal., 375. 
 Mule Pass Mountains, Ariz., 176. 
 Munroe, H. S., citation from, 30, 62. 
 Cited on the origin of magnetite, 
 
 153. 
 Scheme of classification of ore de- 
 posits, 52, 53. 
 Murphree's Valley, Ala., 107. 
 Musconetcong iron belt. New Jersey, 
 142. 
 
 Nacemiento copper mines, New Mexico 
 
 261. 
 Nason, F. L., cited on the geology of 
 the Highlands, N. J., 141. 
 
 On geology near Franklin Furnace, 
 N. J., 205. 
 
 On Missouri iron ores, 110, 111. 
 Neck of igneous rock defined, 11. 
 Neihart, Mont., 256. 
 Nelson Co., Va., tin, 325. 
 Neocomiau beds, California, 367. 
 
 Nevada, antimony, 301. 
 
 Geology, 364. 
 
 Lead- silver mines, 230. 
 
 Nickel, 332. 
 New Almaden, Cal., mercury, 309. 
 Newberry, J. S. , cited on the Cave 
 mine, Utah, 339. 
 
 On Clinton ore, 98. 
 
 On Silver Reef, Utah, 360. 
 
 Scheme of classification of ore de- 
 posits, 48, 50. 
 Newberry, W. E., cited on Aspen, 
 
 Colo., 222, 224. 
 New Brunswick, antimony, 301. 
 
 Manganese, 308. 
 New Brunswick, N. J., copper mines, 
 
 181. 
 Newburyport, Mass., lead mine, 185. 
 New Caledonia nickel, 332. 
 New England, outline of geology, 7, 8. 
 New Hampshire, tin, 335. 
 New Idria, Cal., mercury, 309, 310. 
 New Jersey copper ores, 181. 
 
 Iron mines, 141, 143. 
 
 Limonite, 90. 
 
 Outline of geology, 7, 8. 
 
 Zinc mines, 205. 
 New Jersey Zinc and Iron Co.'s mine, 
 
 Franklin Furnace, N. J., 206. 
 Newman Hill, Colo., banded veins, 35, 
 36. 
 
 Figure of faulted vein at, 30. 
 
 Lateral enrichments, 37. 
 
 Mines of, 365. 
 New Mexico, geology, 336. 
 
 Lead-silver mines, 314. 
 
 Silver and gold mines, 336-238. 
 
 Triassic copper ores, 182. 
 
 Zinc, 212. 
 Newton, Amador Co., Cal., copper, 
 
 163. 
 Newton Co., Mo., zinc mines, 196. 
 New York copper mine, Arizona, 178. 
 New York: 
 
 Iron mines of the Highlands, 141. 
 Literature, 143, 143. 
 
 Iron ore of Adirondacks, 138, 139. 
 Literature, 140, 141. 
 
 Lead mines, 185, 186. 
 
INDEX. 
 
 339 
 
 New York: 
 
 Limonite, 89, 94. 
 
 Outline of geology, 7, 8. 
 
 Spathic ore of Burden mines, 98. 
 At Warwarsing, 100. 
 
 Clinton ore, 103. 
 
 Jefferson Co.. 110. 
 Ney Co., Nev., 265. 
 Nicholas, W., cited on precipitation of 
 
 gold, 286. 
 iSTicbolson, F., on tlie St. Genevieve, 
 
 Mo., copper mines, 172. 
 Nickel, Arkansas, 322. 
 
 Nevada, 322. 
 
 Norway, .57. 
 
 Ores and general remarks, 312- 
 314. 
 
 Pennsylvania, 57. 
 Nickeliferous pyrrbotite, igneous or- 
 igin, 56, 57. 
 Northampton, Mass., lead mine, 185. 
 North Carolina, gold mines, 391. 
 
 Limonite, 93. 
 
 Magnetite, 143. 
 
 Literature, 143. 
 
 Nickel, 331. 
 
 Spathic ores, 98. 
 
 Specular ores, 132. 
 
 Tin, 325. 
 Nova Scotia, Clinton iron ore, 108. 
 
 Gold, 294. 
 Nova Scotia, manganese, 308. 
 Oat Hill mercury mine, 309. 
 Ogdensburg, N. J., 204, 205-209. 
 Ohio, Clinton ore, 102, 103. 
 
 Spathic Ores, 97. 
 Okanogan Co.. Wash., 272. 
 Old Dominion copper mine, Arizona, 
 
 178. 
 Oliver mine, Virginia, Minn, 139. 
 Olmstead, I. , cited on the Burden mines, 
 
 New York, 99. 
 Olympic Mountains, 273. 
 Oneida Co., Idaho, 357. 
 Ontario, arsenic mine at Deloro, 303. 
 
 Nickel mines, 315-317. 
 Ontario mine, Utah, 359. 
 Ontonagon, Mich., 269. 
 Ophir Caiion, Utah, 228, 359. 
 Oquirrh Mountains, Utah, 236, 259. 
 Orange Co., N. Y., iron mines, 141. 
 Ore deposits, bibliography, 68-71. 
 Oregon, geology, 273. 
 
 Mercury, 309. 
 Oregon, nickel ores, 331. 
 Ore Knob, N. C, copper mines, 160, 
 
 161. 
 Ores, minerals forming, 23. 
 
 Original source of, 33. 
 
 Of iron, table of, 76. 
 
 Organic matter as a precipitating agent, 
 
 59. 
 Orton, E., cited on dolomitizatiot, 33. 
 Osmium, with platinum, 323. 
 Ouachita uplift of Arkansas, 198, 335, 
 
 337. 
 Ouachita Mountains, Ark., iron ores, 86. 
 Ouray Co., Colo., 339. 
 Owybee Co., Idaho, 257. 
 Oxford, N. J., 141. 
 Ozark uplift, 7, 110, 133, 198, 337. 
 Pacific slope, geology, 10. 
 Pahranagat district, Nev., 365. 
 Palmer Hill iron mines, N. Y., 140. 
 Park Co., Colo., 346. 
 Passaic iron belt. New Jersey, 143. 
 Pearce, R., bismuth with gold in Col- 
 orado, 386. 
 
 On gold ores of Gilpin Co., Colo., 
 248. 
 Pechin, E. C, on Virginia iron ores, 85. 
 Penfield, S. L., on pentlandite, 58. 
 Peninsula copper mines, Michigan, 168. 
 Pennsylvania, Cornwall, 146. 
 Penrose, R. A. F., on Arkansas iron 
 ores, 86. 
 
 On Louisiana iron ores, 87. 
 
 On manganese, 306-308. 
 Pennsylvania, brown hematites. See 
 under Iron, brown hematite. 
 
 Chromite, 303. 
 
 Clinton ore, 103. 
 
 Lead mines, 165. 
 
 Limonite, 83, 90, 93, 94. 
 
 For index of counties see under 
 Iron ores, limonite. 
 
 Mansfield ore, 109. 
 
 Spathic ores, 96. 
 Penokee-Goffebic district, Lake Supe- 
 rior, 133. 
 Pentlandite, 313. 
 
 Pequest iron belt, New Jersey, 143. 
 Perkiomen copper mine, Pennsylvanif , 
 
 181. 
 Phelps Co., Mo., iron ores. 111. 
 Phillips, S. A., scheme of classification 
 
 of ore deposits, 49. 
 Phoenix copper mine, Michigan, 169. 
 Phosphorus in iron ores, 77, 78. 
 Pilot Knob, Mo., 132. 
 
 Bibliography, 136, 137. 
 Pima Co., Ariz,, 263. 
 Pinal Co.. Ariz., 263. 
 Pincbes and swells in a vein, ,37. 
 Pioche, Nov., 264. 
 
 Pipe clays in California gravels, 380. 
 Pitkin, Colo., 245. 
 Piute Co., Utah, 260. 
 Placer Co., Cal., iron ores, 144 
 
 Chromite, 303. 
 
340 
 
 INDEX. 
 
 Placers, 277-384. 
 
 Plateau region of Wyoming, 350. 
 
 Platinum, 833. 
 
 Platoro, Couejos Co., Colo,, 346. 
 
 Point Orford, Ore., 374. 
 
 Poorman lode, Idalio, 357. 
 
 Portage Lake, Michigan, 169. 
 
 Porter, J. B., cited on Clinton ore, 108. 
 
 Port Henry, N. Y. , iron mines near, 
 
 139, 140. 
 Posepny, F. , on the origin of ores, 64. 
 Cited on replacement theory for 
 
 Raibl, 83. 
 Power, F. D., on classification of ore 
 
 deposits, 66. 
 Prairie region, 9. 
 
 Of Wyoming, 350. 
 Prescott, Ariz., 179. 
 Prickly Pear Gulch, near Helena 
 
 Mont. , 355, 379. 
 Pride of the West mine. Eagle Co. 
 
 Colo., 345. 
 Prime, F., and Von Cotta, scheme of 
 
 classification of ore deoosits, 46 
 
 47. 
 Printer Boy mine, Leadville, Colo., 217 
 Prosser mines, Oregon, 83. 
 Psilomelane, 304. 
 Puget Sound, 373. 
 Pumpelly, R., cited on replacement, 88, 
 On suhaerial decay, 59. 
 On Keweenaw Point copper mines 
 
 170. 
 On Missouri iron ores, 110. 
 Scheme of classification of ore de 
 
 posits, 51, 53. 
 Putnam Co., N. T., iron mines, 141. 
 Pyrite, 154, 155. 
 Literature, 155. 
 Origin of, 155. 
 Pyrite ore bodies, general relations, 
 
 337. 
 Pyrolusite, 804. 
 Quaquaversal defined, 11. 
 Quaco Head, X. B., manganese, 308. 
 Quartz veins, 62. 
 Quincy copper mine, Mich., 169. 
 Quicksilver (mercury), 309-311. 
 
 See also under Mercury. 
 Quogue, Long Island, magnetite sands, 
 
 151. 
 Radnor Forges, Quebec, 81. 
 Raibl, Austria, silver-lead deposits, 
 
 originating by replacement, 33. 
 Rainbow lode, Butte, Mont,, 354. 
 Rainier Mountain, 373. 
 Ramapo iron belt, N. J., 143. 
 Ramshorn mine, Custer Co., Idaho, 
 
 ' 357. 
 Ranges of ore deposits, 336, 327. 
 
 Raymond & Ely mine, Piocbe, Nev., 
 
 264. 
 Raymond, R. W., 828. 
 Red Cliff, Eagle Co.. Colo., 245. 
 Red Mountain, Birmingham district, 
 
 Ala., 107. 
 Red Mountain, Mont., 254. 
 Red Mountain, Ouray Co., Colo., 234. 
 Red Rock, San Francisco, manganese, 
 
 308. 
 Reese River district, Nov., banded 
 
 veins, 35. 
 Geology of, 364. 
 Rensselaerite, 113. 
 Replacement, method of vein filling by, 
 
 83. 
 Residual deposits, 61. 
 Reyer, E., on the Marquette ores, 130. 
 Rickard, T. A., on Australian gold- 
 quartz, 388. 
 Rico, Dolores Co., Colo., lead-silver 
 
 mines, 334. 
 Riddle's, Oregon, nickel, 831. 
 Rifting in granite at Cape Ann, Mass., 
 
 13. 
 Rim of deep gravels. California, 379. 
 Rio Grande Co., Colo., 346. 
 River gravels with gold, 377. 
 Roaring Fork Creek, Colo., 333. 
 Robert E. Lee mine, Leadville, Colo., 
 
 317. 
 Robinson mine. Summit Co., Colo., 
 
 330. 
 Rockbridge Co., Va., tin, 335. 
 Rocks, classification of, 6. 
 
 General percentage of iron oxide, 
 
 78. 
 Rockv Mountains, geology, 9. 
 
 Zinc ores, 309. 
 Rogers, H. D., on geology at Franklin 
 
 Furnace, N. J., 305. 
 RoLker, C. M., cited on Colorado iron 
 
 ores, 144. 
 On Silver Reef, Utah, 360. 
 Rominger, C, on the Marquette dis- 
 trict, 115, 116. 
 Ropes mine, gold, Michigan, 293. 
 Rosenbusch, H., cited on succession of 
 
 rock forming minerals, 34. 
 Rosita, Colo., 346, 347. 
 Rothpletz, A., cited on oolites, 59. 
 Rothwell, R. P., on Silver Reef, Utah, 
 
 360. 
 Roubidous sandstone, Mo., 110. 
 Roxbury, Conn., spathic ore, 100. 
 Ruby, Colo., 245. 
 Russell, I. C, cited on Clinton ore, 
 
 108. 
 Russia, platinum, 323. 
 Rye, N. Y., bog ore, 81. 
 
INDEX. 
 
 341 
 
 Sacramento Valley, 277. 
 Saddles of gold-bearing quartz in Aus- 
 tralia, 288. 
 Saguache Co., Colo., 24iX-2iS. 
 Salt Lake Co., Utah, 259. 
 San Benito Co., Cal., antimony, 301., 
 San Bernardino Co., Cal,, iron ore, 145. 
 Sandberger, F., cited on source of ores, 
 
 25. 
 Barite in limestone, 26. 
 On lateral secretion, 30. 
 San Diego Co., Cal., iron ores, 145. 
 San Emigdio, Kern Co., Cal., antimony, 
 
 801. 
 Sangre de Cristo range, Colorado, 246. 
 Sandia Mountains, N. M., 238. 
 San Joaquin Co., Cal., 308. 
 San Juan Co., Colo., 239. 
 
 Bismuth, 302. 
 San Juan Mountains, 239. 
 San Juan region, Colo., 239. 
 San Luis Obispo Co., Cal., chromite, 
 
 303. 
 San Miguel Co., Colo., 240, 279. 
 Santa Fe Co., N. M., 238. 
 
 Placers of, 279. 
 Santa Rita, N. M. , copper mines, 178, 
 
 179. 
 Santa Rita Mountains, 237. 
 Saucon Valley zinc mines, Pennsyl- 
 vania, 204, 205. 
 Schmidt, A., on Missouri iron ores, 
 
 110, 236. 
 On replacement theory as applied 
 
 to Missouri iron ores, 33. 
 On zinc mines of southwestern 
 
 Missouri, 196. 
 Schapbach in the Black Forest, veins 
 
 at, 31. 
 Schuyler copper mine. New Jersey, 
 
 181. 
 Sedimentary rocks defined and roughly 
 
 classified, 6. 
 Forms assumed by, 10, 11. 
 Segregation as applied to magnetite, 
 
 153. 
 Senarmontite, 301. 
 Sevier Co., Ark., antimony, 301. 
 Shasta Co., Cal., chromite, 303. 
 Shear zones defined, 13. 
 Sheet of igneous rock defined, 11. 
 Shepherd Mountain, Mo., 134. 
 Shumagin, Alaska, 254. 
 Siderite, iron ore, 95-100. 
 Genetic relations, 101. 
 Sierra Co., Cal., iron ore, 144. 
 Sierra Nevada, chromite, 303. 
 Sierra Nevada in California, 275. 
 
 Geology of, 289. 
 Sigmoid fold defined, 11. 
 
 Silliman, B., on gold quartz, 284. 
 Siluro-Cambrian limonites, 327. 
 Silver and gold, mode of occurrence, 
 
 233 *^34 
 Silver belt of Utah. 326. 
 Silver Bow Co., Mont., 254. 
 Silver Bow Creek, Butte, Mont., 162. 
 Silver, California, 276. 
 Silver City, Idaho, 257. 
 Silver Cliff, Colo., 246, 247. 
 Silver Islet, Lake Superior, vein illus- 
 trating lateral secretion, 31. 
 
 Literature, 31. 
 
 Mines, 235. 
 Silver King mine, Arizona, 262. 
 Silver minerals, 284. 
 Silver Plume, Colo., 248. 
 Silver Reef, Utah, 182, 260. 
 Silverton, Colo., 241. 
 Silver, Washington, 273. 
 SI ay back lode. New Mexico, 238. 
 Slickensides, or slips, defined, 18, 19. 
 Smithfield iron mine, Colorado, 144. 
 Smuggler Mountain, near Aspen, Colo., 
 
 223. 
 Smyth, C. H., Jr., on Clinton oolitic 
 ores, 101. 
 
 On Clinton ore, 108. 
 
 On Jefferson Co. , N. Y. , red hema- 
 tites, 112. 
 Snake River, Idaho, basalt, 256. 
 
 Placers, Idaho, 279. 
 Socorro Co., N. M., 238. 
 Sonora, Mex., antimony, 802. 
 Soret's principle, 57, 145. 
 South Dakota, lead-silver ores, 225. 
 
 Geology, 250. 
 Southern States, gold, 291. 
 South Mountain, Penn., iron mines, 
 141, 193. 
 
 Literature, 142, 143. 
 South Park, Colo., 246. 
 South Wailingford, Vt., manganese, 
 
 305. 
 Spanish Peaks, Colo., 246. 
 Spathic iron ore, 95-100. 
 Spenceville, Cal., copper mines, 162. 
 Sperrylite, 320, 323. 
 Spurr, J. E., on Mesabiores, 129. 
 St. Clair limestone, Arkansas, 307. 
 St. Frangois Co., Mo., gash veins, 194. 
 St. Genevieve, Mo., copper mines, 171. 
 St. Lawrence Co., N. Y., lead mines, 
 
 184. 
 St. Mary's mine, Penn., 150. 
 Stanley-Browne, J., cited on gold in 
 
 sea beaches, 274. 
 Stannite, 324. 
 
 Star district, Utah, iron mines, 151. 
 Staten Island bog ore, 81. 
 
343 
 
 INDEX. 
 
 Steamboat Springs, iSTev., illustrate in- 
 filtration by ascension, 32. 
 Mercury mines, 309. 
 Stein Mountains, Ore., 273. 
 Stelzner, A. W., cited on source of 
 
 ores, 25. 
 Sterling Hill zinc mines, Ogdensburg, 
 
 N. J., 204-208. 
 Stevens Co., Wash., gold, 372. 
 Stibnite, 301. 
 
 Stokes Co., N. C, magnetite, 148. 
 Storey Co., Nev., 266. 
 Straban, A. , cited on explosive slicken- 
 
 sides, 19. 
 Stream tin, 324. 
 Structure of veins, 35. 
 Sudbury, Ontario, 154. 
 Sudbury, Can., nickel ores, 57, 315, 
 
 317. 
 Sullivan Co., N. Y., lead mines, 186. 
 Sullivan, Me., silver mines, 235. 
 Sulphur Bank, Cal., mercury mine, 
 
 309. 
 Summit Co., Colo., 245. 
 
 Ten. Mile district. 319, 320. 
 Summit Co., Utah, lead silver, 329. 
 
 Silver mines, 259. 
 Summit district, Rio Grande Co., Colo., 
 
 286. 
 Sunrise, Wye, copper, 180. 
 Sweden, lake ore, 82. 
 Sweetwater district, Wyo , 279. 
 Sylvanite mine, Gothic, Colo., 345. 
 Syncline defined, 11. 
 
 Cause of cavities, 14. 
 Tacoma Mountain, 373. 
 Tamarack copper mines, Michigan, 
 
 169. 
 Tarr, R. 3., on rifting, 13; cited; 64. 
 Telegraph mine, Utah, 228. 
 Telluride ores, Colo., 248. 
 Tellurides in gold quartz, 284. 
 Temescal tju mines, California, 335. 
 Tem Pahute district, Nev., 365. 
 Ten-Mile district, Colo., 319, 245. 
 Tennessee, Clinton ore, 104. 
 Tennessee, limonite, 86, 91. 
 Tenny Cape, N. S., manganese, 308. 
 Terrane defined, 5. 
 Texas, copper, Llano Co., 166. 
 Iron ores, 87. 
 Triassic or Peruvian copper ores, 
 
 182. 
 Thiess-Hutchins antimony mines, Nev., 
 
 301. 
 Three Rivers, Quebec, bog ores, 80. 
 Thunder Bay, Lake Superior, 336. 
 Tilly Foster iron mine, N. Y., 141, 143. 
 Tin," 324, 325. 
 Tin Cap, Colo., 245. 
 
 Tintec district copper mines, Utah, 180. 
 
 Utah iron ores, 88. 
 
 Lead-silver, 238. 
 
 Other silver mines, 359. 
 Titaniferous magnetite, 140, 145. 
 
 In the Adirondacks, 145. 
 
 In Canada, 145. 
 
 Colorado, 146. 
 
 Minnesota, 146. 
 
 New Jersey, 146. 
 
 North Carolina, 146. 
 
 Norway, 146. 
 
 Virginia, 146. 
 Tombstone district, Arizona, 363. 
 Tooele Co., Utah, 338, 259. 
 Tourtelotte Park, near Aspen, Colo., 
 
 323. 
 Toyabe range, Nev., 366. 
 Treadwell mine. Alaska, 394. 
 Triassic copper ores, 180-183. 
 
 Copper mines, general relations, 
 337. 
 Trigg Co. , Ky. , iron ores, 85. 
 Trotter zinc mine, Franklin Furnace, 
 
 N. J., 306. 
 Tucson, Arizona, 363. 
 Tuolumne Co.. Cal., 385. 
 Turner, H. W., on the California grav- 
 els, 283. 
 Tuscarora district, Nev., 366. 
 Tybo, Nev., 265. 
 Ueberroth zinc mine, Penn., 204. 
 Uintah Mountains, 10, 258. 
 Ulster Co., N. Y., lead mines, 186. 
 U. S. Antimony Co., Philadelphia, 301. 
 United States Geological Survey, 
 terms used by in geological 
 classification, 4. 
 
 Results of work in the Sierras, 283. 
 United States, general geology, 7-10. 
 
 General topography, 6, 7. 
 Uralitization in the rocks of the Corn- 
 stock lode, 270. 
 Utah, antimony, 301. 
 
 Copper, 180. 
 
 Geology, 258. 
 
 Iron ores, 88. 
 
 Lead-silver ores, 226-330. 
 
 Magnetite, 151. 
 
 Silver mines, 326. 
 
 Triassic copper ores, 182. 
 Vadose circulations, 65. 
 Van Diest, P. H., on Boulder Co., 
 
 Colo., 348. 
 Van Dyck, F. C. , analysis by, 307. 
 Van Hise, C. R., cited on replacement, 
 33. 
 
 On the Marquette district, 115, 116. 
 
 On the Penokee-Gogebic district, 
 Lake Superior, 134. 
 
INDEX. 
 
 343 
 
 Veins, metlaods of filling, 28. 
 
 Verde River, Ariz., 179. 
 
 Vermilion district, Lake Superior, 135. 
 
 Vermilion Lake iron ores, origin of, 
 
 60, 61. 
 Vermont, copper ores, 160, 161. 
 
 Limonite, 89. 
 Versliire, Vt. , mines of pyrite, 154. 
 
 Chalcopyrite, 160. 
 Virginia, Clinton ore, 104. 
 
 Limonite or brown hematite, 91. 
 
 Louisa Co., pyrite, 154. 
 
 Magnetite, 143. 
 
 Manganese, 305. 
 Virginia City, Mont., 353. 
 Vogt, J. H. L., on nickel ores, 57, 330. 
 
 On the origin of pyrite bodies, 156. 
 Von Herder, on filling of veins, 38. 
 Von Richthofen, on the Comstock lode, 
 
 367-370. 
 Vuggs of a vein, 35. 
 Wadsworth, M. E., on the Marquette 
 district, 115, 116. 
 
 On Silver Islet, 336. 
 
 On classification of ores, 64. 
 
 Origin of the ores, 118. 
 Wagon Wheel Gap, Colo., 343. 
 Wall rock of veins, precipitating influ- 
 ence of, 81. 
 Wardner, Idaho, lead-silver ores, 336. 
 Warren or Bisbee copper district, Ari- 
 zona, 176. 
 Warrior coal field, Ala., 107. 
 Wasatch Mountains, 9, 358. 
 Washington Co., Mo., lead and zinc 
 
 mines, 194. 
 Washington, geology, 372. 
 Washoe Co., Nev., 266. 
 Webb City, Mo., zinc and lead mines 
 
 near, 195-199. 
 Webster, N. C, nickel. 321. 
 Weed, W. H., on siliceous sinters, 59. 
 Weissenbach, Von, scheme of classifi- 
 cation of ore deposits, 44. 
 Wendt, A. F. , on Arizona copper mines, 
 
 175. 
 Western sandstone, Keweenaw Point, 
 
 168. 
 Westport, N. Y., iron mines, 138. 
 West Virginia, Clinton ore, 104. 
 
 Oriskany, red hematite, 109. 
 
 Spathic ores, 97. 
 Wet Mountain Valley, Custer Co., 
 
 Colo., 246. 
 Wheatfield mine, Penn., 150. 
 Wheatley lead mine, Penn., 165. 
 White Pine Co., Nev., 265. 
 Whitney, J. D., cited on Missouri ores, 
 136. 
 
 On California gravels, 281. 
 
 Whitney, J. D., on gold veins, 286. 
 On lead and zinc veins of the Mis- 
 
 sissipi Valley, 191. 
 On Washington Co., Missouri, lead 
 
 and zinc mines, 194. 
 Scheme of classification of ore de- 
 posits, 48. 
 Wickes, Mont., lead-silver mines, 336, 
 
 854. 
 Williams, J. P., on Arkansas bauxite, 
 
 397. 
 Willis, B., on Cornwall, Penn., 149. 
 Willow Creek, near Creede, Colo., 343. 
 Wiltsee, E., on the Half Moon mine, 
 
 Pioche, Nev., 264. 
 Winchell, H. V., on Mesabi ores, 139. 
 Winchell, N. H. and H. V., cited on 
 origin of Vermilion Lake iron 
 ores, 63. 
 Winchell, N. H., cited on the Vermil- 
 ion Lake district, 125. 
 Winchell, H. V., on origin of ore, 127 
 Winslow, A., on Missouri lead and zius 
 
 200. 
 Winslow, tin, 325. 
 
 Wisconsin, Clinton ore, Dodge Co., 102. 
 Lead and zinc mines, 189. 
 Menominee district, 121, 122. 
 Penokee-Gogebic district, 132, 124. 
 Wood River mines, Idaho, lead-silver, 
 
 225, 257. 
 Woods mine, chromite, 308. 
 Wright, C. E., origin of Lake Supe- 
 rior ores, 120. 
 Wyoming copper mines, 180. 
 Geology of, 250. 
 Iron mines, 144. 
 
 Iron ore near Fort Laramie, 132. 
 Spathic iron ore, 98. 
 Specular ore near Fort Laramie, 
 
 133. 
 Tin ores, 325. 
 Wythe Co., Va., zinc, 201. 
 Xenogenites, 65. 
 Yakima Co., Wash., gold, 272. 
 Yakutat Bay, Alaska, 274. 
 Yarmouth, N. S., 294. 
 Yavapai Co., Ariz., 362. 
 York Co., N. B., antimony, 301. 
 Yuma Co., Ariz., 263, 363. 
 Yukon River, Alaska, 393. 
 Zinc minerals, 204. 
 Zinc ores at Hanover, N. M., 362. 
 In Rocky Mountains, 311. 
 Virginia, 201. 
 Statistics, 313. 
 Zirkel, F., on the rocks of the Com- 
 stock lode, 370. 
 Zone of oxidized ores in a vein, 38. 
 Of sulphides, 38. 
 
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