DUKE UNIVERSITY LIBRARY Digitized by the Internet Archive in 2016 with funding from Duke University Libraries https://archive.org/details/deeprivercoalfie01camp NORTH CAROLINA GEOLOGICAL AND ECONOMIC SURVEY JOSEPH HYDE PRATT, Director and State Geologist BULLETIN No. 33 The Deep River Coal Field of North Carolina BY MARIUS R. CAMPBELL and KENT W. KIMBALL N ti 3fi ?/'? fn> *Y TlT T / Cnwu* . I 6 ^ ft 557. 5C K873 B TiO . 33' LETTER OF TRANSMITTAL Chapel Hill, 1ST. C., June 1, 1923. To //is Excellency, Cameron Morrison, Governor of North Carolina. Sir : — There has just been completed a report on “The Deep River Coal Field of North Carolina,” which has been prepared by the State Survey in cooperation with the United States Geological Survey. The investigation of this coal field has aroused a great deal of interest throughout the State in regard to the occurrence of a commercial quantity of coal in North Carolina. There is a very large demand for information regarding this occurrence, and I would submit the report for publication as Bulletin No. 33 of the series of publications of the North Carolina Geological and Economic Survey. Yours respectfully, Joseph Hyde Pratt, Director, North Carolina Geological and Economic Survey. % 2 0 (o<3 TABLE OF CONTENTS Page Preface 7 Introduction ! 11 General statement 11 History of discovery and development 12 Present investigation 16 Geography of the field 17 Geologic formations 18 General statement IS Pekin formation 21 Cumnock formation 25 General statement 25 In the Carthage trough 28 As offset by the Deep River fault 35 In the Corinth trough 41 Sanford formation 43 Igneous dikes 45 Geologic structure 49 General statement 49 Carthage trough 50 General description 50 Minor structures 51 Colon cross-structure 54 Corinth trough 55 Jonesboro fault 55 History of the development of geologic structure 60 General statement 60 Deformation accompanying sedimentation — 60 Torsional stresses resulting in cross-structure 61 Normal faulting in a longitudinal direction 62 The coal 64 Thickness of the coal beds 64 Extent of workable coal and available tonnage 76 Character of the coal SO Tests by the Bureau of Mines - S6 Possibilities of Petroleum 01 LIST OF PLATES Plate Page 1 Map of the Deep River Coal Field In pocket 2 A. Deep River from the Horseshoe Bridge 18 B. Outcrop of the Cumnock coal bed near Gulf 18 3 The Cumnock coal mine 28 4 A. Boulders of schist in the Sanford formation 44 B. Boulder of granite in the Sanford formation 44 5 A. Minute dikes euting red saudstoue 48 B. Sandstone tilted by a dike 48 6 A. Hydroelectric plant at Carbonton 54 B. Dike cutting shale irregularly 54 7 Jonesboro fault in railroad cut 60 Figure 1 Section of Cumnock formation, as exposed in the Cumnock shaft and in boreholes on the Cumnock property 27 2 Cross sections showing the probable effect of the Carbonton fault on the outcrop of the Cumnock formation between Carbonton and Horseshoe Bend of Deep River 32 3 Diagram showing various forms that normal faults may assume 53 4 Diagram showing the character of the Jonesboro fault 59 5 Sections of coal beds 66 6 Graph illustrating comparative heating values of competing coals 86 7 Diagram showing form of oil pools in an anticline 93 - ■ : ; * PREFACE For about one hundred and fifty years coal has been known to occur in North Carolina, and for many years there has been more or less interest aroused amongst our people as to the possibility of developing commercial fields of coal. Considerable prospecting and some mining has been done during this period, but most of the work was a failure due to several causes, chief of which perhaps was lack of capital and having men unfamiliar with coal mining in charge of operations. As a result the public began to consider that either the coal was so poor or the mining conditions so bad that it was doubtful if coal mining could ever be made to pay. This was probably a natural sequence considering what was known of the occurrence of some of the coal which was in very thin seams and obviously could not be worked profitably. Also considerable of the coal that was first used was weathered and did not have the heating properties expected of it. The present investigation was undertaken with the idea that the coal of the Deep River Field is much more valuable than has been generally believed and that it should become a source of fuel, not only for mills and railroads of Eastern North Carolina, but for a domestic use in the form of coke. There are two areas in the State in which coal occurs : one known as the Deep River Coal Field covering portions of Chatham, Lee and Moore counties, and which is described in detail in this report ; and the other, the Dan River Coal Field covering portions of Stokes and Rock- ingham counties. The coal beds of both these fields occur in sandstones and shales of Triassic age, which outcrop in comparatively narrow belts. The Dan River Field has been described in detail by Mr. R. W. Stone, Geologist of the United States Geological Survey, in Economic Paper 34, 1914, pages 115-149, of the State Survey’s publications; and the conclusion reached in regard to this coal field was that “after a thorough and careful examination of the Triassic beds in the Dan River Field the conclusion is reached that there is no reason to expect to find commercially valuable coal beds in this district.” This report sub- stantiated the information that the Survey had regarding this field, and since this report came out there has been no further prospecting or consideration given to this field from a commercial standpoint. The Deep River Coal Field has been investigated from time to time over a period of nearly one hundred years, but only one of these investigations was more than a superficial examination. This was the PREFACE report of Dr. H. M. Chance, made in 1884-85 for the North Carolina Department of Agriculture. Dr. Chance’s conclusions, which were not particularly favorable and which are discussed in this report, were that in the area described “the prospects are sufficiently encouraging to warrant a thorough exploration of each individual tract by the landowners; that in the area between Farmville and Gulf two beds of coal exist that may be considered workable.” In discussing the subject the authors give a very interesting history of the discovery and development of coal in this field. It seems evident that the coal was discovered at Gulf some time prior to 1775, and from that time to the present there has been considerable uncertainty as to the quantity and quality of the coal in the area. The geography of the field shows it to extend from a short distance northeast of Cape Fear River in a southwesterly direction to Carthage and in the other direction from Sanford on the southwest to a few miles beyond Gulf on the northwest, embracing portions of Chatham, Lee and Moore counties. It is known and designated as the Deep River Coal Field because almost all the prospecting and developing has been on or near that stream from near Glendon to the point where Deep and Haw rivers unite to form the Cape Fear. The area in which the presence of coal has been demonstrated is only a small part of the area outlined above. The geologic formations and structure cover a considerable portion of the report and are discussed in great detail. The coal beds are associated with sandstones and shales which are of Triassic age and belong to the Newark group. This Newark group of rocks includes the red sandstones of the Connecticut Yalley in Connecticut and Massachusetts, and the red sandstone and shale of Virginia. This Newark group in the Deep River Field consists of three generally recognized parts : a lower formation to which the name Pekin has been given, composed largely of red and brown sandstone; a middle forma- tion of light colored or drab shale, sandstone and coal beds, to which has been given the name Cumnock ; and an upper formation called the Sanford, consisting mainly of red conglomerate of great though unknown thickness. This portion of the report also describes the character and location of the dikes cutting through the formations, and faults that were noted; and shows cross-sections of the formation at various places throughout the area. A geologic map of the area also accompanies the report. In describing the coal, attention is called to the occurrence of two oenches known as the upper and lower. Formerly in speaking of the thickness of the coal beds both benches were included in the width PREFACE 9 given as seven feet six inches, and it is believed that this entire thickness was originally mined. It is only the upper bench, where the coal varies in thickness from three feet to nearly four feet, that is considered at the present time as commercial coal, although it is believed that under certain conditions this lower bench might be mined and cleaned profitably. The extent of the workable coal and available tonnage is estimated by the geologists as approximately sixty-eight million tons of recoverable coal in the district west of the Deep River fault; and that mining can be carried on profitably to a depth of two thousand feet. The area in which this tonnage is included is about twenty-five square miles, and it is considered reasonable to assume that the coal bed throughout this area averages at least three feet in thick- ness of recoverable coal. The character and quality of the coal have been very carefully studied and physical and chemical analyses are given of coal taken from various sections of the area. One interesting feature of the chemical composition of the coal is that it contains approximately two per cent of nitrogen, which could be obtained in the form of ammonium sulphate as a by-product in coking the coal, which would give approximately twenty-three pounds per ton of coal. The coking test showed that the coal would make a coke of very good quality in so far as could be determined by a laboratory test and is fairly equal to either Freeport or Pittsburgh cokes. It is believed that one use of the Deep River coal that should be given careful considera- tion is to coke it, using the coke obtained as a domestic fuel, and the yield of gas for generating electric power for transmission. The ammonium sulphate, obtained as a by-product, will be of large value for agricultural purposes. There would also be obtained as another by-product approximately twenty-two gallons of tar (dehy- drated) per ton of coal. The by-product yield in coking this coal compares very favorably with yields from Freeport coal. The report also discusses briefly the possibilities of oil in the area, and the conclusions of the geologists are that from a geological point of view all the evidence collected in the field bearing on this question is of a negative character. The present report has been prepared through the cooperation of the United States Geological Survey and the ISTorth Carolina Geological and Economic Survey. Geologists were detailed from the Federal Survey staff to make the investigation. The United States Bureau of Mines also cooperated in the investigation by sampling the coal and making chemical and physical analyses and washing and coking tests of same. 10 PREFACE The Director of the Survey, who made several trips into the field during the investigation, wishes to extend the thanks of the Survey and of the geologists making the investigation to the citizens of the community for their kindness and courtesy in assisting in securing data on the mineral resources of the area. Others who were particularly interested in the coal itself were most liberal in giving their services and means at all times, and the Survey desires at this time to express its special thanks to Mr. Charles Reeves of Sanford, Mr. William Hill of Cumnock, Mr. Bion Butler of Southern Pines, Mr. J. S. Cox of the Norfolk Southern Railway, General E. F. Glenn of Glendon, Dr. M. E. Street of Carthage, and Mr. Mclver, for these services. While the history of coal mining operations in this Deep River Field has been one of many failures due to lack of adequate capital to develop a mine under the prevailing mining conditions, to lack of experience in coal mining of those in charge of the work, and to lack of adequate transportation facilities, today, on account of changed conditions of marketing and transportation facilities and the thousands of homes calling for domestic fuel supply, there seems to he no reason why the mining operations should not be reasonably successful. This of course is predestined on there being an adequate supply of coal that can be obtained at moderate cost, the probability of which is discussed in this report. Director, North Carolina Geological and Economic Survey. The Deep River Coal Field of North Carolina by MARIUS R. CAMPBELL and KENT K. KIMBALL INTRODUCTION General Statement The Deep River coal field of ISTorth Carolina (see Key map on PI. 1 in pocket), although it has been known for about 150 years, has had an unfortunate history of failure after failure in attempts to mine and market the coal, until the general public has either forgotten that such a coal field exists, or is strongly imbued with the idea that the coal is so poor and the mining conditions are so bad, that it is doubtful if it ever could be made to pay. The present report contains the results of a recent examination by geologists of the United States Geological Survey cooperating with the ISTorth Carolina Geological and Economic Survey, which shows that the coal is of excellent quality; that the mining conditions are fairly good for a rather steeply dipping coal bed; and that the general conditions in the surrounding region are favorable for the development, on a larger scale than has ever been attempted, of that part of the margin of the trough extending from Cumnock (PL 1, in pocket) south westward at least to Carbonton, and possibly from Cumnock for a few miles southeastward toward Colon. The coal beds of the Deep River Field occur in sandstone and shale of Triassic age, which crop out in a comparatively narrow belt from Oxford near the northern border of the State to the South Carolina line, twelve or fifteen miles west of Pee Dee River. Coal has been reported at many places in this belt, but the only known coal of com- mercial importance is found on Deep River, west and northwest of Sanford. It was found necessary, before attempting a study of geologic con- ditions in the Deep River Field, to make a base map upon which the geologic data could be plotted, as no map of this region, worthy of the name, could be found. The map, shown in Plate 1, is the result of a survey carried on by the junior author assisted by William J. Cox and Lynn J. Adcock, and much of the success of the report is due to the indefatigable work of these men in covering the ground in the appointed time. The survey was made with plane-table and telescopic alidade and distances were determined by stadia measurements. When the major part of the map had been completed it was found that the 12 THE DEEP RIVER COAL FIELD dikes, which are present in great numbers, are magnetic and have a decided influence on the magnetic needle of the plane-table. As courses were determined by this needle, any local attraction produced by a dike would tend to cause an error in the direction of the line being surveyed. Owing to this source of local attraction many errors will be found in the directions of the roads, and the geographic relations of features shown on the map may be quite different in detail from the relations of the same features on the ground ; but, as the local variation due to one dike may be in an opposite direction from that due to another dike, the effect of one tends to neutralize the effect of the other and for that reason the map, taken as a whole, is approximately correct. The public is, however, cautioned against depending, in im- portant matters, solely upon this map for distances and directions of surveyed lines and acreage inclosed by such lines. In carrying on both the topographic and the geologic work in this field, the writers found the citizens, as a rule, willing and anxious to help in securing data on the mineral resources of the country; and as it is impossible to enumerate individuals who furnished information of this sort, the writers wish to extend their thanks to all for their kindness and courtesy. Those who are most deeply interested in the coal itself contributed in many ways to the success of the work; chief among those who gave their services and means at all times are Mr. Charles Reeves, who assisted very materially by furnishing information regarding coal prospects, maps, and the result of drilling operations of the Carolina Coal Company; Mr. William Hill, then General Manager of the Cumnock Coal Company, who assisted the writers in gathering information concerning the Cumnock mine, the prospecting work that had been done by the Cumnock Coal Company and the logs of deep wells which the company had drilled on its property; Mr. Bion Butler of Southern Pines, who furnished geologic data which has been of great value in solving some of the difficult problems encountered in the field, and without which the writers would have found it impossible to have completed their work in the time alloted for that purpose; and Mr. J. S. Cox, local superintendent of the Horfolk Southern Railroad for a motor car trip over this line from Hemp to Raleigh. General E. F. Glenn, Doctor M. E. Street and Mr. Mclver were also helpful in furnishing information regarding general conditions and in assisting the writers in getting about the field. History of Discovery and Development The history of the discovery and development of coal in this field has never been recorded in print, and consequently much of it has been lost, or if preserved, it exists only in tradition. THE DEEP RIVER COAL FIELD 13 The first published account of coal that the writers have discovered is contained in a letter written by Professor Olmsted 1 from Chapel Hill in 1820. In this letter he says : An extensive secondary formation lias lately been discovered near us. On the road between this place and Raleigh, traveling eastward, we come to it four miles from the college; but at another point it has been discovered within two miles of us. It is a sandstone formation . . . It was natural to look for coal here and I have for some time directed the attention of my pupils, and of stonecutters to this object. Two or three days since one of the latter brought me a handful of coal, found in this range, on Deep River, in Chatham County, about 20 miles south of this place. The coal is highly bituminous, and burns with a very clear and bright flame. It is reported that a sufficient quantity has already been found to afford an ample supply for the blacksmiths in the neighborhood. From the quotation just given, it would seem that the Deep River coal was discovered only a few years before 1820. It is, however, probable that it had been known locally for many years, but had not been brought to the attention of the State Geologist. This view of the case is substantiated by Professor Olmsted’s 2 3 statement in his report of 1824, which is as follows : In addition to the foregoing presumptions that coal might be found in the district of country under consideration, we have it in our power to say that coal has actually been discovered in this region, and that a bed of consider- able extent has been opened not far from the Gulf3 on Deep River. It is about 50 years since this coal bed was first discovered. Mr. Wilcox, an enterprising gentleman, proprietor of the Old Iron Works at the Gulf, took some pains to have it opened, and to introduce the coal into use. Professor Emmons 4 corroborates this statement in his report of 1852 in which he says : “It [the Horton mine at Gulf] was known in the Revolution, and a report made to Congress, respecting it, is still extant.” The writers have searched for this report, but have not been able to find it. It also is probable that the outcrop of the coal beds from Farmville to Carbonton was known and prospected in the early part of the nineteenth century. Chance 5 says: Coal was dug from open pits for blacksmithing in the Deep River coal field early in this, if not indeed in the last century, but no systematic attempt was 1 01msted, Prof. D., Red sandstone formation of North Carolina, Am. Jour. Sci., vol. 2, page 175, 1820. 2 See manuscript, page 5. 3 The name Gulf was given to the settlement at the sharp bend of Deep River, by boat- men who found here an unusually deep portion of the river between shallows formed by the dikes where they cross the stream. ‘Emmons, Ebenezer, Report of Professor Emmons in his Geological Survey of North Carolina, p. 131, Raleigh, 1852. “Chance, H. M., Report on North Carolina coal fields to the Department of Agriculture, p. 23, Raleigh, 1885. 14 THE DEEP RIVER COAL FIELD made to open the field to market until the slackwater improvement of the Deep River. As these improvements were seriously damaged by floods sood after the completion, the people were discouraged from further attempts at that time. The next attempts were made upon the completion of the rail- road from Fayetteville to Egypt and the Gulf. Some coal was shipped ovei this road from the shaft at Egypt, but the cost of transportation to Fayette- ville and trans-shipment and towing down the Cape Fear River to Wilming- ton ... on a river full of shoals, was doubtless too great to leave any profit. Operations were most actively pushed in the period immediately preceding the [Civil] war. During the war coal was mined at Farmville, Egypt, Gulf, and the Evans’ place, and shipped by river to Fayetteville and to Wilmington, where it was used to some extent by blockade runners, but the aggregate amount thus shipped must have been quite small. From tlie quotations given above and from information gathered in the field it seems evident to the writers that the coal of this field was discovered at the Gulf some time previous to 1775 and that the Horton coal mine was in operation at that place at least some of the time during the Revolution, but without doubt the mine was operated in a small way to supply local needs. It is also probable that within the next 50 years after the Horton mine was opened the outcrop of the coal bed had been prospected and was fairly well known from Farmville (now the Carolina coal mine) at least as far as Gulf. Peter Evans, who owned the plantation in the great northward bend of Deep River, including the village now known as Cumnock, began mining coal, it is reported, on his property, then called Egypt 1 in 1830. In 1851 the Egypt plantation was sold to L. J. Houghton and Brooks Harris. Harris soon acquired the interest of Houghton, and in 1852 sank the Egypt shaft, probably the most important single piece of development work ever undertaken in this coal field. The shaft pierced the principal or Cumnock coal bed at a depth of 430 feet, but was continued to a total depth of 460 feet. The property changed hands frequently, and in 1854 passed into the ownership of the Governors Creek Steam Transportation and Mining Company, which operated the mine until after the Civil War when, by order of the Convention, the name was changed to “The Egypt Company.” The market for this coal was then largely to the east and the great problem was to get it to seacoast cities at a cost that would enable it to be sold at a profit, in competition with coals from other fields. Two lines of outlet for the coal were considered: (1) an all-water 1 The original name of the settlement on this plantation was LaGrange. but this name was changed by Peter Evans to Egypt, as the result of a facetious remark by one of his neighbors. One day, as the story goes, Evans met Peter Smith, a Scotchman, on the road and asked him where he was going. Smith replied that he was going to the “land of Egypt” to get corn. Evans was so pleased with having his plantation called “The land of Egypt” that he ordered a gift of corn to Peter Smith, and soon thereafter had the name of his plantation and the little settlement changed from LaGrange to Egypt. THE DEEP BIVEK COAL FIELD 15 route by the establishment of slack-water navigation on Deep and Cape Fear rivers, and (2) by railroad to Fayetteville and then by barges down Cape Fear River from that place to Wilmington. The railroad was the first to be secured, construction beginning at Fayette- ville in 1855. Egypt was, during the Civil War, the western terminus of this road and considerable coal mined at Farmville, Egypt and Gulf was shipped to Fayetteville to supply the arsenal at that place or to be transshipped to Wilmington for the use of blockade runners. The building of locks and dams to secure slack-water navigation between Fayetteville and Carbonton was begun by private parties about the same time as railroad construction was begun, but it resulted in failure and the State took over the project. Just as the locks and dams were completed war broke out and they were forgotten in the stress of wartime conditions, and all of the dams went out, except the Lockville, Gorgas and Gulf dams, which were kept up to supply water-power for grist mills. Upon the termination of the war, atten- tion was again attracted to the need of slack-water navigation on Deep River and the Deep River Navigation Company was organized and began rebuilding the locks and dams, largely for the purpose of transporting iron ore from the vicinity of Buckhorn on Cape Fear River to the Endor furnace on Deep River. This company maintained locks and dams on Cape Fear River at Battles and Buckhorn and on Deep River at Lockville, Gorgas, Endor and Gulf. A dam was also built at Carbonton, but the lock was never used. It is reported that slack-water navigation was carried on in 1873 and for several years thereafter, but eventually the locks and dams were permitted to fall into decay as the iron business declined and finally all were swept out of existence, and slack-water navigation on Deep River was a thing of the past. The Egypt mine (PI. Ill) had a checkered history after the Civil War; ownership changed frequently, but no one seemed to be able to operate at a profit. Finally in 1870 the mine was closed down and it remained flooded until 1888 when it was reopened, but with no better success in mining and marketing the coal than had been attained before. The mine continued in operation until 1902, but owing to several bad explosions of gas and to financial difficulties it was again closed and remained under water until 1915. At the last mentioned date the property passed into the hands of the Norfolk Southern Railroad Company and was rehabilitated under the name of the Cumnock Coal Company, the name Egypt being no longer acceptable on account of the many disastrous explosions that had occurred in the mine when it was operated under that name. From 1915 down to 1922 16 THE DEEP RIVER COAL FIELD the entire output of Cumnock mine has been used for railroad pur- poses, but this has not been great, as the mine has been operated in only a small way. In September, 1922, the property was bought by the Erskine Ramsey Coal Company with the intention of greatly enlarging the mine and increasing its output. About 1921 the Carolina Coal Company was organized for the purpose of developing a mine at the site of the old village of Farmville in Chatham County, just across the river from the Cumnock mine. The company began the shipment of coal in a small way in the summer of 1922 by trucking the coal to the railroad at Cumnock, but recently grading has been done for a direct connection with the Norfolk Southern Railroad and it is probable that by the time this report goes to press the rails will have been laid and all-rail shipments begun. The entire history of coal mining operations in the Deep River Field has been one of many failures, due to lack of adequate capital to develop a mine under the mining conditions here prevailing, to lack of experience in coal mining, and to lack of adequate transportation facilities to reach the consumers who were located mostly on the sea- shore many miles distant. Today conditions of marketing and trans- portation are very different; the railroads, the cotton mills, and other manufacturing plants are ready and eager for fuel, to say nothing of the thousands of homes that call for a domestic supply, and as the field has now fairly adequate railroad service, there seems to be no reason why mining operations should not be reasonably successful provided there is an adequate supply of coal in the ground that can be obtained at moderate cost. The Present Investigation The present investigation was undertaken with the idea that the coal of the Deep River Field is much more valuable than has been generally believed and that it is a source of fuel for the mills and railroads of Eastern North Carolina if it could be demonstrated that there is large enough tonnage available at a reasonable depth to warrant the invest- ment of capital. It was fully realized, before systematic work was undertaken, that exposures of coal and the associated rocks are poor and totally inade- quate for a minute survey of the field. It was also realized that most of the coal prospects had been opened many years ago and that almost without exception they are now caved so that the coal is as effectually concealed as if mines and prospect pits had never been opened. To the writers it seemed possible, however, to map the field and determine in a general way whether the coal is lenticular or whether THE DEEP RIVER COAL FIELD 17 it extends indefinitely along the belt of Triassic rocks as well as across the trough toward the southeast. It also seemed possible, by careful field observation and the plotting of dips to determine with some degree of accuracy the shape of the trough and also the depth of the coal at different points within the trough. The results of the examination herewith presented are far from satisfactory to the writers, but they are about as accurate as it is possible to make them without deep drilling in the interior of the trough. GEOGRAPHY OF THE DEEP RIVER COAL FIELD The Deep River coal field, as outlined on the accompanying map, extends from a short distance northeast of Cape Fear River in a southwesterly direction to Carthage and in the other direction from Sanford on the southeast to a few miles beyond Gulf on the northwest. It embraces parts of Chatham, Lee and Moore counties. It has long been known as the Deep River Coal Field because almost all the prospect- ing and development has been on or near that stream from near Glendon to the point where Deep and Haw rivers unite to form Cape Fear River, but it should be clearly understood that the presence of coal has been demonstrated in only a small part of the area outlined above. The field here considered lies mainly in the valley of Deep River and the surface consists of a number of low plateaus or terraces that, near the river and also along its more important tributaries, have been sharply dissected. The altitude ranges from about 165 feet above sea level at Avants Ferry on Cape Fear River to 580 feet on the ridge at Carthage. The latter is the highest land in the field and is a narrow remnant of a plateau that was doubtless once continuous throughout this part of the State, but now has been so dissected by streams that only remnants of its once even surface remain on the inter-stream areas. On the southeastern margin of the field the coal-bearing rocks have been in places deeply covered with white sand which prevents, in large measure, dissection by the streams and consequently this part of the field consists generally, except in the immediate vicinity of the larger streams, of an undissected plain in which the bed rock is effectually concealed by the imneer of white sand. The area represented by the map is essentially an agricultural country, the principal crops being cotton and tobacco. Recently the raising of fruits of various descriptions has become quite successful in adjacent areas and it seems probable that their cultivation may extend into this district. The river bottoms are particularly fertile, being almost universally cleared and in a high state of cultivation, except Geol. — 2 18 THE DEEP RIVER COAL FIELD a deep fringe of trees, vines, and weeds which line the immediate banks of the rivers, as shown in PL 2-A. The highways generally follow the inter-stream divides, for these, except near the rivers, are generally flat and well suited for highway construction. In building some of the new automobile roads, however, less attention is paid to the surface features and the roads pursue more direct courses than would be possible were they to follow the divide between streams. The railroads, on the contrary, generally follow the minor drainage lines in their courses across the major drainage basins of the region, for in so doing they secure nearly a water grade. The principal railroad in the field is the main line of the Seaboard Air Line which enters the field from the north near Moncure, passes south through Sanford and leaves the field 1 miles west of Jonesboro. The Atlantic and Yadkin (a branch of the Southern Railway) extends southeastward from Greensboro to Sanford where it terminates, but through passenger trains are run on to Wilmington over a branch of the Atlantic Coast Line. The Norfolk Southern Railroad has recently acquired or built a line running southwestward from Raleigh to Charlotte. This railroad enters the Deep River Field at Corinth, east of Cape Fear River, traverses the developed coal district about Cumnock and Gulf and leaves the mapped area at Putnam. Two small narrow-gauge lines also serve the field : the Atlantic and W estern from Sanford to Broadway and Lillington; and the Randolph and Cumberland through Hallison, Carthage, and Cameron. Formerly a narrow-gauge branch of the Norfolk Southern extended from Carthage to Pinehurst, but train service had been abandoned for some time when the present field examination was made. The Deep River Coal Field lies near the center of the State, being about 45 miles southwest of Raleigh, 60 miles southeast of Greensboro, 125 miles east of Charlotte, 35 miles northwest of Fayetteville, and 30 miles north of Southern Pines and Pinehurst. Sanford, the principal town, is situated on the main artery of automobile travel from Washing- ton and Richmond to the winter resorts of the South and it also has good automobile roads leading to the more important cities and towns in the surrounding region. GEOLOGIC FORMATIONS General Statement The sandstone and shale which are associated with the coal beds in the Deep River Field extend in a narrow belt of outcrop nearly across the State in a north-south direction. This belt begins in a point *in PLATE II A. Deep River from the Horseshoe Bridge. The bottom on the left is cleared and farmed, except for a fringe of trees and vines on the river bank. B. Outcrop of the Cumnock coal bed near Gulf. This outcrop, in a recent cut made by the Norfolk Southern Railroad, shows about 4 feet of badly watered THE DEEP RIVER COAL FIELD 19 the vicinity of Oxford in Granville County and extends southwestward through the towns of Durham, Sanford, and Carthage, about as shown on Kerr’s 1 geologic map of the State to beyond Wadesboro, where it crosses into South Carolina near its southern terminus. There has been much written on the subject of the geologic age of these rocks, which, according to the fossil remains found in them, appears to have been well determined. The writers, during the course of the present investigation, gave no attention to this phase of the subject, accepting the usage current in geologic literature. The red sandstone of the Connecticut Valley in Connecticut and Massachusetts; the great belt of red sandstone, shale and trap rock extending from the Hudson River to Culpepper, Virginia; the Rich- mond, Earmville, and other scattered areas of similar rocks in Virginia; and the rocks of the Dan and Deep River fields of North Carolina all are of Triassic age and belong to what geologists call the Newark group, a name given to them by W. C. Redfield, because of their excellent development in the vicinity of Newark, N. J. Redfield introduced the name as follows : 2 I propose the latter designation [Newark group] as a convenient name for these rocks [red sand stones and shales of New Jersey and Eastern Pennsyl- vania], and those of the Connecticut Valley, with which they are thoroughly identified by foot prints and other fossils, and I would include also the con- temporary sandstones of Virginia and North Carolina. Later I. C. Russell 3 definitely applied the term Newark group to the rocks of both the Dan and the Deep River fields of North Carolina with the idea that possibly future workers might subdivide the group into a number of formations. In the Deep River Field geologists have recognized certain differences in the rocks, some of the rocks being distinctly red and others being generally drab or gray, but no one, with the exception of Ebenezer Emmons, one of the former State geologists, has definitely attempted to map such distinctions and to give them specific names. Emmons, in his report of 1852 (p. 120), refers to the various divisions of the Newark group as follows: The coal seams of Deep River may be described under three grand divisions, proceeding from the inferior to the superior beds : 1. Inferior conglomerates and sandstones below the green and black slates. 2. Black slates, with their subordinate beds and seams. 3. Sandstones, soft and hard, with freestone, grindstone grits, and superior conglomerates. HCerr, W. C. : Report of the Geological Survey of North Carolina, vol. 1, Raleigh, 1875. -’The name Newark as applied to a geological formation was proposed by W. C. Redfield in a paper, “On the relations of the fossil fishes of the sanustone of Connecticut and other Atlantic States to the Triassic and Colitic periods.” Am. Jour. Sci., 2d series, vol. 22, pp. 357, 1856, and Prac. Am. Asso. Adv. Sci., vol. 10, pp. 181, 1856. 3 Russell, I. C. : Correlation papers — the Newark system. U. S. Geological Survey, bulletin 85, 1892. 20 THE DEEP RIVER COAL FIELD In his report of 1856 (p. 228), Emmons recognizes in his text the three divisions enumerated in his earlier paper, for he says: A natural division seems to exist when we take into account the physical characters of the formation only ; and indeed it would be disregarding im- portant features, were these to be passed by unnoticed. According then to these features, the series should be divided into three great deposits, the lower red sandstone and its conglomerate ; the coal measures including slates, shales and drab-colored sandstones, with their subordinates ; and lastly, the upper red sandstones and marls. But on the map accompanying this report he represents four divisions in the Newark group, as follows : (4) Upper sandstone. (3) Salines. 1 (2) Coal slate and coal. (1) Lower sandstone. Although Emmons shows the four divisions on his sketch map in the report for 1856, it is doubtful if he could, in the field, generally distinguish the “Coal slate and coal” from the “Salines,” the latter being simply drab shale, above the coal in the Cumnock shaft, which, because of the salt that it contains, can there he readily separated from the underlying coal-bearing rocks. The writers made no attempt to differentiate the “Salines” from the “Coal slate and coal,” for it seems extremely doubtful if, in the weathered exposures generally found in the field, the two phases could he identified and differentiated. The Newark group in the Deep Iiiver Field consists of three generally recognizable parts, by geologists called formations; a lower formation composed largely of red and brown sandstone, a middle formation of light-colored or drab shale, sandstone and coal beds; and an upper formation of mainly red conglomerate of great, though unknown thick- ness. In places these formations are clearly marked and easily followed on the surface, but in other places the middle formation disappears, being either faulted out or replaced by red sandstone or conglomerate similar to that in the other formations. As it is desirable to map and describe these formations, it seems best to give them specific names so as to simplify the descriptions and the reference to the formations as much as possible. In accordance with this idea, the name Pekin is selected for the lowest formation, Cumnock for the middle formation, and Sanford for the upper formation. The reasons for the selection of these names will be given under the description of each of the formations. In the following description the formations will be con- VThrough an obvious error in preparing the geologic map for this report the “Salines” was placed below the “Coal slate and coal.” THE DEEP BIVER COAL FIELD 21 sidered in ascending order, beginning with the lowermost one which was laid down probably on a land surface of the ancient crystalline schist and slate. Pekin Formation IN" o specific name has heretofore been applied to the lowermost forma- tion of the Newark group in this field; it has generally been referred to as the “Lower red sandstone.” As it is one of the most definite formations of the group, it seems best to propose a geographical name for it. Unfortunately the names of the towns situated on the outcrop of this formation in the Deep River Coal Field are either in current use for other formations in nearby states, or the formation at the particular place does not show in typical form, hence no name within this field is suitable. At the close of geologic work in the area here considered, the writers made a hurried examination of the Newark formations in Montgomery and Randolph counties. In this reconnaissance the succession of rocks in the group was found to be identical with that observed in the Deep River Field. The lowermost formation is prevailingly red and occupies a belt of outcrop about 2 miles in width on the northwest side of the trough of Newark rocks; this is succeeded by the overlying light and black shales of the Cumnock formation. The best exposure of the lowermost formation was seen on the road running due east from Mt. Gilead. This road crosses Little River 4 miles to the east and on the second terrace about one-half mile east of the river the red sandstone of the Newark appears. The road continues on this rock for a distance of 2 or 2 1 /o miles and then passes onto the characteristic light-colored rocks of the Cumnock formation. In the midst of the lower red rocks is the village of Pekin, and it is proposed to call the lowermost red sandstone and shale Pekin for this place, as the formation here is in typical form. In the Deep River Coal Field the Pekin formation shows in outcrop in a belt of fairly even width but more or less broken because of inability of the writers to recognize in places the overlying Cumnock formation, from the Carthage-Charlotte road on the southwest to Cum- nock, and in a much narrower belt 8 miles or so northeast to Moncure on Deep River. Professor Emmons appears to have been the first person to assign a thickness to the lower sandstone. His original state- ment (Report of 1852, p. 137) is as follows: The inferior mass or that below the slate, is about fifteen hundred [feet] 22 THE DEEP KIVER COAL FIELD In his later and more comprehensive report (Report of 1856, p. 231), Emmons revises his figures to some extent, as follows : The thickness of the lower red sandstones at the Gulf and Egypt [Cumnock] is at least fifteen hundred feet, and probably nearer two thousand. Other writers on this field generally give the thickness of these sandstones as 1,500 or 1,600 feet, apparently accepting the estimate of Emmons as given above. During the course of the present examination almost all roads crossing the Pekin formation were carefully surveyed by plane-table and telescopic alidade, distances being measured by stadia. As the survey progressed most of the outcropping rocks were noted and dips and strikes recorded in their proper positions on the plane-table sheet. Cross-sections of the Pekin formation made up from these data give fairly accordant results, as far as the best sections are concerned, of about 2,000 feet. This thickness was obtained on the new Carthage- Charlotte highway near Calvary Church, on the road running north- westward from Carbonton, and on the road running north from the bridge over Deep River at Cumnock. In that part of the field north and east of Colon, the upper limit of the Pekin formation was not definitely determined, as the light-colored shale and sandstone which carry coal beds appear to be poorly developed and it was impossible to trace them continuously and determine the contact between them and the Pekin formations, but in a general -way as far as Deep River the Pekin formation appears to be much thinner than it is farther south. A rough measure north of Zion Church shows a thickness of about 1,000 feet and a similar thickness seems to he present at Rockville at the crossing of Deep River. East of Deep River the contact of the Pekin formation and the ancient schist makes a turn toward the northwest nearly at right angles to its previous course, and north of Moncure these beds appear to regain their normal thickness of about 2,000 feet. The reason for this abrupt change in direction of the line of contact was not apparent in the field, hut it may be due to great irregularities in the surface on which the Pekin formation was deposited. Emmons in his report of 1856 (pp. 231-232) noted the extreme thinness of the Pekin formation at Jones’ Palis (Rockville). He reports less than 40 feet, hut he offers no adequate explanation of the anomalous conditions which reduced it to this thick- ness. He interprets the great mass of conglomerate which the writers saw on the railroad north of Moncure as an overlap of the upper red sandstone across the eroded edge of the light-colored shale, but this can hardly he the case as the belt of outcrop of the light-colored beds THE DEEP RIVER COAL FIELD 23 is continuous and the rocks are well exposed on the Capital Highway in the north edge of the village. The most remarkable member of the Pekin formation is a gray conglomerate composed of white quartz pebbles ranging up to 2 inches in diameter. This bed is hard and very resistant and has been exten- sively quarried iu the past for millstones. It is the basal conglomerate of the Pekin formation and was laid down on the eroded edges of the ancient schist and slate which form the basement complex of the region. The pebbles were doubtless derived from quartz veins that are of common occurrence in the underlying rocks. They are well rounded and show by their shape that they have been rolled for a considerable distance by a fairly rapid stream of water. The matrix also consists of the same material reduced to a still finer condition. The millstone conglomerate is found in its best development on the northwest border of the field from the Carthage-Charlotte highway northeastward to the vicinity of Putnam. It was also noted by the writers on the east side of Deep River southeast of the Carolina coal mine, and fragments were found on the west side of the river north of the coal mine. This rock was in great demand in the early days for the manufacture of millstones, and quarries were opened at many places on its outcrop. The largest operation of this kind, the ruins of which were seen by the writers, was on McCallum Fork of Richland Creek, about 300 feet below the crossing of the highway that connects Calvary Church with Ilallison and Putnam. Here there was a large quarry from which the raw material was obtained, and an extensive plant for the shaping of the raw material into the finished product. Trees have completely overgrown the ruined mill and office and water has flooded the quarry, so that little now remains to mark the site of a once flourishing industry. The quarry noted above is certainly 100 years old, as it is described by Professor Olmsted in his report (p. 15) of 1824, as follows: The region of sandstone embraces several beds of that conglomerate rock which is used for millstones. But the most distinguished locality for the millstone grit occurs on Richland Creek in Moore County, near the west- ern limit of the formation. . . . This excellent bed of millstone grit is exposed to view directly on the bank of the creek, forming three horizontal strata or layers, each composed of large tabular masses. The lowest stratum is the best quality for millstones. It consists of a hard grayish red sandstone in which are thickly imbedded water-worn pebbles of white flint or quartz. These millstones are very much valued for grinding coni, and are sought for from distant parts of the State, and bring from $30 to $100 per pair. Chance in his report of 1885 (p. 24) makes the following statement : In Moore County the conglomerate at the base of the formation yields an excellent stone for corn-mills. A factory has recently been established by 24 THE DEEP RIVER COAL FIELD the North Carolina Millstone Co., and complete mills ready for the belt are now made and shipped in large numbers. This conglomerate was also found on the east bank of Deep River where it is cut by the Deep River fault, about a mile east of the old Endor iron furnace. It was not seen northeast of that place, although the base of the Pekin formation was crossed at a number of places. At Rockville, a coarse conglomerate occurs on both sides of Deep River at what appears to be the same horizon as that of the millstone grit, but here the matrix is a strong red color and the pebbles or rather the boulders — for they range up to at least twelve inches in diameter — are of schist. The rock bears no resemblance to the white quartz conglomerate of the millstone grit, although it seems to be at that horizon. The red conglomerate is well shown in the cuts of the Capital Highway where this road climbs to the upland south of the river and it was also seen in full force on a branch of the Seaboard Air Line Railway which runs due north from Moncure to Pittsboro. Curiously enough, however, this conglomerate does not show on the main automo- bile road to Pittsboro which turns to the left about one-quarter of a mile beyond Lockport. On this road the schist makes its appearance in less than one-half mile and from that point for about one-quarter of a mile the road runs practically on the contact of the red schist conglomerate and the underlying bed-rock. Professor Emmons noted (report of 1856, p. 237) this appareut thinning of the Pekin formation at Jones’ Falls (now Lockport) and the presence of the red conglomerate noted above, but instead of regard- ing the conglomerate as the basal member of the Pekin formation, he considered it as belonging to the red sandstones of the Sanford forma- tion. He accounted for its present position as being due to uncon- formable deposition across the eroded edges of the Cumnock formation. Professor Emmons proved his case, as he supposed, by the discovery of certain fossil plants above the schist conglomerate near Rockville and by the finding on Haw River of the same fossil plants overlying one of the conglomerate beds of the Sanford formation. Whether or not Professor Emmons is correct in attributing the presence of this schist conglomerate in contact with the schist itself as due to overlap the writers cannot affirm or deny, as time did not permit of a close examination of the rocks or of the collecting of fossils from them. In some respects Emmons’ theory seems to apply, hut in others it is contrary to the observed facts. The writers are not in a position to settle this question, so merely call attention to it as one of the interesting points that future workers may look forward to as a problem worthy of their best efforts. THE DEEP RIVER COAL FIELD 25 The other members of the Pekin formation are fairly uniform in character throughout the field and have no striking characteristics that call for comment. Professor Emmons’ description of the rocks com- posing this formation is very good and the writers can add little or nothing to it, except that in places the formation carries considerable hematite which appears to be very pure, and, if it could be found in great quantity, would be extremely valuable as an ore for iron-making. An exposure of this hematite was found in a cut of the Norfolk Southern Railroad about a half a mile northwest of the station of Colon. This occurs as a mass about five feet long and one foot broad and of unknown depth ; it is in sandy shale which strikes nearly east-west and dips twenty-six to thirty degrees to the south. Similar masses, though of smaller dimensions, were seen in the clay pit of the brick works at Colon in shale that also appears to dip to the south. If the dip and strike are at all indicative of the general geologic structure, this shale belongs in the Pekin formation and underlies the Cumnock formation which outcrops farther to the south. The iron ore exposed in the vicinity of Colon is doubtless of secondary origin and due to the segre- gation of iron in the deeply oxidized shale and shaly sandstone. All of the red rocks of the Newark group contain much iron, but until segregation takes place, the iron is too widely disseminated to be of value as an ore. Cumnock Fosmation General Statement. The coal-bearing rocks are not so well exposed as are those belonging to the Pekin formation. In fact, were it not for the section in the mine shaft at Cumnock, geologists would have a very inadequate idea of the composition of the coal-bearing formation in this field. Because the shaft section is regarded as the type of the formation and because the development of the coal has been much more extensive here than at any other place in the field, the name Cumnock is given to the generally light-colored rocks bearing coal or associated with the coal. The Cumnock formation varies greatly in thickness and composition throughout that part of the field examined so that it is doubtful if the section exposed in the Cumnock mine will hold in distant localities. The Egypt (now Cumnock) shaft, shown on PI. Ill, was sunk, according to Captain Charles Wilkes 1 of the United States Navy, by the Governor’s Creek Coal and Iron Company, but local information gathered in the field indicates that the shaft was sunk by Brooks Harris in 1852, and that Harris in 1853, disposed of his interest in 1 Report on the examination of the Deep River district, North Carolina Senate, Doc. 26, 35th Congress, 2d Sess., p. 6, 1859. 26 THE DEEP RIVER COAE FIELD the property to Thomas Andrews, who, in the same year organized the Governor’s Creek Steam Transportation and Mining Company. The geologic world is greatly indebted to Captain Wilkes for preserving a record of the rocks penetrated by this shaft, for, so far as the writers are aware, his is the only report in which the original section was published and even the present owners of the property have no other record than that given in Captain Wilkes’ report. Emmons’ description (Report of 1856, pp. 232-234) of the Cumnock formation and its thickness and component parts is somewhat vague and indefinite and the writers are not satisfied that they have correctly interpreted his statements. He apparently divides the coal measures into two parts: (1) the black and green beds of the bottom and, (2) drab-colored beds at the top. The thickness of the former is given as extending 150 to 200 feet above the top of the Cumnock shaft section and 200 feet below its base. This would give the black and green beds a thickness of about 800 feet. The drab-colored beds he states are 1,200 feet thick on Mclver’s plantation near Egypt. 1 These measurements give a total thickness of about 2,000 feet, but Emmons states clearly that the formation is probably thicker at Egypt than it is at any other place in the field. In comparatively recent years four core-drill holes have been put down to the Cumnock coal bed on the Cumnock property, and as one of these holes penetrated the coal bed at a depth of 1,064 feet 7 inches it affords an even better section than that revealed by the Egypt shaft. The logs of these four wells and also the section of the Egypt shaft, as given by Capt. Wilkes, are shown on Eigure 1. In borehole Ho. 1 the lowest red rock penetrated by the drill is 548 feet above the Cumnock coal bed; in borehole Ho. 2 it is 561 feet; and in borehole Ho. 3, 506 feet. The average of these measurements is 538 feet. If all the exposures in the field were as clear as the logs if the boreholes there would seemingly be little difficulty in determining ;he top of the Cumnock formation, but in deeply weathered rocks it is not always possible to distinguish brown from gray unless both rocks are strongly marked. Judging from the experience of the writers in the field, it seems highly probable that the brown sandstones and shales noted in logs, 1, 2, and 3 (see Fig. 1) are in reality included in the Cumnock formation, and that as so constituted, it extends 800-850 feet above the Cumnock coal bed and from 100 to 150 feet below that bed. On this assumption the Cumnock formation at the Cumnock mine is about 1,000 feet thick, instead of 2,000 feet, as determined by Emmons. x It is possible that Emmons intended this measurement of 1.200 feet to include the rocks showing in the Egypt shaft. If so, it would represent the full thickness of the Cumnock formation, and would be more nearly in accord with, but still thicker than, thicknesses determined in surrounding acres. The statements, however, are too vague to be taken seriously. THE DEEP RIVER COAL FIELD 27 The writers endeavored to apply the Cumnock shaft section to the same belt of rocks observed in other parts of the field, but there seems to be little or no agreement in the thickness of either the forma- tion as a whole, or its various members. In fact in several places the formation appears to be lacking, either faulted out or replaced by red conglomerate similar to that which constitutes the major part of the Sanford formation overlying the coals. Emmons, in his report of 1856, states that he experienced difficulty in tracing the belt of drab sandstone and shale which constitute the Egypt shaft cumnqCk mine Coal 2 '- 2 " Shah'Sandy S " Shale, black 6" Coal, bony 4-" 31ackband /O" Coal /- 6 “ Shale ,hlack 6" Analysis 8559b Analysis 85590 3 kia/ys is B553A- Fig. 1. Section of the Cumnock formation, as exposed in the Cumnock shaft and in boreholes on the Cumnock property. upper part of the Cumnock formation. He attributed the apparent vari- ation in thickness and even the absence of the coal-bearing rocks in cer- tain places to an unconformity at the top of the drab member (Cumnock formation) which allowed the lowest bed of the upper red sandstone to overlap and conceal a part or the whole of the coal-bearing member. The present writers looked in vain for indications of such an overlap, 28 THE DEEP RIVER COAL FIELD but none was found, and they came to the conclusion that the apparent thinning and even disappearance of the Cumnock formation could he explained in another way which seems to agree with observed facts better than does the theory that Emmons advanced. The theory adopted by the present writers is that the difference in the formation is due in large part, if not wholly, to variations in sedimentation and conse- quently, red shale, sandstone or even conglomerate may have been laid down in one part of the field at the same time that drab shale or even shale containing much black carbonaceous matter was being deposited in another part. In fact it seems much more reasonable and in accord with observed facts to assume that coal-forming swamps were of local occurrence in Triassic time in much the same manner as they are limited today and that a swamp extensive enough to cover North Carolina from north to south is much less probable than one five, ten, or even twenty miles in extent. In order to present some of the evidence regarding the variation of the Cumnock formation in this field it will first be necessary to describe the distribution of the outcrop. Before beginning such a description it is well to explain that, although the territory covered by the writers, as shown on the map, extends from Carthage to beyond Haw River, much of this area was examined in a reconnaissance manner only, in order to determine the general structure and that detailed examination was limited to localities where the prospect of finding coal in commercial quantity is more promising than it is in most of the area represented on the map. The description begins at the southwest extremity of the area and extends northeastward to the farthest point examined in the vicinity of Moncure. In the Carthage Trough. On the new-cut highway which extends northwestward from Carthage the rocks are excellently exposed from a point about IV 2 miles west of the courthouse at Carthage to the northwestern margin of the field. The rocks as far as the crossing of Richland Creek are prevailingly red and as they dip continuously to the southeast, they without doubt belong to the Sanford formation. The red rocks continue beyond the creek for a distance of about 400 feet where they rest conformably upon light-colored rocks of the Cum- nock formation. These rocks extend along the highway, except where they are cut by a large dike near the middle of the belt, for a distance of 2,200 feet, and to all appearances they are conformable and the full thickness of the formation is present. The rocks near the dike are somewhat disturbed, but beyond its influence they dip with considerable regularity sixteen degrees to the southeast. This dip, if it were regular throughout the entire formation would indicate a thickness of only PLATE III B. The Cumnock coal mine. THE DEEP KIVER COAL FIELD 29 600 feet. As this measurement is much less than that obtained a few miles to the north, as explained on another page, one is forced to the conclusion that either the Cumnock formation is here unusually thin or that it has been cut by a fault and part of the formation has disappeared in the process. The fault-hypothesis seems hardly tenable as in other longitudinal faults of considerable magnitude in this region the movement has been such as to duplicate a part or all of the outcrop and thus give it a greater width and the formation an apparently greater thickness than it normally has rather than to reduce the width of its outcrop. The rocks exposed are principally gray sandstone and drab shale, but near the dike the shale has been baked to a dark, almost black color resembling black carbonaceous shale. No sign of coal was observed but reports are current that coal has been seen in Richland Creek somewhere in this vicinity. It is possible that coal is present here, for it is only eight and one-half miles in a direct line to the old coal mine on the Jones’ farm east of Glendon, but whether or not the coal is of workable thickness here is another problem that can be solved only by prospecting with pick and shovel, or with a core drill. The next line of observation is along the public road from Mooshaunee to Friendship Church. As this road has never been improved there are few exposures, but so far as the surface indications go, there is no evidence that the Cumnock formation crosses this road. The same condition holds on all of the roads crossing the territory west of McLennon’s Creek and for a distance of five miles northeast of the Randolph and Cumberland Railroad. This country was crossed on the road leading to the southeast from Putnam, also on the road running in a similar direction from Cool Springs Church, and on a road intermediate between the two. On all these roads the only rocks that were seen are red rocks which in all probability belong to the Pekin formation. The next line across the field on which traces of the Cumnock formation were found is the Carthage-Glendon road. As far north as Cole’s Mill the roads both to the south and the west of the main road gave no indication of the light-colored rocks of the Cumnock formation ; in fact, there seems to be no possibility of the northeastward extension of the belt of outcrop of the Cumnock formation, showing on the Charlotte road northwest of Carthage, for the road from Carthage to Mooshaunee and also the road from Carthage to Cole’s Mill shows nothing but red rocks which, unless the Cumnock formation changes in color in this locality, cannot belong to that formation. Likewise the 30 THE DEEP KIVER COAL FIELD road from Cole’s mill to Mooshaunee is on red rocks from one of these places to the other. On the west side of the Glendon road, about one and one-half miles north of Cole’s Mill, the Cumnock formation suddenly appears in full force, for its outcrop extends from the Carthage-Glendon road for fully one-half mile to the west. From this place northward the light-colored rocks were seen at a number of places as also were the bands of black shale which are a characteristic feature of the formation. The black shale is particularly well exposed and prominent by the side of the road near the forks where the road to the Horseshoe bridge turns off to the right from the regular Glendon road. The Cum- nock formation was also seen on all the roads turning to the northwest from the main Carthage-Glendon road toward Putnam and Cool Springs Church. On the main Glendon road nearly the full width of lutcrop was seen on the slope northward toward McLennon’s Creek, and the contact between the light-colored rocks of the Cumnock forma- tion and the red beds, which are supposedly of the Pekin formation, were crossed three-quarters of a mile from the point where the road forks and the right hand fork leads to Horseshoe Bridge. Between that point and the creek and also on the northwest side of the creek for some distance no rocks but those which are red were seen, but at a fork of the road about one mile north of the creek, with one branch turning to the left toward Cool Springs Church and the other turning off the main road to the right toward the old coal mine on the Jones property, the light-colored rocks of the Cumnock formation appear in outcrop. This band of outcrop is only 900 feet wide, being about one-third of the normal width of outcrop of the entire formation. The dip of the Cumnock formation could not he determined here as the rocks are soft and massive and no bedding planes could he detected. Horth of this narrow band of outcrop the rocks are universally red as far as the bridge across Deep River north of Glendon where the red beds of the Pekin formation rest upon the crystalline schist. The two bands of outcrop of the Cumnock formation, mentioned above, can be traced northeastward until they unite two miles south- west of Carbonton. Thus there is a main hand of outcrop of the Cumnock formation from a short distance north of Cole’s Mill north- eastward through the Horseshoe Bend of Deep River and on to Carbon- ton which appears to be the normal outcrop on the northwestern limb of the Carthage trough; and a second band of outcrop which begins in a sharp point one-half mile southwest of the Carthage-Glendon road, increases in width to 900 feet where it crosses the road just mentioned, and gaining the full width of outcrop soon after it crosses Deep River THE DEEP RIVER COAL FIELD 31 and before it readies the village of Haw Branch. This belt of outcrop continues northeastward to the vicinity of Carbonton where it appears to blend with or unite in some manner with the other band of outcrop lying to the south. There are therefore two problems here that call for an explanation : (1) The failure of the outcrop of the Cumnock formation on the Cartilage-Charlotte road to connect w T ith the outcrop of the same forma- tion north of Cole’s Mill, and (2) the bifurcation of the outcrop of the Cumnock formation between Carbonton and Haw Branch. Several explanations might be offered for the solution of problem Ho. 1, but each one is open to some objection which, in the light of the evidence at hand, appears to be fatal. The possible explanations that should be considered by any geologist working in this field in the future are as follows : (A) That the outcrop of the Cumnock formation, as known north of Cole’s Mill, really swings to the west and connects with the outcrop of the same formation on the Carthage-Charlotte road west of Rich- land Creek, and that, owing to poor exposures, it was not observed north or northwest of Mooshaunee. (B) That the Carthage trough here has been cut by a cross-fault and the part south of the fault has been dropped with reference to the part north of the fault. This might explain the offset of the Cumnock formation, but it is difficult to conceive of such a fault occurring without leaving some offset in the line of contact between the Pekin formation and the underlying schist. (C) That the disappearance of the typical Cumnock formation in the region between Cole’s Mill and the Carthage-Charlotte road is due to a local change in sedimentation, by wffiich the generally drab rocks of the Cumnock formation are displaced by red sediments similar to both the overlying and the underlying formations and hence are indistinguishable from them. (D) That there is here an overlap of the red rocks of the Sanford formation across the upturned edges of the rocks of the Cumnock formation, which conceals all indications of the presence of the latter formation. (2) The question of the bifurcation of the outcrop of the Cumnock formation between Carbonton and Haw Branch is simpler, but of somewhat greater economic importance, because it affects the forma- tion where it possibly contains a workable bed of coal. Such a bifurca- tion, as that shown on the map, could have occurred in only one of two ways : being the result of either a low fold or wrinkle on the side of th<> lqr£-e though, or of a normal fault which has dropped the block THE DEEP RIVER COAL FIELD STRUCTURE PRODUCED BY FAULTING Carbonton Haw Branch. Horseshoe Bend of Deep River Geologic Structures THE DEEP EIVEB COAL FIELD 33 of rock on the northwest side or raised the one on the southeast side, so that the outcrop of the Cumnock formation is repeated for a distance of about three and one-half miles. The fold hypothesis is the simpler one and, in regions in which the rocks are subject to such disturbances, it would be accepted without much question, but in this trough folds in the rocks are almost unknown and normal faults are the rule, hence in all probability the bifurcation of the outcrop of the Cumnock formation is due to a fault which cuts the outcrop at a slight angle, as shown in Figure 2 and described more fully under the subject of Geologic Structure. The trace of this fault follows the southern margin of the belt of outcrop that passes through Haw Branch and, if it extends northeast- ward as it probably does, it must pass somewhere to the southeast of Carbonton, but its position was not determined, for at the time of the field examination the presence of this fault was not realized. The wide floodplain of Deep River about Carbonton makes the collection of data bearing on the position of the fault difficult, but it seems probable that if search were made in the vicinity of the site of the old village some evidence of the inter-fingering of the light-colored rocks of the Cumnock formation and the red rocks of the Sanford formation would be found. The representation of the fault on the map as well as the outcrop of the formations southeast of Carbonton are largely hypothetical, but they serve to express the idea that the writers hold that probably there is at this place a fault which separates an upraised block of the earth’s crust on the southeast from a dropped block on the northwest, and the junction of the two belts of outcrop of the Cumnock formation in the vicinity of Carbonton merely means that here the fault passes across the Cumnock formation and farther northeast lies entirely within the Sanford formation, or at least is in this position for a number of miles. On this assumption the belt of outcrop of the Cumnock formation which extended into this area from the Horseshoe Bend of Deep River comes to an end in a sharp point somewhere in the vicinity of Carbonton, and the belt lying to the northwest and passing through Haw Branch continues on to the northeast through the present village of Carbonton to Gulf. Ho direct measurement of the thickness of the Cumnock formation was made in the vicinity of Carbonton, but in constructing the cross-sections shown in Fig. 2 it was found that, according to observed dips and details of distribution of outcrop, the formation must be at least 1,000 feet thick. From Carbonton to Gulf the base of the Cumnock formation is quite well marked on the ground and its position in a number of places was accurately determined. This line is nearly straight, the only Geol. — 3 34 THE DEEP RIVER COAL FIELD irregularities being those due to the influences of dikes which are very abundant and seemingly cut the coal nearly parallel to the outcrop. The upper limit of the formation was not nearly so well determined as the lower limit, for it follows in a general way the floodplain of Deep Kiver, and this floodplain is so broad that it was not thought practical to seek for evidence regarding the exact position of the upper limit of the formation. East of Gulf the writers, when in the field, were puzzled by the apparent lack of parallelism between the line marking the lower limit of the Cumnock formation and the line marking the upper limit. Eh attempt was made to actually follow the lower boundary of the forma- tion from Gulf to the Cumnock bridge, but it was assumed that it is regular and conformable in its curve and direction with the line marking the base of the Pekin formation nearly two miles to the north. Considerable data were obtained on the upper boundary of the Cumnock formation and it was found not to be conformable with the line marking the base of the Pekin formation, but to offset decidedly to the south at a distance of about a mile from Gulf. A careful study of the com- piled map shows at once that the point here in question lies almost on the continuation of the supposed Carbonton fault and that if it were granted that this fault might continue as far to the northeastward as this place, it would account for the irregularity in the upper boundary of the Cumnock formation. All of the facts in the hands of the writers indicate that the line marking the top of the Cumnock formation crosses Deep Piver about 700 feet below the bridge at the old mill directly south of Gulf. This does not agree with the statement made by Chance (pages 13-14) that at the old coal mine which was once opened west of the village, and which was abandoned because in a short distance a large dike was encountered, red sandstone appears directly south of this great dike. It is also well known that deep drilling was done here years ago, but no authentic account of the results could be obtained; there is, however, a vague rumor that a well near the river bank found the coal at a con- siderable depth and that most of the rocks penetrated near the surface are the red rocks of the overlying formation. If these rumors are correct, the geology about Gulf is very complicated and different from that which is represented on the present map, but the writers, while not making a special examination of this particular locality, have no hesitation in saying that the evidence collected in the surrounding territory does not agree with such an interpretation as would have to he made if the rumor mentioned above were correct, and hence they are inclined to class this hearsay evidence as too vague and indefinite THE DEEP RIVER COAL FIELD 35 to be seriously considered, unless it were substantiated by a detailed examination. As stated before, the writers believe that tbe line marking the top of tbe Cumnock formation crosses Deep River a short distance below tbe bridge, but this line if projected to tbe east would not include a great mass of light-colored sandstone which shows still farther down the river and at an old quarry about half way between the river and the line of the Southern Railway, about a mile southeast of Gulf. As this apparent offset in the upper boundary of the Cumnock formation is on the prolongation of the Carbonton fault, it is suggested that perhaps this fault is longer than has been supposed and really is responsible for this offset as well as the much larger offset of the same formation southwest of Carbonton. This idea of the extension of the fault is offered more in the nature of a suggestion than as an established fact and should be considered by any coal operator who is interested in the development of this part of the field. As the evidence in the vicinity of Haw Branch shows that the fault which is supposed to be responsible for the offsets in the Cumnock formation is diminishing in throw or magnitude northeastward, it is probable that south of Gulf it may not have lifted the coal bed more than 100 feet and it probably dies out before it reaches the schist at the northern point of the syncline. As the movement on the fault plane was such as to cause the block of rock on the southeast side of the fault to move upward with respect to the block on the northwest side, both the upper and the lower boundary of the Cumnock formation will be found to offset to the southwest, but for only about 1,500 feet for the lower boundary and 4,000 feet for the upper boundary, the difference being caused by the increasing magnitude of the fault toward the southwest and the different angle at which the fault cuts the boundary line. From the offset just described to Cumnock and the Carolina mine the outcrop of the Cumnock formation appears to be exceedingly regular and without offsets of any kind. It is possible, however, that if it could be followed in detail, small offsets would be found for some small faults have been encountered in the mines which would doubtless produce such features where they come to the surface, but they are so small that it would be almost impossible to detect them.- As Offset by the Deep River Fault . — East of Cumnock and the Caro- lina mine the outcrop of the Cumnock formation is more complicated than it is at any other point seen by tbe writers. As those working in the coal of this region are in doubt about the continuation of the beds the writers spent considerable time tracing the outcrop between the points at which the coal has been prospected in the vicinity of the 36 THE DEEP BIVEE COAL FIELD Carolina mine and the Capital Highway north of Sanford. Professor Emmons, in his report of 1856, gives a colored geologic map of the Cumnock formation from the present village of Carbonton to Cape Pear River. One of the most interesting features of the map is the great bend which he supposed the outcrop of the formation to make just east of Earmville (now the Carolina mine) and the swing to the southwestward across the river some distance east of the old Endor iron furnace below the mouth of Buffalo Creek. The outcrop of the Cum- nock formation is represented as continuing in this direction to beyond the house of Evander Mclver where it turns abruptly to the southeast, paralleling approximately the line marking the contact of the Pekin formation and the underlying crystalline schist. Emmons gives no facts in support of his conception of the great bend in the outcrop of this formation, merely stating in the text (p. 244) that, “The outcrop crosses the river between Evander Mclver’s and the Hornville property, thence by Farmville, it crosses the river obliquely at Egypt, and soon recrosses it again near the fish-trap, and passes into the Taylor plantation.” Haturally the writers made a very detailed examination of this part of the field, for the interpretation of the Structure neces- sarily has an important bearing upon any conclusion regarding the area and tonnage of available coal. The position of the outcrop of the Cumnock coal bed from Gulf to the Carolina coal mine (Earmville of the old reports), barring a hypothetical offset, is quite well known and the writers were able by means of prospect pits to continue the tracing southeastward beyoud the Carolina mine to the edge of the flood plain, about 1,300 feet from Deep River at the bend where the course of the river changes from nearly due east by the mouth of Pretty Creek to a northward course toward Woodard’s Bridge. As the outcrop of the coal bed shows no trace of irregularity save a gentle curve toward the south, one would scarcely expect in a distance of 1,300 feet a decided change in direction of the outcrop of the formation. When, however, one tramps from Woodard’s Bridge up the river bank on the southeast side he finds high hills of schist opposite the mouth of George’s Creek and even further south, and when he reaches a point in strike with the outcrop of the coal at the last prospect pit, he finds equally high rugged hills made of a white quartz conglomerate, in all respects similar to the millstone grit exposed, on McCallum Creek. A 0 ) o .S o 4eH - CM <5 m g ci ° o tC O - o3 ■ “ .9 ^ a "o >-5 <3 a O S “1 4) C33 a ■£ " .9 o t- O pn ~ o3 ■ .9 ^ o. r o ^ < (i eJ o «*H 00 o -73 co .. O *-H a 05 £ 40 o 00 o II ANALYSES OF COAL SAMPLES FROM OTHER FIELDS, WITH WHICH THE DEEP RIVER COAL MAY HAVE TO COMPETE 84 THE DEEP RIVER COAL FIELD THE DEEP RIVER COAL FIELD 85 In using the figures given in the table of analyses it should be remembered that the sampler is much more careful in excluding impurities than is the miner or even the operator in time of great scarcity of coal, and consequently the coal that reached the market from these mines is liable to contain much more ash than that shown in the analysis of the mine samples. A comparison of results obtained on mine samples and on railroad car samples shows that on the average the ash in the car sample may be from 30 to 50 per cent greater than it is in the mine sample. Thus coal which shows 6 per cent ash in the mine sample is likely in the car sample to run from 7.8 per cent to 9 per cent, but if the increase exceeds 50 per cent, it indicates gross carelessness in mining the coal or preparing it for the market. The composition of the mine sample may be regarded as the ideal toward which the commercial coal of the mine approaches more and more closely as better methods and more care is exercised in min- ing, and commercial coal will agree with the mine sample when the best methods are used and every employee cooperates with the management in excluding impurities from the output of the mine. As the most important point in the consideration of the value of a coal for ordinary purposes is its heat-producing power, the column headed B. t. u. 1 in the table of analysis is worthy of most careful consideration. As a direct comparison of figures is not easy to make, the graph, shown in Big. 6, has been prepared to show the comparative heating values of the coals listed in the table of analyses. It is apparent from the graph that Cumnock coal is somewhat inferior in heating value to the best Pocahontas and Hew River coals, and that it is about the same as the coal mined at Dante, Toms Creek, and Big Stone Gap, Virginia, and Oliver Springs and Jellico, Tennessee, but is considerably better than the poorer coals mined in most of these districts. The table of analyses shows that the Cumnock coal is relatively high in sulphur, averaging in eight mine samples, 2.2 per cent, as against an average of 1.1 per cent in the other coals listed in the table. The difference between 1.1 and 2.2 is not serious, unless the coal were used for the manufacture of metallurgical coke, where difference of 1.1 per cent would be a rather important matter. In steam-raising the percentage of sulphur in the Cumnock coal will probably have little U3. t. u. is an abbreviation of the term British thermal unit. This unit is the one by which heat is generally measured and expressed in English speaking countries. The heat-producing value of a coal is determined in the laboratory by exploding a small amount of coal within a steel bomb and carefully measuring, by a delicately graduated thermometer the increase in temperature. The amount of heat thus generated is ex- pressed in British thermal units, one of these units being the amount of heat required to raise one pound of water one degree Fahrenheit, the water being at the temperature of maximum density, 39.1 degrees F. 86 THE DEEP RIVER COAL FIELD B.TUS F , 1 1 P H . w. / 1 s 8 | , | 1 1 - VA V i m 1 .8 .. 8 c p — SJ ! 4 13,000 — I I 'S o c- a j *3 8 R o | 8 $ ! 8 1 a 1 s w 8 a £ £ f 1 ! 8 I i I I 1 f s n; . 3 1 3 | P 1 ■Si "■ ‘q ■ 1 $ 1 $ ' o — 1 1 1 1 1 | Fig. 6. Graph illustrating comparative heating values of competing coals. or no effect, except that the sulphur will tend to corrode the grate bars more rapidly than pure coal. It should he remembered by operators, however, that the sulphur in the coal as shipped to market is liable to he much greater than that shown in the mine samples. This is an imminent danger, for in places the coal contains many “sulphur” balls from 1 inch to 2 or more inches in diameter. In mine sampling these nodules of pyrite were excluded from the samples on the theory that in actual mining it is possible to remove them if the coal is properly hand-picked, and no careful operator who is at all mindful of the reputation of his output, will allow such material to remain in the commercial coal. Tests by the Bureau of Mines The Deep River coal is generally regarded as a coking coal, hut up to the time of the present examination, no reliable test of its coking properties had been made, or if made, the winters were not aware of the fact. The coal has been noted since its earliest exploitation as a fine smithing coal and this in itself is an indication of its coking quality, as one of the prime requisites of a smithing coal is that it will coke and thus make a “hollow” fire. At the request of Col. Joseph Hyde Pratt, State Geologist, the United States Bureau of Mines has recently made tests of the coking quality of the Deep River coal and of its adaptability to washing as a means of reducing the sulphur and ash so as to make it suitable for the manufacture of metallurgical coke. Through the courtesy of the THE DEEP EIVEE COAL FIELD 87 Director of tlie Bureau of Mines the essential features of these tests are given herewith. A large sample of washed coal from the top bench in the Cumnock mine was tested at the Experiment Station of the United States Bureau of Mines at Pittsburgh, Pennsylvania, for its coking properties and for the by-products w’hich it would yield in the operation. The sample of washed coal which was to he tested had the following composition : PEOXIMATE AND ULTIMATE ANALYSES OF WASHED COAL AND COKE Moisture Volatile matter Fixed carbon Asli Hydrogen Carbon Nitrogen Oxygen . Sulphur . B. t. u. Coal Per Cent 1.0 33.0 59.6 6.4 5.2 78.9 2.1 5.8 1.6 14220 Coke Per Cent 0.5 3.8 87.2 8.5 1.2 86.0 2.0 1.0 1.3 13350 The results of the laboratory coking tests on the washed coal is as follows : Final coking temperatures .... 775° to 800° C. Weight of charge 15 pounds. Coke yield 75 per cent of charge. Gas yield 8.000 cu. ft. per ton of coal. Ammonium sulphate 23 pounds per ton of coal. Tar (dehydrated) 13.9 per cent of coal charged or 22 gallons per ton. The report of the Bureau of Mines on this test is as follows : “The by-product yield of this coal is entirely satisfactory and compares favorably with yields from Freeport, Pa. coal. It is felt that with a full cooking temperature (950°C.) and 18 hours time, it would be reasonable to expect a 70 per cent yield of matallurgical coke, 10,000 to 12.000 cubic feet of good gas, 11 gallons of tar, and 25 to 27 pounds of ammonium sulphate. In general, the coke, as far as it can be judged by a laboratory scale test is of very good quality fully equal in all respects to Freeport or Pittsburg cokes. The sulphur in the coke is somewhat high (1.3 per cent), but this could be cut down by admixture of a low-sulphur steam coal. Such a mixture of coal is now considered to be good by-product practice.” This test seems to establish the coking quality of the Deep River coal and also the fact that even by washing, the sulphur is too high to yield a metallurgical coke without the admixture of a coal containing less sulphur. As there is probably little or no demand for this kind of 88 THE DEEP EIVEE COAL FIELD coke in North Carolina, the relatively high percentage of sulphur is not an important matter. It seems probable that the best market in the State for coke is for domestic use as a substitute for anthracite, and for this use the sulphur is not excessive. In an agricultural country, such as central North Carolina, it is probable that the ammonium sulphate is a very important, if not the most important, by-product of the coking process. In using the figures given in such a report, it should be understood that the results of a general test are significant only in sug- gesting what may be secured in actual practice, but the actual yield of any by-product depends largely upon the method used, and the method best suited to produce a large quantity of a certain constituent is not the one best suited to obtain a large yield of another constituent. The results of the Bureau of Mines test show that, if the coal is coked in by-product ovens, a good quality of coke may he secured for domestic or manufacturing purposes, a normal amount of gas, a rather large yield of ammonium sulphate for the cotton and tobacco fields, and a medium amount of tar. As the two coal beds in the vicinity of Cumnock are only 18 inches apart, they may easily be regarded as two benches of a single coal bed, but there is no advantage in so considering them unless the coal con- tained in the lower bench, as well as the black band (iron carbonate) between them, can be utilized. As shown by the analyses of the coal from the lower bench that are given in the table (p. 83), the coal in the raw state contains too much ash to be salable in competition with better coals, therefore if it is to be utilized, some way of improv- ing its condition must be devised. In order to determine the possibility of reducing, by washing, the percentage of ash in the lower bench from about 30 per cent to 6 or 8 per cent, a washing test was made by the United States Bureau of Mines. In order to make a thorough test about 1,150 pounds of coal was sent to the Bureau of Mines testing laboratory at Urbana, Illinois, and elaborate float-and-sink test were made with liquids ranging in specific gravity from 1.3 to 1.8. Tests were also made in washing the coal in jigs and on tables, but without very satisfactory results. The conclusions arrived at by the Bureau of Mines experts are as follows : The sample of coal received at the laboratory representing the bottom bench of the Cumnock bed from the Farmville (Carolina Coal Company’s) mine, consists very largely of bony coal and carbonaceous shale. Only a small amount of coal low in ash content is present. It is, therefore, impossible to treat this coal successfully by the usual coal-washing methods to secure a reason- able yield of coal as low in ash content as the coal of the top bench (S to 10 per cent, of the bed ) . The treatment of this coal at % inch minimum size on THE DEEP RIVER COAL FIELD 89 either jigs or tables would probably yield 50 to 70 per cent of washed coal with an ash content in the neighborhood of 24 per cent. As stated before, this test shows that washing will probably not improve the coal of the lower bench sufficiently to justify the erection of a washery and therefore some other method must be sought, if this bench of the coal is to be utilized at the same time that the upper bench is being mined. As the sulphur content of the upper bench of the Cumnock coal bed is too great for the manufacture of metallurgical coke, a washing test of this coal was also made by the United States Bureau of Mines at its Urbana, Illinois plant to see if it were possible by ordinary washing methods to materially reduce this element. Elaborate tests were made by float-and-sink methods, by washing in jigs, and by washing on tables. The coal to be tested was crushed to different sizes and subjected to a float-and-sink test on liquids of various densities with the result that it appears to be entirely feasible to reduce both the sulphur and ash by washing processes. The float-and-sink test showed that with a solution whose specific gravity is 1.5 the ash could be reduced from 12.7 to 6.5 per cent; the sulphur could be reduced from 2.32 to 1.76 per cent; with a consequent loss of the sample tested of 9.4 per cent. After this preliminary test had been made the raw coal was washed in a jig. This test yielded 87.6 per cent of washed coal, having 7.1 per cent of ash and 1.85 per cent of sulphur. The results of this test are very satisfactory, as far as the ash is concerned, but rather disap- pointing as the percentage of sulphur was not materially reduced. A table test showed a yield of washed coal of 87.6 per cent, having an ash content of 7.1 per cent, and a sulphur content of 1.79 per cent. A table test of coal crushed finer than that noted above, yielded 90.0 per cent of washed coal, having 6.8 per cent of ash and 1.82 per cent of sulphur. As these various tests agree very closely, it may be said that, as far as a single test on a small scale will determine, the coal from the upper bench of the Cumnock bed, if subjected to washing in a jig, would have its percentage of ash materially reduced, but that, as far as the sulphur is concerned, the results hardly justify the expense of the operation. The failure to greatly reduce the content of sulphur is explained as follows : The general sample representing the entire lot of coal contained 1.52 per cent of pyritic sulphur and 0.S0 per cent of organic sulphur. The total sulphur content amounted to 2.32 per cent, of which 34.5 per cent was present as organic sulphur and 65.5 per cent as pyritic sulphur. Sulphate sulphur was not determined as the analysis made at the Pittsburg station of the mine 90 THE DEEP RIVER COAL FIELD samples showed a maximum value of only 0.026 per cent. . . . This con- dition is favorable for a good sulphur reduction, but it is counterbalanced by the finely disseminated nature of the pyritic sulphur present in the coal. Ash reduction by Trent process . — A final attempt to reduce tlic percentage of ash. in the coal of the lower bench of the Cumnock coal bed was made by the Trent process — a patented process which, in certain coals, will reduce the ash very materially indeed. The test was made at the works of the company in Alexandria, Virginia. The Trent process for reducing ash in coal, consists in dry pulveriz- ing the coal so that it will go through 100-mesh sieve; wetting of the pulverized material with water from the tap; and then the addition of a small percentage of standard ISTavy fuel oil. The oil tends to unite with the carbon, freeing the earthy matter which settles to the bottom. The sample to be tested, which consisted of run-of-mine coal from the lower bench in the Carolina mine, had the following composition : moisture, 1.4; volatile matter 29.4; fixed carbon 42.0; ash, 27.2. The so-called “amalgam” resulting from the combination of the oil and carbon had the following composition : volatile matter, 48.5 ; fixed carbon, 38.1; ash, 13.4. If this amalgam is then subjected to low temperature distillation until the oil that has been added is driven off, the resultant purified coal contains 17.1 per cent of ash. If the coal were treated by this process, the result would be the so-called amalgam which contains about 21.6 per cent of fuel oil in addition to the finely divided carbon and ash, or if the oil were distilled it would leave only the finely divided carbon and ash. In either form the product can be used as a fuel — if in the amalgam form with a content of ash of 13.4 per cent and if in the form of dry purified coal with an ash content of 17.1 per cent. The reduction of the ash by this process is rather disappointing and is said to be due to the fact that the earthy material is present in a very finely divided condition and this means that to reach the carbon itself, the crushing would have to be possibly to 200 mesh which would be quite expensive. There is no question about the effectiveness of this process, but in certain cases the reduction in the ash is not nearly so marked as in others. The operator considering this process should calculate closely the cost of separating this bench of coal from the upper bench, its crushing down to the required degree of fineness and finally the market- ing of the product, either in the form of oil-amalgam, powdered fuel, or briquettes made from the powdered material. THE DEEP RIVER COAL FIELD 91 POSSIBILITIES OF PETROLEUM IN THE DEEP RIVER FIELD Much speculation has been indulged in here as well as in other States crossed by the belt of rocks of Triassic age as to the possibility of obtaining oil or gas from the sandstone which forms such a large proportion of their bulk. Many reports are current regarding so-called oil seeps and gas is supposed to bubble up through the water in many of the streams. The writers examined a number of these localities supposed to show signs of oil, but none was seen, though the oxide of iron which generally forms an iridescent scum on stagnant water was seen at a number of places. Persons finding such an iridescent scum on water may easily test it by stirring the water with a stick. If the scum can be drawn out and stirred into whorls without breaking, it is probably oil of some kind, but if it is brittle and breaks when stirred, it is oxide of iron and worthless. As there are apparently no signs of petroleum at the surface, the next step in the investigation is to study the rocks of tbe region to see if the conditions, which by long experience geologists have come to regard as essential, are present or not, for in many of the well known oil fields there were absolutely no surface indications of the presence of oil or gas before drilling began. In conducting the geologic study of the possibility of oil pools there are four elements that enter into the problem. These are: (1) the presence of rocks of such a character that they may have served as the place of origin or source of oil or gas; (2) porous sandstones or limestones into which the oil when formed, can collect; (3) a geologic structure or fold of such a character that it will trap the oil and gas as they migrate through the porous rock; and (4) a nonporous shale or clay above the sandstone to seal in its oily .contents and prevent their escape* (1) As petroleum has been derived largely, if not wholly, from organic remains which were buried in the mud or sand that now form the country rock, it will be necessary to find a fairly thick formation which contains fossil remains in abundance. All of the ISTewark rocks of the Deep River Field appear to have been laid down in fresh water or on the land, hence they do not contain a marine fauna from which the oil could have been derived. The presence of beds of coal and some black shale are indications of abundant vegetal growth, but in all except the Cumnock formation the materials are so coarse that air could easily have reached the enclosed vegetal matter and cause its destruction. The black shale and coal of the Cumnock formation would probably supply some material for the formation of oil, but the volume of such shale and coal is so small that the amount of oil that may have been produced from them in the past is negligible. It is true that 92 THE DEEP RIVER COAL FIELD some layers of the shale are quite rich in bituminous material, and that at one time there was a manufacturing plant in operation at Farmville for the distillation of oil from the shale and coal, but, as described on a previous page, the Cumnock formation is in many parts of the field apparently thin and in places is apparently replaced by red conglomerate, and consequently the volume of possible oil-producing shale is small. On account of this replacement toward the southeast, the part of the field most promising, as a source of oil, is about Cumnock and Gulf where the formation is thickest and contains the most bitu- minous material. But here erosion has cut deeply into the formation without exposing any trace of the coveted substances. (2) There are many beds of porous sandstone in the Cumnock forma- tion, where it is well developed, that might serve as reservoirs for oil or gas, and even in the overlying Sanford formation there are coarse brown sandstones that might serve a similar purpose, if other conditions were favorable. (3) Wide experience of petroleum geologists all over the world has demonstrated that about 90 per cent of the oil is found in anticlines or arches in the rocks, hence the first thing the oil geologist does is to look for such structures. As stated previously there are few known anticlines in this field. In general the rocks have been depressed into basins or troughs rather than raised into anticlines or arches. Thus the Carthage and the Corinth troughs are both essentially synclinal in structure, although in each case the scycline is not complete because of the great fault along the southeast side. On account of this structure neither basin nor trough can he considered a favorable place to drill for oil. As described previously these troughs are united by a cross-anti- cline at Colon, but this fold has raised the formation so high that the Cumnock formation crops out at the surface as far east as Colon, hence there are scarcely any rocks below the surface on this anticline that might he considered as sources of oil or gas. Another disturbing factor in this anticline is the possibility, if not probability that it is broken along its crest, by a fault which follows the system of dikes north to Colon and there turns to the northwestward to the margin of the field. Altogether the Colon cross-anticline does not seem promising from a geological point of view. In referring to anticlines as the most favorable rock structures for holding accumulations of oil or gas, it must he understood that this statement applies only to rocks that are saturated with water and that in dry rocks the oil accumulates, if it accumulates at all, in very different places. This is illustrated by Fig. 7, which is supposed to he a cross- section representing the rocks as they would appear in the side of THE DEEP RIVER COAL FIELD 93 a deep trench, cutting an anticline and a syncline. A B represents a moderately coarse porous sandstone which is the reservoir rock. C D is the overlying impervious shale which serves as a blanket and retains any fluid that may he in the reservoir rock. As water is heavier than oil and as both of these substances are heavier than gas, the three will arrange themselves, under the influence of gravity, in the order shown in the figure, gas at the top, oil next lower in the anticline, and then water occupying almost all of the synclinal fold. If a well is drilled at a it will encounter gas; at b, oil; and at c, water. In some cases there is little or no gas and then the oil is forced into the crown of the arch and a well drilled at a would strike oil. If the rocks are not saturated with water, then there is no force to drive the hydrocarbons into the anticline, and, under the pull of gravity, the oil would tend to migrate toward the bottom of the syncline at E. Such cases are seldom met with, but some of the oil pools in western Pennsylvania are in dry rocks and the oil, though much dis- seminated in the reservoir rocks, appears to be slowly migrating down- ward, but is arrested locally by denser portions of the sandstone and small pools on the limbs of the syncline are of common occurrence. If the oil is not trapped by barriers of dense rock, it finally reached the bottom of the syncline, but a pool in such a situation is rare indeed. (4) The different beds of the formations in this field are not well enough known to enable one to say positively that any given porous sandstone is overlain by a nonporous shale, but generally the succession of shale and sandstone is the rule and it is probable that most porous sandstones have a shale cap. So far as this element of the problem is concerned, it may be taken for granted that it is favorable. In addition to the elements of the oil problem enumerated above, geologists are now coming to acknowledge a fifth element in the degree of metamorphism which has affected the rocks and which is apparently all important in determining in advance of drilling or even geologic investigation whether or not there is a possibility of obtaining oil if a well were drilled. Metamorphism means change and changes in the 94 THE DEEP RIVEK COAT FIELD rocks are induced by crustal movements, probably accompanied by the development of sensible heat. When rocks have been squeezed to such an extent as to produce heat, their condition and character have been changed so that the geologist has little difficulty in recognizing the marks of this change and he can pronounce at once on the general question of whether or not the rocks are liable to contain oil. Thus the crystalline schist and slate underlying the Newark rocks bear all the ear-marks of having been greatly metamorphosed and no geologist would consider for a moment the possibility of their containing oil, except possibly very locally, where oil may have recently migrated into them from some adjacent oil-sand. The Newark rocks, on the other hand, on casual inspection, show no signs of having been affected by heat or pressure, but such a test is not always satisfactory, because in the incipient stages of change there is little outward effect apparent. The most satisfactory indication of metamorphism is the condition of the coal as shown by a chemical analysis (pp. 82 and 83). The com- parison of many coal analyses in the Appalachian region shows that the great oil pools are found where the fixed carbon in the coal in the C form (see table of analyses) is less than 60 and that little if ar.y oil is found where the fixed carbon is more than 65 per cent. The fixed carbon in the Deep River coals ranges in the C form from 62.4 to 64.9, hence the rocks are metamorphosed to such an extent that it is doubtful if any oil remains, granting that it formerly existed in the rocks. It seems certain that no oil pool of consequence would ever be found in these rocks, but the chance for finding natural gas is much better than that for finding oil. The relation of the dikes to the possible occurrence of oil has already been mentioned (p. 48), but it is worth repeating here for the benefit of those who may be tempted to drill test wells in this field. The dikes act as barriers to the circulation of water and the inhabitants have long ago learned that the most favorable place to find a supply of water is near a dike. If the dike serves as a barrier to the circulation of water, it doubtless would serve the same purpose to the circulation of oil, and hence, if there is any oil in the rocks, it would be liable to accumulate near the dike and a well located in such a position as to penetrate the oil sand near a dike would be much more likely to be successful than would one located at a distance from a dike. As many of the dikes are doubtless inclined one way or the other, it would be impossible to determine the exact distance from the dike on the surface at which a well should he located so as to penetrate a given sand close to the dike, but an attempt should be made to secure this sort of a location. THE DEEP KIVER COAL FIELD 95 Conclusions . — From a geological point of view, the writers have no hesitation in saying that all of the evidence they were able to collect in the field, bearing on this question, is of a negative character. The thinness of strata bearing organic material and its apparent restriction to the northwestern margin of the troughs makes it impossible to conceive of it as a possible source of a commercial quantity of oil. But even if we grant that at some time in the past, oil may have been distilled from the organic material entombed in the rocks, there are few, if any, anticlines in which it may have accumulated, and without such structures the volatile constituents of the oil have had ample opportunity to escape through the coarse conglomerate which composes most of the ISTewark group. As, however, many of the citizens of this field would like to see a deep well drilled so as to settle the question regarding the presence or absence of petroleum, the writers were on the lookout throughout the time spent in the field for a location that might be considered the best, from a geological point of view, to drill a test well, but after mature consideration of all of the facts that were obtained they regard all locations as unfavorable and are unable to say that any one location is more favorable than another. IST o one, even the most experienced geologist can say positively that oil does not occur in these rocks, hut they can say that all of the facts obtainable are of a negative character, and that in their opinion it is not worth spending time or money in prospecting where conditions appear to be so unfavorable. Sometimes the drilling of a test well will satisfy public opinion regarding the presence or absence of petroleum much better than the opinion of the most eminent geologist, but in such a case as the Deep River Coal Field, where there is no pronounced anticline, one well would test only the possibilities in its immediate vicinity, hut would tell noth- ing about oil possibilities in the territory surrounding the well. Under such conditions, it would require many wells, unless the driller were fortunate enough to strike oil in his first or second venture. Altogether the adequate testing of this field might prove to be very expensive, with no returns, and in such an event it would have been much better to spend the money in building good roads or in improving the soil, or in some enterprise that would redound to the benefit of the entire community, rather than in a hole in the ground that yielded nothing. OctiS’fTft l a r:-'38V Date Due JAN I 3 *47 lJUV 2 IP 2 $ ? ' Form 335— 40M— 6-39— S * "557.56 N873B 82069 N« C. - ft e o lo si oal a nd -.Econo- mic - S u rvey — Bulletin No. 32 557.56 N873B no. 33 82069