Cornell MAniversity Library THE GIFT OF ENGINEER LIBRARY 1248 ENGINEERING LIBRAM WISCONSIN GEOLOGICAL AND NATURAL HISTORY SURV x A. BIRGE, Director. Cc. R. VAN HISE, Consulting Geologist. BULLETIN NO. VI. ECONOMIC SERIES NO. 3. PRELIMINARY REPORT ON THE COPPER-BEARING ROCKS oF DOUGLAS COUNTY, WISCONSIN. BY ULYSSES SHERMAN GRANT, Ph. D, Professor in Northwestern Untverstty. MADISON, WIS. PUBLISHED BY THE STATE. 1900. Wisconsin Geological and Ratural History Survey. BOARD OF COMMISSIONERS. Epwarp Scorimxp, Governor of the State. L. D. Harvey, State Superintendent of Public Instruction Cuarues K, ADAMS, President, President of the University of Wisconsin. Epwiwn E. Bryant, Vice-President, President of the Commissioners of Fisheries. CHARLES S. SLICATER, Secretary, President of the Wisconsin Academy of Sciences, Arts, and Letters. E. A. BirGe, Director of the Survey. C. R. Van Hisz, Consulting Geologist. E. R. Buckey, Assistant Geologist. In charge of Economic Geology. 8S. Wermpmay, Assistant Geologist. In charge of Geology of Wausau District, L. 8. Surry, in charge of Hydrography. 5. V. PErPen, Chemist. F. RB. DENNISTON, Artist. WISCONSIN GEOLOGICAL AND NATURAL HISTORY SURVEY. E. A. BIRGE, Director. Cc. R, VAN HISE, Consulting Geologist. BULLETIN NO. VI. ECONOMIC SERIES NO. 3. PRELIMINARY REPORT ON THE COPPER-BEARING ROCKS OF DOUGLAS COUNTY, WISCONSIN. BY ULYSSES SHERMAN GRANT, Ph. D., Professor in Northwestern University. MADISON, WIS. PUBLISHED BY THE STATE. 1900. TN WYS J ( SI6 19 oD — 1901 A, js305 7 Wisconsin Geological and Watural history Survey. BOARD OF COMMISSIONERS. EDWAED SCOFIELD, Governor of the State. L. D, Harvey, State Superintendent of Public Instruction. CuHaARgugs K. ApaAMs, President, President of the University of Wisconsin. EpwIn E. Bryant, Vice-President, President of the Commissioners of Fisheries. CuaRLEs S. SLICHTER, Secretary, President of the Wisconsin Academy of Sciences, Arts, and Letters. E, A. Brres, Director of the Survey. C. R. VAN Hisz, Consulting Geologist. E. R. Buck ey, Assistant Geologist. In charge of Economic Geology. S. WEIDMAN, Assistant Geologist. In charge of Geology of Wausau District. L. S. Smrru, in charge of Hydrography. §. V. PEPPEL, Chemist. F. R. DENNISTON, Artist. tt Bu [ TABLE OF CONTENTS. PAGE, INTRODUCTION: «285600: cisiards dcensinvaacereaaew etna ee eBUES ARES MOSS NARS TS 1 Acknowledgments: .via0s cdimcs comes cae s swe ss aee so atanw «sere 3 CHAPTER I. GEOLOGY OF DOUGLAS COUNTY..........0 ccc eens 5-24 Previous descriptions ...... cc ccc cee eee ween rene Salis 3ORS 5 Surface features cs cases t "ag t bat Se a atte He Fault Breccia in the Traps. Middle river contact of Traps and Lake Superior Sandstone. GEOLOGY OF DOUGLAS COUNTY. 19 Effects on the Sandstone. As a rule the sandstone does not show this marked breccia- tion near the contact. Only in one place,—at the Middle river contact in Sec. 25, T. 48 N., R. 12 W.,— does the sandstone exhibit evidence of so complete a shattering as do the traps. But the sandstone has been affected in a different manner and has been thrown into folds, or broken into large, faulted blocks. Black River Contact. For a short distance below Black River falls the river flows in a gorge cut in the traps, but with- in 800 feet of the falls the Lake Superior sandstone occurs in a few isolated exposures. These dip in various directions, and in one place strata of the sandstone are found included in the trap breccia which exists near the contact line. Some 200 feet farther down the river the sandstone is exposed more continu- ously and near the contact the dip is 35° toward the north. Farther north the dip becomes less and the sandstone, except for a few minor undulations, becomes practically horizontal. The general effect on the sandstone at this contact is a bend- ing upward of the beds near the fault line, while in the imme- diate vicinity of the contact there has been some faulting of the sandstone. Copper Creek Contact. Here, on the west bank of the stream, the two rocks occur within ten feet of each other. The trap shows a precipitous wall facing north and rising some fifty feet above the stream, and ten feet to the north of this is an exposure of sandstone rising fifteen feet above the water. The sandstone dips toward the north an at angle of 60°, while a few feet. farther from the contact the dip is 40° toward the north, and within a distance of 100 feet from the contact the sandstone has become practically horizontal. The bending up- ward of the sandstone beds at this contact is represented in the section on plate VIII. Aminicon River Contact. Here the contact plane, as exposed, dips to the south at an angle of 45°. At the contact the sand- stone has been sharply flexed upward and also probably faulted. Within forty feet of the fault plane the sandstone is nearly hori- 20 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. zontal and continues so, with the exception of a few minor 1r- regularities, to the sandstone quarry, about half a mile to the northwest. See section AB on plate IX. Middle River Contact. The contact between the sandstone and the traps is crossed three times by this river in Sec. 25, Te 48 N., R. 12 W., and the exposures are such as to render this contact of more interest than any of the others. The upper layers of the sandstone, as seen here, are shaly sandstones or red and gray shales with some bands quite rich in lime. In the immediate vicinity of the traps the shaly sandstone is very much brecciated, to as high a degree as the brecciation of the traps before described. ‘The sandstone has been thrown into a marked series of folds, so that the dip is, for a distance of nearly half a mile from the contact, at a high angle toward the south. This dip varies from practically vertical near the contact to 40°, the average in this half mile being nearly 70°. (See plate VI.) At the contact there is perhaps a sharp syn- clinal fold so that for a few feet the dip is toward the north. Beyond this half mile (i. e., to the north) exposures are not very continuous, but such as occur show first flat dips, dips of from 40° to 60° toward the north, dips of 20° toward the south, and lastly horizontal strata. All these occur within a mile and a quarter of the contact. The section CD, on plate IX, shows the folding of the rocks as above described. THE LATER FORMATIONS. In Douglas county there are no strata known which are younger than than the Lake Superior sandstone and older than the glacial drift. No attempt was made in the examination of the copper-bearing rocks to investigate the drift deposits of the county. It is only necessary to state that the glacial de- posits take three distinct forms: (1) unstratified drift or till which exists largely in the second, third, and fifth topographic districts already described ;? (2) stratified drift, which exists in the barrens or the fourth topographical district; and (3) 1See p. 18 and plate V. 2Pp. 6-7. WISCONSIN GEOL. AND NAT. HIST, SURVEY, BULLETIN NO, VI., PL. Vi. Tilted strata of Lake Superior Sandstone. Middle river, contact of Traps and Lake Superior Sandstone. GEOLOGY OF DOUGLAS COUNTY. 91 clays deposited near the end of the Glacial] epoch in the Lake Superior basin. These are underlain by, and mingled with, the unstratified drift and the two together form the marked red clays which cover the northern part of the county. GEOLOGICAL STRUCTURE. To the statements already made it is only necessary to add that the structure of the Keweenawan rocks is that of a syn- cline, with the synclinal axis running northeast and southwest through the center of the tract underlain by the rocks of Upper Keweenawan age. To the southeast of this axis the strata dip northwest, while to the northwest of it the dip is toward the southeast and south. This fold is a very open and shallow one, the dips near the center being small, while on the edges they become more steep, here averaging perhaps 40°. (See section on plate I.) The junction between the Keweenawan traps and the Lake Superior sandstone on the north is marked by a fault, as has already been described. The sandstone dips at a very low angle toward the center of the Lake Superior basin, or is practically horizontal. Joints. Intersecting the strata of the Keweenawan, both the sand- stones and the traps, are frequently joint planes. There are commonly two series of these, one coinciding practically with the dip and the other at right angles to the first and running with the strike. There are also frequently joints of another system which are practically at right angles to those of the first system and run with the direction of the dip. In outcrops where the dip and strike cannot be definitely determined these joints, especially those of the system which coincides with the dip, give an indication, but not always a reliable one, of the dip and strike. 22 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. GEOLOGICAL HISTORY. In a very early period (Algonkian) of geological time, but later than the deposition of the rocks which contain the iron ores of the Lake Superior district, Douglas county was being cov- ered by successive flows of molten rock. These flows were built up, one on top of another, until a mass of igneous rock sev- eral thousands of feet in thickness had accumulated. These are the rocks of the Lower Keweenawan age. These flows at last ceased and were followed, without any great lapse of time, by the deposition of a series of sedimentary rocks of Upper Ke- weenawan age. These sediments lie above and conformably upon the older lava flows, and consist essentially of material derived directly from these lava flows. After the deposition of these sedimentary rocks the land was raised above sea level, where it stood, exposed to erosion, for a long period of time. Some time after the deposition of Upper Keweenawan rocks, and quite probably accompanying the elevation of these rocks above the sea, compressive forces acting in a general northwest and southeast direction flexed the strata into their present synclinal form (compare section AB on plate I). Later the region, or at least the northern part of it, was again covered by water, and in this water were deposited the strata of the Lake Superior sandstone. These strata are of Cambrian age and were deposited in an approximately horizontal position,—a position they have largely retained to the present day. At some unknown time after the deposition of the sandstone the district was visited by an east and west fissure, along which there was a displacement of the rocks. This is the fault already described which at the present time separates the Lake Superior sandstone from the Keweenawan traps. The downthrow was on the north side of the fault line. During all the long ages which have elapsed from the time of the Lake Superior sandstone (Cambrian) until the present day Douglas county seems to have been above water,—at least there are today no remnants of strata younger than the Cambrian. It is possible, of course, that such strata might have been deposited GEOLOGY OF DOUGLAS COUNTY. 93 and afterwards removed by erosion. The glacial deposits which now 80 universally cover the bedrock throughout the county owe their origin to the ice sheet which covered the northern part of the United States in, as it were, the geological yesterday. GEOLOGICAL MAPS. ‘Accompanying this report are four geological maps. The first (plate I) is a general geological map of Douglas county. The others (plates VII, VIII and IX) are more detailed maps of limited areas. The extent of each of these detailed maps is indicated on the map of Douglas county. On the detailed maps practically all of the data (except the topography and such feat- ures as the abundance of certain kinds of boulders) which the Survey depends upon in locating the boundaries between the different formations are presented. The maps then will enable one to tell at a glance hew accurately the boundary lines between the different formations are drawn, the accuracy being a direct function of the amount of information at hand. This feature of the maps will appeal directly to those who are interested in exploring or selecting copper lands. For example, a given “forty” can be seen to be positively without or positively within the area underlain by the copper-bearing rocks; or it may be on or near the border line, in which case the map will give the evi- dence as to whether the boundary line is here located with definiteness, and the consequent probability of the given “forty’s” being on the copper range. Along the north boundary line of the copper-bearing rocks in plates VIII and IX the topography (i. e., the marked escarp- ment at the northern limit of the Douglas range’) and the in- tense brecciation of the traps near the contact line? made it pos- sible to locate the limit of the Keweenawan traps much more carefully than the maps indicate on their faces, for these two features are not represented. However, in T. 48 N., R. 11 W., on account of the scarcity of the exposures and the lack of the marked escarpment, this boundary line is much less definitely located than elsewhere on these two maps. 1See II on p. 6. 3See p. 18. 94 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. On the county map (plate I) outside of the areas of the de- tailed maps the geological boundaries have been located by, in- formation obtained from different sources. The north bound- ary of the Lower Keweenawan in T. 46 N., R. 15 W., is taken from the maps of the former Geological Survey of Wisconsin. The southeastern boundary of the Lower Keweenawan north- east of the area shown in plate VII is not definitely located be- cause of/the lack of outcrops. The only rock exposures noted by the parties of the Survey in the vicinity of this boundary line are some knobs of coarse melaphyre in Sec. 15, T. 45 N., R. 12 W., at the “rock cut” on the C., St. P., M. & O. railway in Sec. 12 of the same township, and near the northeast corner of See. 31 and the southwest corner of Sec. 29, T. 46 N., R. 11 W. The boundary between the Upper and Lower Keweenawan in the southeastern corner of the county is located from the work of the former Geological Survey of Wisconsin,! from a map by Irving,* and from information kindly furnished by Prof. J. A. Udden, of Rock Island, Illinois. On the detailed maps (plates VII, VIII, and IX) the occur- rence of copper ore,—the native metal, or carbonates, or sul- phides,—is indicated only in those localities where parties of the Survey have actually seen it. Copper has been reported from other localities, and farther search will undoubtedly reveal many more. 1Moses Strong. “Geology of the Upper St. Croix District;’? Geol. of Wis., vol. ITI, pp. 363-428, 1880. 2“The Copper-Bearing Rocks of Lake Superior;’’ U. 8. Geol. Survey, Mon. V, plate 1, 1883, THE 8T. CROIX COPPER RANGE. 25 CHAPTER II. THE ST. CROIX COPPER RANGE. This name is applied to the belt of copper-bearing rocks which are exposed just to the northwest of the St. Croix river in the southwestern part of Douglas county. The part of this range about which we have the most information is shown on the ac- companying geological map, plate VII. Outside of the area shown on this map exposures are not common except along cer- tain parts of the Tamarack and Spruce rivers in T. 43 N., R. 15 W. A few exposures are also known in Sees. 28, 29, and 32, T. 44 _N., R. 14 W., and near the south side of Sec. 6, T. 43 N., R. 14 W. The igneous rocks here exposed are readily separable into basic lava flows of slightly varying characters and coarse mela- phyres. The presence of the latter rocks make it possible to di- vide the area into a number of parallel belts which trend north- east and southwest. The melaphyres, on account of the greater thickness of the beds and the more resistant character of the tock, outcrop more frequently than the thinner-bedded and softer lava flows. ‘These harder rocks commonly form low ridges, and by means of these ridges the melaphyre belts can often be traced when outcrops are very few. These ridges can be distinguished from drift ridges by their straight outlines, their uniform southwest and northeast trends, their steep north- western slopes and their more gentle southeastern slopes. Some of the finer grained melaphyres are distinct flows, having a markedly amygdaloidal upper surface, but the nature of others is not so clear. It is not improbable that some of the coarser grained melaphyre belts are intrusive sheets, but in no case has it been possible to establish this. 96 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. SPECIAL DESCRIPTIONS. Below are descriptions of some of the more important out- crops. ‘The locations of all of the outcrops known in the most important part of the range can be seen by consulting the map, plate VII. T. 46 N., R. 11 W. The most northeasterly exposures known to the Survey on the St. Croix range are two in the 8. W. 4 of Sec. 29 (240 paces N. and 1,875 W., and 640 N. and 1,795 W.). They are of melaphyre. Near the northeast corner of Sec. 31, and extend- ing to the north line of this section 160 paces west of the north- east corner, is a marked ridge of the same rock. This ridge runs southwest from this locality for a distance of about 400 paces, and has a precipitous northwestern face from 50 to 80 feet in height. The exposures in these two sections undoubtedly represent but one belt of melaphyre. T. 45 N., R. 12 W. At what is known as “the rock cut” on the C., St. P., M. and O. railway, near the center of the west side of the N. W. i of Sec. 12 (1,200 paces N. and 1,850 W. to north end of cut), there is a cut extending 215 paces through a ridge of melaphyre. A few small seams exist in the rock. ‘In one of these a very small amount of native copper was seen. Near the center of the south half of Sec. 15 (400 paces N. and 1,120 W.) is another expos- ure of melaphyre. ‘The exposures mentioned above are all that are known to the Survey in Ts. 46 N., R. 11 W., and 45 N., R.12 W. It is very probable that all these exposures belong to one melaphyre belt. T. 45 N., R. 13 W. In the S. W. 4 of Sec. 25 (50 paces N. and 500 W.) is a large exposure of melaphyre. This is a continuation of the most northwesterly belt of melaphyre shown on plate VII. On the THE 8T, CROIX COPPER RANGE. QT Moose river near the southeast corner of Sec. 14 (50 paces N. and 60 W.) is a decayed reddish trap. On the same river in the S. W. } of Sec. 13 (125 paces N. and 1,700 W. and extend- ing to 65 N. and 1,600 W.) are exposures of amygdaloidal traps. I 34 Do te We Moose River. The most southerly exposure of igneous rock on this river is on its west bank near the south side of Sec. 14 (130 paces N. and 540 W.). The rock is a fine grained, some- what luster-mottled, amygdaloidal diabase. The amygdules contain quartz, chlorite, epidote, and calcite. In irregularly outlined areas the rock is highly charged with epidote, and in some of these areas is a small amount of native copper. The rock is cut by a few small, red flinty, vein-like forms and where these cut the epidotized areas the veins sometimes carry a little copper. This flow represents the youngest, or almost the young- est, of the) Lower Keweenawan rocks in this vicinity, for just across the river occurs a conglomerate of Upper Keweenawan age. Several other exposures occur along the river in this section; one of these (675 paces N. and 925 W.) is of much interest. It is on the west bank, near the water’s edge, and consists evidently of only one flow. It is a reddish, amygdaloidal diabase, which in its coarsest parts is luster-mottled. At the southern end of the exposure is a highly epidotized part of the rock which is two feet in width, runs northeast and appears to stand in a vertical position. It can be traced for only a few feet and disappears under the soil on one side and under the water on the other. In the amygdules and cracks in this epidotized part of the rock is a considerable amount of native copper. In See. 2, on the south bank of the river, is an outcrop of an amygdaloid (385 paces N. and 190 W.) which contains large porphyritic crystals of reddish feldspar. Such porphyritic amygdaloids are rare on the St. Croix range. In the same sec- tion, at a marked bend in the river, is a series of at least three highly amygdaloidal flows (580 paces N. and 750 W.). Farther 28 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. up the stream in Sec. 2 on the west bank, is a low ledge (785 paces N. and 870 W.) which is poorly exposed and lies mainly under the water. ‘The rock is a hard, dark reddish amygdaloid. The amygdules are filled by quartz, chlorite, calcite, prebnite and native copper. The ledge is about eight feet in width and seems to be copper-bearing throughout. The water rendered a careful examination of this ledge impossible. This is a favor- able place for exploration, as a comparatively small amount of work would give more definite information concerning the worth of this copper-bearing layer. : Crotty Brook. Several exposures exist along this stream in Sees. 30 and 31. The most northerly exposure in Sec. 30 (1,400 paces N. and 880 W.) is on the west bank. The rock is. a reddish amygdaloid and in it are a few seams and small highly epidotized areas, both of which at times carry a little native copper. T. 48 Ni, R.18 W. Crotty Brook. The most southerly exposure of igneous rock on this stream is in the N. W. + of Sec. 7 (1,420 paces N. and 1,565 W.). ‘This is near the top of the Lower Keweenawan.* The rock is a reddish diabase which is distinctly luster-mottled in the center and lower part of the flow, but is amygdaloidal near the upper surface. In this amygdaloidal portion are some: irregularly outlined masses of roughly spherical form and from two to ten inches in diameter. ‘These masses appear to be parts or the ordinary rock which have been highly charged with epi- dote, and some of them contain small amounts of native copper. Farther up the stream, but in the same quarter section, are other exposures of amygdaloid cut at times by small vein-like forms: of reddish, hard, flinty rock which occasionally carries small specks of copper. In one of these amygdaloids (1,880 paces N. and 1,720 W.) is an oval mass of the rock which is rich im epidote. As exposed this mass is ten inches wide and fifteen inches long, but more of it evidently exists under the water. In the amygdules of this mass of rock metallic copper is abundant.. 18ee p. 16. THE 8T. CROIX COPPER RANGE. 99 At the Copper mine dam on Crotty brook, in the S. W. } of Sec. 6, three pits were sunk perhaps thirty years ago. The rock thrown out is a fine grained reddish diabase with amgydules of chlorite and quartz. Some of the rock is rich in epidote. None of the material examined showed any copper, although it is not unlikely that this mineral occurred in the epidotized parts of the rock and thus attracted exploration at this place. This is the only locality on the St. Croix range where any serious pros- pecting for copper seems to have been carried on. 2. 44 Nik. Th W. The only exposures noted in this township outside the area shown in the geological map (plate VII) are in Secs. 28, 29, and 32. In the last section (400 paces N. and 1,505 W.) is a ridge of medium grained reddish diorite, which is in places slightly porphyritic with feldspars. This rock contains a few metallic-appearing particles which might be mistaken for cop- per, but which are of some micaceous mineral that has devel- oped in the alteration of the rock. Similar rock, most probably of the same mass, occurs to the southwest (15 paces N. and 1,845 W.) in the same section and also forms a prominent ridge which runs northeast and southwest through the center of Sec. 28. In the N. W. 4 of See. 29 are three exposures of melaphyre. These are near the east bank of the Tamarack river and a short distance above the buildings at the Tamarack farm. PAS Ni Re dd We There are many exposures of melaphyre in this township and a number of amygdaloids in Secs. 2, 11, and 16. In the last section (260 paces N. and 1,040 W.) is an outcrop of amygda- loidal porphyry very similar to the porphyry noted on the Moose river in Sec. 2, T. 44 N., R. 13 W.1 The two outcrops are in about the same stratigraphic position and perhaps represent one flow. On the south line of Sec. 22, (1,235 paces west of the south- east corner of this section) is an exposure of reddish amygda- 1See p. 27. 30 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. loid which has epidote, chlorite and abundant calcite in the amygdules. Some malachite, which is undoubtedly an altera- tion product from native copper, occurs in these amygdules. F413 NB. 15 W. ‘Along the Tamarack river in Secs. 10, 15, 16, 20, 21, and 29 are a number of exposures of amygdaloidal rocks. Similar rocks occur on the Spruce river in Secs. 8 and 17. On the east bank of the former stream in Sec. 16 (about 795 paces N. and 900 W., and extending for 50 paces down stream) is some hard reddish diabase with amygdules holding chlorite, calcite and quartz. In some of the amygdules is also metallic copper. The coarser parts of the rock show luster-mottling. Farther down the river in the same section are four other outcrops, the most southern (400 paces N. and 1,130 W.) of which is of rock simi- lar to that just mentioned. Here a small piece of native cop- per was found in one of the amygdules. In Sec. 29 three exposures of melaphyre occur on the east bank of the Tamarack river. These probably belong to the same layer, which is quite likely the southwestern continuation of the layer exposed in three places in Sec. 29, T. 44 N., R. 14 W., mentioned above. T. 42 .N., R. 15 W. Along Chases brook in Secs. 9 and 16 are some interesting ex- posures. In the latter section (1,840 paces N. and 1,050 W.) is a mass of coarse melaphyre forming a barrier across the stream. The augite crystals in this rock are at times an inch in diameter. Further up the stream in Sec. 9 (1,479 paces N, and 537 W. and extending northward to the north line of this section) are a series of amygdaloidal rocks. In the upper part of several of these flows native copper occurs. THE DOUGLAS COPPER RANGE. 31 CHAPTER III. THE DOUGLAS COPPER RANGE. ‘This name is applied to the belt of copper-bearing rocks which are exposed along the hill range that marks the northern limit of the Lower Keweenawan rocks in Douglas county. The most important parts of this range are shown in detail on the accompanying geological maps, plates VIII and IX. Outside of the area of these maps there are very few rock exposures. Along this hill range to the east of Douglas county no outcrops of the traps have been reported, while to the west of this county some outcrops occur in Minnesota. In some particulars the rocks of the Douglas range differ from those of the St. Croix range: (1) Prehnite is much more common on the former than on the latter. (2) The melaphyre belts, which are so characteristic a feature of the latter range, are lacking on the former, although there are in a few places rocks which approach rather closely to the typical melaphyres of the southern range. (3) On the Douglas range intrusive rocks are in places abundant, while they are practically lacking on the St. Croix range, unless some of the melaphyre belts should prove to be of this nature. These intrusive rocks con- sist of diabases, gabbros, granites, and syenites. The gab- bros and syenites, which approach the gabbros in composition and which may be parts of the same general magma, are the most common of these intrusive rocks. On the west the intrusive rocks were first noticed at Pilot mound in Sec. 15, T. 47 N., R.13 W. East of here they occur in abundance along the Aminicon river in many places between Rockmontand the south- ern limit of the Lake Superior sandstone. Some of the intru- sive rocks are seen along the Middle river, especially in Sec. 2, T. 47 N., R. 12 W., and a bold knob of gabbro and associated rocks exists in the northern part of the N. W. 4 of Sec. 25, T. 48 82 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. N., R. 12 W. The more acid of these intrusive rocks (granites and syenites) are in general of later date than the gabbros. The strike of the lava flows on the Douglas range is northeast and southwest toward the western end. On going eastward the strike gradually becomes more nearly east and west, and at the eastern part of the range has this latter direction. The strike is approximately, but not exactly, parallel to the fault line which separates the traps from the Lake Superior sandstone to the north, the direction of the fault averaging a little more nearly east and west than does the strike which is inclined more toward the east-northeast and west-southwest. Thus in going from the eastern end of the range towards the west, one passes over lower and lower, and consequently older and older, flows. SPECIAL DESCRIPTIONS. Serious prospecting for copper has been carried on in the rocks of the Douglas range at intervals for over fifty years, and there are indications of some prehistoric attempts at copper min- ing. The history of these explorations has already been pub- lished by the Wisconsin Survey,! and the present preliminary report does not attempt to duplicate these descriptions. Below will be found brief accounts of the various locations where ex- plorations for copper have recently,—mostly in 1898 and 1899, —been carried on. The Culligan Location. Explorations at this place have been made in the S. W. + of Sec. 29, the S. E. 4 of Sec. 30 and the N. E. 4 of Sec. 31, T. 47 N., R. 14 W. In Sec. 30 the most work has been done and here are four test pits, which were filled with water when the examination was made. The pits are located along a small creek near the southeast corner of this section. One pit is re ported to be thirteen feet in depth, the lower three feet being in rock. ‘Another one is also thirteen feet in depth, while another is thirty feet deep, the lower seventeen being in rock. The ma- terial thrown out of these pits is all highly brecciated and some 1H. T. Sweet. Geol. of Wis., vol. III, pp. 358-362, 1880. THE DOUGLAS COPPER RANGE. 33 of it shows slickensided surfaces. On some of this material there are greenish stains which resemble malachite. These pits are regarded as located near the junction of the traps and the Lake Superior sandstone. In See. 29 (770 paces N. and 1,150 W.) a shallow trench has been dug and the rock thrown out is mainly a greenish gray, hard amygdaloid. The amygdules are small, but numerous, and most of them contain quartz. Many of the amygdules hold native copper. Water in the trench prevented a careful exam- ination. The copper-bearing belt of rock is reported to be five feet in width. If the rock thrown out is a fair sample of this belt,—and such seems to be the case,—this flow ought to be prospected more fully. Along the creek in the N. E. } of Sec. 31 there are exposures showing several flows which in some places carry copper both in the amygdaloidal parts of the rock and in small veins. The bed richest in copper has been struck in a test pit (1,697 paces N. and 113 W.), which passes through about four feet of hard, greenish brown, barren rock and then strikes an amygdaloid rich in epidote. ‘This last rock carries considerable native cop- per. Many of the amygdules are completely filled with the metal, which also occurs in small seams. The exploration has not been carried far enough to determine how extensive this cop- per-bearing rock is, in fact the amygdaloid which carries the copper has been penetrated for only a few inches. The locality was visited again later in the season, but practically no more work had been done. This copper-bearing flow, like that men- tioned above, ought to be exploited more fully. A little more work would determine whether the parts already exposed were fair averages in copper content, or were richer or poorer than the rest of the copper-bearing amygdaloidal portion of the flow. And at the same time the thickness and probable extent of the copper-bearing rock could be determined. These prospects in Secs. 29 and 31 are more encouraging than those in Sec. 30, where most of the work has been done on this property. 34 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. The Copper Creek Location. This property includes the S. W. 4 of Sec. 14 and the 8. E. 4 of Sec. 15, T. 47 N., R. 14 W. In former years considerable work was done here and several test pits and shafts were sunk and strippings made in the vicinity of the junction of the two branches of Copper creek. Unfortunately the information gained by this work has been lost, or is not available. During 1899 work was resumed again, mainly in different places from the old work. Near the junction of the creeks there are a series of flows which strike approximately northeast and southwest. The dip is from 54° to 62° towards the southeast. The flows have amygdaloidal upper parts and in several cases, at the junction of two flows or in the upper part of a flow, are fractures whose dips correspond with the dip of the flows. Commonly along the fractures there is some brecciation. The broken parts of the rock are cemented by vein material,—quartz, calcite and preh- nite,—and it is in this vein material that most of the copper occurs, although it is also found in the amygdules. On the main stream, south of the junction, several flows are seen. In the upper part of one of these (159 paces N. and 43 W., Sec. 15) and the lower part of the next upper flow native copper occurs in amygdules. ‘The copper-bearing bed is about a foot in thickness. On the high ground between the two creeks and south of their junction is a pit (233 paces N. and 41 W., Sec. 15) which is perhaps 50 feet in depth, but now is, like all the others, filled with water. The pit slopes at an angle of 60° towards the south-southeast. To the northeast is a trench running along the junction between two flows,—probably along the lower side of the flow in whose upper surface is the pit just mentioned. Thrown out of the pit or the trench is a quantity of rock which can be termed copper ore. It is brec- ciated rock cemented by quartz, calcite, prehnite, and some native copper. The brecciation is evidently along a fracture between two flows, for the rock is in part the dense fine grained portion from the base of a flow and in part the porous amygdaloidal por- tion of the top of a flow. THE DOUGLAS COPPER RANGE. 35 To the east of the main creek and north of the junction of the streams are several pits and in one place a tunnel. From what can now be seen these pits do not show as encouraging pros- pects as that just mentioned. On the west side of the main stream, just north of the junction of the two streams, is a perpendicular rock face which has been exploited recently. The rock is in many places brecciated and along the broken sides of the fragments are slicken-sided sur- faces. In some very irregular and limited areas the brecciation is more intense and the broken rock is cemented by nearly pure white calcite, and in this calcite is some native copper in the form of fine wires,—averaging less than a thirty-second of an inch in thickness. In addition to the calcite there is here also quartz and prehnite, both in amygdules and in fissures. The copper here is not so abundant as at the pit described above. On the eastern of the two creeks there are a number of ex- posures, and at one of these (245 paces N. and 1,900 W., Sec. 14) is a brecciated belt which appears to be parallel to the dip. This belt is from one and a half to two feet in width and con- sists of rock fragments cemented by vein material, which here is mainly quartz and prehnite. The exposure is near the bed of the stream, and above this belt of broken rock is a highly epido- tized area, evidently of the same flow. In the vein material is native copper, commonly in wire-like forms; these wires appear to be coated by native silver. Later in the season this locality was visited again; the vein had been uncovered for a distance of thirty feet. It retained an approximately uniform width,—one and a half to two feet,— but was not as rich in copper as in the place where it was first uncovered. On the northern brow of the high hill in Sec. 15 (480 paces N. and 500 W.) a pit has been sunk along the top of an amyg- daloidal flow. The rock is a brown-weathering, reddish diabase. The south wall of the pit is the bottom of the next overlying flow. The strike and dip at the pit are rather anomalous, the former being N. 30° E. and the latter 78° towards the south of this. In this immediate vicinity a chance was had to measure the 36 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. strike and dip along a larger distance than could be obtained at the pit; the strike is N. 20° E. and the dip averages 70° to- wards the south of this. The upper three feet of the flow ex- posed in this pit contain most of the ore, although it occurs in smaller amounts through a thickness of twelve feet. The ore consists of two metallic minerals which have altered consider- ably. One of these is of a silver white color but has largely changed to a rusty brownish material. ‘In the field this min- eral was thought to be a nickel sulphide. The other mineral is regarded as a copper sulphide now almost completely changed to the green carbonate, malachite, which not only occurs in the amygdules but also exists as green stains along cracks. This pit is in similar rock, and near the same horizon stratigraphically, as another pit which was sunk for nickel several years ago about half a mile farther northeast (935 paces N. and 1,790 W., Sec. 14). The Fond du Lac Location. Prospecting at this location has been carried on in the N. E. 4 of Sec. 8, T. 47 N., R. 13 W. In former years two deep pits were sunk here, called the Stewart and the Parker shafts. The former is about 400 paces northeast of the latter. In 1899 a considerable amount of stripping was done on this property, and several shallow pits and trenches were made in the rock. This work was of such a nature as to expose a large surface of the copper-bearing amygdaloids; in fact the work here has resulted in an examination of a larger amount of rock in which copper might occur than at any other of the recent explorations on the Douglas range. At the brow of the hill range, crossed by the road on the east line of Sec. 8, is an exposure of hard, reddish, flinty rock which has been much fractured. ‘The fractures are frequently healed by calcite. This exposure is 245 paces south of the northeast corner of Sec. 8, and other exposures of the same rock occur both to the west and to the east. About 100 paces west of the road a cross cut has been made from the rock just mentioned south for 100 paces across some amygdaloidal flows, WISCONSIN GEOL. AND NAT. HIST. SURVEY. BULLETIN NO, VI., PL. X. Trenching at the Fond du Lac Mine. N.E 14 Sec. 8, T. 47 N.,R.13 W. THE DOUGLAS COPPER RANGE. 37 The Stewart shaft (1,400 paces N. and 345 W.) is said to be 65 feet deep. At the time the Survey parties examined it, it contained water to within about 25 feet of the top. The shaft goes down along a vein-like mass of rock which dips southward at an angle of 35°. The country rock is here a medium grained reddish diabase and the rock of the vein-like mass is a coarser grained diabasie rock which has been highly charged with epi- dote. The latter rock at the shaft varies from 10 to 18 inches in thickness. It can be traced, as exposed in strippings, almost continuously for 100 paces to the east of the shaft and for 200 paces to the west. ‘Towards the east it becomes smaller and where last seen is about six inches in thickness. This vein-like mass appears to be a sheet of igneous rock which has been in- truded along a fissure in the country rock, the fissure practically coinciding in direction with the dip and strike of the inclosing rocks. ‘The copper content of this rock varies considerably at different points; in some places no copper at all is seen, at others this metal is quite abundant. The flow, in which is the vein-like mass of rock just described, is markedly amygdaloidal at its upper surface. About 200 paces west of the Stewart shaft a cross-cut has been made from this flow south for over 100 paces. One of the rocks struck in this cross cut is a melaphyre which approaches in coarseness and general characters the characteristic melaphyres of the St. Croix range. Near the north end of this cross cut, and apparently in the upper part of the same flow, in which is the Stewart shaft, is atest pit. Here the amygdaloidal upper part of the flow has a horizontal breadth of about 18 feet. Pieces of sheet copper are reported from this place. These occur in seams in the rock, the seams being parallel with the dip. The specimens from this place seen by the writer were about one-eighth of an inch in thickness and from two to three inches across. This amygda- loidal layer is known as the Admiral Dewey vein or lode. ‘The Parker shaft (1,060 paces N. and 520 W.) is said to be 80 feet in depth. It goes down on the junction between two flows and slopes 22° to 38° toward the south. The plane of division between the two flows is the foot wall of the shaft, as 38 COPPER-BEARING ROCES OF DOUGLAS COUNTY. nearly as could be seen, the shaft being practically full of water when the examination was made. The upper part of the lower flow here is amygdaloidal, the amygdaloidal portion being ten to twelve feet in thickness. At the shaft and just to the west, where some trenching has been done, this amygdaloid carries copper. The upper flow at the shaft is also amygdaloidal and at one place (1,010 paces N. and 615 W.) west of the shaft a trench has been cut across the amygdaloidal part, which here has a horizontal width of 18 feet. (See plate X.) This is known as the Little Maude vein. In places the amygdaloid has been fractured, probably along a plane parallel with the surface of the flow, and the fractures have been filled with quartz, prehnite, calcite and epidote. With these minerals is considerable native copper, which has partly altered to malachite. Small nuggets of copper, weighing several ounces, are reported from this place. To the south of this one or two other flows have been uncoy- ered; they bear copper in small amounts, but not as much as occurs in the Little Maude vein. The Catlin Location. In the 8. E. 4 of Sec. 34, T. 48 N., R. 13 W., some explora- tory work has been done. This consisted of blasting in a few places and the sinking of two test pits. One of these is on the St. Croix road (590 paces N. and 120 W.) and strikes the upper part of a porphyritic amygdaloid. The other (50 paces N. and 620 W.) is on a small stream. The rock here is a reddish me- dium grained diabase. The Starkweather Location. This property has been known as the Edwards mine and also as the Wisconsin mine. It is situated in the N. W. 4 of Sec. 2, T.47 N., R. 18 W. In the N. W. 4 of this quarter section several pits, or shafts, have been sunk. During the time the Survey parties were in this district there was no work being done at this locality, and the pits were full of water. Consequently no careful examination could be made. It is evident that the 1H. T. Sweet. Geol. of Wis., vol. III, p. 360, 1880, THE DOUGLAS COPPER RANGE. 39 property is crossed by a series of amygdaloidal flows and that some of these are copper-bearing. The rock thrown out of the pits is in general of four kinds: (1) dense diabasic rock evi- dently belonging to the base of a flow; (2) amygdaloid from the upper part of a flow; (3) fine grained, vein-like material, prob- ably acting as a cement to the broken up upper surface of a flow; (4) brecciated rock cemented by vein material which is mainly quartz, calcite, epidote and a red mineral (probably laumon- tite). Native copper, altered in places to malachite, occurs in the amygdules, and also in the vein cement of the brecciated rock, but more commonly in the latter. Most probably the rich- est specimens of the copper-bearing rock have been taken away by people who not uncommonly visit this location. Nothing can be said, from the examination it was possible to make, concern- ing the thickness and richness of the copper-bearing rock. The general relations and manner of occurrence of the copper appear to be the same as in the other localities already described. The Aminicon Location. This is situated in the N. W. } of Sec. 11, T. 47 N., R. 13 W. Some stripping and blasting has been done along the bold rock hill that extends northeast and southwest through this quarter section. ‘The most serious work was done in sinking a test pit (1,625 paces N. and 1,110 W.) at the base of this hill near its northeastern end. ‘This pit goes down on a small vein, which is from one-fourth to two inches in width. It has slickensided sur- faces and is filled mainly with calcite, quartz, tale and soft clay selvage. ‘The vein strikes nearly east and west and dips 75° to the north near the surface, but the dip varies to more nearly vertical a few feet below the surface. It is the expectation of the owners that this vein will widen out and become copper-bear- ing some feet below the surface. Just to the north of this pit is an irregular vein, from two to eighteen inches in width. It is about vertical, strikes north and south and towards the south splits into two veins. The vein is a brecciated portion of the rock cemented by quartz, cal- cite and red feldspar. There is also chalcopyrite, chaleocite and 40 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. malachite in the vein. The latter is most probably secondary, possibly after native copper, which is reported from this vein. Chaleopyrite and chalcocite also occur in amygdules in several places along this hill. The North Wisconsin Location. This property is located in the S. W. 4+ of Sec. 3 and the N. W. 4 of Sec. 10, T. 47 N., R. 12 W. The outcrops noted at this place and the prospecting done is confined to the immediate vicinity of the line between these sections and does not extend over 200 paces eastward from the west corner post on this line. ‘Along the Middle river, just below the dam, are exposures of several flows which are markedly amygdaloidal in the upper parts, the amygdules being frequently of laumontite. Here, on the east side of the river, a pit has been sunk. This is said to be 51 feet in depth and has drifts running from the bottom. In these drifts considerable copper has been reported. At the time this property was examined the pit was full of water. On the west bank of the river is a vein-like form, six inches wide, cutting one of the flows. The vein rock is hard, very fine grained, and greenish to yellowish in color. It contains specks of native copper and there are malachite stains along the cracks. ‘A shaft (22 paces N. and 1,853 W., Sec. 3) is being sunk in one of the flows. This is east of the dam, and just to the south of the shaft are three pits full of water. The shaft slopes about 62° to the south. It is seven and a half by twelve feet, inside the timbers, and in August, 1899, had reached a depth of about 80 feet. At this time machinery for hoisting and drilling was being put in. (See plate XI.) The shaft goes down in the amygdaloidal upper part of a flow, and this rock carried native copper in the amygdules, although not so abundantly as reported from the pit, mentioned above, on the east bank of the river. The Astor Location. No extensive work has been done on this property, which is in the N. W. 4 of Sec. 28 and the N. E. 4 of Sec. 29, T. 48 N., R.10 W. In the former section (1,275 paces N. and 1,820 W.) WISCONSIN GEOL. AND NAT, HIST. SURVEY, BULLETIN NO.VI., PL. XI. The North Wisconsin Mine. S. W. 14 Sec. 3,T.47N..R.13 W. THE DOUGLAS COPPER RANGE. 41 is a pit which at the time of the examination had not certainly reached the solid bed rock, although very close to it. The ma- terial thrown out was practically all of one rock which had been brecciated and cemented by vein minerals. About 150 paces north of this pit and at a little falls on a small stream is an ex- posure which shows evidence of having been explored a num- ber of years ago, and just to the north of it is a filled test pit. The rock here shows an epidotized area, two to four feet in width. In this, and in cracks adjoining, is chalcopyrite, and native copper is also reported. To the west in Sec. 29 there are a number of exposures, usu- ally of amygdaloidal rock which bears chalcopyrite. In one locality there seems to be evidence of some very ancient at- tempts at prospecting, the ground now being covered by large trees which have grown up since this was done. The Percival Location. ‘The principal explorations on this property have been in the N. $ of S. W. 4 of N. E. 4 of Sec. 27, T. 48 N., R.10 W. Con- siderable work was done here a number of years ago, and work has been actively resumed recently. An old pit (1,303 paces N. and 1,110 W.) west of the present shaft goes down perhaps 30 feet. The pit was sunk to investi- gate a vein which trends nearly east and west. The vein is from one to ten inches in width and is mainly of calcite. It car- ries some native copper. Just to the east of this is a stripping which exposes the same vein. Prospecting on at least two veins of similar character, also carrying copper, has been done in sev- eral places a short distance east of this pit. One, at least, of these veins differs from the other veins met in the explorations already described in that it is not parallel to the dip and strike of the beds of igneous rock in which it les. This vein dips to the north at an angle of about 65°, while the dip of the flows is toward the south. It is not unlikely that the other veins at this locality also fill fractures which do not lie parallel with the surfaces of the flows. The principal work at this locality is now being done at a 42 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. shaft (1,432 paces N. and 722 W.) which is eight by six feet in size. Drilling, hoisting, and pumping at this shaft are done by steam, this being the only locality on the Douglas range where machinery was used during the summer of 1899. The shaft goes down in the amygdaloidal part of a flow, and the hanging wall of the shaft is the bottom of the next higher flow. The dip of the upper part of the shaft is about 40° towards the south, but towards the bottom it becomes steeper, being 46°. In Aug- ust, 1899, the shaft had reached a depth of 90 feet. The amyg- daloid penetrated by this shaft contains the minerals common to the amygdaloids of the district, but is noticeable for the lau- montite and the large amount of prehnite. This rock is in places highly charged with epidote, the masses rich in this min- eral being, as far as can be seen, roughly spherical in shape. Several of these epidotized masses have been found in the shaft. These areas vary in size, but the writer did not see evidence that any of them yet found here are over six feet in diameter. It is in these highly epidotized masses that the chief part of the copper occurs, and at times specimens from such parts of the rock are very rich in this metal, which occurs in the amygdules, in cracks and in irregularly disseminated particles. About 200 and 400 paces east of this shaft are pits probably sunk on the same flow. ‘At each the amygdaloid contains con- siderable quantities of laumontite. Some stripping has re- cently been done on a small stream about a quarter of a mile northeast of the shaft. THE COPPER DEPOSITS. 43 CHAPTER IV. THE COPPER DEPOSITS. In this chapter it is proposed to present a brief discussion con- cerning the mode of occurrence of the copper, where to search for copper and the value of the deposits. MODE OF OCCURRENCE, ‘The copper found in Douglas county occurs mainly as the na- tive metal. At times this has suffered alteration, where exposed to the agents of weathering, to the green carbonate, malachite, and less frequently to the blue carbonate, azurite. These two minerals occur only in small amounts. In many places on the Douglas range copper occurs in the form of chalcopyrite (a brass-yellow mineral composed of sulphide of copper and sul- phide of iron) and in smaller amounts as chalcocite (a dark, al- most black mineral composed of sulphide of copper). In no places in this district have the last two minerals been found in sufficient quantities to attract exploration, nor does it seem prob- able that deposits of these minerals of economic importance will be discovered. In order to be of value as ores chalcopyrite and chalcocite must occur in greater abundance than is necessary for the native metal. Thus the deposits of copper which are liable to prove of economic value are those in the native state. Native copper occurs in this district in three ways:—(1) in amygdules, or in pseudamygdules, or in small particles scat- tered through the rock; (2) in minute seams; (3) in veins. The commonest mode of occurrence is in amygdules where the copper partially or completely fills the amygdaloidal cavities. The minerals associated with this metal in the amygdules, and imbedded in which the copper frequently occurs, are quartz, cal- cite, prehnite and epidote. Commonly at least two of these min- erals are present in any copper-bearing amygdaloid. 44. COPPER-BEARING ROCKS OF DOUGLAS COUNTY. ‘An exceedingly abundant accompaniment of the copper is epi- dote. Very frequently along seams or in areas of indefinite shape the rocks have been highly charged with this mineral. Commonly these epidotized masses are of roughly spherical form and vary in diameter from an inch to a few feet. With the epidote in such masses is much quartz, especially in the amyg- dules. ‘The copper occurs in the amygdules and also scattered throughout the rock. Many of the occurrences of copper on the St. Croix range are in epidotized parts of the rock, and the same is true on the Douglas range, especially at the Percival location where the richest parts of the rock are those highly charged with epidote. Prehnite is comparatively rare on the St. Croix range, but is known from at least two places. One of these is on the Moose river in Sec. 2, T. 44 N., R. 18 W., where this mineral occupies the amygdules in common with the copper. The other locality is on Crotty brook near the center of Sec. 30 (1,120 paces N. and 995 W.) in the same township. On the Douglas range, however, prehnite is a common accompaniment of the copper, as for instance at the Copper Creek and the Percival locations where this mineral is abundant in the copper-bearing rock. In minute seams in rock, which is otherwise copper-bearing, there are at times films or thin sheets of this metal. These are most common in places where the rock is highly charged with epidote. The true veins thus far discovered in the copper-bearing rocks of Douglas county are most frequently parallel to the layers of rock. These veins occur most commonly in the upper amygda- loidal parts of the flows, and frequently along these veins there has been a brecciation of the adjoining rock. Where this brec- ciation has not taken place the vein is narrow, commonly only a few inches in width, but where the adjoining rock is brecciated the vein minerals have cemented the rock fragments and the total thickness of vein material may be increased to a few feet. The minerals of these veins are chiefly quartz, calcite and preh- nite. Copper occurs in small irregular pieces scattered through 1See p. 28. THE COPPER DEPOSITS. 45 the vein material. One peculiar occurrence of copper in these veins is at the Copper Creek location where this metal is in wire-like forms penetrating either calcite or quartz. In one vein these wire-like pieces of copper appear to be covered by a thin coating of native silver. A few small veins have been found which cut the rocks at a marked angle to the different layers, as at the Percival loca- tion. ‘These contain the same minerals as the other veins al- ready mentioned and also carry copper. Mention should also be made of two kinds of vein-like forms which sometimes occur in the copper-bearing rocks. The first are found in the upper parts of certain lava flows and consist of very fine grained flinty rock, which is red to yellow in color. This exists in vein-like forms an inch or more in width, and sometimes carries copper, as on Crotty brook in Sec. 7, T. 43 N., R. 13 W., on the St. Croix range, and at the North Wisconsin location on the Douglas range. ‘The second kind of vein-like form occurs at the Aminicon location. Here a fracture is filled with material, which has likely fallen into a crack in the top of a lava flow, and this material was later cemented by certain minerals. In this vein are chalcopyrite and chalcocite; native copper has also been reported. The vein-like form at the Stewart shaft at the Fond du Lac location is not a vein, but an intruded layer of igneous rock which has been epidotized and impregnated with copper. WHERE TO SEARCH FOR COPPER. In prospecting for copper operations should be confined to the area underlain by the igneous rocks of the Lower Keweenawan (see geological maps, plates I, VII, VIII and IX). ‘There is very little probability of copper being found in any considerable amount either in the sandstones of the Upper Keweenawan or in the Lake Superior sandstone. In the northern belt of Lower Keweenawan rocks the search should be confined within a few miles of either the southern or the northern boundary of the traps,—not because there is no copper in the intervening dis- 2S8ee p. 41. 46 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. trict, but because outcrops are so scarce that the chances of dis- covering a copper-bearing layer are very much less. The hills and the streams should be visited, for in these two places out- crops are more likely to occur. An outcrop of some peculiar kind of rock may sometimes be located by tracing fragments of this rock, which have been distributed by a stream or by gla- cial agencies, back to their original source. In doing this it must be borne in mind that the glacial movement in this dis- trict was from north to south or from northeast to southwest. It is not necessary here to go into a discussion of the origin of the copper deposits. It is only needful to state that the cop- per, while it may have been originally disseminated in very mi- nute particles throughout the igneous rocks, has been deposited in its present position by circulating waters. Those areas in which the water was most free to circulate, other things being equal, would be areas in which the most copper was deposited. Thus it is evident that the deposits of this mineral are to be searched for in those parts of the rock which were actually loose- ly textured or which were crossed by fractures. And such loosely textured portions of the rock are the amygdaloidal up- per parts of the lava flows. When these were also fractured, they became still better places for the deposition of copper. The copper deposits of Douglas county most commonly occur in these upper amygdaloidal parts of the lava flows. The cri- teria by which a separation can be made between two flows, and consequently the upper part of one flow located, have al- ready been given.t When such an amygdaloid part of a flow has been located, careful search should be made for copper both in the amygdules and in any veins or fractured parts of the rock. At times at the surface the native copper is not discernible, and its presence may be detected by the green and blue alteration products or stains, malachite and azurite. Areas where the rock is highly charged with epidote, i. e., areas of a yellow or yellowish-green color, should be searched for particularly, as in these copper is likely to occur. When the upper amygdaloidal part of a flow has been lo- 1See pp. 12-15. THE COPPER DEPOSITS. 47 cated, the following conditions may be of service in determin- ing whether it should be prospected farther than can be done by a careful examination of the surface and of those parts which can be easily broken off with a hammer or pick: (1) The actual presence of native copper, or of the alteration products. (2) The loose texture of the rock, i. e., the presence of large amyg- dules near together or of very numerous small ones. (3) A layer of such amygdaloid which is several feet in thickness. (4) The presence of fractures or veins in the rock, in which are the usual vein materials. (5) The presence of areas which are highly charged with epidote. There is very little chance of success in further prospecting in an amygdaloidal layer un- less at least one, and preferably several, of these conditions are fulfilled. And to this may be added that, other things being equal, such an amygdaloidal layer which immediately underlies, or immediately overlies, a thick non-amygdaloidal layer of rock, or which lies between two such thick layers, furnishes a more promising place to prospect. During the Glacial period practically all the decayed or weathered rock was removed from the traps of the Keweenawan, leaving them fresh and sound except for such changes as had gone on at a considerable distance below the surface. Post- Glacial weathering commonly extends only a fraction of an inch from the surface, and only in a few places, such as in some fissured and very porous rocks, do the effects of weathering reach several inches or possibly a few feet below the surface. The de- posits of copper were formed very long ago and since their for- mation very many feet of rock have been removed by erosion in this district, so that what is now exposed at the surface was once deeply buried. With these two facts in mind,—i. e., the slight amount of weathered rock and the presence at the sur- face today of rock which was once deeply buried,—it becomes clear (1) that there is just as much likelihood of deposits of copper being found at the surface as at a distance of many feet below the surface, and (2) that such deposits are fully as lia- ble to be rich at the surface as many feet farther down. The practical application of these principles will lead, not to deep 48 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. shafts for exploratory purposes, but to the less expensive sur- face explorations, especially where the rock can be uncovered by the removal of only a few feet of overlying unconsolidated material. Stripping, accompanied possibly by shallow trenches or test pits in the rock, will bring to view a much larger area of a given copper-bearing bed than the same amount of ener- gy and money expended in sinking a deep test pit or a shaft. Where the drift material overlying the bed rock is so thick as to make stripping very expensive or impossible, recourse must be had to a shaft or deep test pit, but even here the copper-bear- ing rocks can be explored more easily by running drifts and cross cuts from the bottom of a shallow shaft than by sinking a deep shaft. Exploratory shafts should be sunk, not in a ver- tical direction, but along the dip of the lava flows. Very com- monly it is advisable to sink the shaft in the very top of one flow, using the bottom of the next overlying flow as the hang- ing wall of the shaft. But, as long as there is so much copper- bearing rock which can be explored on or very near the surface, it is not advisable to sink shafts until the surface and shallow explorations have brought to light deposits which have consid- erable extent and value. The advantage of surface or shallow explorations is spoken of here because there is a rather prevalent opinion, among those who are engaged in exploratory work for copper in Douglas county, that rich copper ore is not to be expected at the sur- face, that any copper-bearing layer will grow richer with depth, and that a given layer is not satisfactorily proved to be worth- less until it has been followed to a depth of at least 200 or 300 feet from the surface. There is absolutely no known reason why the copper deposits in Douglas county should increase, or decrease, in richness with depth. A given amount of a cop- per-bearing bed explored in a horizontal direction is just as reliable an index of the contents of the bed as the same amount of exploration in a vertical direction, and the former is usually by far the cheaper method of exploration. In fact if, as is reported, the copper deposits in Michigan are elongated more in a vertical (i. e., in the direction of dip), than in a horizontal THE COPPER DEPOSITS. 49 direction, the ore at times occurring in ore chutes, a given amount of horizontal exploration is worth more than the same amount of vertical exploration. During a visit to the cop- per district of Keweenaw point the writer made it a particu- lar point to inquire concerning this idea of a deposit’s in- creasing in richness with depth. ‘The question was put to mine superintendents, mining engineers, and mining captains, and the invariable answer from these men, whose practical work and long experience rendered their statements reliable, was that this idea had no basis in fact; a given deposit might grow richer, or it might grow poorer, with depth; there was no rule. In the description of the fault along the line of junction of the Keweenawan traps and the Lake Superior sandstone? atten- tion was called to the marked brecciation of the traps for a considerable distance from the contact. Such a brecciated zone would form an excellent channel for circulating waters to pass through and might consequently be regarded as a very favora- ble location for copper deposits. As far as known, however, this brecciated zone has not furnished much promise in this line, and there is reason to think that it does not contain richer de- posits of copper than can be found elsewhere. A probable ex- planation of this is that the most of the copper was deposited in its present position in the traps prior to the date of this fault, and that since the faulting there has been little copper deposi- tion. A similar fault exists between the traps and the Lake Superior sandstone on the eastern side of Keweenaw point, and along this fault no important copper deposits have been found. Large veins have not been discovered in the traps in Douglas county, but if such can be found they will furnish promising locations for exploration. VALUE OF THE COPPER DEPOSITS. As has already been stated, and as the foregoing description of the geology of Douglas county has confirmed, the Kewee- nawan traps of this district are the same in nature, in origin and in age as the copper-bearing rocks of Keweenaw point, and 18ee pp. 17-20. 50 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. consequently might contain similar deposits of copper. ih re- gard to the identity of the rocks of the two districts it may be well to quote certain statements made by Prof. R. D. Irving :* It is therefore proper that I should insist here that this identification (of the bedded diabases and amygdaloids of the St. Croix Valley with those of Keweenaw Point) is also indisputable, and that it is so be- cause of the absolute identity in nature and structure of the rocks of the two regions, and because the Keweenaw belts have been followed continuously from the eastern end of Keweenaw Point to the Saint Croix River. In support of the first of these assertions, I have to advance the fol- lowing facts. The predominant fine-grained basic rocks of the two regions are so completely the same in mineral composition, even to the alternation-products, that thin sections of rocks from the two dis- tricts placed side by side are not distinguishable from one another. The only approach to an exception to this statement is the somewhat greater prominence of prehnite as an alteration-product on Keweenaw Point than on the Saint Croix. The rocks of the two regions present precisely the same amygdaloidal, pseudamygdaloidal, and compact phases. The amygdules are made of the same minerals in both, asso- ciated in the same ways. Native copper occurs in the Saint Croix Val- ley in the same manner, and with the same associates as on Kewee- naw Point. Here and there an exposure may represent a dike so far as can be perceived, but almost everywhere the Saint Croix Valley rocks present precisely the same bedded structure as seen in those of Ke weenaw Point. This is displayed, not only in the common step-like contours of the exposures, but the individual beds may be readily sep- arated from one another, each bed often showing sharply marked its upper vesicular and lower compact portions. Moreover, where the dip is high and the exposures are large, as on the Snake and Kettle rivers of Minnesota there is to be seen a continuous series of beds, in all many hundred feet thick and in every respect similar to the alterna- tions which obtain on Keweenaw Point. The same interstratified por- phyry-conglomerates and sandstones are met with in both regions, and in both regions carry at times native copper. Interbedded original felsitic porphyries also occur in both regions. In support of the second assertion, as to the actual continuity of the Keweenaw Point and St. Croix rocks, I have to say, in the first place, that the evidence of this continuity is precisely the same for the distance between the Montreal and the Saint Croix, as for that between the Montreal and Keweenaw Point, or even the distance 1“The Copper-bearing Rocks of Lake Superior;” U. 8. Geol. Survey, Monograph V, pp. 239-241, 1883. THE COPPER DEPOSITS. 51 between the eastern part of Keweenaw Point and its western portion at Portage Lake; that the continuity has never been disputed for the two latter d{stances; and that it should therefore be accepted at once for the first named distance. The evidence for all the distance between Keweenaw Point and the Saint Croix is just as strong as that ever appealed to to prove the continuity of geological formations anywhere, save in those very rare and exceptional regions where the rocks are completely bare. This evidence consists in the frequent recurrence, at short intervals, of the same kinds of rocks, with the same structure and stratigraphical arrangement; and such evidence is forthcoming in the present case. From Keweenaw Point to the Saint Croix, the formation has been traced mile by mile with a constant recurrence of precisely the same bedded basic rocks, with the same amygdaloidal and compact portions to the beds, of the same associated felsitic por- phyries, of the same interstratified porphyry-conglomerates, and of the same native copper in veins, altered amygdaloids and conglomerates. The same division of the series into a Lower or prevailingly eruptive member, and an Upper or detrital member, is also everywhere present. From Keewenaw Point to the region of Long Lake, some even of the subordinate members are recognizable as continuous. For the par- ticulars of this evidence, I refer to the detailed description of Foster and Whitney’s report, of Vol. III of the Geology of Wisconsin, and of the present work; to the United States Land Office township plats; and to the collections of the Wisconsin Geological Survey, and of the sur- vey made for this report. If this evidence does not constitute proof of continuity, then no geological formation in the United States has ever been proved to be continuous for more than a very few miles— rarely for more than a mile—except in the plateau region of the west- ern territories. Other members of the former Geological Survey of Wiscon- sin,—Prof. T. C. Chamberlin, State Geologist, and Messrs. E. T. Sweet and Moses Strong,—all agree with Prof. Irving in regard to the identity of the traps of Douglas county with those of Keweenaw point. In fact the actual identity of the rocks of these two districts is today regarded by all students of the geol- ogy of the Lake Superior region as established beyond a doubt. With this fact established, and the actual presence of deposits of copper in these rocks also established, there remain only two important points to be determined concerning the value of the copper deposits under discussion. These points are the richness and the extent of the deposits. 52 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. The results of several analyses of copper-bearing rock from the St. Croix and the Douglas ranges are given below, the first, two being from the former and the others from the latter range :1 I. An average three pound piece of rock from the highly epidotized area on the Moose river in Sec. 14 (675 paces N, and 925 W.), T. 44.N., R. 13 W., described on page 27. Specimen No. 8,054.... 0.51 per cent. II. Average of samples from the Moose river in Sec. 2 (765 paces N. and 870 W.), T. 44.N., R. 13 W., described on page 28. Specimen No. 8,072...... 0.67 per cent. III. Average of samples of the smal! part of a flow ex- posed in the bottom of a test pit at the Culligan location in Sec. 31 (1,697 paces N. and 113 W.), T. 47N., R. 14 W., described on page 33. Speci- men No, 8,497 ..5.scccceeece seen cree eee esee eens 4.19 per cent. IV. Average samples from the ore thrown out from a pit or trench at the Copper Creek location in Sec. 15 (233 paces N. and 41 W.), T. 47 N., R. 14 W., described on page 34. Specimen No. 8,401...... 0.29 per cent. V. Average samples from the brecciated belt at the Copper Creek location, described on page 35. Specimen No. 8,417 7.... 0... ccc cee cece eee ceee 0.35 per cent. VI. Selected samples from pit on hill top at the Copper Creek location, Sec. 15 (480 paces N. and 500 W.), T. 47 N., R. 14 W., described on page 36. Speci- mien No, 854252. soe. oo ck cexecateaiess vests wee 1.60 per cent. VII. Selected four pound piece from the “ vein ’’ at the Stewart shaft on the Fond du Lac location, de- scribed on page 37. Specimen No. 8,764. Ses MOXt ANALYSIS wssiciae cece aie ce wa bine dug eaeiere te aa erese saree 3.64 per cent. VIII. Same as last. In taking from No. 8,864 the forty grams for examination two pieces of metallic eop- per were found weighing 1.34 grams. To ascer- tain if this was an average sample another por- tion of forty grams was taken which gave....... 0.39 per cent. 1These analyses, except .. and XII, were made by Prof. W. W. Daniells of the University of Wisconsin. XII was made by Mr. George H. Ellis of Chicago and X by Mr. EH. F. Burchard of Northwestern University. 2The copper here appears to be coated by a film fo silver, but a test for silver gave a negative result. 8 Also tested for nickel, but with a negative result. THE COPPER DEPOSITS. 53 IX. Average samples from a fractured vein-like area in the Little Maude lode, Fond du Lac location, de- scribed on page 38. Specimen No. 8,326........ 0.99 per cent. X. Other samples same as last..........00.ec sees cere 1.25 per cent. XI. Average six pound piece from one of the highly epidotized areas in the shaft at the Percival lo- cation, described on page 42. Specimen No. 8,706. 1.37 per cent. XII. Same as last, one pound piece.............2.. eee 1.21 per cent. In regard to the richness of the deposits the foregoing analyses show that there are certain bodies of rock, as far as known of limited extent, however, which contain sufficient copper to be termed copper ore. Ore which averages one per cent. of copper will, with the present prices, under favorable conditions and economic working produce a profit. But such ore must occur in beds or veins several fect in thickness and of considerable ex- tent vertically or horizontally, i. c., large amounts of the ore must be accessible. It should be borne in mind, however, that these analyses, while being in some cases analyses of the average of small masses of the rock, are in no cases analyses of average samples of a bed or vein which have been shown to be of any considerable extent. And just here is the last, and consequently the important, point to be established concerning the value of these copper deposits,—are zany of them extensive enough to be worked at a profit? This is a question, not of theory, but of fact, and a perfectly conclusive answer to it can be had only as a result of extensive exploration. At the same time some light may be thrown upon it by a consideration of the results of the exploration already done and by a consideration of certain geo- logical features. As far as the results of the exploration which has been carried on thus far,—and there has been considerable of it,—were open to the inspection of the Survey, it can be stated that in no place was a deposit of copper, which was of sufficient richness, shown to be of any great extent. The results of some of the old ex- plorations were net available, nor was it possible to investigate certain workings now filled with water, but the Survey parties were very freely allowed to investigate the workings in active operation. In several places a layer of sufficiently good ore one 54 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. or two, or possibly more, feet in thickness was exposed, but on following this a few feet along the strike, or in the direction of the dip, the copper content rapidly decreased. In layers, in which were highly epidotized masses containing copper in con- siderable amount, it was found, where full investigation. was made, that these masses were of limited extent and that outside of them there was only a small amount of copper. On the other hand there were a few places where a small amount of a copper- bearing layer was exposed, and what was exposed was of a good quality of ore. In these cases further work is necessary to demonstrate the extent of this good ore. ‘One noticeable fact in the copper-bearing rocks of Douglas. county is this irregular and uncertain distribution of the copper in any given bed. This “bunchy” nature of the deposits is also a characteristic of the Keweenaw Point district, where even the best copper-bearing layers are in places very poor in copper, and where in even the richest mines at times considerable barren rock is found. Because of this uncertain and sporadic distribution of rich rock in a given copper-bearing layer, it is clear that am investigation of such a layer at one point will show nothing con- clusive either as to the richness of the layer. It is a noticeable fact in the Keweenawan traps of the Doug- las and St. Croix ranges that the flows are of small thickness and that in one locality several of these flows are copper-bearing. Thus in a given thickness of rock there are several amygdaloidal layers, in each of which copper is deposited in smal] amounts. It seems reasonable to state that, if in this same thickness of rock there had been but one amygdaloidal layer, this would have served as a place of concentration for the copper which is now scattered in several layers. ‘This was in view when the state- ment was made that, other things being equal, an amygdaloidal layer between two thick non-amygdaloidal layers was a promis- ing place to search for copper. As far as the writer knows, the amygdaloidal layers in the best parts of the Keweenaw Point district are, in a given thickness of rock, much fewer in number than in the localities explored in Douglas county. 1See p. 47. THE COPPER DEPOSITS. 55 The absence of interbedded conglomerates in the traps on the north side of the syncline in Douglas county probably has no bearing on the question of the value of the copper deposits. The frequently reported finding of “float” copper in the drift should be noted, but these loose pieces of copper may have been trans- ported by glacial ice from localities many miles distant. The writer has attempted to give a calm and unprejudiced statement of the facts which bear upon the question of the value of the copper deposits on the Douglas and St. Croix ranges. These facts may be summarized as follows: (1) The identity of the rocks with those of Keweenaw point. (2) The presence of native copper. (3) The presence, in places, of sufficient copper to form an ore of value. (+) In most of these places exploration has shown that the rich rock is only of limited ex- tent. (5) In a few places exploration has not gone far enough to show the extent of the rich rock. (6) The “bunchy’ dis- tribution of the copper in any layer. (7) The presence in a given thickness of rock of several amygdaloidal layers, rather than one layer. From a consideration of these facts it is, with our present knowledge, impossible to answer satisfactorily the question as to whether or not copper deposits of economic value will be found in this district, but to the present time no such deposit has been shown to exist. Note. After this report was written some of the localities on the Douglas range were again visited (March, 1900). Explorations at the Copper Creek and at the Culligan locations have been carried for- ward to a small extent. At the Fond du Lac a shaft has been sunk on the Little Maude lode. At and just above the upper falls of Black river some blasting has been done in two copper-bearing layers. Just below Black River falls two tunnels are being dug. One of these is in the traps, but near the contact with the sandstone, and runs about parallel with this contact. The other cuts across the trap flows about at right angles to the strike. The results of these additional explora- tions do not make it necessary to alter any of the statements made in this report. Recent explorations for copper in the southeastern corner of Doug- las county, on the south side of the syncline of Keweenawan rocks and outside of the area studied by the Survey, are reported to show very encouraging prospects. Wisconsin Geological and Natural History Survey. The Wisconsin Geological and Natural History Survey was established by act of the Legis!ature in 1897. Its publications are issued as bulletins, which are numbered consecutively, and each bulletin is independently paged and indexed, no attempt being made to group them in volumes. The bulletins are issued in three series: A. Scientific Sertes.—The bulletins so designated consist of original contributions to the geology and natural history of the state, which are of scientific interest rather than of economic importance. B. Economic Series.—This series includes those bulletins whose in- terest is chiefly practical and economic. ©. £ducational Series.—The bulletins of this series are primarily designed for use in the schools. The following bulletins have been issued: Buiuetin No. I. Economic Seaixs No. 1. On the Forest Resources of Northern Wisconsin. F. Roth, Special Agent, U. S, Department of Agriculture. Pp. 78;1 map. Sent on receipt of 10c. Bourtetin No. II. Scorzntiric Serrzs No. 1. On the Instincts and Habits of the Solitary Wasps. G. W. Peckham and E.G. Peckham. Pp. 241; 14 plates, of which 2 are colored. Sold at the price of $1.50 in paper and $2.00 bound. Bourerin No. III, Scizntiric Series No.2. - A Contribution to the Geology of the Pre-Cambrian Igneous Rocks of the Fox River Valley, Wisconsin. Samuel Weidman, Assistant Geologist Wisconsin Geological and Natural History Survey. Pp. 63; 10 plates. Sent on receipt of 10c. Buuurtin No. IV. Economic Serizs No. 2. The Building and Ornamental Stones of Wisconsin. E. R. Buckley, As- sistant Geologist Wisconsin Geological and Natural History Survey. Pp. 544; 69 plates, of which 7 are colored and 1 map. Sent to citizens of Wis- consin on receipt of 30c.; to others for $1.25. Bortetin No. V. Epucatrionat Sxrizs No. 1. Geography and Surface Geology of the region of Devil’s Lake and the Dalles of the Wisconsin. R. D. Salisbury, Professcr of Geographic Geol- ogy, University of Chicago, and W. W. Atwood. Pp. 146; 38 plates, 17 figures in the text. Sent on receipt of 30c. Bouterin No. VI. Economic Serres No. 3. . The Geology of the Copper-bearing Rocks of Douglas County, ‘by U.S. Grant, Professor of Geology, Northwestern University. Sent on receipt of 5c. The following bulletins are in preparation: The Forest Trees of Wisconsin. L. 8. Cheney, Assistant Professor of Pharmaceutical Botany, University of Wisconsin. The Temperature of Lakes in Southern Wisconsin. E. A. Birge, Director Wisconsin Geological and Natural History Survey. The Physiography of Southern Wisconsin. G. L. Collie, Professor of Geology, Beloit College. The Clays and Clay Industries of Wisconsin. E. R. Buckley, in charge of Economic Geology, Wis. Geol. Survey. The Lake Region of Northern Wisconsin. D. P. Nicholson, Professor of Geology, Lawrence University. ‘ 3 ; There have also been prepared hydrographic maps of the principal lakes of southern and eastern Wisconsin. This work is in charge of L. 8. Smith, | Assistant Professor of Topographical Engineering, University of Wisconsin. — The following maps are now printed: No.1. Lake Geneva. No. 2. The Oconomowoc-Waukesha Lake District. No. 3. Lake Beulah. No. 4. Elkhart Lake. No. 5. The Chain of Lakes, Waupaca. No. 6. Delavan and Lauderdale Lakes. No. 7. Green Lake. In all of these maps the depths of the lakes are indicated both by 10-foot contour lines and by tints. They are sent on receipt of 15c., except No. 2, for which 20c. is required. They may be had, either mounted in a cover or unmounted. The following maps are in the hands of the draughtsman or printer: No. 8. Lake Mendota. No. 9. Big Cedar Lake. No. 10. Jake Monona. A survey of Lakes Waubesa, Kegonsa, and Wingra is in progress. All correspondence relating to the Survey should be addressed to E, A. Brrex, Director, Madison, Wis WISCONSIN GEOLOGICAL anp| Natura HISTORY SURVEY. E. A. BIRGE, Director. Cc. EK. VAN HISE, Consulting Geologist. BULLETIN NO. VI. (SECOND EDITION.) ECONOMIC SERIES NO. 3. PRELIMINARY REPORT ON THE COPPER-BEARING ROCKS P or DOUGLAS COUNTY, WISCONSIN. SECOND EDITION. CONTAINING A PRELIMINARY REPORT ON THE COPPER-BEARING ROCKS. OF PARTS OF WASHBURN AND BAYFIELD COUNTIES. BY ULYSSES SHERMAN GRANT, Professor of Geology in Northwestern University. MADISON, WIS. PUBLISHED BY THE STATE. 1gol. ‘ Wisconsin Geological and Watural History Survey. BOARD OF COMMISSIONERS Ropugt M. LaFou.erre, Governor of the State. L. D, Harvey, Vice-President, State Superintendent of Public Instruction Cuaguus K, ApAMs, President of the University of Wisconsin. Epwin E, Bryant, President, President of the Commissioners of Fisheries, CHARLES 8S. Suicu TER, Secretary, President of the Wisconsin Academy of Sciences, Arts, and Letters, E. A. Biraz, Director of the Survey. C. R. Van Hisz, Consulting Geologist. T.C. CHAMBERLIN, Consulting Geologist (Quarternary Geology). E. R. Buczuzyr, Geologist. In charge of Economic Geology. 5. Warman, Geologist. In charge of Geology of Wausau District, L, 8. Surrs, in charge of Hydrography. WISCONSIN GEOLOGICAL AND NATURAL HISTORY SURVEY. E. A. BIRGE, Director. C. R. VAN HISE, Consulting Geologist. BULLETIN NO. VI. (SECOND EDITION.) ECONOMIC SERIES NO. 3. PRELIMINARY REPORT ON THE COPPER-BEARING ROCKS oF DOUGLAS COUNTY, WISCONSIN. SECOND EDITION. CONTAINING A PRELIMINARY REPORT ON THE COPPER-BEARING ROCKS OF PARTS OF WASHBURN AND BAYFIELD COUNTIES, BY ULYSSES SHERMAN GRANT, Professor of Geology in Northwestern University. MADISON, WIS. PUBLISHED BY THE STATE, gol. Wisconsin Geological and atural history Survey. BOARD OF COMMISSIONERS Ropert M. LAFouLetTTeE, Governor of the State. L. D. Harvey, Vice-President, State Superintendent of Public Instruction CHARLES K. ADAMS, President of the University of Wisconsin. EpwIn E, Bryant, President, President of the Commissioners of Fisheries, CHARLES S. SurcnTeR, Secretary, President of the Wisconsin Academy of Sciences, Arts, and Letters. E. A. BirGeE, Director of the Survey. C. R. Van Hise, Consulting Geologist. T. C. CHAMBERLIN, Consulting Geologist (Quarternary Geology). E. R. Buckey, Geologist, In charge of Economic Geology. S. WEIDMAN, Geologist. In charge of Geology of Wausau District. L, S. Smrrg, in charge of Hydrography. PREFACE, The field work which furnished the basis for the first edition of this Bulletin, published early in 1900, was done in the sum- mer vf 1899. During the summer of 1900 further study on the copper-bearing rocks was undertaken, and the present edi- tion contains a preliminary report of both seasons’ field work. In the second edition pages 1 to 42 (the introduction and chap- ters I to III) and plates I to XI are identical with those of the first edition; chapter IV (on the Minong copper range) and plates XII and XIII have been added; and chapter V. (chapter IV of the first edition) has been enlarged and in part rewritten. In chapter IV an account of the geology of the Minong copper range, in so far as it differs from that of the St. Croix and Douglas ranges, is given in addition to the de- scriptions of special localities. The maps for both editions were drawn by Mr. Frank J. Huse, of Evanston, Illinois. TABLE OF CONTENTS. PAGE PREPAGH: 6:6 ier ncaa sia 8 GAA ea eee Caw a A Rie ened ase vii ENTRODD CTION:, oases Saeees cigntareneyeie vie eae Meee gieew aes weiss aes 1 ACEO WIC EMON TS o seids ies sdsieieiand cate ard ao nslrvenaetle dale ab Sa tees. ieee 3 Cuaprer I. Gronoay oF DouGLas COUNTY........- ccc cece eee neee 5-24 Previous descriptions. .............0.. 008. He aihipapeialeiclatice Biore Sos ote 5 Surface features: .v.cccescucveea causa awe vive oaescewres si cect 6 Sketch of the different formations. ........ 0... ccc cece ee ee eens 8 The Lower Keweenawan.......... cee cece cece cen cnet enan ones 9 Sedimentary LOCKS <5. es sicca dk cee eaealneawewd ae eee iets 9 EBVO GUS: FOC) giiersic csovere wciccs ain dcopase airerenenra ae eka Cees oe 10 Basic lava flows ss 200d etna s 2 asitls's Gta aes ee eS 11 Dip and :sttike isis oeninesiev oe aie dsmenwarcaace® sie eisia's 12 Separation of the different flows ...... cc. cece eee eee ee The Upper Keweenawan..........-cee eee cece cece cece cetaeees 15 The Lake Superior sandstone............. cece eee eee eee tees 17 Junction of the Lake Superior sandstone with the traps........ 17 Effects On: the traps ssissciak eo seat adwiceeneaseine cece eas Ws 18 Effects on the sandstone.......... 2. eee eee cee cee ewes 19 Black: River: contact <3: 20sis2 05 etadinoadadat evs eee ys 19 Copper Creek contact 2.2.0... cece cece cece cue ceeeeees 19 Awinicon River contact ...... 0... ccc cece eee eee noes 19 Middle River contact ..........cccecee csc cvevecvceees 20 The later formations s:...ccsice. cay 64 saws achewaved eis, 4 404 wie 64. aindccceis doe 20 Geological structure: .ocosvaie vse ke sean eee eanereex seeders ates 21 SOMES scene ecu eee a wale Ue eaelea end eens ese eogens eas 21 Géolopical: history ccs wens vicia ses oaieeaeisaals ss ee ei aeaeaes 22 GOI ICA IAS yes cnlsgesiecs-teors Soe Areas Saeed ASSN a a er elena tea 23 Cuaprer II. Tue Sr. Crorx Copper RANGE....... ccc cece cece ces 25-30 special, Destriplichs.s sAcauec ene os neselanda we auaeee Ahem eviews 26 HDs AG. Ney i TL Wea seccedcete ee oye 6 0 es cssreeeeacis doa weve a lodelnlee a binst ers. tte 26 ED ADIN gis dds Weigttestescn haa dined rdethar o's ssa Ave annatearecn a 8 26 oe ee usista eeseca ssn canis 26 Cuapter III, Tue Dovcias Copper RANGE Special Descriptions TABLE OF CONTENTS. Cuarrer II. Tue St. Crorx Copper Rance—Continued. Special Descriptions: Dat N GR: AS OW eee s sesweeaeis yee ee od oan Reins Moose river .........c eee ceee SGA Toe Kae Vere SSG Crotty brook 24 i635 -sscacanaenes Vieeueseee sucess TT. 43 Ni Re 18 Wee wccsseaieatetnceles nawn cigs aa 0's Slataneamwuagios Crotty DIOOK esc ccssdicvniccreas B0bS5 oS LAM e Ones Td4 Ne Rel 4 “Weascutesancauhs sed cas i aeeteulnenwe sees T43 Ni Reda Wisssocounaeeeavckse heiiietenaiteaeieien cies ASIN 5 Rs LDN Wscotslaccrnssiareise Saaele aa cmstsavniaGranmarsuasaaeea S358 Pe42N., Re ld: Wieweiune es secs vanes saisoetinaeseae reas Cuaptrer TV. THe Mining Copper RAnGk.......e cece cece ee nee Introduction Other conglomerates. ......... cee cence eee cn eeeeeee TP ENCOUS LOCKS? vsives oes Wk ss ¢-Wainisctineereagne's wae erie aareoneetagere Typical section of the Lower Keweenawan............. Dip ADE SOP Oreo ccs. scesacersitsiciein oleae a: actuined ¥ anesaieie Wiesgeeinuaceieid Limits of the Lower Keweenawan...........0.esee ener The Upper Keweevawan Special Descriptions ee ee ee ee ee ee ed The: Culligan locations vss caiscsee wrdaweaveeneeses The Copper Creek location... 0.0.0.0... ce ceee eens neens The Fond du Lac location ........ 0... cee cece eee eee ee The Catlin lOCAtiOwy, e233 cacdac-e ois scans eee aaines F248 The Starkweather location............ cece cece cece seen The Aminicon location.............ccc sess sceesscenes ekeisiees The North Wisconsin location. ........ 00.0: e eee eeeee The Astor loCatiOn ccc s os careainnteie ca iseiee Hae esa samaie The: Percival lOCation. saccsacanieciewsi sae nara su toe 03's aieeei Dee eee meee eee eee meee ewe ewe ee eee en ee wees Geology of northwestern. Wisconsin The Lower Keweenawan Dee eee ne ee wee wee eee meee seen Sedimentary LOCKS 2. coc cokes nckaccuwssiaws eee ss eeeee o Theo first conglomerate... 2... ccc cece eee eee ee eeee The second conglomerate ..........+..eeee eee eseiaereiarsie The third conglomerate... 1... .. cece cence ene eees The fourth conglomerate... 6... . cee eee eens eee ee ce Phe. Mudge loCation ors < eiediate scopreisisteimuservial deta teeta. aece The Weyerhauser location ........ 0.0 :c cece ee eee eee Tho Montrosé LOCatlOn wises ce cisaa cacuaasae sos vee se see S Other l6cations: aiciisksd soe) SEAR cee eS eets Sees yaiats BL 52 52 53 54 55 55 57 59 vi TABLE OF CONTENTS. PAGE Cuaprer V, THe Copper DEPOSITS........000eee cere eeen ones Shales 61 Mode of occurrence... ....ccce cece cece tens cene cece eeee cece cnns 61 Where to search for COPper.... eee cece cence ee eee teeter eee enee 64 Value of the copper deposits... .... cece cece eee cece eee eee e eens 70 Gon CIS 1O VS ets ss isreets aco sesase Santrscelercnlom nnd ec eB MOREA aS e eRe aE 78 IAPR NDER a dcswserces pesssck soe bversiduegduaipeceiaudie Via SNR SIND NES a oF eR 81 Recent work on the St. Croixrange........ cece eee cece cee tees 81 Recent work on the Douglas range.... 0.2.0... eee ee eee eee 82 Culligan LOCA totic ia.c0 cise avorcracoiaidsieieiaiene sida erenasdiglaieraioteial aes 82 Upper Black River Falls location. ........ 0... cc. eee eeee 82 Black River Falls location ............ 0... cece cece ee eeceee 82 Copper Creek location «5c ccnuisswe st ccseancines seears ees 82 Fond du Lac location vs jij ce cacsenaes eo arrcereena sey ena 82 Aminicon Falls location............cccc cece cece eee ences 82 North Wisconsin (or Chippewa) location............+..06- 82 TENDER Aids a aes ew aR be PERAK RE ae ee eS 85 ILLUSTRATIONS. Facing Page. Plate, I. Geological map of Douglas county........0.cec cece neon eens It.” Black River falls: ic ccs nek ecu sind Wave de item ne eeeanne eek .. Uppor surface of lava Row iiss cccieecsies on oc ve easewane sens 1V. Valley between two lava flows. ........cccc cece ceeeesceces V. Fault breccia in the traps ......... 00.0 e0ee ae ABioaehieec Gs VI. Tilted strata of Lake Superior sandstone...........0.0. cee VIL. Geological map of part of the St. Croix copper ranoe....... VIII. Geological map of the western part of the Douglas copper TANGO cons anccdaw vesearw nae ual oeaee eee eerie IX. Govological map of the eastern part of the Douglas copper PSUR O cia coveSticyesticseasasoveatesiat ke 6G a asara.d Jnleuedasounidet marcos Satiat es X. Trenching at the Fond du Lac location................ 0005 XI. The North Wisconsin location. ............ ccc ceee econ eens XII. Geological map of northwestern Wisconsin, showing the ex- tent of the copper-bearing rocks in the state........... XIII. Geological map of part of the Minong copper range ........ Figure, 1, Map of the Montrose location .......... beaieGe tra Auneabonareey 7 16 17 18 20 31 31 40 43 47 Page. 58 THE COPPER-BEARING ROCKS OF DOUGLAS COUNTY, WISCONSIN. INTRODUCTION. The field examinations which form the basis for this report were made during the summer of 1899. In considering the time available in one season it became apparent that a detailed exam- ination of all the rocks in northern Wisconsin, in which copper might occur, was out of the question. Moreover, we already have a fairly good knowledge of the general geology of this part of the state. It therefore seemed advisable to concentrate the work in certain districts, as a careful study of certain important areas was more likely to produce results of value than the super- ficial examination of a large area. At the same time it_was ex- pected that the future would permit a careful examination of other districts in the state underlain by the copper-bearing rocks. With these points in mind the work of this season was concen- trated first on the rocks which lie along, but north of, the St. Croix river in the southwestern part of Douglas county, and second, on those which form the first hill ranges south of lake Superior in the northern part of the county, and in which ex- plorations for copper are being actively prosecuted. The dis- trict first mentioned,—i. e., the southwestern, or what is called in this report the St. Croix copper range,—presented, in its geolog- ica] structure, a more simple problem than the northern, or the Douglas copper range, and was accordingly examined first.? 1The northern range has been known as “‘the South range” and as “the Doug- las County range,’’ while fhe southern has recetved no name, or has been in- cluded with the northern. The two ranges, while alike geologically, are distinct geographically, being separated by a belt of country several miles in width in which there are practically no rock exposures, and it is expedient to have a distinct name for each. The writer understands that the names used above,— Douglas range and St. Croix range,—are coming into use among those interested in the exploration for copper in northern Wisconsin, and these names have been adopted in this report. 9 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. This examination was made between the 17th of May and the 20th of June. The remainder of the season, until the last of August, was spent on the northern district. But during this time a visit was made, for the purpose of comparative study, to the copper-mining region of Keweenaw point. The method followed in the season’s field work was to visit all parts of the two areas above mentioned which were known to have rock outcrops, or in which outcrops might be reasonably expected. In such parts north and south traverses were made at intervals of one-half mile, or more frequently when occasion demanded. ‘Thus, in the region where outcrops occur fre- quently, the north and south section lines, the north and south quarter section lines and some of the east and west section lines were followed. The larger streams, and in fact all the streams which might be expected to cut down to the bed rock, were also followed. The outcrops seen were located carefully by pacing, and the position of each was indicated as so many paces north and so many paces west of the southeast corner of the given section. In this manner of locating 2,000 paces equals one mile. Rock samples were taken from most of these outcrops. In all about 775 rock numbers and a considerably greater num- ber of specimens were collected. Because of the active interest which is being manifested in the copper deposits of northern Wisconsin, it was deemed best to publish a report on the district without unnecessary delay. Accordingly this report is presented with the hope that it will be of service to those who are at present engaged in exploration for copper, or who are interested in the material development of this part of the state. It should be borne in mind, however, that this report was written before it was possible to make a care- ful study of the whole district underlain by the copper-bearing rocks, and even before it was possible to make an exhaustive study of the facts and specimens collected in those areas in which the work was concentrated. Thus this report is necessarily of the nature of a preliminary rather than of a final report.. At the same time it should be stated that the essential facts concern- ing the geological structure of the areas examined, the geograph- INTRODUCTION. 3 ical distribution of the different rocks, the manner of occurrence of the copper deposits, and the general distribution of these de- posits have been determined by the work already done. It is accordingly expected that the facts here presented are correct and that future work will tend to confirm rather than to alter ‘them. It is manifestly impracticable for parties of the Wisconsin Survey to discover every outcrop of the copper-bearing rocks in the state, especially when these outcrops are of small extent, are far removed from each other and are accessible with difficulty. It is therefore requested that individuals, who know of solid ledges of rock anywhere in the northern part of the state, com- municate with the Survey, giving as nearly as possible the exact location of these ledges. If convenient, small samples illustrat- ing the rocks should be sent. Acknowledgements. In the field work the writer was assisted by Dr. C. P. Berkey, Instructor in Mineralogy in the Univer- ‘sity of Minnesota, who had previously had experience in study- ing the copper-bearing rocks in the district of Taylors Falls and St. Croix Falls on the St. Croix river. It was exceedingly fortunate that Dr. Berkey’s services were available in this work, both on account of his knowledge of the copper-bearing rocks and also because it made it possible to discuss and investigate jointly in the field certain important problems. ‘Mr. Charles Cole, of ‘South Range, and Mr. A. L. Hinman, of Downing, and in the latter part of the season Mr. R. B. McLean, of Superior, acted as compassmen and located all the outcrops seen. Their knowl- edge of woodcraft and their acquaintance with the county ex- amined aided materially in the season’s field work. To the Di- rector of the Survey, Prof. E. A. Birge, and to the Consulting Geologist, Prof. C. R. Van Hise, and to Mr. C. K. Leith the writer’s thanks are especially due for a large number of courte- -sies. The work was undertaken and carried on under the di- rection of Prof. Van Hise, who spent several days in the field reviewing important points and who was especially helpful in suggestion and advice regarding the work. The analyses were made by Dr. W. W. Daniells, Professor of Chemistry in the Uni- 4 COPPER-BEARING ROOKS OF DOUGLAS COUNTY. versity of Wisconsin. One fact became particularly apparent during the season spent in this examination ; it was the universal and cordial interest shown in the work of the Survey by the people of Douglas county. Their willingness to codperate in whatever manner possible was very marked. Among these peo- ple was Mr. Ernest A. Arnold, of West Superior, who gener- ously placed his knowledge of the county and a considerable part of his time at the disposal of the Survey. GEOLOGY OF DOUGLAS COUNTY. 5 CHAPTER I. GEOLOGY OF DOUGLAS COUNTY. Douglas county is the northwestern county of Wisconsin. It is bounded on the north by St. Louis county, Minnesota, and by lake Superior; on the east by Bayfield county, Wisconsin; on the south by Burnett county, Wisconsin; and on the west by Pine and Carlton counties, Minnesota. Douglas county com- prises all those parts of townships 43 to 49, Ranges 10 to 15, which lie in Wisconsin. The total area of the county is 1336 square miles. PREVIOUS DESCRIPTIONS. The following are the more important papers which refer to the copper-bearing rocks in this county: T. ©. Chamberlin. “General Geology” ; Geol. of Wis., vol. I, pp. 96-118, 1883. “Economic Geology”; Ibid., pp. 656-661. R. D. Irving. “General Geology of the Lake Superior Reg- ion”; Geol. of Wis., vol. III, pp. 7-15, 1880. “The Copper- Bearing Rocks of Lake Superior”; U. S. Geol. Survey, Mono- graph V., pp. 234-259, 1883. Moses Strong. “Geology of the Upper St. Croix District” (edited by T. C. Chamberlin) ; Geol. of Wis., vol. III, pp. 363- 428, 1880. E. T. Sweet. “Geology of the Western Lake Superior Dis- trict” ; Geol. of Wis., vol. III, pp. 303-362, 1880. The report by Strong deals especially with the St. Croix range; that by Sweet with the Douglas range and gives an account of the earlier explorations for this metal. These re ports are out of print. Both ranges are discussed by Irving in “The Copper-Bearing Rocks of Lake Superior.’’* 1Thts book contains the best and most complete account yet published of the copper-bearing rocks in the Lake Superior district and will prove of value to any one {interested in the geology of these rocks. It can be procured from the Director of the U. 8. Geological Survey, Washington, D. C. The price is $1.85. 6 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. SURFACE FEATURES. The surface of Douglas county, considered broadly, is com- paratively level ; there are no districts which approach the moun- tainous, nor are there certain parts which are elevated many hundreds of feet above other parts. When examined in detail, however, this surface presents some marked features and can readily be divided into several distinct zones, each of which is characterized by certain peculiarities of topography. It may be stated that these different topographic zones correspond, in general, to the belts of rock which underlie the glacial deposits. There are five of these topographical zones. They are described below, beginning at the north. I. That part of the county which borders on lake Superior is a plain. This plain is from five to twelve miles in width and extends from the lake shore southward to the northern edge of the hills which form the Douglas range. The plain slopes gently toward the north, and, while this slope is sufficient for drainage, to the eye the ground frequently appears perfectly level. At the town of South Range, about six miles from lake Superior, the plain is 164 feet above the lake level, and a mile farther south it ends abruptly against the northern flank of the Douglas range. This topographic district is underlain by till and by water-deposited clays which were laid down when the waters of the Lake Superior basin were at a considerably higher level than at present. Beneath these superficial deposits is the Lake Superior sandstone, and the outlines of that formation are the outlines of this plain (see geological map, plate I). II. The hills which form the Douglas range rise abruptly, from the plain just mentioned, to a height of from 100: to 300 feet. The marked escarpment formed by the northern slope of these hills is a very noticeable feature of the topography, espe- cially when viewed from the plain to the north. This escarp- ment is analogous to the still more marked escarpment which rises, in Minnesota, from the northern edge of the plain. This hill range, which forms the second topographical district, ex- tends east and west through the county, taking towards the west, GEOLOGY OF DOUGLAS COUNTY. a however, a west-southwesterly direction. The hill range is from one to four miles in width, and its southern slope is much more gentle than its northern. On the south it merges gradu- ally into another zone of different topography. The rocks un- derlying, and very frequently coming to the surface, in this hill range are igneous rocks of Lower Keweenawan age, and in places superimposed on these rock hills are hills of drift, especially in the north half of T. 47 N., R. 11 W., and in the southwest quar- ter of T. 47 N., R. 14 W. III. To the south of this hill range and extending nearly to the St. Croix river is a comparatively level tract of land in which prominent elevations are uncommon. Here the ground is fre- quently so level that extensive swamps exist. This district is underlain by glacial drift, largely in the form of till, while be- low the drift and rarcly outcropping, are the igneous rocks of Lower Keweenawan age. IV. What are known as “the barrens” form a sandy plateau which stretches northeast and southwest through the county. The surface of this plateau is at times noticeably hilly and is also supplied with depressions in which are frequently lakes. The northwestern border of this tract enters the county near the St. Croix river in T. 48 N., R. 14 W., extends northeastwardly and crosses the eastern border of the county in T. 47 N., R. 10 W. The St. Croix river and the Brule river for a considerable dis- tance flow in the barrens, but near their northwestern border. The southeastern border of the barrens is approximately the same as the southeastern border of the sandstone of the Upper Keweenawan,—in fact the area underlain by rocks of this age is practically the area occupied by the barrens. (See plate I.) V. The extreme southeast corner of the county, i. e., that underlain by the rocks of the Lower Keweenawan age, is very similar to the third topographic district mentioned above, except that the underlying rocks more frequently outcrop through the till. The streams of the county are all comparatively young and consequently do not possess broad, deep valleys. The streams of the plain which borders on Jake Superior have cut shallow steep- 8 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. sided troughs into the unconsolidated deposits which form the surface of the plain. The divides between these streams are wide and flat-topped. Many of these streams head on the north- ern flanks of the hills which form the Douglas range. The larger streams flow directly across this range, and, where they pass from the range to the plain to the north, have cut noticeable gorges, the most marked of which are along Black river and Cop- per creek. Commonly along these gorges are rapids or water- falls. The best known of these is Black River falls (see plate II) which is 110 feet in height. To the south of this plain the streams have very shallow channels. ‘The only exception to this last statement is the St. Croix river, which has cut down 100 or more feet into the unconsolidated drift deposits through which it flows. ‘This river flows in a broad, flat-bottomed valley which is out of proportion to the size of the present stream. The val- ley was excavated when the St. Croix acted as the outlet for the waters of the Lake Superior basin, the water level of the lake then reaching and overflowing the divide between the head- waters of the present Brule and St. Croix rivers. SKETCH OF THE DIFFERENT FORMATIONS. The rocks of Douglas county are readily separable into three distinct series (see geological map, plate I), as follows, in de- scending order: Cambrian: Wake Superior sandstone. Upper Keweenawan: Conglomerates, sandstones, and shales. Lower Keweenawan: Igneous rocks, largely basic lava flows. The oldest rocks exposed in the county are of Lower Kewee- nawan age. They consist of igneous rocks which are almost al- ways basic in nature and which are largely in the form of lava flows. These lava flows, in the northern part of the county, dip toward the southeast or south, while in the extreme southeastern corner of the county are similar rocks dipping toward the north- west. Younger than these and resting directly upon them are a series of conglomerates, standstones and shales of Upper Ke- weenawan age. Younger still is another series of rocks, mainly sandstones, which outerop in many places along the southern WISCONSIN GEOL. ANO NAT. HIST. SURVEY, BULLETIN NO, VI., PL. il, Black River Falls. 110 feet high, S. E. 14 Sec. 21, 7.47N.,R. 14 W. GEOLOGY OF DOUGLAS COUNTY. 9 shore of lake Superior and to which the name Lake Superior sandstone has been applied. The Lower Keweenawan rocks are the ones which contain the copper deposits. THE LOWER KEWEENAWAN. These rocks are of the same age and of the same origin as the eopper-bearing rocks of Keweenaw point in which the most ex- tensive deposits of native copper known in the world occur. Moreover, in lithological character the rocks of the two areas are the same in all broad features and in most minor features. The belt of these rocks in the southeastern corner of Douglas county is directly continuous geographically and geologically with the same rocks on Keweenaw point, and the Lower Ke weenawan rocks of the northern part of the county are unques- tionably continuous, beneath the surface, with those in the south- eastern corner of the county (see section AB, plate I). Sedimentary Rocks. The only sedimentary rocks which have been reported from the Lower Keweenawan of Douglas county are certain beds of conglomerates lying between lava flows in the southeastern part of the county. These conglomerates are composed of débris de- rived from the closely adjacent, underlying, igneous rocks. Careful search was made for such conglomerates in the northern belt of Lower Keewenawan rocks, but no indication whatever that such exist was discovered. It is of course possible that such conglomerates do exist here interbedded with the lava flows, and future search may bring them to light. Should they be found, the close parallel in lithology between the rocks of this district and those of Keweenaw point would be practically complete. Moreover, it is known that such interbedded conglomerates exist in this northern belt of lava flows on the Snake river in Pine county, Minnesota, and also on the north shore of lake Superior. 10 COPPER-BEARING ROCKS OF DOUGLAS COUNTY. Igneous Rocks. In general these lava flows are dark colored and basic (i. é., low in silica) in character. To such rocks the non-committal name of trap can be conveniently applied. It is not necessary at this place to enter upon a detailed analysis of the different kinds of rocks included under this comprehensive and elastic term, but a few of the commoner types should be mentioned. The term diabase is applied to a rock composed essentially of lath-shaped plagioclase feldspars and of augite, the latter min- eral filling in the angular spaces between the feldspars. These rocks are commonly of such fine grain that this relation between the minerals can be determined only by a microscopic examina- tion. Frequently one grain of augite completely surrounds one or more of the feldspars. These augite grains vary in size from very minute ones to those an inch across. When they become. of noticeable size and include many feldspars, the rock has a mottled appearance due to reflections from the cleavage faces of the augites, and such a rock is known as a luster mottled diabase. Most commonly such rocks contain olivine and are then known as melaphyres. The melaphyres become prominent rocks in places, especially in the St. Croix range, where the augite grains. are not uncommonly a quarter of an inch across and the feld- spars, on account of their color or their minute size, are usually clearly seen only under the microscope. Gabbro is composed of the same minerals as diabase, but the constituent grains are of approximately uniform size and shape. The gabbros found in Douglas county are usually of considerably coarser grain than are the rest of the Keweenawan rocks. A porphyry is a rock which contains crystals of one or more minerals imbedded in a groundmass which is of much finer grain when compared with these porphyritic crystals. ‘An amygdaloid is a rock which contains roundish cavities which have been more or less filled by secondary minerals. These cavities are due to gas which escaped from the molten lava on cooling. They vary in size from those of microscopic dimensions to those which are an inch or more in diameter. GEOLOGY OF DOUGLAS COUNTY. 11 The mincrals which occur most commonly in such cavities are quartz, calcite, epidote, chlorite, and prehnite. Native copper also occurs. The last two names,—porphyry and amygdaloid—are tex- tural terms and are also applicable to acid (i. e., those high in silica) igneous rocks, but such are rare in Douglas county. The acid rocks seen are granites, syenites, and quartz-porphy- ries. Granite is composed of quartz and orthoclase feldspar with one or more of the following minerals: mica, hornblende and augite. The grains are of approximately uniform size and shape and the rock is in general coarser grained than the or dinary traps. Syenife is the same as granite except for the lack of quartz. Quartz-porphyry is a porphyry which has porphy- ritic crystals of quartz and the mineral composition of granite. Most of the rocks of the Lower Keweenawan are in the form of lava flows and almost all of these are basic in character. In only one place (on Copper creek) were Java flows seen which approached an acid composition. Quartz-porphyry, however, undoubtedly exists in small quantities associated with these basie lava flows, for a few pebbles of such rock occur in the conglomerate at the base of the Upper Keweenawan. Whether this quartz-porphyry exists in the form of lava flows or intruded massces is not known. SS A SS K< <7 Nascennacccaamaa Se UNKNOWN UMMM, CLAY TALUS SAND SANDY LOAM TYPICAL SECTIONS ACROSS THE WOLF RIVER CHANNEL ABOVE SHIOCTON. ESTUARINE DEPOSITS. 153 This yard was opened about twenty-two years ago and has been operated each year since that time. The average annual output during the last three years has been about 500,000. The brick sold in 1899 for about $6.00 per M. kiln run. The brick yard owned and operated by the Sanborn Brick and Ice Company was opened in 1874 and has been operated each year since that time. The clay bank which is being worked has a thickness of twenty feet and consists of interstratified sand and clay similar to that which oc- curs at A(feldt's yard. The clay is soaked in vats and tempered in pug mills operated by steam power. The brick are moulded by hand,* dried in hacks on the yard, and burned in scove kilns. Building and sidewalk brick are manufactured. During the last three years the average annual output of this yard has been about 800,000. Drinker’s Brick Yard is located in the western part of the city. The clay bank consists of about two feet of yel- lowish brown clay at the top, underneath which occurs one foot to one foot and a half of fine sand and twenty feet of grayish colored clay which is worked to a depth of four or five feet. The clay is conveyed from the bank to the works by means of cable cars and is tempered in a pug mill. The brick are made in a Creager and Son’s soft mud machine, dried on pallets under sheds, and burned in scove kilns. The clay burns to a cream color but the sand used in moulding gives the brick a grayish tint. Laboratory Exramination.—Both the clay and moulding sand used at this yard were examined in the laboratory of the Survey. The top or yellow clay slacks very readily breaking down into a finely pulverulent mass. It is free * Since writing this report Mr. Sanborn has purchased the machinery formerly used by A. P. Drinker, and the brick are now made in a Jon- athan Creager & Son's soft mud machine. 154 THE CLAYS OF WISCONSIN. from coarse particles and very plastic. The microscopic ex amination shows that it is composed of grains which have an average diameter of about .0058 mm. The largest grains do not exceed .011 mm. in diameter while the smaller ones are less than .001 mm. in diameter. The indi. vidual grains have an irregular and occasionally roundisk outline. Besides the iron oxide which stains the mass oi the clay, calcite and quartz are the principal recognizable constituents. The sample of blue clay slacked somewhat slower than the yellow, breaking down into fine flakes. In its smooth, plastic character it is very similar to the preceding sample. Under the microscope it was found to consist mainly of grains which correspond in size with those of the clay above described. A few grains of sand were observed which measured .25 to .20 mm. in diameter. One of the samples of moulding sand submitted for in- spection was composed of grains not over .33 mm. in diam- eter and having an average size of about .1 mm. The in- dividual grains were mainly quartz, although a consider- able quantity of calcite and feldspar were noticeable. The second sample of moulding sand examined was. somewhat finer than the first. A large part of the sand was made up of grains having an average diameter of .083 mm. although a majority of the grains were less than .005 mm. in diameter. Many of the individuals are angular in outline, showing clean, sharp, fractures. Calcite and feld- spar, as well as quartz, are abundant constituents. The grains are discolored with iron oxide giving them a slightly yellowish brown tint. This clay is unsuitable for the manufacture of either vitrified or refractory wares. SCHLEISINGERVILLE. Schleisingerville is located near the center of Washing: ton county, about twenty miles west of the limit of the la eustrine clay deposits. The bank which is being worked consists of four feet of loam, which is stripped, underneath ESTUARINE DEPOSITS. 155 which occurs from three to five feet of yellowish colored clay, which burns red, and from fifteen to twenty feet of blue clay all of which burns white. An occasional pocket of limestone gravel occurs in the clay necessitating care in working the bank. Two brick yards are located at this place, one of which is owned and operated by L. Rosenheimer and the other by P. W. Kortmeyer. Both yards are located a short dis- tance cast of the village and are on opposite sides of the Wisconsin Central railroad. The clay bank connected with the Kortmeyer yard has been worked out and clay is now obtained from the Rosen- heimer yard. The clay is most easily worked when it has been weathered over winter. It is mixed with about one-fourth sand and soaked in vats over night. The brick are moulded in an “Old Reliable” soft mud machine, dried in hacks on the yard, and burned in scove kilns. This yard was opened in 1884 and has been operated each year since that time. During the last three years the average annual output has been 400,000. The brick sold on the market in 1899 for $4.50 per M. At Rosenheimer's yard the clay is worked in about the same manner as at Kortmeyer’s. The brick are moulded in a soft mud machine, dried in hacks on the yard, and burned in scove kilns. This yard is equipped with a combination brick and tile machine and a crusher, neither of which have been used for several years. It requires from eight to nine days to burn the brick and about one half cord of wood is consumed for each thousand brick burned. During the last three years the average annual output of the yard has been about one million brick. The brick were sold at the yard in 1899 for about $5.50 per M. kiln run. 156 THE CLAYS OF WISCONSIN. SPRINGFIELD. Springfield is located near the central part of Walworth county and about eight miles from Elkhorn. The Spring- field Brick and Tile Company of which R. Trist is owner is located about one-half mile south of the village. The clay which occurs at this place has a thickness of from two to ten feet above which is a stripping of from six to eight inches of sod. The clay contains very little limestone gravel and the brick and tile which were examined on the yard show no evidence of its occurrence. The distribution of the clay is irregular and in places it is overlain with de posits of limestone gravel. After removing the clay from the bank it is soaked in vats over night and then passed through a Potts disin- tegrator. The brick and tile are made in a Little Wonder brick and tile machine, dried in a three story building con- structed for the purpose, and burned in round down draft kilns of latest pattern. This yard was opened in 1896 and has been operated each year since. The annual output of brick has been in the neighborhood of 100,000. The brick sold in 1899 at prices ranging from $7.00 to $9.00 per M. kiln run. The clay which occurs at this place burns a beautiful cherry red and the brick and tile manufactured therefrom are of excellent quality. From all appearances this is one of the best clays in southern Wisconsin for the manufac- ture of red flower pots, drain tile, and brick. The clay might also be used in the manufacture of terra cotta. For a number of years the clay from this locality has been used by the Edgerton Art Pottery Works for the manufac- ture of ornamental pottery. Laboratory Examination.—The microscopic examination of samples of this clay shows that it consists of grains which are moderately coarse. One of the samples was com- posed of grains which averaged about .02 mm. in diameter. The largest grains observed in this sample were .125 mm. ESTUARINE DEPOSITS. 157 in diameter while there were myriads less than .01 mm. in diameter. The other sample examined consisted of individuals averaging about .014 mm. in diameter. The largest grains observed were .1 mm. in diameter, while a small percentage of the grains were under .003 mm. in diameter. Between the largest and smallest grains in both samples there are all gradations. The individuals are mainly sub- angular in outline, although the larger grains are usually somewhat rounded. The grains are stained brown or yel- lowish brown with iron oxide. Quartz appears to be the main constituent. A few grains of calcite were observed but the proportionate amount is thought to below. The kaolin occurs among the finer grained constituents and comprises a moderately small percentage of the clay. The chemical composition of the clay is shown by the analysis in table I of the Appendix. WATERTOWN. Watertown is situated near the northern boundary of Jefferson county on the Chicago, Milwaukee & St. Paul railroad. Two brick yards are located at this place, one of which is owned by L. H. Cordes and Company and the other by Cordes, Vaughn and Company. Both are now be ing operated under the management of L. H. Cordes and Company. The combined output of the two yards is in the neighborhood of five million brick per year. The stock is graded and sold as common, chimney, sidewalk, well, and veneering brick. The clay at this place has a total thickness of about twenty-five feet. The upper four or five feet contains a considerable percentage of sand and has a yellow color. The remaining twenty feet has a blue color and contains much less sand. The bank is now worked to a depth of about ten or twelve feet and the yellow and blue clays are mixed together in equal proportions. To the clay as it 158 THE CLAYS OF WISCONSIN. comes from the bank about one-fifth sand is added. The clay is run through a crusher and then soaked for twenty- four hours in vats. The brick are moulded in soft mud machines, operated by steam power, dried in hacks on the yard, and burned in scove kilns. The clay from this bank is very free from gravel and was at one time used in the manufacture of pottery. The clay which occurs at the yard owned by Cordes, Vaughn and Company is essentially the same as that at the yard just described. The clay is mined with a pick and shovel and soaked in a vat over night. The brick are made in a soft mud machine, dried in hacks on the yard, and burned in scove kilns. The brick manufactured at both yards have a white or cream color. Laboratory Examination—The clay from the first named yard was examined in the laboratory of the Survey. It is somewhat hard and brittle when dry but slacks very readily in water, breaking down into a scaly mass which is very smooth and plastic. The microscopic examination shows that the clay con- sists of individuals which have an average diameter of .003 mm. Many of the grains, however, are .014 mm. in diam- eter, and the largest have diameters of .04 mm. Quartz and calcite are both present in the clay but in undetermin- able proportions. Asarule the individuals have sub-angu- lar outlines and are unequi-dimensional in size. The chemical composition of the clay is given among the analyses recorded in table I of the Appendix. The brick which are manufactured from this clay have a white or cream color and are among the more desirable products of the calcareous clay region. Besides building brick, the clay is undoubtedly suitable for the manufacture of some of the commoner kinds of earthenware such as flower pots. WIND LAKE. The Wind Lake Brick and Tile Company is located at Wind Lake in the north central part of Racine county. ESTUARINE DEPOSITS. 159 The clay at this place resembles very closely the lacustrine clays which have been described in the previous chapter. The clay bank consists of a stripping of from one foot to one foot and a half underneath which occurs an unknown thickness of clay which is worked to a depth of eight or ten feet. Limestone gravel is abundant in some portions of the bank but the clay which is now being used contains only an occasional pebble. The upper two feet of the clay burns red and the remainder white. The clay is soaked for twenty-four hours and then passed through a crusher into a stiff mud brick and tile machine, provided with an automatic end cut-off. The brick and tile are dried in sheds, by air, and burned in square down draft kilns. Laboratory Examination.—The clay from this yard was examined in the laboratory of the Survey. It was found to be moderately hard when dry and very plastic when wet. It slacks readily breaking down into thin flakes. The microscopic examination shows the clay to consist of grains having an average diameter of about .03 mm. With the exception of rhombic individuals supposed to be calcite or dolomite, the individuals are mainly well rounded or sub-angular in outline. 160 THE CLAYS OF WISCONSIN. CHAPTER IX. CLAYS OF THE DRIFTLESS AREA. The Driftless Area comprises that portion of the state which has not been modified by the ice sheets of the glacial period. It comprises the southeastern portion of the state as outlined on the general map, plate I. None of the rivers of this region with the exception of a small part of the Wisconsin drain that portion of the state comprising the two areas previously described. The northern and northeastern parts of the area have been slightly modified with overwash from the glaciers but other than this it is a region of typical erosion topography in which the surface deposits are either the result of rock disintegration in situ or deposition from streams and air. The underlying rocks consist of sandstone and limestone. The northern part of the area, including Adams, Juneau, Monroe, Jack- son, La Crosse, Trempealeau and Buffalo counties, is largely underlain with Potsdam sandstone. The southern two-thirds of the area is mainly underlain with limestone. The clay deposits of this region are largely residual having been formed through the decomposition of the underlying limestone and sandstone. In the transported deposits large quantities of quartz which has been derived from the decomposition of the asso- ciated sandstone is frequently mingled with the clay result- ing from the decomposition of the limestone. Through the decomposition of the limestone most of the calcium and magnesium salts are taken into solution and removed by percolating waters, leaving a residuum of quartz, iron oxide, and kaolin. BULLETIN NO. Vil, PL. XXXII. WISCONS N GEOL. AND NAT. HIST. SURVEY. SANDSTONE. GFE LIMESTONE. Z ai O & OO) az £ § UNKNOWN. NT HILL IN THE DRIFTLESS AREA; SHOWING THE POSITION OF THE TYPICAL SECTION OF A RIVER VALLEY AND ADJACE CLAY DEPOSITS. THE DRIFTLESS AREA. 161 The clay deposits in this region are mainly a result of the decomposition of the country rock, while the clay in the two regions previously discussed has resulted very largely from disintegration of the underlying rock. It is thought by T. C. Chamberlin, R. D. Salisbury, and others that the clay occuring on the tops of the high bluffs and ridges extending for some distance east of the Missis- sippi river has been carried to its present position by winds. For this reason these clay deposits are known to geologists as “Loess.” These deposits of loess are very similar to the brown or reddish brown clay which has been classed in many places over the driftless area as residual. In fact so close is the similarity between the brown residual clays and the loess that it is difficult to map them as dis- tinct and separate deposits. The approximate extent of the loess deposits is shown on the map, plate I. (After Chamberlin.) I do not feel sure that the loess and residual clay deposits can be clearly differentiated from each other in this region and therefore no attempt is made to separate them in the following dis- cussion. The limestones of the Driftless Area are both quartzose and ferruginous and it would be natural to anticipate that the clays resulting from their decomposition would con- tain considerable quantities of quartz and iron oxide. An examination of the clays from many parts of this region verifies the above presumption. Further, it is found that the residual clays of this region which have been worked over and re-deposited by the rivers usually contain greater quantities of quartz than those that have been undisturbed. The clays of this region are both residual and trans- ported. The residual clays are the unmodified deposits resulting from the decomposition of limestone. They oc- cur mainly on or near the tops of the ridges, hills, and tablelands which are or have been capped with limestone and frequently contain fragments of flint or chert. The 11 162 THE CLAYS OF WISCONSIN. transported clays are residual deposits which have been moved a greater or less distance and assorted and re-de- posited either by water or wind. The residual and loess deposits and their equivalents which have been transported only a short distance are the richest clays of the area. The transported clays have as a rule been carried through a region partially composed of soft incoherent sandstone, which has contributed large quantities of fine quartz sand to the rivers. This sand now occurs mingled with the residual limestone material which has been transported from higher altitudes. Moreover, in the lower courses of the streams the tributaries often supply no other material than sand, so that the clay may constitute a very small per- centage of the alluvial deposit. For this reason the de posits which are now accumulating in the quiet stretches of the river channels and those which have been formed in the past, often contain scarcely sufficient clay to hold the particles together when moulded. All the clay of this region contains considerable quanti- ties of iron oxide and is low in calcium. Accordingly the brick and tile which are manufactured are different shades of red depending upon the amount and condition in which the iron oxide is present. The deposits are everywhere comparatively thin and the continuous areal extent varies greatly. Residual deposits of clay occur adjacent to most of the cities throughout a greater part of this area. The clay is comparatively easy to work and when not too sandy makes a good common building brick. Brick yards are quite numerous in this region but owing to the situation and character of the clay the factories are small and the methods of manufacture somewhat primitive. The brick are manufactured mainly to supply local demands. The following is a brief description of the more import- ant brick yards which are now operated in this region. There are undoubtedly a number of factories located some distance from any railroad which have been unintention- ally omitted. THE DRIFTLESS AREA. 163 ARCADIA. Arcadia is situated in the western part of Trempealeau county on the Green Bay & Western railroad. Two brick yards are located at this place, one of which is owned and operated by Ernest Pahl and the other by Zimmermann and Company. The clay which occurs at both yards is of alluvial origin and consequently laminated. The yard owned and operated by Ernest Pahl was opened in 1891 and has been operated each year since that time. The average annual output of the yard for the last three years has been in the neighborhood of 250,000. The clay bank consists of a stripping of about one foot and a half of black loam, underneath which occurs four feet of yellow and two feet of blue clay, both of which burn red. The blue clay is not used in the manufacture of brick. About one-tenth of the black loam is mixed with the yel- low clay to serve the purpose of sand. The brick are made by hand, dried in hacks on the yard and burned in scove kilus. It requires a little over one-fourth of a cord of wood to burn each thousand brick. The brick yard owned by Zimmermann and Company is located north of the plant owned by Ernest Pahl. It was opened in 1898 and has been operated each year since that time. The clay is essentially the same as that which is mined at Pahl’s yard. The average annual output of the yard is from 250,000 to 500,000. The brick are moulded in a Quaker soft mud machine operated by horse power, dried on pallets under sheds, and burned in scove kilns. The brick at both factories are not burned very hard owing to the sandy character of the clay and the difficulty experienced in controlling the heat. The brick were sold in 1899 at an average of $5.00 per M. kiln run. BANGOR. Bangor is located in the western part of La Crosse county on the Chicago, Milwaukee and St. Paul railroad. 164 THE CLAYS OF WISCONSIN. One small yard owned by Max Stegman is located about four miles south of the village in what is known as Dutch Valley. The clay at this place has a reddish brown color and occurs near the bottom of the hills where the yard is Jocated. The clay is mainly a residual limestone deposit which has been washed from above. The clay is mixed in a wooden pug mill operated by horse power. The brick are moulded by hand, dried in hacks on the yard, and ‘burned in scove kilns. The brick have a bright red color and are a good average of the red brick manufactured from similar clay in this region. BLOOMINGTON. Bloomington is situated in the northwestern part of Grant county and about ten miles from Lancaster. The Bloomington Brick Yard which is located at this place is owned and operated by Mr. Hutton. The yard was opened in 1897 and has been worked each year since that time. ‘Common red brick are manufactured. The clay bank has a working depth of five feet. The clay is fairly rich at the top but very sandy near the bot- tom. The clay is soaked in vats over night and tempered in wooden pug mills operated by horse power. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. It requires seven days to burn the brick and about one-third of a cord of wood is consumed in burning each thousand brick. The average annual output of the yard has been about 350,000. The brick sold at the yard in 1899 for about $7.00 per M. kiln run. Between Bloomington and Cassville various thicknesses of clay similar to the above are found on the tops and near the bottom of the ridges, and at the heads of the valleys. THE DRIFTLESS AREA. 165 CASSVILLE. Cassville is situated in the western part of Grant county on the Chicago, Burlington, and Northern railroad. The brick yard which is located at this place is owned and operated by James Barrows and Son. The yard is sit- uated in the north end of the city. The clay has a yellow- ish brown color and has apparently been washed into the valley from the adjacent hills. The clay is very sandy, and the brick examined were not very strong. The clay is soaked in a vat over night and tempered in a wooden pug mill operated by horse power. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. ELROY. Elroy is located in the western part of Juneau county on the Chicago & Northwestern railroad. The only brick yard at this place is owned and operated by Loveland (E. N.) and Wade (J.). The plant is located on the Chicago & Northwestern railroad about one-half mile east of the city. The clay bank which is being worked has a thickness of about two and a half feet. The clay has a yellowish brown color and burns red. In the valley of the Lemon- weir river, adjacent to which the yard is located, occurs a large quantity of blue clay which, however, contains a large percentage of sand and is thought to be less suitable for the manufacture of brick than that which is now being used. The clay is soaked over night in a vat and tempered in a wooden pug mill operated by horse power. The brick are moulded by hand, dried on pallets under sheds, and burned in scove kilns. The company owns a stiff mud machine which is not being used at the present time. During 1900 the company manufactured in the neighbor- hood of 250,000 brick. 166 THE CLAYS OF WISCONSIN. GALESVILLE. Galesville is situated in the southern part of Trempea- leau county on the Chicago & Northwestern railroad. One brick yard, owned and operated by B. T. Dale, is located about two miles west of the city. The bank from which the clay is obtained is situated at the base of one of the low ridges and has a thickness of from twelve to fourteen feet. The top of the bank is richest and has a deep yellowish brown color. Toward the bottom of the bank the clay has a light yellowish tint and is very fine grained and quartz- ose. The clay has a laminated structure which gives it very much the appearance of being of sedimentary origin. The lamination, however, is probably due to other causes than sedimentation. This yard was opened in 1893 and about 500,000 brick are manufactured annually all of which are sold in the vicinity of Galesville. The clay is soaked over night in a vat and conveyed to an Eagle soft mud machine, operated by horse power, in which the brick are moulded. The brick are dried on pal- lets under sheds and in hacks on the yard and burned in permanent up draft kilns. It requires about twelve days to burn the brick. The brick are various shades of red and do not differ materially from other brick manufactured in this area. HILLSBORO. Hillsboro is located in the eastern part of Vernon county about seven miles west of Wonewoc. The plant which is located at this place is owned and operated by Joseph Bezucha. ‘The clay which is mined has a deep reddish brown color and is very similar to that which occurs in many places throughout this region. The clay has a depth of from six to ten feet and is very sandy. It is mixed in wooden pug mills operated by horse power. The brick are THE DRIFTLESS AREA. 167 moulded by hand, dried in hacks on the yard, and burned in scove kilns.* Kiln run brick were sold in 1899 for $6.00 per M. and chimney brick for 88.00. The brick are only manufac- tured to supply the local demand. INDEPENDENCE. Independence is located in the northwestern part of Trempealeau county near the northern limit of the mag- nesian limestone region. The only brick yard operated at this place is owned by Henry Hartzfeldt. The clay oc- curs near the base of one of the numerous ridges of this region. It has a thickness of about four feet and has a deep vellow or yellowish brown color. The clay at the bot- tom of the bank is mainly sand. The clay is soaked in a vat and mixed in wooden pug mills operated by horse power. The brick are moulded by hand, dried in hacks on the yard and on pallets under sheds, and burned in scove kilns. This yard was opened in 1895 and has been operated each year since that time. The brick have the usual red color to which the clay of this area burns. The brick sold in 1899 for 47.00 to 38.00 per M. kiln run at the yard. The market is local. LA CROSSE. La Crosse is situated in the western part of the state near the junction of the La Crosse and Mississippi rivers. Four brick yards are located near the outskirts of the city and are owned respectively by Anton Keppel, Hermann Ikeppel, Mike Meyer, and Schnell Brothers. The vard owned by Anton Keppel is located three miles east of La Crosse. The clay is obtained from the side of small knolls or near the base of the bluffs which skirt the * Since writing this report this yard has been equipped with modern machinery. 168 THE CLAYS OF WISCONSIN. river at this place. The bank which is now being worked has a thickness of from three to six feet. The clay has a yellowish brown color and contains very much fine sand. After the clay is removed from the bank it is soaked over night in a vat and mixed with a tempering wheel. The brick are made by hand, dried in hacks on the yard, and burned in scove kilns. This yard was opened twenty-six years ago and has been operated each year since that time. The average annual output has been from 100,000 to 300,- 000. The brick sold in 1899 for about $5.00 per M. kiln run. The brick yard owned and operated by Herman Keppel is about one-fourth of a mile north of Anton Keppel’s yard. The clay bank is situated at the foot of the blutts border- ing the river and has a thickness of about seven feet. The clay in the lower portion of the bank is very sandy. It is soaked in a vat over night and mixed with a tempering wheel operated by horse power. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. It requires about seven days to burn the brick and about one-fourth of a cord of wood is consumed for each thousand brick burned. This yard was opened thirty-three years ago and has been operated each year since that time. The average annual output of the yard has been about one million brick. The market price in 1899 was about $5.25 per M. kiln run at the yard. The yard owned and operated by Mike Meyer is located about two miles east of the city. This yard was opened in 1883, and has been operated each year since that time. The clay occurs in a small valley between the bluffs which skirt the river. The clay bank has a depth of about eight feet, one to two feet of which is sand and six feet clay. The clay has a reddish brown color and is moderately tough and plastic. The clay is soaked over night in a vat and mixed with THE DRIFTLESS AREA. 169 a tempering wheel. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. During the last three years the average annual output of this yard has been about 175,000. Common brick sold at the yard in 1899 for about $5.00 per M. kiln run. The yard owned and operated by Schnell Brothers, which is located about four miles east of La Crosse, was opened in 1890 and has been operated each year since that time. The clay bank occurs near the base of a low bluff and has a depth of about twelve feet. The upper four or five feet is a tough yellowish brown clay, underneath which occurs from six to seven feet of yellow sandy clay. The clay is soaked in vats and mixed with a tempering wheel. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. It requires from seven to eight days to burn the brick and about one-fourth of a cord of wood is consumed for each thousand brick burned. During the last three years the average annual output has been in the neighborhood of 1,200,000 brick. The brick sold in 1899 for about $5.00 per M. kiln run. } LE FARGE. Le Farge is a small village in Vernon county, situated at the northern terminus of the Kickapoo & Northern railway. The only brick yard located at this place is owned and operated by V. V. Miller. The clay bank occurs near the base of the bluffs which border the Kickapov valley. The clay has a yellowish brown color and has a depth of about two and a half feet. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. It re quires about seven days to burn the brick and one-fourth of acord of wood is consumed for each thousand brick burned. The output in 1899 was about 200,000 brick. They sold at the yard in 1899 for $6.00 per M. kiln run. 170 THE CLAYS OF WISCONSIN. LANCASTER. Lancaster is located near the center of Grant county. The only brick yard at this place is owned and operated by William Barrows. The clay occurs near the top of the table land area on which the city is situated. Well bor- ings in this vicinity indicate that the clay has a maximum depth of forty feet which is far above the average for this region. The clay is now worked to a depth of three feet. It has a yellowish brown color with an occasional blue spot. The three feet of clay immediately underneath is hard and tough and is seldom used owing to a tendency which the brick made therefrom have of cracking during the process of drying. Underneath this layer of tough clay there is re- ported to be ten feet of smooth putty-like blue clay. In most places in this vicinity, however, there is no clay be low the yellow bed which itself does not exceed three to six feet in thickness. The clay is tempered in a pug mill operated by horse power. The brick are moulded in a hand press, dried in hacks on the yard, and burned in scove kilns. The average annual output of the yard is about 200,000 brick. In 1899 the brick sold at the yard for about $6.00 per M. kiln run. MAUSTON. Mauston is located in the southeastern part of Juneau county on the Chicago, Milwaukee & St. Paul railroad. The clay which is being worked at this place differs some what from that which occurs in most parts of this area. The deposit is in the valley of the Lemonweir river and is of alluvial origin. The exposed clay bank consists of a foot of black loam or sod which is stripped, two and one half to three feet of bluish, sandy clay, and an unknown thickness of laminated red clay which is now worked to a depth of four or five feet. The brick yard located at this place is operated by the Dayton Brick Company and is owned by James Dayton. The yard was opened in 1890 and has been operated each THE DRIFTLESS AREA. 171 year since that time with the exception of 1896. The clay is soaked for several days in a vat and from thence conveyed directly to a Penfield stiff mud machine in which the brick are moulded. The brick are dried on pallets un- der sheds and in hacks on the yard and burned in scove kilns. The average annual output of this vard is about 100,000. The average price of the brick in 1899 was about $7.00 per M. kiln run. PLATTEVILLE. Platteville is located in the eastern part of Grant county on the Chicago & Northwestern and Chicago, Milwaukee & St. Paul railroads. The only brick yard located at this place is owned and operated by John Grindell. The bank from which the clay is obtained has a thickness of from five to ten feet. Below the sod at the surface occurs a thickness of two and a half fect of workable clay, from three to eight feet of clay known as hard pan, and an unde- termined depth of gravel. The clay at the surface has a dark yellowish brown color and is very plastic. It is mixed and tempered in pug mills. The brick are madeina Monarch soft mud machine, dried on pallets under sheds, and burned in scove kilns. This is the only brick plant in the state where the power is furnished by a gasoline en- gine. Laboratory Examination. The clay which occurs near the surface has a somewhat lighter color than that which occurs deeper within the bank. Both samples examined slacked quickly in water breaking down into fine scaly masses which were very plastic. The plasticity of the lower clay appears to be somewhat greater than that of the clay which occurs near the surface. Under the microscope it was observed that the largest grains are not over .1 mm. in diameter. The surface clay consists mainly of grains ranging from .014 mm. to .003 172 THE CLAYS OF WISCONSIN. mm. in diameter. The lower clay consists of grains that. are mainly under .003 mm. in diameter. Many of the larger grains are fairly well rounded, but the smaller individuals are irregular and angular in shape. Quartz, iron oxide, and an occasional calcite grain could be detected. The chemical composition of both the upper and lower clays will be found in the table of chemical analyses. REEDSBURG. Reedsburg is located in the northwestern part of Sauk County on the Chicago and Northwestern Railroad. There are three brick yards operated in the neighbor- hood of this city, which are owned respectively by Fred Bergmann, Henry Fuhlbohm, and Lewis Halbersleben. The yard of Fred Bergmann is located about one mile southwest of the city. The bank from which the clay is obtained has a thickness of from four to five feet. The clay has a yellowish brown color and burns red. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. The brick yard owned by Henry Fuhlbohm is east of Bergmann’s yard and has been idle for two years. The clay is the same as that occurring at Bergmann’s yard and the brick are manufactured in the same manner. The yard owned and operated by Lewis Halbersleben is about one mile west of the city. The bank from which the clay is obtained has a thickness of about five feet. The clay is soaked in a vat for two days and then mixed in a wooden pug mill operated by horse power. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. All of the brick manufactured in this vicin- ity are red. RICHLAND CENTER. One brick yard is located at this place which is owned and operated by Lewis Minisini. The clay is of residual origin modified by running water. It is quite sandy and THE DRIFTLESS AREA, 173 burns a red color. The brick are made by hand and burned in up draft kilns. SPARTA. Sparta is located in the western part of Monroe County on the Chicago, Milwaukee and St. Paul Railroad. The Sparta Brick Works are owned and operated by P. S. Sparling. The clay bank occurs near the base of one of the bluffs in this vicinity and consists of one foot of black loam at the surface, from eight to nine feet of yellowish brown clay, and an undetermined thickness of sand. The quantity of sand in the clay increases as the bottom of the bank is approached. The clay is soaked in a vat over night. The brick are manufactured in a Quaker soft mud machine, dried in hacks on the yard, and burned in scove kilns. The brick are burned eight days and it requires about one-fifth of a cord of wood for each thousand brick burned. The brick have a red color. This yard was opened in 1877. The average annual out- put is about 400,000. In 1899 the brick sold at an aver- age of $6.00 per M. kiln run. SPRING GREEN. Spring Green is located in the southwestern part of Sauk County on the Chicago, Milwaukee and St. Paul Railroad. The only brick yard located at this place is owned and operated by G. F. Post. It was opened in 1898 and has been operated each year since that time. The clay which occurs at this place has a blue color and is streaked with red and yellow. After removing the clay from the bank it is soaked in a vat. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. The output of this yard in 1898 was 250,000. The brick sold at the yard in 1899 at an average of $6.00 per M. kiln run. 174 THE CLAYS OF WISCONSIN. SOLDIERS GROVE. Soldiers Grove is located in the southeastern part of Vernon County on the Kickapoo and Northern Railroad. The brick yard operated at this place is owned by Atley Peterson. The yard is located on the west bank of the Kickapoo River, one-fourth of a mile north of the city. The clay which occurs at this place is about two and a half feet deep and has a reddish brown color. The clay is mixed in a wooden pug mill operated by horse power. The brick are moulded by hand, dried in hacks on the yard and burned in scove kilns. It requires about seven days to burn the brick. VIROQUA. Viroqua is located on the Chicago, Milwaukee, and St. Paul Railroad in the central part of Vernon County. The only brick yard in this vicinity is owned and operated by Silas Foster. The bank from which the clay is obtained is near the base of cne of the numerous hills in this region. The clay has a total depth of about three feet. It is mixed with about one-eighth cf its bulk of coarse sand, and soaked in a vat over night. The brick are moulded in a Quaker soft mud machine, dried in hacks on the yard and on pal- lets under sheds, and burned in scove kilns. It requires nine days to burn the brick and two-fifths of a cord of wood is consumed for each thousand brick burned. This yard is supplied with an excellent red sand for moulding on account of which the brick have a cheerful red color. This ferruginous sand is also used for coloring mortar and as such answers the purpose of the red pig- ment which is ordinarily used for this purpose. Laboratory Examination——The samples of clay exam- ined from this yard slacked readily in water breaking down into loose fluccolent masses. The samples differ mainly in the size of the grains and the quantity of quartz present. The individuals are mostly THE DRIFTLESS AREA. 175 stained 2 dirty brown with the iron oxide which occurs in considerable quantities. The individuals vary in size from those having diameters of .1 of a mm. to those in which the greatest diameter is less than .001 mm. The large grains are fairly well rounded, while the small individuals are somewhat angular. The only minerals which could be identified with cer- tainty were quartz and iron oxide. The chemical compo- sition of the clay is given in table I of the Appendix, to which the reader is referred. WONEWOC. Wonewoce is located on the Chicago and Northwestern Railroad in the southern part of Juneau County. The brick yard located at this place is owned and operated by Benjamin Truber. The clay is an alluvial deposit oc- curring in the valley of the Lemonweir River. The bank consists of a stripping of soil of from ten to eighteen inches and three feet. of clay. The clay has a bluish color mottled with streaks of yel- lowish brown iron oxide. The clay is soaked in a vat over night and then passed directly into a Quaker soft mud ma- chine in which the brick are moulded. The brick are dried mainly on pallets under sheds and burned in scove kilns. This yard is equipped with a dry press machine and per- manent up draft kilns. The dry press machine has not yet been used and the suitability of the clay for this kind of brick has not been demonstrated. Mr. Truber first began making brick by hand and alone. Later he installed a foot press and finally purchased a soft mud machine operated by steam power. The brick were first dried in hacks on the yard but later pallets and sheds were constructed, upon which the brick are now being dried. Laboratory Eramination—Two samples of clay from this yard were examined in the Survey laboratory. The surface clay differs from that underneath simply in con- 176 THE CLAYS OF WISCONSIN. taining less sand and having grains of more uniform size. The clay from both parts of the bank slacks quickly in water, breaking down into a granular mass which is very plastic. The microscopic examination shows that the grains are from .057 mm. to .0014 mm. in diameter. They are roundish to subangular in outline. The large grains are mainly quartz. A small amount of chlorite occurs throughout the clay and iron oxide is present as an abund- nant staining agent. The chemical composition of the clay is given in table I of the Appendix, to which the reader is referred. GLACIAL CLAYS. 177 CHAPTER X. GLACIAL CLAYS FROM THE REGION NOT UNDER- LAIN WITH LIMESTONE AND OUTSIDE OF THE AREA OF LACUSTRINE CLAYS. The clays of this class have a greater areal extent than any of those previously described. The region through- out which they occur comprises a large part of the north- ern half of the state, all of which is underlain either with the pre-Cambrian crystalline rocks or Potsdam sandstone. These clays have been derived mainly from the igneous rocks and their mineralogical composition resembles some- what the residual deposits which might result from the de- composition of such rocks. The glacial deposits in the northeastern part of the state contain some limestone gravel derived from the finely crystalline marble and lime- stone occurring to the northeast. The glacial abrasion of this section was not on the whole as intense as it was in the southeastern part of the state in the region traversed by the Green Bay glacier, owing partially to the harder and more resistent character of the country rock. This. naturally resulted in decreasing the quantity of silt fur- nished to the rivers by the melting glaciers. In some parts of this region, as in the southeastern part of the state, the river channels were at times during the glacial epoch nearly, if not quite, filled with almost stag- nant water in which was deposited «. considerable thick- ness of clay. These deposits, however, have since that 12 178 THE CLAYS OF WISCONSIN. period been largely removed. Only occasionally is there a part of this deposit found in some sheltered part of the present river channels. In some places the clay has been re-deposited along the present stream channels and on the bottom of the lakes, forming the most recent clay deposits, Much of the clay, however, occurs as it was deposited from the glacial ice, mingled with gravel and boulders. The deposits have a very uncertain and variable thick- ness. The composition may be very different in two de- posits which are almost contiguous. The clays occurring in this region are among the best and poorest in the state. The most valuable deposits are those which are supposed to have been formed prior to and contemporaneous with the last glacial epoch. These deposits sometimes attain a thickness of forty or fifty feet and are remarkably uni- form over considerable areas. The clays that are supposed to be pre-glacial consist of pure white kaolin which has been derived from the residual deposits of feldspathic rocks. These kaolin deposits are discussed in Chapter XIII. In some places the clay is very quartzose and is mixed with boulders and gravel. Beds of this character are very common and are usually not over four or five feet in thickness. The following descriptions of the individual brick plants are intended to give a clearer idea of the deposits of clay and the methods of manufacture. AMERY. Amery is located on the Soo Railroad in the south cen- tral part of Polk County. The only brick yard at this place is located about one-half mile southwest of the depot and is owned and operated by J. P. Peterson. This yard was opened in 1881 and has been operated each year since that time. The clay bank has a thickness of from three to five feet and extends over a considerable area. The color of the GLACIAL CLAYS. 179 clay is blue, irregularly streaked with yellow iron oxide. It contains considerable quartz and burns red. The clay is mixed in a wooden pug mill. The brick are moulded by hand, dried on pallets under sheds, and burned in scove kilns. The yard is equipped with an Adrian brick and tile ma- chine and a Quaker soft mud machine, neither of which were being used when the yard was inspected in 1899. During the last three years the average annual output has been about 150,000. The brick sold in 1899 for about $4.50 per M. kiln run. ANTIGO. Antigo is located in the south central part of Langlade County on the Chicago and Northwestern Railroad. There are five brick yards in operation in this vicinity which are owned by Edward Boetcher, Edward Grabowski, Keen Brothers, William Laechm, and Herman E. Meyer. The clay which occurs at all of the yards is essentially the same and the methods of manufacture do not differ materially. At Grabowski’s yard the clay bank has a thickness of about three feet. The upper eight inches, which consists of black loam, is removed. Underneath the stripping the clay has a yellowish brown color streaked with blue. Be low the clay granite gravel occurs to an unknown depth. The clay is mixed in wooden pug mills operated by horse power. The brick are moulded by hand, dried on pallets under sheds, and burned in scove kilns. It requires seven days to burn the brick and about one-fourth of a cord of wood is consumed for each thousand brick burned. This brick yard was opened in 1887 and has been oper- ated each year since that time. The average annual out- put for the last three years has been about 150,000 brick. The brick were sold in 1899 for about $4.00 per M. kiln run. Edward Boetcher’s brick yard is located in the north- western part of the city. The clay bank has a thickness 180 THE CLAYS OF WISCONSIN. of about two and onehalf feet and passes below into gran- ite gravel. The color of the clay is yellow streaked with blue. It is very quartzose and burns red. The clay is soaked in a vat over night and mixed in a wooden pug mill. The brick are moulded by hand, dried on pallets under sheds, and burned in permanent up draft kilns. This yard was opened in 1887 and has been worked each year since that time. During the last three years the aver- age annual output has been about 120,000 brick. The yard owned and operated by Keen Brothers is lo- cated in the southwest + of Section 1, Town 30, Range 11 east. The clay bank has a thickness of about twelve feet, only four or five of which are now used. The clay is mixed in apug mill. The brick are moulded in a Reliable soft mud machine, dried under sheds, and burned in scove kilns. This yard was opened in the spring of 1897 and during the following year the output was about 200,000. William Laehm’s yard is about one-fourth of a mile west of that owned by Boetcher. The clay has a thickness of from one and one-half to two feet and is dug from be- tween tree stumps which are scattered over the field. The color of the clay is yellowish brown streaked with blue. The clay is soaked in a vat over night and then trans- ferred to a Quaker soft mud machine in which the brick are moulded. The brick are dried on pallets under sheds and burned in scove kilns. The brick yard owned by Herman Meyer is situated about one-fourth of a mile west of the city limits. The clay bank has a thickness of about two and one-half feet underneath which gravel occurs. After soaking in @ vat the clay is mixed in a wooden pug mill operated by horse power. The brick are moulded by hand, dried on pallets under sheds, and burned in scove kilns. This yard was opened in 1887 and has been operated each year since that time. The average annual output of the GLACIAL OLAYS. 181 yard is about 125,000 to 200,000. The brick sold in 1899 for about $5.00 per M. kiln run. ATHENS. Athens is located in the northwestern part of Marathon County on the Abbottsford and Northeastern Railroad. The only brick yard at this place is located about a mile north of the city and is owned and operated by Carl Deg- ner. The clay occurs in a valley and is probably of allu- vial origin. The clay is from four to seven feet deep and has a yellowish blue color resembling that which is mined at Antigo. The clay is obtained from two different banks and mixed in definite proportions. It is soaked in a vat over night and then mixed in a wooden pug mill operated by horse power. The brick are moulded by hand, dried on pallets under sheds, and burned in a permanent up draft kiln. The color of the brick is red. It requires about fourteen days to burn the brick and one-half of a cord of wood is consumed for each thousand brick burned. This yard was opened in 1883 and has been operated each year since that time. The brick sold in 1899 for $7.00 per M. kiln run. AUGUSTA. Augusta is located in the southeastern part of Eau Claire County on the Chicago, St. Paul, Minneapolis, and Omaha Railroad. The only yard located at this place was opened about twenty-five years ago. It is now owned and operated by E. W. Johnson. In 1898, 350,000 brick were manufactured. Since that time the yard has been idle. The clay occurs close to the factory and has a thickness of from two to two and a half feet. It has a blue color streaked with brown and yellow iron oxide. The clay is covered with one foot of loam which is mixed with the clay for the manufacture of brick. 182 THE CLAYS OF WISCONSIN. The clay is soaked over night in a vat. The brick are made in an iron Quaker soft mud machine operated by horse power, dried on pallets under sheds, and burned in either permanent or scove up draft kilns. The clay which occurs at this locality contains too great a percentage of sand to make a strong brick. About two or two and a half miles west of the city a yellowish brown residual or loess clay occurs, which is to all appearances much more suitable for the manufacture of brick than that which is being used. There are large quantities of this clay and I believe that better brick can be manufactured therefrom than are now being manufactured from the clay at Augusta. BARRON. pry Barron is located in the central part of Barron County on the “Soo” Railroad. The clay which is being used at Carey’s Brick Yard has a reddish brown color and does not differ materially from the ordinary glacial clay found abundantly throughout this region. The field from which the clay is now being obtained contains a great many stumps and boulders. The surface is covered with from six to eight inches of loam which is stripped. The clay has a depth of from three to four feet, underneath which oc- curs an unknown depth of sand. The clay is mixed in a vat over night, after which it is moulded in a Quaker soft mud machine operated by steam power. The brick are dried on pallets under sheds and burned in scove kilns. The color of the brick is red. An attempt is apparently made to burn all the brick hard but in so doing five or six tiers of brick above the arches are cracked and broken. The shrinkage in burning is very little on account of the high percentage of quartz sand which the clay contains. GLACIAL CLAYS. 183 BARRONETT. Barronett is situated in the northwestern part of Bar- ron County on the Chicago, St. Paul, Minneapolis and Omaha Railroad. Two brick yards are located at this place, one of which is owned by Martin Peterson and the other by Peter Larson. The clay at this place has a max- imum thickness of sixteen feet, although at the present time it is only worked to a depth of seven feet. The color of the clay is yellowish brown streaked with blue. ‘At Peter Larson’s yard the brick are manufactured in an Anderson soft mud machine, dried on pallets under sheds, and burned in permanent up draft kilns. This yard is also equipped with a dry kiln having a capacity of about 15,000 brick. It requires about six days to burn the brick, and about one-fourth of a cord of wood is consumed for each thousand brick burned. The average annual output of the yard is between 800,000 and 900,000 brick. The yard owned by Martin Peterson has an equipment very similar to that of Larson’s yard. The brick are manu- factured in a Quaker soft mud machine, dried on pallets under sheds, and burned in up draft kilns. BAY CITY. Bay City is located in the southern part of Pierce County on the Chicago, Burlington and Northern Railroad. The Bay City Brick Yard is owned and operated by Peter Miller. The clay which is used at this place is very sim- ilar to the modified residual clay which occurs in aH parts of the driftless area. The clay is obtained from a bank near the base of the bluffs along the Mississippi River. The clay contains an occasional limestone pebble and should therefore be worked very carefully. Otherwise it is of the ordinary residual type. The clay is soaked over night in a vat and mixed in a 184 THE OLAYS OF WISCONSIN. wooden pug mill. The brick are made in a hand power press, dried in hacks on the yard, and burned in scove kilns. This yard was opened in 1891 and has been operated each year since with the exception of 1895. During the last three years the average annual output of the yard has been in the neighborhood of 250,000. The brick sold in 1899 at prices ranging from $5.50 to $8.00 per M. kiln run. CHIPPEWA FALLS. Chippewa Falls is located on the Chicago, St. Paul, Min- neapolis and Omaha and Wisconsin Central railroads in the southwestern part of Chippewa County. In 1899 the only brick yard at this place was owned and operated by J. B. Theriault. This yard is located in the town of Tilden near the city limits and was opened in 1890. The bank from which the clay is obtained is situated near the base of the bluffs back from the Chippewa River and has a thickness of from four to eight feet. As in most of the clay banks of this area the clay is richest at the top, becoming more quartzose as the bottom is approached. The clay in the upper part of the bank is massive but that comprising the lower five feet is thinly laminated with streaks of white sand. The clay has a reddish brown color and burns red. The sand used in moulding is obtained underneath the clay and has a depth of about seven feet above the sandstone with which it is underlain. The clay is mixed in a pug mill. The brick are moulded in a Craycroft soft mud machine, dried on pallets under sheds, and burned in scove kilns. This yard is in excellent condition and has a very com- petent superintendent. A number of very clever devices have been constructed to save labor in the manufacture of the brick. The brick which were examined at the yard were among the best common brick which are made in this area. GLACIAL CLAYS. 185 Laboratory E.ramination—The clay was examined in the Survey laboratory. It is of medium hardness when dry and slacks readily in water breaking down into a finely pulverulent mass which has a fair degree of plasticity. Under the microscope the grains were observed to have diameters ranging from .10 mm. to .003 mm. A very small percentage of the individuals are less than .0058 mm. in diameter. The larger grains are fairly well rounded but the smaller ones have angular outlines. The clay is deeply stained with iron oxide and contains a large percentage of quartz. Kaolin constitutes a very small proportion of the mass. The chemical composition of the clay is given in table I of the Appendix. A number of years ago the French Lumber Company manufactured brick a short distance from the yard now being operated by Mr. Theriault. The brick were manu- factured in a soft mud machine, dried on pallets under sheds, and burned in scove kilns. The clay was not ex- amined but it is thought to be about the same as that oc- curring at Theriault’s yard. COLBY. Colby is located in the eastern part of Clark County on the Wisconsin Central Railroad. The only brick yard which is located at this place is owned and operated by Joseph Haslbeck. The yard is situated in the south part of the city and not far from the railroad. The clay bank has a thickness of from three to four feet. The color of the clay is blue mottled with streaks of yellow. The clay is mixed in a wooden pug mill. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. The brick have a red color and vary considerably in hardness in different parts of the kiln. The output of the yard in 1898 was about 100,000. The brick sold at the yard in 1899 for about $7.00 per M. kiln run. 1R¢ THE CLAYS OF WISCONSIN. CONOVER. Conover is located on the Chicago and Northwestern Railroad in the northeastern part of Vilas County. The plant which is located at this place is known as the Kagle River Briek Yard and is owned and operated by a com- pany of which N. A. Coleman is secretary. The bank from which the clay is obtained has a thick- ness of from five to eight feet. The upper two or three feet consists mainly of yellow sand, underneath which occurs from one and one-half to two feet of laminated red clay, two feet of grayish colored clay, and an undetermined thickness of sand. The upper surface of the clay is un- even and billowy on account of which the thickness of the bed is quite variable. The brick are manufactured in a Big Wonder auger machine, dried on pallets under sheds and in hacks on the yard, and burned in scove kilns. It requires about fourteen days to burn the brick, green wood being used for fuel. The clay burns red. This plant was erected in 1898 and has been operated each year since. During 1898 the company manufactured in the neighborhood of 300,000 brick which sold at the yard for about $8.00 per M. kiln run. DORCHESTER. Dorchester is located in the northeastern part of Clark County on the Wisconsin Central Railroad. North of this village in the northwestern part of Section 1, Town 29, Range 1 east, is a small plant which is owned and oper- ated by J. M. Fisse. The bank from which the clay is taken has a thickness of about three feet and the clay is very similar in appearance to that which occurs at Colby, with the exception that it contains many small granitic pebbles. The brick are moulded in a hand press machine, dried in hacks on the yard, and burned in scove kilns. It requires about eight days to burn the brick, and about one- third of a cord of wood is consumed for each thousand GLACIAL CLAYS. 187 brick burned. The brick have a bright red color and when properly burned they are very satisfactory. This yard was opened in 1885 and has been operated each year since that time. The average annual output is about 60,000. The brick sold in 1899 at an average of $7.00 per M. kiln run. DURAND. Durand is located on the Chippewa River in the south central part of Pepin County. The only brick yard at this place is located about one mile east of the city and is owned and operated by J. T. Dorchester. The clay which is be- ing used is hauled from the top of bluffs about half a mile south of the plant. It is a yellow sandy clay, similar to the residual limestone or loess clays previously described. The clay is mixed on a board platform adjacent to a horl- zontal Potts soft mud machine in which the brick are moulded. The brick are dried on pallets under sheds and burned in scove kilns. It requires two weeks to dry the brick and eight days to burn them. One-third of a cord of oak wood is consumed for each thousand brick burned. A shale which occurs interlaminated with the sandstone of the Potsdam formation at this place has been tested by Mr. Dorchester and is thought by him to be suitable for manufacturing fire brick. The writer has not examined the clay and no statement can be made relative to the same. EDGAR. Edgar is located in the west central part of Marathon County on the Chicago and Northwestern Railroad. Two brick yards are located at this place, one of which is owned by the Edgar Brick and Tile Company and the other by the Edgar Pressed Brick Company. The plant of the Edgar Pressed Brick Company has been operated for the last three years. The equipment is in good condition and consists of four large kiln sheds hav- ing a capacity of about two million brick, pallet sheds hav- 188 THE CLAYS OF WISCONSIN. ing a capacity of about 350,000 to 400,000 brick, three pug mills, and a Frey-Sheckler stiff mud machine. The clay occurs near the creek but could not be exam- ined at the time the yard was inspected on account of the water which filled the pits. The brick when properly burned have a cheerful red color. The plant of the Edgar Brick and Tile Company was erected in 1897. The bank from which the clay is ob- tained consists of one foot of loam which is stripped, one foot of tough grayish black clay, and one to one foot and a half of blue clay mottled with streaks of yellow iron oxide. The clay is conveyed in dump cars from the bank to the plant and tempered in a Potts wooden pug mill. The brick are moulded in a Potts soft mud machine, dried on pallets under sheds, and burned in scove kilns. It re quires about fourteen days to burn the brick and about three-fourths of a cord of wood is consumed for each thou- sand brick burned. When properly burned the brick have a pleasing red color. EDSON. Edson is a small village located in Chippewa County two and a quarter miles south of Boyd. The yard at this place has been owned and operated for five years by J. T. Somers but at the present time it is idle. The clay, which occurs in a depression in which runs a small sluggish stream, has a depth of about four feet underneath a cover- ing of one foot of sod and loam. The color of the clay is blue streaked with yellow iron oxide wherever roots of grass or trees have penetrated. The clay contains consid- erable sand as it occurs in the bank but more is added for the manufacture of brick. This clay is typical for all this region. The clay is mined with pick and shovel and hauled in carts to vats where it is soaked. The brick are made in a Quaker soft mud machine, dried on pallets under sheds and burned in scove kilns. The market for the brick which WISCONSIN GEOL. AND NAT. HIST. SURVEY. {BULLETIN NO. Vil., PL, XXXI/, Ree } \ A | PSche HI “of Keke Menomonie seas ~~ Xe — : ICD is, Brick: yore’ ® SKETCH MAP SHOWING LOCATION OF THE BRICK YARDS AT MENOMONIE. GLACIAL CLAYS. 189 are manufactured at this place is entirely local and the yard will probably not be operated until there is an in- creased demand. ELLSWORTH. Ellsworth is located in the central part of Pierce County on the Chicago, St. Paul, Minneapolis, and Omaha Rail- road. The only brick yard at this place is located about one mile and a half southwest of the city and is owned and operated hy C. I. Peterson. The yard was opened in 1887 and has been operated continuously since that time with the exception of two or three years, The clay has a thickness of from two to two and a half feet. The color is a yellowish brown, resembling very much the residual or loess clay of the driftless area. The bank is plowed and the clay weathered before being used. When used it is soaked in a vat and then pugged in a brick machine. The brick are moulded in a Quaker soft mud machine operated by horse power, dried on pallets under sheds and in hacks on the yard, and burned in scove kilns. When properly burned the brick have a bright red color. However, the sand which is used in moulding gives the brick a grayish color which may be partly due to a small percentage of calcium carbonate in the sand. The average annual output of this yard during the last three years has been about 500,000 brick. The brick were sold at the yard in 1889 for $5.00 per M. kiln run. GLENWOOD. Glenwood is located in the west central part of St. Crvix County on the Wisconsin Central Railroad. The Glenwood Brick Yard is owned and operated by Syme, Baldwin and Company. It was opened during the summer of 1900 and during that season 200,000 brick were manufactured. The clay is of a rich yellow nature and burns an excel- lent red color. The clay is mined with pick and shovel 190 THE CLAYS OF WISCONSIN. and transferred from the bank to the machine on cars. The brick are manufactured in a “Standard” sand mould machine which has a capacity of 24,000 brick per day. The brick are dried in hacks on the yard and burned in common scove kilns. This company contemplates increasing the capacity of the plant to 5,000,000 brick annually. HAMBURG. Hamburg is located in Marathon County in Section 28, Town 30, Range 5, East. The only brick yard operated at this place is owned by John A. Amen and Oompany. fhe bank from which the clay is obtained has a thickness of from two to four feet and an area of about three-fourths of an acre. The clay contains numerous granite pebbles. It is mined with picks and shovels and mixed in wooden pug mills. The brick are moulded by hand, dried on pal- lets under sheds, and- burned in scove kilns. The output of this yard in 1899 was about 200,000 brick. LOYAL. Loyal is located on the Wisconsin Central Railroad in the east central part of Clark County. The only brick yard at this place is owned and operated by C. Buhlman. The bank from which the clay is obtained consists of one foot of sod and soil which is stripped, from three to six feet of blue clay streaked with yellow, and ten feet of blue clay, underneath which is sand. The clay contains an occa- sional granite pebble which, however, does not seriously impair the value of theclay. In places at the surface there is a tough black clay which when mixed with that which occurs underneath causes the brick to crack in drying. Black clay similar to this occurs in many parts of this reg- ion and is always avoided on account of the tendency which brick made therefrom have of cracking when drying. The clay is soaked in vats and mixed in pug mills oper- ated by horse power. The brick are moulded in a hand “ALNNOO NNN ‘JINOWON3W 4O ALINIOIA 3HL NI SNOILLVNYO4 YSHLO 3HL OL SLISOd3G AV1I9 JO NOILV13Y JHL ONIMOHS NOILOSS 1V3dI NMONYNN --——————ANMONYNNI yy NMONYNN AV19 NMONXNN “TAAVE SD “QNVS ‘GNVS & 15AV4D ‘WW0O71 $S307 “ANOLSANYS “AXXX ‘Id ‘HA TON NIL3TING “ABAYNS “LSIH "LYN ONY "1039 NISNOOSIM GLACIAL CLAYS. 191 press, dried in hacks on the yard, and burned in scove kilns. The brick have a red color. It requires from ten to eleven days to burn and about one-third of a cord of wood is consumed for each thousand brick burned. This yard was opened in 1896 and has been operated each year since that time. The average annual output during the last three years has been about 250,000 brick. The brick sold at the yard in 1899 for about $5.00 per M. kiln run. The brick yard owned by the York Brick Company is located about five miles south of Loyal in Clark County. The bank from which the clay is obtained has an average thickness of two and one-half feet. The clay has a bluish color and is streaked with yellow iron oxide. After re moving the clay from the bank it is soaked in a vat over night. The brick are moulded in a soft mud machine, dried on pallets under sheds and in hacks on the yard, and burned in scove kilns. It requires from eight to nine days to burn the brick and about one-half of a cord of wood is consumed for each thousand brick burned. MARSHFIELD. Marshfield is located in the northwestern part of Wood County on the Chicago and Northwestern and Wisconsin Central Railroads. For a number of years two brick yards have been operated near this city but at the present time only the Central Wisconsin Pressed Brick Company is in operation. Lyons, Reese, and Lyons are the proprietors of this company, T. F. Lyons is secretary and J. D. Pratt is superintendent. The bank from which the clay is obtained is about three hundred feet from the machine and consists of six inches of black tough clay at the surface, six to eight inches of quick sand, two to two and a half feet of greenish gray clay, two to four feet of blue clay streaked with yellow, six inches of gravel, and forty feet of blue clay. When the works were examined in 1899 from six to seven feet of the 192 THE CLAYS OF WISCONSIN. clay down to the gravel bed was being worked. The blue clay below the gravel bed contains streaks of red iron oxide in sufficient quantity to give the brick when burned a deep red color. : 4 The clay is conveyed to the factory on cars operated by rope and winding drum and mixed in the machine. The brick are manufactured in a Quaker soft mud machine, dried on pallets under sheds,and burned in scove kilns. It requires about nine days to burn the brick and about one- third of a cord of wood is consumed for each thousand brick burned. This yard was opened in 1887 and has been operated each year since that time. The present company, however, have had control only since 1899. During the four years prior to 1900 the output of the yard was in the neighborhood of 500,000 brick per year. In 1900 the output reached one million and a, half. With the exception of the clay occurring at three or four other localities the Marshfield clay differs very materially from that which is worked in other parts of this area. Laboratory Examination—Three samples of the clay from different parts of the bank were examined in the lab- oratory. Each slacked rapidly breaking down into very fine granular masses which were uniform in texture and moderately plastic. When mixed with water the three samples had very few macroscopic characteristics to dis- tinguish them apart. Under the microscope they also appear very much the same. The largest grains observed were about .11 mm. in diameter. A greater part of the clay consists of grains which have diameters of less than .012 mm. in diameter. One of the samples is composed of grains which average less. A small percentage of the clay consists of grains -001 mm. and less in diameter. The grains are mainly sub- angular in outline, only a few of the larger ones being well rounded. Quartz is the principal constituent. Iron oxide and WISCONSIN GEOL. AND NAT. HIST. SURVEY. BULLETIN NO. Vil., PL. XXXVI, 2 THE WISCONSIN RED PRESSED BRICK CO., MENOMONIE. VIEWS OF CLAY BANK. GLACIAL CLAYS. 193 kaolin occur in lesser amounts, while an occasional grain of calcite can be recognized. The chemical composition of the clay is given in table I of the Appendix, to which the reader is referred. From the composition there given and the evidence derived from the physical examinations as thus far conducted, I believe that it is worth while to con- sider this clay for the manufacture of clay wares other than brick. MEDFORD. Medford is located on the Wisconsin Central Railroad in the southeastern part of Taylor County. The only brick yard in this vicinity is located about three and a quarter miles north of the city. It is owned and operated by Otto Fischer. The plant was erected in 1897 and has been operated each year since that time. The clay has a thickness of thirteen or fourteen feet but only the upper three feet is now being used. The clay which occurs deeper in the bank contains a less percentage of quartz and consequently the brick made therefrom dry more slowly than those made from the surface clay. The clay is soaked in a vat over night and mixed in a pur mill operated by horse power. The brick are moulded in a hand press, dried in hacks on the yard, and burned in scove kilns. During the last three years the average annual output has been 250,000. The brick were sold in 1899 for $6.00 per M. kiln run at the yard. MENOMONIE. Menomonie is located in the central part of Dunn County on the Chicago and Northwestern and Chicago, Milwaukee, and St. Paul Railroads. Since brick making began at this place at least five different plants have been in operation. At the present time, however, these yards are all controlled by two companies, known as the Me- 13 194 THE CLAYS OF WISCONSIN. nomonie Hydraulic Pressed Brick Company and the Wis- eonsin Red Pressed Brick Company. The Wisconsin Red Pressed Brick Company own and operate a single yard located directly west of the city and on the west side of the Red Cedar River. The Menominie Hydraulic Pressed Brick Company own four yards, only three of which are being operated at the present time. An- other yard known as the Standard was abandoned several years ago on account of a scarcity of clay and it is prac- tically of no value at the present time. The plant of the Wisconsin ‘Red Pressed Brick Com- pany is owned by a Minneapolis Company, and operated by NV. M. Sargent and I. M. Phillips, the latter of which is the superintendent of the yard. This yard was opened in 1885 and has been operated each year since that time. At present the brick are all manufactured by the soft mud process, although an attempt was made several years ago to use a dry press machine. The bank from which the clay is obtained has a stripping of five to eight feet of sand and gravel, underneath which occurs a thickness of thirty-six feet of clay, and an un- known depth of sand. The clay occurs in layers which are from one to twelve inches in thickness. Hach layer is separated from the one above and below by thin laminae of sand. The thickness of these laminae increases as the bottom of the bank is approached until the bank becomes mainly sand. The bank is divided according to the color of the clay into two parts. The part comprising the upper two feet and a half of the bank contains layers of clay which have a deep red color and is known as the red clay. The re mainder of the bank contains very few red layers and is known as the blue clay. A close inspection of the different layers in the lower part of the bank shows that they are mainly blue, green, and yellow, with only an occasional red colored laminae. The red and blue portions of the bank, as well as the blue clay and sand layers underneath gradu- WISCONSIN GEOL. AND NAT. HIST. SURVEY, BULLETIN NO, VII, PL. XXXVIL WISCONSIN RED PRESSED BRICK CO., MENOMONIE. NEAR VIEWS OF CLAY BANK SHOWING JOINTING PLANES. GLACIAL CLAYS. 195 ally grade into one another. The bank is traversed by dis- tinct sets of joints on account of which the clay breaks away from the bank in large polygonal blocks. The clay bank is worked by digging a trench back from the face of the bank and filling it with water. The water loosens the blocks and they fall in a heap at the foot of the bank. The clay is conveyed from the bank to the mill on cars operated by cable and winding drum. The clay is mixed and tempered by passing it through three pug mills. The brick are made in a Monarch soft mud machine, dried on pallets under sheds, and burned in permanent up draft kilns. It requires about one hundred car loads of clay to make 50,000 brick. The capacity of the pallet sheds is about 500,000 and that of the kilns something over one million. The average annual output of the yard during the last three years has been in the neighborhood of five million brick. The average price of the brick in 1899 was $4.00 per M. kiln run at the yard. For a number of years Mr. Phillips has been considering the manufacture of paving brick out of this clay. The brick about the arches of the kilns are frequently well vitrified, making excellent brick for sidewalk purposes. This, combined with the fact that similar clay from a neighboring yard has been tested for the manufacture of paving brick and reported to be suitable, has led to the be- lief that paving brick can be successfully manufactured. There is no doubt that the brick can be vitrified but the most important point which has not yet been settled, is: whether an entire kiln of brick can be thoroughly vitrified without excessive loss. Until the laboratory tests with this clay have been completed nothing positive can be said concerning this point. Laboratory Examination.—The samples of clay exam- ined in the laboratory were soft both in the wet and dry state. All of the samples slacked very readily in water, 196 THE CLAYS OF WISCONSIN. : breaking down into flakes and fine grains, forming a mod- erately plastic mass. Under the microscope the clay was seen to consist of grains not exceeding .014 of a mm. in diameter and rang- ing from this down to less than .001 mm. The top clay consists of grains which were on an average about .003 mm. in diameter. The other two samples examined con- sist mainly of individuals ranging in size from .0058 to .003 mm. in diameter. With the exception of the largest grains the individuals are very irregular in outline and unequi-dimensional in size. Quartz isan abundant constituent of the clay. The quantity of iron oxide which occurs as a staining agent is comparatively small except in the red colored layers. The green colored layers contain a chloritic mineral which im- parts to the clay the distinguishing green or bluish color. The thin sandy seams which separate the layers of clay consist of grains which are uniformly much larger than those of the clay layers. Numerous measurements show that the large grains of quartz in this layer have a di- ameter of from .33 to .20 mm. The chemical composition of this clay is given in table I of the Appendix. The Menomonie Hydraulic Pressed Brick Company own four of the brick plants situated in the vicinity of Menom- onie. These plants were formerly known as the Northern Hydraulic Pressed Brick Co., two yards, known as No. 1 and 2; the Menomonie Pressed Brick Yard, now known as No. 3; and the J. K. Caldwell Brick Yard, known as No. 4. At the present time the yards numbered 1, 2 and 3 are the only ones which are operated. At the No. 3 yard only soft mud brick are manufactured. At the No. 1 and 2 yards both soft mud and dry press brick are made. The clay bank which occurs at the yard formerly owned by the Menomonie Pressed Brick Company has a depth of from nine to eleven feet. The upper portion of the bank is moderately rich but the lower four or five feet is very GLACIAL CLAYS. 197 sandy. The clay has a yellowish brown color and is thinly laminated. It is conveyed from the bank to the mill on dump cars operated by steam power and cable. The brick are manufactured in two Eagle soft mud machines, having a capacity of 50 M. each per day, dried on pallets under sheds, and burned in permanent up draft kilns. At the No. 1 and 2 yards one bank of clay is worked. The clay used for manufacturing dry pressed brick is ob- tained from a bank having a thickness of from seven to eight feet. The clay has a yellowish brown color and re- sembles the residual clay which is found abundantly throughout the driftless area. The clay is plowed and weathered before being hauled under the sheds. As the clay dries at the surface it is collected with wheeled ex- cavators and conveyed under sheds. For the manufacture of some mottled brick, clay has been obtained from other points. The brick are manufactured in hydraulic ma- chines and burned in kilns designed and constructed by the company owning the yard. When taken from the kiln the red dry press brick are carefully sorted into ten different shades so that one can readily obtain any desired quantity of brick, all of which will have the same tint. The company also manufacture 410 special shapes of brick of almost every staple design. The reddish brown clay which is used in the manufact- ure of the dry press brick occurs at a higher level than the laminated clay and has a very limited areal extent in this region. It covers the upper portion of the sandstone knolls and is more distant from the river than the lamin- ated deposits. The No. 2 yard is equipped with a Henry Martin soft mud machine and pallet sheds which are used for the manufacture of veneering brick. Laminated clay similar to that mined at the other yards is used for this purpose. The capacity of the pallet sheds on No. 2 and 3 yards is in the neighborhood of 1,800,000, and the kiln capacity is about 3,800,000. The average annual output of the 198 THE CLAYS OF WISCONSIN. three yards is in the neighborhood of 12,000,000 veneering brick and 5,000,000 pressed brick. Common brick sold in 1899 at an average of about $4.50 per M. kiln run. Veneer- ing, sand moulded brick sold at an average of about $9.00 per M. Pressed brick sold at an average of about $14.00 per M. The clay which occurs at the Caldwell yard, which has been lately acquired by the Menomonie Hydraulic Pressed Brick Company, is thinly laminated and appears very similar to that which is being worked by the Wisconsin Red Pressed Brick Company. The layers are interlam- inated with very thin laminae of comparatively coarse sand. The upper portion has a general reddish brown color while the lower is a bluish green. The layers are from one-sixteenth of an inch to several inches in thick- ness. The clay has a maximum thickness of twenty-two feet below which occurs an unknown depth of sand. At the place examined the bank was exposed to a depth of about thirteen feet. The clay in this vicinity is essentially free from gravel. Occasionally a granite or greenstone pebble is met with but there is no evidence of limestone. Extensive deposits of clay similar to, although not iden- tical with, that which occurs at the Caldwell and Wiscon- sin Red Pressed Brick Company’s yards are found at sev- eral places along the tributaries of the-Red Cedar River. The clay is of alluvial origin having been derived from the disintegrated igneous rocks to the north and northwest. They are essentially non-caleareous and are among the best brick making clays occurring in the area under dis- cussion. MERRILL. Merrill is located in the southeastern part of Lincoln ‘County on the Chicago, Milwaukee and St. Paul Railroad. ‘Two brick yards are operated at this place, one of which is owned by Herman Boetcher and the other by August GLACIAL CLAYS. 199 Meyer. The clay which occurs at these yards has an average thickness of about three feet. About one foot of black loam is stripped from the surface underneath which occurs two to two and a half feet of yellowish brown clay. In some places the clay contains small pockets of granite gravel. The brick made at both yards are known as “slop” brick. The yard owned by Herman Boetcher was opened in 1876. The clay is soaked in a vat and mixed in a wooden pug mill operated by horse power. The brick are moulded by hand, dried on pallets under sheds, and burned in scove kilns. The average annual output is about 275,000 com- mon red brick. The brick sold on the market in 1899 for $5.25 per M. kiln run. The brick yard owned and operated by August Meyer is located across the road from Boetcher’s yard. The clay is soaked in a vat and mixed in a wooden pug mill. The brick are made by hand, dried on pallets under sheds, and burned in scove kilns. It requires from eight to nine days to burn the brick and about one-half cord of wood is consumed for each thousand brick burned. MERRILLAN. Merrillan is located in the north central part of Jackson County at the junction of the Chicago, St. Paul, Minneap- olis, and Omaha and Green Bay and Western Railroads. Only one brick yard has been located at this place and this has not been operated for several years. The yard is situ- ated about two and a half miles north of the city and is owned by Frank Robertson. The clay occurs on low land adjacent to a small stream and has a thickness of from three to four feet. It is prob- ably of alluvial origin. The clay is fine grained, smooth, and moderately plastic. The clay has a yellowish blue color and resembles in all respects the ordinary glacial clay which occurs throughout this region. 200 THE CLAYS OF WISCONSIN. The clay is soaked in vats and mixed in wooden pug mills operated by horse power. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. The yard was opened in 1889 and was operated each year until 1898, since which time it has been idle. MILLTOWN. Milltown is located near the north central part of Polk County and some distance from any railroad. The only brick yard in this vicinity is owned and operated by Lud Peterson. The clay bank which is being worked has a thickness of about fifteen feet. It consists of a stripping of three to four feet of sand and gravel and from ten to twelve feet of laminated reddish brown clay. The clay is mixed in a pug mill and the brick are manufactured in a machine which was made by the owner of the yard. The brick are dried on pallets under a shed and in hacks on the yard and burned in scove kilns. It requires from eight to nine days to burn the brick. This yard was opened in 1897 and has been operated each year since that time. During the last three years the average annual output has been in the neighborhood of 60,000 brick. NEILLSVILLE. Neillsville is located in the south central part of Clark County on the Chicago and Northwestern Railway. A. W. Schoengard owns and operates the only brick yard in this vicinity. The clay which is mined has a depth of six to eight feet and a general yellowish blue color. It is soaked in a vat over night and mixed in a wooden pug mill which is operated by horse power. The brick are made in a Quaker soft mud machine, dried on pallets under sheds, and burned in scove kilns. It requires about nine days to burn the brick, and about one-half of a cord of wood is consumed for each thousand brick burned. The color of the brick is red. GLACIAL CLAYS. 201 This yard was opened in 1884 and has been operated each year since that time. The average annual output during the last three years has been about 300,000. The brick sold in 1899 at an average of $5.00 per M. kiln run at the yard. OSCEOLA. Osceola is located in the western part of St. Croix county on the “Soo” railroad. The only brick yard at this place is located eight miles south of the city and is owned and operated by Charles Englehart. The yard was opened in 1890 and has been operated each year since that time with the exception of 1891 and 1895. The clay has a thickness of eighteen to twenty feet. The upper two to four feet is much richer than the sixteen feet which occurs below. The lower portion of the bank con- tains a large percentage of sand and numerous small, granite pebbles. The brick are made in a Quaker soft mud machine, dried in hacks on the yard, and burned in scove kilns. It requires about seven and a half days to burn the brick and about one-third of a cord of wood is consumed in burning each thousand brick. During the last three years the average annual output has been 50,000 brick. The brick sold at the yard in 1899 for $6.00 per M. kiln run. NEW RICHMOND. New Richmond is located in the eastern part of St. Croix county. The only brick vard at this place is situated one and a half miles west of the city. This yard has been owned and operated by E, Brevold for sixteen years. The clay which is mined is covered with a foot of black loam and has a thickness of from four to fourteen feet. It has a general blue color, streaked and mottled with yellow. The clay is taken from the bank and weathered for a week or two after which it is soaked over night in a vat. The clay is removed from the vat and tempered in a pug mill 202 THE CLAYS OF WISCONSIN. operated by horse power. The brick are moulded in an “Old reliable” hand press machine, dried in hacks on the. yard, and burned in scove kilns. The brick are strong and of good quality when properly burned, although some- what irregular in shape owing to the method of manufac- ture. PLUM CITY. Plum City is located in the southeastern part of Pierce county nine miles from the nearest railroad. The brick plant at this place is owned and operated by Nicholas Oberding. The yard was opened in 1884 and has been operated each year since with the exception of 1899 and 1891. The bank from which the clay is obtained has a total thickness of six and a half feet. A stripping of a foot and a half of black loam and soil occurs at the top, underneath which is a thickness of five feet of clay. The deposit is near Plum creek and is probably of alluvial origin. The brick are moulded by hand, dried on pallets under sheds, and burned in scove kilns. The brick have an excellent red color although the white sand used in moulding im- parts a grayish tint to the surface. The average annual output of this yard during the last three years has been in the neighborhood of 100,000 brick. The market for the brick is entirely local. In 1899 they sold at prices ranging from $7.00 to $8.00 per M. kiln run at the yard. RICE LAKE. Rice Lake is located on the Chicago, St. Paul, Minne- apolis and Omaha railroad in the north central part of Bar- ron county. The only brick yard at this place is situated about a mile north of the city and is owned by Mr. Skilper. It was operated in 1899 by J. Mitchell. The clay has a depth of from one to five feet and is covered at the surface with a foot of black loam. The brick are manufactured in Missing Page GLACIAL CLAYS. 203 a Quaker soft mud machine, dried on pallets under sheds, and burned in scove kilns. The color of the brick is red. RIVER FALLS. River Falls is located in the western part of Pierce county, on the Chicago, St. Paul, Minneapolis, and Omaha railroad. The only brick yard at this place is located one mile south of the city and is owned and operated by George H. Smith. The clay bank is said to have a total thickness of thirty-six feet of which ten feet is yellow clay and twenty-six feet blue clay. The portion of the bank which was open at the time the yard was inspected exposed a thickness of from six to eight feet of yellowish blue clay. The deposit appears to be of alluvial origin. Sand is added to the clay which occurs in the upper por- tion of the bank and the whole is mixed together in a pug mill. The brick are made in a Quaker soft mud machine, dried on pallets under sheds, and burned in an up draft permanent kiln. This yard was opened in 1896 and has been operated each year since that time. The average annual output during the last three years has been from 400,000 to 800,000. The brick sold in 1899 for $6.00 per M. kiln run at the yard. The clay which occurs at this place is better than the average clay of this region. The brick if properly burned ought to have a cheerful red color and be sufficiently strong for all ordinary building purposes. The chemical compo- sition of the clav from this bank is given in table I of the Appendix. ST. CROIX FALLS. St Croix Falls is located in the western part of Polk county on the “Soo” railroad. The only brick yard at this place is situated about two and one-half miles east of the city and is owned and operated by August Dombrook. The clay has a thickness of about six or seven feet. It is laminated, has a brown color, and is richest near the top 204 THE CLAYS OF WISCONSIN. of the bank. The clay is soaked in a vat over night, and then passed through a pug mill. The brick are moulded in a foot press, dried in hacks on the yard, and burned in scove kilns. The average annual output of the yard dur- ing the last three years has been about 100,000. The price of the brick at the yard averaged $7.00 per M. kiln run in 1899. SCHULTZ SIDING. Schultz Siding is located in Lincoln county about eight miles north of Merrill. The brick plant located at this place is owned and operated by J. H. Schultz. It was opened in 1899 and has been operated each year since that time. The clay bank is four feet deep and consists of a stripping of one foot of loam and sod, one foot of heavy grayish blue clay, and two feet of yellow clay which passes gradually into sand below. The brick are manufactured by hand, dried on pallets under sheds, and burned in per- manent up draft kilns. During the last three years the average annual output of the yard has been 125,000. The average price of the brick in 1899 was $5.00 per M. kiln run. SPENCER. Spencer is located in the southwestern part of Marathon county on the Wisconsin Central railroad. Two yards are located in the vicinity of this village, one of which is owned by Charles Stoltenow nd the other by William Baedeker. The Stoltenow Brick Yard is situated at the west end of the village. The clay has a working depth of about five feet, is of a yellowish blue color and burns red. A blue clay which also burns red occurs a short distance north of the plant. The clay is mined with a pick and shovel and soaked in a vat over night. The brick are moulded in a soft mud machine, dried in hacks on the yard, and burned in scove kilns. This yard was opened in 1887 and has been operated each year since that time. The average annual *S33AO01dW3 ONIMOHS AUOLOWS 30 M3IA HW3N “IMVHVINOL ‘quya Wold AMVHVIOL SHL *XIXXX "Td ‘HA ‘ON NILZTING “ABAUNS “LSIH ‘LYN GNV “1039 NISNOOSIM GLACIAL CLAYS. 205 output during the last three years has been about 200,000 brick. The market price in 1899 was $6.00 per M. kiln run. The plant owned by William Baedeker is located about three miles north of Spencer and is close to the Wisconsin Central railroad. The clay is very similar to that which occurs at Stoltenow’s yard. The brick are moulded by hand, dried in hacks on the yard, and burned in scove kilns. The color of the brick is red. This yard was opened in 1898 and the output during that year was 150,000. TOMAHAWK. Tomahawk is located in the north central part of Lin- coln county on the Wisconsin river. The works of the Tomahawk Brick Manufacturing Company are located in the eastern part of the city. The clay which is being used occurs eight miles distant and is hauled to the plant on the Marinette, Tomahawk, and Western railroad. The brick plant and clay banks are owned by W. H. Bradley. W. E. Jeannot is superintendent. The bank from which the clay is obtained occurs adjacent to the railroad and con- sists of about twelve feet of clay interstratified with lay- ers of coarse sand which contains an occasional pebble of igneous rock. As far as could be ascertained no limestone occurs in this vicinity. The bank is streaked or laminated with thin red layers of clay although the greater part of the clay has a general pinkish gray color. The clay ap- pears to be somewhat arenaceous in character. It is not very well exposed in the bank but according to borings made in this vicinity there is an unlimited quantity close to the railroad. The clay is either mixed with sand or used as it comes from the bank depending upon its richness. The brick are manufactured in a Brewer Auger machine. The clay is so thoroughly mixed and tempered that there is no evi- dence of lamination in the brick when dried. The machine is equipped with a side cut off and the brick manufactured 206 THE CLAYS OF WISCONSIN. have an excellent appearance. The brick are handled twice in hacking but the fingers are not allowed to touch the faces or ends of the brick. The yard is to be equipped in the near future with a Ray- mond re-press and permanent kilns for burning the brick. The machinery is run with a stationary engine. At present the brick are dried in hacks on the yard and burned in scove kilns. This yard was opened during the summer of 1900 but up to the present time only 200,000 brick have been burned. The color of the brick is red. TRAMWAY. Tramway is located near the central part of Dunn county on the Chicago, St. Paul, Minneapolis, and Omaha rail- road. Until 1898 two brick yards have been operated at this place, one of which was erected by the East Tramway Brick Company and the other by the St. Paul Brick and Tile Company. The property of the latter company has been purchased by the Menomonie Hydraulic Pressed Brick Company and the machinery removed. The East Tramway Brick Yard, which is owned by Mrs. 8. J. Kirkland, is the only one being operated at the present time. This yard was opened in 1884 and has been operated eleven or twelve years since that time. The bank from which the clay is obtained has a thickness of about twenty- six feet, and consists of from three to four feet of coarse sand at the surface, six feet of sandy clay, two to two and a half feet of banded red clay, six to eight inches of blue clay, and thirteen feet of reddish blue clay. Underneath the clay occurs an unknown depth of sand. The red color of the clay in the upper portion of the bank is due to the oxidation of chloritic minerals similar to those which oc- cur in the layers below. The clay in this bank is very sim- ilar to that which is being worked by the Wisconsin Red Pressed Brick Company at Menomonie. The clay occurs in thin layers which are separated from one another by “OWVA 3HL NO SNOVH NI ONIAUG NONE ONY O3HS NTN “MMVHVWOL ‘OYVA HONS YMVHVWOL 3HL “Vd SHA CON NILZTING *AZAUNS ‘1SIH “14N ONY “1039 NIBNOOSIM GLACIAL CLAYS. 207 thin laminae of sand. The bank is intercepted by numer- ous jointing planes which break the clay into large poly- gonal blocks. Ripple marks were observed between the beds of clay. The brick are made in an Anderson Chief soft mud machine, dried in a compartment steam drier and on pallets under sheds, and burned in scove kilns. The brick made at this yard do not differ materially from the sand moulded brick made at Menomonie. When well burned they have a deep red color. However, the white sand which is used for moulding imparts a grayish tint to the exterior of the brick. During the last three years the average annual output of this yard has been about three million brick. The brick sold in 1899 at an average of $4.25 per M. kiln run. Laboratory E.ramination—The Tramway clay was ex- amined in the laboratory of the Survey and found to re- semble very closely that used by the Wisconsin Red Pressed Brick Company at Menomonie. It is rather soft and crumbly when dry and smooth and moderately plastic when wet. The clay slacks very readily breaking down into a fine granular or scaly mass. The red clay from the top of the bank consists of grains that have average diameters of about .012 mm. The larg- est grains observed were .057 mm. in diameter. Only a small percentage of the grains are under .003 mm. in di- ameter. Quartz is the predominant constitutent in this sample. Many of the grains are somewhat rounded in out- line although some are angular and unequi-dimensional in size. The bottom red clay is finer grained than the preceding, the largest individuals measuring about .64 mm. in diam- eter. The average grains are perhaps .0058 mm. in diam- eter. Many of the grains have angular outlines although some are fairly well rounded. Quartz is an abundant con- stitutent and the mass is well stained with iron oxide. The blue clay contains many grains which are from .1 to -2 mm. in diameter. They have angular outlines and are 208 THE CLAYS OF WISCONSIN. unequi-dimensional in size. The grains will probably av- erage about .014 mm. in diameter. About one-eighth of the mass consists of grains that are less than .0058 mm. in diameter. Quartz is an abundant constituent. The faint green color which the clay exhibits is thought to be largely due to chlorite. WAUSAU. Wausau is located in the central part of Marathon county on the Chicago & Northwestern and the Chicago, Milwaukee & St. Paul railroads. Five brick yards are lo- cated at this place which are owned respectively by Frank Doetschal, F. W. Garske, August Goebel, Henry Goebel, and Henry Rehlitz. F. W. Garske’s plant is located about two miles north- west of the city. One of the banks from which the clay is obtained has a thickness of three to three and a half feet. The color of the clay is reddish brown and is mixed with de- composed granite. The other clay bank has a depth of three feet and consists of one foot of heavy black clay and two feet of blue clay. The best brick are made by mixing the clays and weathering them over winter on the yard. The clay is mixed in a pug mill operated by horse power. The brick are made by hand, dried on pallets under sheds, and burned in a permanent up draft kiln. This yard was opened in 1874, and has been operated each year since that time. The average annual output during the last three years has been about 250,000. The average price of the brick in 1899 was $7.00 per M. kiln run. The yard owned by Frank Doetschal is located about three and one-half miles northwest of Wausau on the Mer- rill road. The bank from which the clay is taken has a thickness of five to six feet, consisting of one foot of black tough clay and four to five feet of blue clay variegated with streaks of yellow. The clay is soaked in a vat over night and mixed in wooden pug mills. The brick are GLACIAL CLAYS. 209 moulded by hand, dried on pallets under sheds, and burned in a permanent up draft kiln. This yard was opened in 1899 and during that year about 35,000 brick were made. The brick sold for $7.00 per M. kiln run at the yard. The yard owned by August Goebel is about two and one- half miles northwest of Wausau. The clay bank has a thickness of from two to four feet and the clay is essentially the same as that occurring at the previously described yards. The clay bank has a thickness of from two to four feet and the clay is essentially the same as that occurring at the previously described yards. The clay is soaked in a vat over night and afterwards mixed in a wooden pug mill operated by horse power. The brick are moulded by hand, dried on pallets under sheds, and burned in permanent up draft kilns. This yard was opened in 1895 and has been operated each year since that time. The output during the last three years has averaged about 250,000. The brick sold in 1899 at the yard for about $5.50 per M. kiln run. The brick plant owned by Henry Goebel is not far from that operated by August Goebel. The clay bank has a thickness of from two to three feet and is very similar to that which occurs at the previously described yards. The clay is soaked from one to three days in a vat and then mixed in pug mills operated by horse power. The brick are moulded by hand, dried on pallets under sheds, and burned in permanent up draft kilns. This yard was opened in 1893 and has been operated each year since that time. The average annual output of the yard daring the last three years has been about 200,000. The yard owned by Henry Rehlitz is located a little southeast of the city. The clay bank consists of a strip- ping of soil and sod at the top, four feet of yellowish blue clay, and three feet of blue clay stained with yellow spots. The clay is soaked in vats over night and afterward mixed 14 210 THE CLAYS OF WISCONSIN. in a pug mill. The brick are moulded by hand, dried on pallets under sheds, and burned in permanent up draft kilns. The output of this yard in 1899 was 300,000. The brick sold in 1899 for $6.50 per M. kiln run. All of the clay which occurs at the different Wausau brick yards is essentially the same. It differs mainly in the percentage of loam and sand. The brick are manufactured in practically the same way. They are made by hand, dried on pallets under sheds, and burned in permanent kilns. The pallets which are used are frequently single boards without cleats. Such pallets have a tendency to warp and in drying the brick are distorted thereby. WITHEE. Withee is located in the north central part of Clark county on the Wisconsin Central railroad. The only brick yard at this place is situated about one mile east of the vil- lage and is owned and operated by P. K. Peterson. It was opened in 1893 and has been operated each year since that time. The clay bank has a thickness of about two feet. The clay has a yellowish blue color and contains occasional small granite pebbles. Underneath the yellow clay there is a considerable depth of blue clay which can not be worked on account of the quantity of gravel and boulders which it contains. The clay is soaked in a vat for half a day and then mixed with a tempering wheel. The brick are mouiued by hand, dried in hacks on the yard, and burned in scove kilns. The average output of this yard during the last three years has been about 80,000. The brick sold in 1899 for about $5.00 per M. kiln run. WHITTLESEY. Whittlesey is located in the northeastern part of Taylor county on the Wisconsin Central railroad. The plant which is located at this place is owned and operated by the GLACIAL CLAYS. 2it Langenberg Brick Company of which George Langenberg is superintendent. The clay bank has a thickness of from ten to twelve feet. The clay occurs in thin layers having a reddish brown color and is practically uniform throughout the bank. The clay is very similar to that which is worked at Menomonie but appears to contain somewhat less sand. The company owns about forty acres of land which is prac- tically covered with clay to a depth of twenty-five feet. The clay is transferred from the bank to the plant on dump cars by means of a cable and winding drum. The brick are moulded in a Wellington soft mud machine, dried on pallets under sheds, and burned in permanent up draft kilns. It requires from nine to eleven days to burn the brick. The color of the brick when properly burned is red. The yard was opened in 1898 and during that year 200,000 brick were manufactured. The brick sold in 1899 for $7.00 per M. kiln run, on board cars. Laboratory E.ramination.—In the laboratory this clay was found to be comparatively soft when dry and mod- erately plastic when wet. It slacks quickly in water breaking down into a reddish brown scaly mass. Under the microscope the grains were observed to range in size from .1 to .001 mm. and less in diameter. The average size is perhaps about .003 mm. The large individuals are better rounded than the smaller ones. Quartz is a very abundant constituent and iron oxide serves to color the entire mass a reddish brown. Numerous: thin, translucent flakes which were observed in the clay were taken to be kaolin. Some feldspar was also observed. The chemical composition of the clay both at the top and bottom of the bank is given in table I of the Appendix. The analyses there recorded show that the clay is es- sentially the same at the top and bottom of the bank. A comparison with the analyses of clays from Menomonie 212 THE CLAYS OF WISCONSIN. and Marshfield shows that this clay is a trifle higher in aluminum and lower in the percentage of calcium, mag- nesium, potassium, and sodium. This is one of the best common clays that has come under my observation. THE HUDSON RIVER SHALE. 213 CHAPTER XI. THE HUDSON RIVER SHALE. This formation, which extends in a narrow belt through the eastern part of the state, limited above by the Niagara limestone and below by the Trenton, consists of a very cal- careous shale interlaminated with occasional beds of lime- stone. Outcrops of this shale occur at intervals through- out the entire area from the southern boundary of the state to Green Bay. The shale weathers very rapidly and breaks down into a coarsely pulverulent mass which can easily be reduced sufficiently fine for the manufacture of brick. This is practically the only shale of any consequence oc- curring among the Silurian rocks of Wisconsin. The only rocks that can be in any way compared with these are the shaly lavers of the lower portion of the Potsdam sandstone and the decomposed beds of pre: Cambrian schists which oc- cur along the border of the northern crystalline area. To some people it is a matter of surprise that this forma- tion is not used more largely in the manufacture of brick. Some even have gone so far as to prophesy that the shale of which this formation is largely composed would eventually be used for the manufacture of paving brick. However, the high percentage of calcium carbonate which it contains renders it altogether unsuitable for the latter purpose. For the manufacture of common brick it is quite satisfac- tory although the percentage of calcite and dolomite is somewhat higher than in the lacustrine clays of the east- 214 THE CLAYS OF WISCONSIN. ern and southern parts of the state. It is important when using this shale that it should be weathered for at least one season before being used. It must also be ground in a dry pan before it is suitable for tempering. In many localities the lacustrine clays are equally as valuable for the manufacture of common brick and have the advantage of not requiring to be weathered or ground before being used. The principal advantage in using this shale lies in the fact that it is free from limestone or other gravel and there is little or no danger of the brick or tile bursting from slacking of the limestone after the brick are burned. At the present time only two brick yards are using this shale for the manufacture of brick. One of these is oper- ated by Frenzel Brothers at Oakfield, and the other is owned and operated by the Cook and Brown Lime Com- pany at Stockbridge. OAKFIELD. Oakfield is located in the south central part of Fond du Lac county on the Chicago & Northwestern railroad. The only plant in operation at this. place is situated about one mile north of the village and is known as the Frenzel Brick and Tile Yard. This is one of two plants which are using the Hudson River shale for the manufacture of brick and tile. The shale in the upper part of the bank has a yellowish color while that below is blue. The blue clay is hard and resembles slate when fresh but upon ex- posure to the atmosphere it breaks down into an irregular granular mass. After the clay has been weathered it takes on a grayish color and shows occasional streaks of yellow iron oxide mainly along the jointing planes. The clay is passed through a crusher and conveyed by means of an elevator to a vat where it is soaked. The brick and drain tile are made in an Adrian stiff mud ma- chine equipped with a side cut-off. The brick are dried on THE HUDSON RIVER SHALE. 215 pallets under sheds and in hacks on the yard and burned in permanent up draft kilns. The brick have a white or cream color with the exception of such as are underburned. The plant is supplied with both water and steam power. This yard was opened in 1895 and has been operated each year since that time. The average annual output of brick during the last three years has been about 250,000. In 1898, $500.00 worth of tile were sold. Laboratory Examination.—The shale which occurs at this place was examined in the laboratory of the Survey. It slacks quite readily breaking down into thin concentric scales which are easily reduced to a powder when pressed between the fingers. The clay is hard when dry and soft and plastic when wet. Under the microscope the clay was found to consist of grains of two sizes. The large grains vary from .1 to .041 mm. in diameter and the small ones from .01 mm. down. The large grains are rhombic in shape and have much the appearance of calcite or dolomite. The shale contains a small percentage of recognizable quartz and kaolin. It is a noteworthy fact that the brick which are burned out of this clay are larger after burning than before. This is owing to the expansion which takes place as a result of the calcite being transformed into the oxide and from that into the hydroxide. STOCKBRIDGE. Stockbridge is located in the west central part of Calu- met county near Lake Winnebago. The Cook and Brown Lime Company own and operate a brick and tile plant at this place and use the Hudson River shale. It has essen- tially the same characteristics here as it has at Oakfeld. The clay is distinctly bedded and possesses several sets of joints which break the rock into various sized polygonal blocks. The following is the succession of beds as they oc- cur at this place, beginning at the top: 216 THE OLAYS OF WISCONSIN. 6 to 8 ft. of yellowish clay, mixed with pebbles and lime stone, all of which should be stripped. 10 ft. of shale. Does not stand much heat. 3 layers of limestone. 3.ft. of shale. Shrinks more than other shale beds and is used mainly in the manufacture of tile. 1 1-2 ft. of limestone. 15 ft. of shale. Shrinks very little in burning. This plant is equipped with four machines, an Andrews Dry press, a Wellington soft mud machine, and two stiff mud brick and tile machines, an intermediate Wonder and a 9-A Brewer. The clay is weathered before using. For the manufacture of soft mud brick the shale is ground be- fore being transferred to the machine. For the manu- facture of tile the clay is ordinarily screened after being ground. The brick and tile are dried in a Wolff drier which has a capacity of about 30,000 per day. The tile are burned in a Eudaly down draft kiln and the brick are burned in permanent up draft kilns. About one-third of a cord of wood is consumed for each thousand brick burned. The brick have a straw yellow color but owing to the sand used in moulding they are usually finely speckled. The brick do not melt around the arches and give evidence of standing a moderate heat. SS J FT _ NS os = ox aa S74 CYR MN. Vai | Ts | THE PRE-CAMBRIAN SHALES. 217 CHAPTER Xil. THE KAOLINIC SCHISTS OR SHALES OF THE PRE-CAMBRIAN ROCKS. Whenever the rivers cut through the sandstone forma- tion near its contact with the pre-Cambrian rocks the lat- ter are frequently very much altered or decomposed to a depth of from ten to forty feet. Immediately at the con- tact, the schists which compose the pre-Cambrian rocks at many places are frequently almost completely kaolinized resulting in a clay which is nearly white. Deeper down the rocks are less and less altered until the hard, little de- composed rock is found. These shales, as they are called, usually contain a moderately high percentage of alumina and silica and are relatively low in calcium and mag- nesium. They can be mined comparatively easy as they occur in the bank but their value is materially increased by weathering for a season. When used the shales should be eround in a dry pan before they are tempered. These shales are being employed for the manufacture of brick at. four different places in this area. In two places soft mud brick are being made, at one plant stiff mud brick, and at the other dry press brick. The following descriptions of the individual plants, combined with the discussion on pages 31 and 382 will furnish the reader a fair idea of the general character and suitability of these clays for the manufacture of brick and other wares: 218 THE CLAYS OF WISCONSIN. BLACK RIVER FALLS. Black River Falls is located in the west central part of Jackson county on the Chicago, St. Paul, Minneapolis, and Omaha railroad. The only brick plant in this vicinity is situated about eight miles north of the city at a place called Halcyon. This plant, which is known as the Hal- cyon Pressed Brick Yard, is owned and operated by H. A. Bright. Mr. B. A. Bright is superintendent and manager and Mr. Perry is foreman at the plant. The brick are made from a very much decomposed schist of pre-Cambrian age which is widely distributed along the Black river and its tributaries known as Hall and Morri- son Creeks. In places the shale is exposed continuously for a quarter of a mile or more along the bank adjacent to the river. Along one of the tributaries a thickness of from ten to twelve feet of shale above the river is exposed con- tinuously for over half a mile. In most places the shale is covered with soft Potsdam sandstone, although fre quently the sandstone is removed and the clay is either ex- posed at the surface or covered with various depths of sand and gravel. In some places the shale is almost completely kaolinized and white. In other places the composition varies and with it the color, which is blue, green, or buff. The accompanying map shows the location of the plant and the distribution of the clays in the immediate vicinity. Where the shale is mined it is comparatively soft at the surface but the hardness increases with depth. The clay can be best worked after it has been weathered on the yard through one season. Up to the present time, however, it has been removed directly from the bank and dried for a short time under a shed, ground in a dry pan, and trans- ferred to the press. No attempt has been made to carefully separate the clay which burns white or buff from that which burns red, on account of which many of the brick havea pink color. The brick are in reality many different shades of red and pink XL, BULLETIN NO, Vi, PL, WISCONSIN GEOL. AND NAT. HIST. SURVEY. EZ3==] SANDSTONE. DECOMPOSED GNEISS. PARTLY DECOMPOSED GNEISS. J Pat il HNN inti i i ii fh lili hati bi da i “ili! Mh i,t "| | ti Mp iin silt, nl tf AT ni AH lyin | "i a Zz ¢ a or J WwW > < a g eee £883 3. Made: UNKNOWN IDEAL SECTION ACROSS THE BLACK RIVER AT HALCYON SHOWING THE SHALE OR PARTLY DECOMPOSED GNEISS. THE PRE-CAMBRIAN SHALES. 219 and great care and experience is required to properly shade them in sorting. The shale occurs in layers which stand nearly on end in the bank. The layers form bands which often differ ma- terially from one another in composition, although when taken separately they are comparatively uniform in com- position. The clay from one of these bands may burn red, another buff, and a third white. The foreman of the bank should possess knowledge of the exact color to which the clay in each of these bands will burn. If this is known and the clay from the different bands is mixed in definite proportions there will be little difficulty in securing brick of almost any color without the necessity of such careful grading after the brick are burned. In the manufacture of dry press brick these clays should be used sufficiently wet so that they will retain their sharp edges when removed from the moulds. The brick should be burned very slowly and when the heat has reached a point a little below vitrification it should be held for some time. The kiln should also be cooled slowly to give the brick time to anneal. The brick which are now manufactured at this place are of excellent quality and sufficiently well graded to be suit- able for the best kind of constructional work. The brick are burned in round down draft kilns. About eight days are required for burning, wood being used for fuel. This plant was constructed in 1892 and has been oper- ated each year since that time with the exception of 1894 and 1895. During the last three years the average annual output of the yard has been about 500,000 brick. The dis- tance from the nearest railroad is the chief hindrance to the successful operation of the plant. Miscellaneous Deposits of Clay and Shale——About one mile and a half north of Black River Falls near the old iron furnace there are from ten to twenty feet of decom- posed ferruginous schist which might be used to mix with the clay at Halcyon for the manufacture of dark red brick. 220 THE CLAYS OF WISCONSIN. However, there is an abundance of clay nearer at hand which contains sufficient iron to color the brick any de- sired tint of red or brown. About one-fourth of a mile south of the city is located an excellent bank of plastic blue clay which has a thickness of from six to thirty feet. The clay is overlain with from ten to thirty feet of sand and gravel which may prevent its economical development. The clay is finely laminated, very plastic, and apparently contains no gravel. Directly underneath the sand the clay has a yellowish gray color but three or four feet deeper down the color is uniformly blue. Itis thought that the clay would make an excellent soft mud and perhaps stiff mud brick. The clay at the top contains more quartz sand than that near the bottom. However, if the clay from the entire bank were used it is thought that the brick made therefrom would be very satisfactory. The location of the clay is such that the brick could be conveyed to the railroad for shipping without any unreasonable expense. Laboratory Examination.—All of the clays from this reg- ion have been examined in the laboratory of the Survey. The shales from the Halcyon district break down slowly when soaked in water but are as a rule very plastic when wet. The greenish blue shale consists of grains which vary in size from .25 mm. to about .003 mm. in diameter. The individuals are irregular and angular in outline. Quartz, kaolin, feldspar, mica, and chlorite are the pre dominant constituents and are present in proportions which could not be determined with the microscope. The white or yellowish white shale slacks very slowly. When pressed with the fingers it forms a very plastic sticky mass. Under the microscope it appears as a mass of many sized grains with sharp angular outlines. The individuals range in size from .2 mm. to .003 mm. and less in diameter. The ereater part of the grains, however, are over .014 mm. in diameter. The grains have a sharp splintery appearance and are far from equi-dimensional in *AHOLOVS ONV Lid AVIO DNIMOHS SXHOM 3H1 40 MIA TWH3N3D “ST1v4a USAIN HOV1E ‘SHHOM 3TIL GNV WOlUS NOAOTVH 3HL HT a UA CON NILZTING "ABAUNE LGIH LYN ONY “1030 NISNODEIA THE PRE-CAMBRIAN SHALES. 921 shape. Kaolin, quartz, iron oxide, and tremolite were observed. It is hardly possible to determine the propor- tions in which the different minerals are present. The clay which occurs near the abandoned iron furnace shows a very high percentage of iron oxide under the microscope. The individuals were unequal in size and ir- regular in shape. Most of the grains are .014 mm. or over in size. The clay consists mainly of quartz, kaolin, mica, hornblende, and iron oxide. The blue clay which occurs below the city slacks very readily in water breaking down into fine scales. When wet it is moderately plastic. Under the microscope it is found to consist of a heterogeneous mass of grains rang- ing in size from .067 to .001 mm. in diameter. The in- dividuals are very generally rounded and cluster together under the field of the microscope. They all have a dirty, greenish brown color. The clay contains a considerable percentage of quartz in grains of moderate size, iron oxide, and other mineral constituents which were obscured by the brown staining. The clay from Hall's Creek, which is not far from the Halcyon Brick plant, was found when examined under the microscope to consist of grains which vary in size from .1 to .001 mm. in diameter. The individuals have sharp, splintery, and in some cases almost crystal outlines. The individuals have a greenish tint although remarkably clear and translucent. Quartz, chlorite, kaolin and other unde- terminable minerals are present in varying proportions. The clay breaks down slowly in water and will require grinding before it is sufficiently fine for the manufacture of brick. The clays are all fairly plastic although not as much so as the samples examined from the Halcyon plant. They have a grayish blue color and will undoubtedly burn red. The following are the chemical analyses of samples from this region: Nos. 117, 118, 119, 120, 121 are from the shales now being used at the Halcyon Brick Plant. Nos. 209 THE CLAYS OF WISCONSIN. 11 and 12 are from Hall’s Creek, and No. 13 is the plastic clay from the river below Black River Falls. No. 117. | No. 118. | No. 119. | No. 120. EDO. Cire ehe cae eh Gen ye motets 5.26 3.68 6.22 4.38 SIO oss ess vie leverastnint ee saphvered adeseseirensions 70.30 72.30 55.87 65.52 AU Oa icparsiat eteigintaveteie sa aut treiece hive 18.07 16.06 19.60 16.33 BGs Oi sercisvecateiein wis utacern'st ea suoerates 1.65 .35 9.22 4.02 CaO. iis savsciwnases kes SOOk waste eases -26 1.05 1.65 MeO bscicasewamemadican’s snes .90 1.50 3.71 3.09 Nas Orexivncuisevinaas as dois wales .76 .40 82 83 Ks Oumuancsonnonaee eee sees eu 2.94 5.23 3.93 3.94 PO). sosancauseniasee Sura nee: .06 trace. .06 .58 Total vic scsotiasina tadcensc 99.94 99.78 99.98 99.94 é No. 121. | No; 11 No. 12. | No. 13. HO}; Cowes oe wees Garnrasce wes 3.86 4.40 7.16 9.10 DIO pesos oo seca ausioees ee 67.96 59.88 50.17 61.22 AlsOg sine sexs va55 Cowsnemamany 17.25 18.10 17.90 13.98 RE Oeyp nn tence ve ranereace 2.27 10.04 12.29 4.66 UO) eee canastiie sactee a 5 so Meet any TET .67 ol 0.55 3.76 MEO ccscccrrcdigneesis oe Nei endeet 2.07 3.13 6.86 2.03 SIN hs Oech tesatetsasahavsvaseascosaceretonsendees 38 .52 0.58 1.32 ERs Osis ssecsce sia, dseieie.neicseveroiausnencesln 5.81 3.72 3.06 3.44 TPs Ob sie cerevteyssatarsssananote eaten dvastuacavovint GEACEL ios iyssene caeavecel prove dtayses gO si| erase eoanencvaye MNO esicraverese ces Hea rararen puqevoaeral| oemeeeceee trace OECD fesesetersreseeue EDC) sceeeseasaric season ois Gaes tere oiatata re tonavene rsionnisNe aarase raranutonogyees 0.75 0.43 Total evcsiisse vie sd eaaveoey 100.27 100.10 99.93 99.94 GRAND RAPIDS. Grand Rapids is located in the central part of Wood County on the Wisconsin River. Two brick plants have been erected near this place. Sons and the other by Scott and Alexander. The plant owned by Scott and Alexander, known as the Grand Rapids Pressed Brick Yard, is located at Sigel Sta- tion about three miles northwest of the city. This yard One is owned by Lessice and "BG3HS ONY SNTIN ONIMOHS MBIA YVSN "ST1V4 YBAIY YOVIG ‘SHYOM 3T1L GNV HONS NOAODTIVH "AINK “Id “HA ‘ON NILZT_ING *ASAUNS “LSIH “LYN ONY “1039 NISNOOSIM THE PRE-CAMBRIAN SHALES. 2293 was opened in 1897 and has been operated each year since that time. The average output during the last two years has been about 1,700,000 common brick per year. The clay occurs in a low, swampy tract of land near the railroad. The bank consists of from one to two feet of sand at the top, three to four feet of blue clay much dis- colored with yellowish brown streaks of iron oxide, and about six feet of decomposed granite schist. The best brick are said to be manufactured out of a mixture of the clay from the upper and lower parts of the bank. The clay is conveyed from the bank to the plant in dump cars operated by a cable and revolving drum. The clay is mixed and tempered by passing through two pug mills. The brick are made in a Monarch soft mud machine, dried on pallets under sheds, and burned in permanent up draft kilns. The capacity of the dry sheds is 225,000 and that of the kilns one million. The clay burns red and it is re- ported that the brick will withstand a high heat. The transportation facilities are not good and for this reason the company have been working under a disadvan- tage in placing their product on the market at a price which can compete with other factories. In the vicinity of Grand Rapids there are extensive areas of residual clay formed out of decomposed granite gneiss, some of which is almost pure white and carries a high per- centage of plastic kaolin. The clay, however, is usually stained with a greater or less percentage of iron oxide on account of which it is unsuitable for the manufacture of white ware. The purest of the clays might, when mixed with silica in proper proportions, make a fire brick which would be suitable for many purposes. Mr. Alexander is contemplating moving the brick yard in which he is interested to a place where the white clay occurs and there begin the manufacture of refractory brick. The establishment of such an industry at this place would provide manufacturers with a product which is at present only obtained outside of the state. Brick manufactured 294 THE CLAYS OF WISCONSIN. out of this clay will undoubtedly be sufficiently refractory for many purposes for which fire brick are now used. Laboratory Examination.—Three samples of clay from unworked banks in this vicinity were examined in the Sur- vey laboratory. Two of the samples were very ferruginous and the third was almost free from iron. The ferruginous samples were hard and slaty when dry and broke down very slowly in water. When ground and soaked with water the color of both was a deep brown. The mass was only moderately plastic. The microscopic examination shows that these samples consist of quartz, kaolin, mica, iron oxide, and chlorite with possibly some tremolite. The grains differ greatly in size depending upon the grinding to which they have been subjected. They are ir- regular in outline and have a splintery appearance. The third sample which had a grayish white color was streaked with a faint coloring of yellow iron oxide. The clay has a puckery taste which is due to the presence of soluble iron and aluminum sulphate. The clay slacks readily in water and is very plastic when wet. Under the microscope the grains were observed to have very irregular, splintery outlines. They differ greatly in size but none are what might be called coarse. The clay consists mainly of quartz, kaolin, a small amount of iron, and probably some feldspar. The follow- ing are the chemical analyses of the three clays above de- scribed. Nos. I and II are the brown samples of shale and No. III is the white clay or kaolin. WISCONSIN GEOL, AND NAT. HIST. SURVEY. BULLETIN NO, VII., PL. XLV, WISCONSIN WMA Gee PEEL sOIL BANDSTONE KAOLIN WEATHEREO GNEISS SECTION ACROSS THE WISCONSIN RIVER VALLEY NEAR GRAND RAPIDS. (AFTER IRVING.) THE PRE-CAMBRIAN SHALES. 925 No. IL. No. IL. No. III. BOO cece teense 4.69 9.10 6.47 BiG accu book aeouninees 52.52 | 34.44 | 67.50 PO axes atte wennceeeacnean 14.65 | 17.26 0.25—Soluble. ASO sie vent eriiece nares c 4 Fnicsars einen. cab ee | (oda etaus a cierere 19.23—Insoluble. We ee reagan esses 18.07 | 23.80 0.06—Soluble. BOO pisiscisiteeiook bane g-cccanyl es Gene Graneloumeneaees 2.60—Insoluble. BO ce eae 0.94 GOT lakatece ds en pO ice encernn ne enced 2.40 | 11.21 83 INE Occ rsatetians aan 0.34 0.22 0.48 BOs canon acer arenes 5.52 1.94 2.50 IO Ga ota ee 1.35 diy seo eioeas MnO eiaibiaosauavezacare «(4sa:i8 o4s S2eleut/0Ue Clans trace W550 | sdex:. pasa tanacewes yobs gas sae ae datonsesil cad ecettade Valet Sponsors 0.26 Dail stad ddvsrein shan 100.48 | 100.26 | 100.18 The deposits of clay in the vicinity of Grand Rapids have been discussed somewhat at length by R. D. Irving in the third volume of the “Transactions of the Wisconsin Academy of Sciences, Arts, and Letters.” The relation of these kaolin deposits to the underlying granite gneiss and the superimposed sandstone is nicely shown in the accom- panying diagram which has been taken from this paper. The gneisses in this region have a well defined lamination or schistosity which strikes between N. 45° E. and N. 80° E. and dips about 50° either east or west. The beds of Pots- dam sandstone which are above the kaolin are horizontal as shown in the accompanying illustration. The following analyses, made by E. T. Sweet and pub- lished as a part of the report of R. D. Irving in the Acad- emy Transactions above referred to, represent very truth- fully the character of the residual kaolins of this region. In all of the samples there is a relatively high percentage of quartz and moderate amounts of sodium and potassium. The presence of from two to three and a half per cent of fluxes lessens very materially the refractory character of the clays. 15 926. THE CLAYS OF WISCONSIN. Analyses.* g . di ;(2| 8 qd] 38 Location. ao & g & |e 8 Le ag 3 §/ 8la/S|/aleia| 8/28) s =) Siecle ig;oi|s| £€/# is 5 a} L J oes zg oe i i i ti i ill UA i ch it itll DECOMPOSED GNEISS. SY GZ PARTLY DECOMPOSED GNEISS., Ww } nh a ri i it i ea anil if ‘ i a i im i "" 0 ee ped { FE a $ < a w on A Zz < yn UNKNOWN IDEAL SECTION ACROSS THE EAU CLAIRE RIVER VALLEY SHOWING THE SHALE OR DECOMPOSED GNEISS. THE PRE-CAMBRIAN SHALES. 231 foot or two below the sandstone the shale may be purple, brown, green, blue or gray. Sometimes one may find broad bands of blue or greenish colored shale, alternating with bands of purple or reddish brown. The bands of light col- ored, almost white clay, are in some places quite extensive. The shale differs in composition in different parts of the formation. It contains kaolin, quartz, mica, chlorite, iron oxide, feldspar, and other minerals in lesser proportions. These minerals occur in individuals that vary greatly in size, ranging from one-fifth to one-thousandth of a mm. in their greatest diameter. The outlines of the individuals are irregular and angular. The chemical composition of these shales will be found in Table I of the Appendix. The samples analyzed and tested were furnished by George T. Thompson of Eau Claire who expects to establish a brick factory at this place. | 282 THE CLAYS OF WISCONSIN. CHAPTER XIII. KAOLIN. The kaolin deposits within the state occur in two very different forms. The most widely distributed deposits are the impure residual clays which are associated with the pre-Cambrian schists, near the contact of these rocks with the sandstone of the Potsdam formation. These de- posits occur in the vicinity of Grand Rapids, Eau Claire, Black River Falls, Rice Lake, Stevens Point, and other places. As a rule the deposits contain considerable amounts of quartz and iron oxide but occasionally they are sufficiently free from these constituents so that kaolin can be obtained by washing, which would be suitable for the manufacture of white ware. These deposits have been considered in detail in the previous pages, with the exception of that which occurs near Rice Lake and Hau Claire. Non-plastic Kaolin. RICE LAKE, @o The Rice Lake kaolin is found in the N. W. 4 of 8S. E. + of Section 19, Town 35, Range 9 West, on property owned by Mr. Mallo. It occurs under a covering of about thirty feet of yellow clay and fragments of brown ferruginous rock. The kaolin bed is reported to have a thickness of seven feet. When the property was inspected in 1899 the WISCONSIN GEOL, AND NAT. HIST. SURVEY. BULLETIN NO. VU., PL. XLIX. Ruz R.16, R.1S. # Haolin. @ KXaotunWorks. A PORTION OF ST. CROIX COUNTY SHOWING LOCATION OF A FEW OF THE KNOWN DEPOSITS OF PLASTIC KAOLIN. KAOLIN. 933 sliafts which had been sunk were not in a condition so that the deposit could be examined. Samples of the kaolin which were sent to the Survey were found to be practically devoid of plasticity. They were hard and yet somewhat crumbly. The samples were intercepted with numerous fine seams, the walls of which were stained with iron oxide. A chemical analysis of this kaolin showed it to be high in aluminum.. Its lack of plasticity, however, renders it altogether unsuitable for the manufacture of porcelain ware when used alone. This kaolin is thought to belong to a later formation than the schists which occur at Eau Claire and other places. However, its age has not been definitely determined. An analysis of this kaolin is given in table I of the Appendix. Plastic Kaolin. The second and best known form in which the kaolin oc- curs is a very plastic sedimentary deposit interstratified with sand. These deposits are younger than the Rice Lake kaolin but are thought to be at least preglacial in age. These kaolins occur mainly in the eastern part of St. Croix County and the western part of Dunn County. A few of the many places where the kaolin may be observed at or near the surface of the ground are shown in the ac- companying sketch map. GLEN WOOD. In the vicinity of Glenwood the kaolin deposits have been ‘quite thoroughly explored by H. J. Baldwin. It has never been my good fortune to have an opportunity to examine carefully the kaolin as it occurs in this vicinity, although I have made borings at several places, all of which show a variable thickness of kaolin. The beds are everywhere covered with boulder clay to a depth of from five to fifteen feet. 234 THE CLAYS OF WISCONSIN, Samples from this region show a very excellent grade of clay. It is remarkably free from iron in some places, but again it may be deeply stained with limonite. The chem- ical composition of this clay is given in table I of the Ap- pendix. HERSEY. Hersey is located in the southeastern part of St. Croix County on the Chicago, St. Paul, Minneapolis and Omaha Railroad. About two miles southwest of the village is lo- cated the plant of the Superior China Clay Company, which is engaged in mining and washing white plastic kaolin. The plant, which is one of the largest of its kind in the United States, was erected in 1893 and has been oper- ated each year since. The washing plant is located imme- diately at the mines and both are operated about seven months during the year, it being impracticable to operate the plant during the severe winter weather of this latitude. Deposits of kaolin occur in irregular beds and pockets in many places in the western part of Dunn County and in the eastern part of St. Croix County. In some places it is found near the surface and in others it is covered to a depth of thirty feet or more with boulder clay. The kaolin in some of the beds is pure white, while in other places it is deeply stained with yellow iron oxide. Very little of the clay that is mined by the Superior China Clay Company is stained with iron. That which is stained is carefully sorted and kept apart from the white. Among these deposits the clay which occurs at the greatest depth is the purest. The kaolin which is near the surface occurs in lumps of boulder form and contains upwards of fifty per cent of free silica, while at a depth of about eight feet the kaolin occurs in parallel sheets or strata varying in thickness from a few inches to two feet or more. The sheets of clay are separated from one another by layers of white sand from a few inches to several feet in thickness. The beds near the surface seldom continue in uninter- rupted sheets, but are usually folded and broken in such WISCONSIN GEOL, AND NAT. HIST SURVEY. BULLETIN NO. Vil., PL. iy SUPERIOR CHINA CLAY WORKS, HERSEY. PITS FROM WHICH KAOLIN 1S MINED. KAOLIN. 235 a manner as to lead one to suspect that they have been sub- jected to pressure. It is supposed that these deposits were formed prior to the last glacial epoch and that the advance of the ice has crumpled and folded the beds. The clay is loosened from the bank by the use of picks and shovels and carefully sorted by hand, all clay showing iron stains being thrown aside. It is placed in iron buckets, raised out of the pits by means of derricks, and loaded into dump carts in which it is conveyed to the wash- ing plant. At the washing plant it is dumped onto a plat- form and shoveled into a pug mill, where it is mixed with copious amounts of water and thoroughly disintegrated. From the first pug mill the clay passes into a second pu mill in which any remaining lumps of clay are reduced to a powder. The thin slip which is thus formed out of the clay and water is conducted into long troughs through which it slowly flows for a distance of from 7,000 to 8,000 feet. These troughs are slightly inclined, the speed of the water being decreased as the outlet is approached. At the end of these precipitating troughs the clay passes through a very fine screen by means of which all foreign material is removed. The slip is then run into a series of large set- tling vats, the aggregate capacity of which is over 2,500,000 gallons. As the clay passes into the precipitating troughs it con- tains a considerable quantity of white sand of all degrees of fineness which, owing to its greater specific gravity, is deposited in the bottom of the troughs as the slip slowly moves toward the settling vats. When the clay has settled to the consistency of thick cream it is drawn off into an underground tank from which it is pumped into filter presses where it is subjected to an hydraulic pressure of from ninety to one hundred pounds. On account of the fineness of the clay and its great plasticity the process of pressing the water out of it is very slow, it taking from six to eight hours to fill a filter press. The clay comes from the filter presses in cakes or discs which weigh about twenty-five pounds and are loaded onto dryer cars which 236 THE CLAYS OF WISCONSIN. are run into a large steam tunnel dryer where the clay is subjected to a steam heat of about 220 degrees F. for about sixty hours. When the clay has been thoroughly dried it is taken from the dryer tunnels and crushed and packed in bags ready for shipment. The company has a warehouse capacity sufficient to store about 5,000 tons of clay. The plant has a capacity of from thirty-five to forty tons of washed clay per day and an annual capacity of from 4,500 to 5,000 tons. During the process of washing the clay enormous quanti- ties of almost pure white sand is removed and thrown into the yard from the precipitating troughs. This white sand is exceptionally pure and might be used in the manufacture of glass or pottery. It is far better than most of the sand that is now being used for filtering purposes. The kaolin which is placed on the market by this com- pany is equal in quality to any of the eastern or southern products which have come under my observation. The clay has been analyzed both in the crude and washed con- ditions. The following analyses show the condition of the clay as it was being mined in 1899. Sample I is the crude kaolin, and sample II is the washed product. Sample I. | Sample II. ED Od aise das) beesteaepareswiacctaies Os Orosas Aolamesoatsiatetas Boaee Se 8.90 11.89 SIO pivwscnsaan: Sead atest iaatavehageseseeyara dds ace apavcnsuash esas 64.50 52.41 All, Of vine aiardinislesantawes cdenieiaciaiduue deans eee 26.20 34.10 6 Og cseiirese a's add ecen a nin ov ogiaa eco aioe Von's Ke .07 15 CaO. vaca seaesc aad vides en aenrinnie be inca sa lawae ye aie .05 MeO we cceee a tartan esa Ses Saeed Sue Mee seed [Sawe vee ee BSE .12 Na; Obes caiios cues phase Ves age ehameee 250s aed ewloskue yea as 18 Ki Ohi yc iccuartveaises ts so bese cheats Foye aw ake 81 46 EDO oy. ecd is Sis elancc nas ee BES 56 USO A SRE ROS EEE He oC CARIES .80 LOU a ciase: seessie @ sieceteains Hiadeeaieeceaaucdnens 99.98 100.16 Reference to the above chemical analyses shows that the percentage of iron is very low, being less than .07 in the sample of crude kaolin and less than .15 in the sample of WISCONSIN GEOL, AND NAT. HIST SURVEY, BULLETIN NO. ViI., PL. LIL 2 SUPERIOR CHINA CLAY WORKS, HERSEY. 1, LOADING A CART FROM A PIT, 2. DELIVERING CLAY AT THE WASHING PLANT. KAOLIN. 237 washed kaolin. The complex chemical composition of the washed kaolin may be partly due to the mineral constitu- ents carried in the water used for washing the clay. The calcium, magnesium, sodium, and potassium may all have been derived from the water, although it is quite possible that certain parts of the clay may contain a small per- centage of feldspar which would easily account for the presence of these elements. Further examination of the crude clay in the laboratory shows that it slacks very readily in water, breaking down into a very plastic mass resembling slacked lime. Under the microscope the crude kaolin was observed to consist mainly of kaolinite grains, although numerous small grains of quartz were observed. The largest grains of kaolin were not over .0025 mm. in diameter. In the washed samples of kaolin very little quartz could be detected with the com- pound microscope. Such quartz grains as were observed were very minute. This would indicate that the separa- tion in the washing process had been very thorough. The output of the plant has been largely consumed by the paper manufacturers of Wisconsin and Minnesota. It has been tested a number of times for the manufacture of porcelain and the reports made indicate that it is well adapted for this purpose. I‘rom my examination I believe that the clay is well adapted for the manufacture of porce- lain and sooner or later it will undoubtedly be used quite extensively for this purpose. EAU CLAIRE. Besides the kaolinic schists that occur in this vicinity there is also a limited area in the valley of the Eau Claire river in which considerable quantities of fine plastic kaolin. occurs. This kaolin is mixed with considerable fine quartz and is interstratified with beds of sand. A proposition was at one time entered into by which this kaolin was to be utilized as a polishing powder. This 238 THE CLAYS OF WISCONSIN. plan, however, never materialized and the kaolin remains as it was, practically untouched. These beds occur in the present valley of the Eau Claire river and are thought to have been derived originally from the kaolinic schists which in some places constitute the bed of the river. When the schists occurring in this region are developed it is very probable that this partly washed kaolin will be utilized. WISCONSIN GEOL. AND NAT. HIST, SURVEY. BULLETIN NO. Vil, PL. Lu. SUPERIOR CHINA CLAY WORKS, HERSEY. SECTION OF 8000 FEET OF PRECIPITATING TROUGHS, SHALES OF THE POTSDAM FORMATION. 939 CHAPTER XIV. SHALES OF THE POTSDAM FORMATION. The base of the Potsdam formation in many places con- sists of alternating layers of tough plastic clay and sand- stone. In some places the clay has been distributed through the body of the stone in such a manner as to form a brown shale which has a maximum thickness of from seven to ten feet. In most places, however, the clay layers are not over an inch in thickness. Occasionally they measure from twelve to eighteen inches. At the present time these clays and shales are nowhere being used for the manufacture of brick or other clay wares. The only use to which the shale is being put is the construction of highways. The mixture of tough clays and moderately hard sandstone makes a roadway which is far superior to an ordinary clay or sand road. This shale or clay occurs at many places, chief among which are Merrillan, Durand, Black River Falls, Eau Claire, Neillsville, and Fond du Lac in Douglas County. MERRILLAN. Merrillan is located in the north central part of Jack- son County at the junction of the Chicago, St. Paul, Min- neapolis and Omaha and Green Bay and Western Rail- roads. Almost the entire region in the vicinity of this city is underlain with clay which has a thickness of three to eight feet. The clay has either a bluish green or red- dish brown color and occurs either as an alluvial deposit 240 THE CLAYS OF WISCONSIN. or interlaminated with thin layers of Potsdam sandstone. The clay which occurs on the farm of Robert Dunlap was especially examined and found to be of excellent qual- ity. The clay iv high in aluminum and comparatively low in the alkalies. This clay is not used at the present time but will undoubtedly be developed for some purpose in the near future. Laboratory Examination.—The clay was examined in the laboratory and found to be hard when dry and very plastic when wet. It has a sour taste due to the presence of aluminum sulphate. Under the microscope the clay is seen to consist of grains having irregular outlines, none of which are over 14mm. in diameter. A greater part of the clay con- sists of grains under .004 mm. in diameter. The identifica- tion of the minerals is obscured by the iron oxide stains, although quartz and kaolin are recognizable. The following analyses give the chemical composition of the clay. Number I is the reddish brown clay and Num- ber II is the blue: No. L No. IT. HO) Chase sesh giskstnsains see tiiecs aielaiciaada eee 18.03 4.15 SiOs sc accuse keatieg case ee teas eeakien aeete er 40.09 fa 5; bes ie: 5.88 None. 1.24 0.52 8.08 trace. Total secon. sarees sievsieaes acveiusaeires eaten’ 99.78 1€0.18 “SNOTIVD 000'009'Z ALIOVdVD ‘SLVA ONITLL3S “A3SYSH ‘SHYOM AV190 VNIHO YOINSdNS WI “Id “WA “ON NILZTING *ABAUNS “LSIH “LYN ONY "1039 NISNOOSIM SHALES OF THE POTSDAM FORMATION. 941 MISCELLANEOUS LOCALITIES. The clay or shale deposits which occur at Durand, Black River Falls, Eau Claire, and other places are not as prom- ising as those at Merrillan. The clay occurs in thinner layers and there is consequently a greater percentage of quartz sand. At Fond du Lac in Douglas County the deposit is a thinly laminated shale having a total thickness of from eight to ten feet. The shale has never been developed. It is situated near Superior and Duluth and ought to prove valuable for the manufacture of brick. The following is a chemical analysis of the clay and it will be seen that the proportions of alumina, silica, and the fluxes are such as to warrant the supposition that a good building brick could be manufactured therefrom. Braet oa pea eee an 6.18 PSU ees aa aye ce wr viaycpatsast A dase tacnmvendvad oo aiayaveyninaustanes scene overt Geaeamecanansh 58.19 BE e dk. cece edn sontor Tyee. sn seesaw 18.77 Be a gee lng ean ont nny 7.90 BO usiicusatimrar en alas duiio aid a's 44 eben ey 49 Ta Mane ul : Me Oiicseianin es ees 46 Gainey. vee HOTTIES oe es Ba hou 3.92 NG. O isc cciecods oeecckamadars ean ets meee eee eee eee Valotemane 0.10 KO GES tea raya oh enn ae 3.78 HO a sisavinsevteanrasen i Sel isGsavsiiahd di ngsanieess lit apusse wes Satoraca recitation ; MnO cs eee oie eee ak ae Strong trace. Total i senses ve eGndiesee secs anaaieu see aes oe 99.98 242 THE CLAYS OF WISCONSIN. CHAPTER XV. FUTURE DEVELOPMENT OF THE CLAY DE- POSITS OF WISCONSIN. Although brick and stone have been used in Wisconsin for a great many years in the construction of public build- ings and business blocks, they have not been used very gen- erally in the construction of residences. The forests have furnished a much cheaper and more easily obtainable ma- terial and throughout the length and breadth of the state it has been an almost universal custom to construct houses out of pine lumber. In the places where lumber has been less abundant and brick have been a common commodity residences and business blocks have in part been built out ‘of the latter material. However, the brick have as a rule ‘been made without regard for beauty and the houses are void of artistic features. Common brick, irregular in size and with uneven, coarse faces, can scarcely be appealed to as things of beauty. Only within the last few years have ornamental brick been used to any extent in this state. Common brick are entirely satisfactory for concealed por- tions of masonry work, but for fronts to buildings and other exterior parts, pressed brick and terra cotta should be used almost exclusively. The quantity of lumber available in Wisconsin is de- creasing each year and the prices have risen very rapidly. At present it is not difficult to foresee a time when lumber will be scarcer and more expensive than brick and terra WISCONSIN GEOL. AND NAT. HIST, SURVEY. BULLETIN NO. Vit., PL. LIV, SUPERIOR CHINA CLAY WORKS, HERSEY. FIGURE 1.—SECTION OF PRESS ROOM SHOWING FOUR OF THE TEN FILTER PRESSES. FIGURE 2,.—TRUCK OF CLAY AS IT COMES FROM THE FILTCR PRESSES. FUTURE DEVELOPMENT OF THE CLAY DEPOSITS. 943 cotta. While the price of lumber has been advancing the price of brick has on the whole been going down. The im- proved methods of brick manufacture and the discovery of enormous quantities of clay have not only tended to lessen the cost of production but have also improved the quality of the brick. Wisconsin possesses clays which are adapted to the manufacture of all kinds of brick. There are but few lo- calities which do not have clay that will make a common brick. There are several localities in which pressed brick of the ornamental type can be made to advantage and it is anticipated that soon this branch of the brick industry will have a much greater development than at present. Im- proved methods of manufacturing common brick will un- doubtedly be constantly sought after but the field of great- est development lies in the direction of ornamental brick. Drain tile have been used quite generally in the south- ern part of the state but the people of the north have not as yet seriously undertaken the task of draining large tracts of now useless swamp land. In the near future there will be a much greater demand for drain tile in this section of the state. Paving brick and sewer pipe are now obtained exclu- sively from neighboring states. Attempts which have been made to manufacture vitrified wares in Wisconsin have thus far been failures. However, most of these trials have been made with a class of clays which are the least suitable of any that occur within the state. Enormous quantities of paving brick and sewer pipe will be consumed in Wis- consin, alone, during the next ten years and it will be well worth time and money to experiment with every clay which offers any possibility of being suitable for the manu- facture of these products. The most promising region in which to search for materials suitable for manufacturing these products is through the central part of the state where the pre-Cambrian shales occur. 244 THE CLAYS OF WISCONSIN. The shales which occur along the Eau Claire River give evidence of being well adapted for this purpose. Some of the shale and clay which occur in the vicinity of Black River Falls in Jackson County, at Fond du Lac in Doug- las County, at Menomonie in Dunn County, at Whittlesey in Taylor County, and at other localities are almost equally as promising. It is thought that these clays, some of which are not now being used, will soon be developed and that the chief products of the plants constructed will be ornamental and paving brick. The shales are very com- plex mineralogical and chemical compounds and can only be worked successfully for the manufacture of paving brick by the most careful and painstaking methods. The clays and shales at some of the above mentioned localities are rather low in aluminum and for this reason may prove to be unsuitable for making the best quality of vitrified ware. For the manufacture of the finer porcelain wares there is an abundance of very plastic white kaolin and pure silica in Dunn and St. Croix Counties. Both are the very best products that are mined in this country today. In this region power is cheap but fuel is comparatively high. The markets of the northwest are open to any company that may locate in this kaolin region. Before many years it is hoped that someone will take advantage of these conditions and establish a much needed pottery. Many of the clays within the state are suitable for the manufacture of earthenware. The purer deposits of lacus- trine clays in the east and the alluvial deposits of the south- ern and central counties are well adapted to the manufac- ture of flower pots, cheap cuspidors, and similar earthen- ware products. In general, there are vast opportunities in Wisconsin for the development of the clay resources. Not brick alone, nor tile, nor sewer pipe, but earthenware and porcelain manufactories are among the future possibilities. WISCONSIN GEOL, AND NAT. HIST. SURVEY. BULLETIN NO, VII., PL. LV. 2 SUPERIOR CHINA CLAY WORKS, HERSEY. FIGURE 1.—CLAY LOADED ON CAR REAOY TO ENTER ORIER. FIGURE 2.—WAREHOUSE; CAPACITY 4,000 TONS, APPENDIX—EXAMINATION OF CLAY DEPOSITS. 945 APPENDIX I. METHODS EMPLOYED IN THE EXAMINATION OF THE CLAY DEPOSITS. IN THE FIELD. Nearly all of the clay deposits described in this re port have been cxamined as they occur in the field. The depth of covering, thickness of the different kinds of clay, and the occurrence of boulders, gravel, and similar impuri- ties were carefully recorded. Note was made of the posi- tion of the clay with respect to the rivers and lakes, the distance of the plant from railroad facilities, and the econ- omy of the methods of manufacture as employed at the brick and tile factories now in operation. Typical samples from one or more parts of the bank were collected and shipped by the owner to the laboratory for testing. These samples usually consisted of: twelve to fourteen inch cubical blocks and were taken as they oc- curred in the bank. Samples of the sand used for mould- ing and mixing with the clay were also sent to the labora- tory for examination. IN THE LABORATORY. Small samples were taken from the large boxes in the laboratory and carefully examined under a compound microscope to determine the physical and mineralogical characteristics of the clays. The bulk of the clay was very carefully mixed and quartered, a small portion being set 246 THE CLAYS OF WISCONSIN. aside for the chemical analyses, the remainder being re- tained for making physical tests. The physical tests have not yet been completed and the discussion of this phase of the subject is deferred until the publication of the second part of the bulletin. The chemical analyses have been performed and compu- tations of the rational analysis made. The method of making these determinations is given below in the report of Mr. 8S. V. Peppel, chemist for the Survey. 4 THE CHEMICAL ANALYSES. * Method of Sampling. The clays which were obtained from the various com- panies in the state were dried sufficiently so that they would break up readily and then carefully sampled in the following manner: The clay was spread on an oil cloth and broken up with a wooden mallet on a cement floor. After the sample had been reduced to particles the size of a grain of wheat it was thoroughly mixed and quartered until a sample of about one-fourth of a pound remained. This was again crushed and quartered until there remained about thirty grains, which was ground very fine in a porcelain mortar. By handling the sample in this manner no extraneous material was introduced unless through the abrasion of the mortar which would only increase the percentage of Silica. Moisture. Many of the clays were so moist when received in the laboratory that they could not be sampled without first drying artificially. Under these conditions determination of the hygroscopic water could not have much significance. To the practical clay worker, unless he is using clays which: are dried at a uniform temperature, the determination of * By S. V. Peppel, Chemist. APPENDIX—EXAMINATION OF CLAY DEPOSITS. 247 the free moisture is of no value because of the constantly changing conditions of the atmosphere which leave the clay saturated with water one day and almost dry the next. Therefore it was thought best to dry all the samples at a temperature of 110° C. for one hour and bottle. The samples thus dried were not allowed to stand any consid- erable time before being used. From a scientific stand- point it may be preferable to determine the free or hygro- scopic moisture by drying a weighed portion one hour at 110° C. and computing the percentage of loss by weight. When a determination of the hygroscopic moisture is made, the percentages in the analysis should be calculated on the basis of the dry sample. Loss on Ignition. Two portions weighing one gram each should be weighed out of the thirty gram sample. The operator should exer- cise great care in selecting and weighing these portions in order that they shall represent the average composition of the sample. A weighing tube, while desirable in many ways, should not be used unless the sample has been care- fully sized through a 100 to 120 mesh sieve, since the coarser particles will be poured out first. Even when carefully sized the heavier minerals or those having the highest specific gravity will leave the tube first, so that two samples weighed from the same tube will not give identi- cal analyses. The plan followed in this report was to spread the entire sample on a clean piece of glazed paper, mix thoroughly with a spoon or spatula and take small portions of clay from all parts of the pile and place directly into the pan and weigh. This method will yield all the duplicates desired. The loss on ignition is determined by heating one of the one gram samples in a platinum crucible of known weight for twenty or thirty minutes over a Bunsen burner and for thirty to forty-five minutes over a blast or until the weight is constant. The loss occasioned thereby represents the 248 THE CLAYS OF WISCONSIN. combined water, or water of crystallization, organic mat- ter, carbon dioxide, and sulphur dioxide. The other one gram portion is placed in a second platinum crucible for fusion. This second portion is not altogether necessary since the residue after loss on ignition of the first sample may be used equally as well. To the ignited or fresh samples, whichever is used, add one-fourth to one-half gram of nitric acid and eight grams of sodium carbonate, place it over a Bunsen burner in an inclined position (5° to 10°), cover, and raise the heat gradually for ten to fifteen minutes until the highest heat attainable is reached. The sample should remain over the burner fifteen minutes or more but not necessarily until the sample has completely melted or become quiet. The crucible containing the sam- ple is then placed over a strong blast where it is left for about five minutes after all bubbles have ceased to be given off and the mass has become very fluid. The lid is then carefully removed from the crucible and turned upside down on a clay triangle stool or other convenient support which will not attack hot platinum. The crucible is lifted with tongs and the fluid caused to rotate and mix in the erucible so that any undecomposed mineral particles will be detached and taken into solution. The operator should continue to rotate the crucible so that the fusion while cool- ing will be spread over as much of the inside surface of the crucible as possible which will facilitate its removal by water. When the fusion has solidified, plunge the cruci- ble into cold distilled water as far as possible without wetting the inside. This sudden cooling of the fusion causes it to crack so that it can be more easily removed from the crucible. When cool the crucible and lid are placed in a four inch casserole covered or nearly covered with hot distilled water, and removed to the hot plate where the temperature is maintained just below that which will cause bumping. Here the fusion is given time to soak loose from the cruci- ble. After the fusion has softened, a glass rod may be APPENDIX—EXAMINATION OF CLAY DEPOSITS. 249 used to loosen it. The rod, however, must be used with the greatest care or the crucible will be injured by scratch- ing or indenting. Determination of th- Silica, Si0.. After the fusion has been loosened from the crucible both the crucible and lid are washed off with hot water and the last traces of the fusion in the crucible are dissolved with a very little hydrochloric acid. In case the crucible or lid is stained with iron, as often happens, add hydro- chloric acid to the crucible, cover and warm gently. The volatilized hydrochloric acid condensing on the lid and sides will remove the stains. This and the washings are added to the fusion care being exercised to avoid loss by spattering when the acid comes in contact with the al- kali of the fusion. If any of the fusien is still hard let the casserole remain on the hot plate until by crushing and soaking it is all soft. If the next step, which is the addi- tion of hydrochloric acid, be taken while the fusion is hard and lumpy, the silica thrown out by the hydrochloric acid tends to form a coating over a part of the soluble salts and thus protects them from solution. The result is an impure silica which gives a high residue of volatilization. The cover glass is kept on the casserole and hydrochloric acid is added until the color of chloride of iron develops after which about five to ten c. c. more is added and the car- bon dioxide boiled out. A few minutes boiling is ordina- rily sufficient. The cover is then removed and the spatters washed into the casserole. The casserole is placed on a water bath, evaporated to dryness, and freed from odor of hydrochloric acid. Dissolve in fifteen c. c. of hydrogen hydroxide, let it set five to thirty minutes, working acid to all parts of the casserole, add hot water until the casserole is about two-thirds full, cover, boil hard for a few minutes to make the silica more granular, allow silica to settle, fil- ter through a 9 cm. ashless filter and wash with hot water. Place the filtrate and washings on water bath in the same 250 THE CLAYS OF WISCONSIN. had casserole, evaporate to dryness again, add hydrochloric acid as before and two or three drops of nitric acid, boil, filter, and wash as before, using a tall beaker of about 450 c. c. capacity. The nitric acid added above was to insure the complete oxidation of the iron and avoid the necessity of boiling just before precipitating with ammonium hy- droxide. This saves much time and avoids the danger of loss from bumping while boiling in the beaker. The precipitate of silica which may contain traces of iron chloride, calcium chloride, titanium oxide, and phosphor- ous pentoxide, is now removed* and ignited either wet or dry. If wet, care must be taken to avoid snapping out by using a very small flame until dry. To ignite either the wet or dry precipitate the filter paper is taken up and folded so as to envelop the entire precipitate. It is then placed in the bottom of a platinum crucible so that the paper will not fly open when heated. The crucible is in- clined at an angle of about forty-five degrees and ignited gently over a Bunsen burner until the paper is entirely con- sumed. The heat is then increased until all within the crucible is white. It is then removed to the blast and heated to constant weight. If the silica is as high as 70 per cent it may require half a day over the blast to bring to constant weight. For this precipitation and for all others that are to be weighed ashless filters should be used. Volatilization of Silica, (SiO,).—After the above precip- itate has been ignited and weighed as above described the silica is moistened with a few drops of water from a spritz. flask, care being taken not to blow out any of the precipi- tate from the crucible with the air which precedes the flow * Many prefer, for silica determination, evaporating to dryness once on water bath and baking in a hot air oven, at 110° to 115° C., until free from hydrochloric acid, instead of taking to dryness twice. However, the method described was followed for several months, and our experience would indicate that the residue from the volatilization of silica and the silica left with the ferric oxide and alumina are both smaller than by the customary method. APPENDIX—EXAMINATION OF CLAY DEPOSITS. O51 of water. Add ten drops of strong sulphuric acid and one- fourth to one-third of a crucible of hydroflucric acid.* Heat at a very low temperature until dry, ignite strongly over the Bunsen burner for fifteen minutes and over the blast for ten minutes, cool and weigh. Deduct the weight of the residue from the total weight of silica and add to weight of ferric oxide and alumina, both of which should be ignited in same crucible. Should milky opalescence ap- pear near the end of the evaporation of the hydrofluoric acid it is very good evidence of the presence of both titan- ium oxide and phosphorous pentoxide in appreciable quan- tities.** If no errors have been made in the preceding work the volume of the first filtrate, about 200 to 250 c. c. which con- tains the possible iron, aluminum, manganese, calcium, magnesium, and the salts due to the fusion, will be about right for the precipitation of Fe (OH), and Al (OH)s. Determination of the Ferrie Oxide, (Fe, O;) and Alumi- nine Oxide, (Al, Og). Ordinary Method.—Heat the above filtrate, add a light excess of ammonium hydroxide, and boil for a few minutes. While raising to a boiling temperature do not allow the precipitate to settle, otherwise there is danger of breaking the beaker. After boiling allow the precipitate to settle and then draw off a portion of the filtrate by decantation into a 500 ¢. ce. beaker and set aside for further determina- tions. If any of the precipitate is drawn over it must be filtered out, washed, and weighed with the iron and alumina. The *Hydrofluoric acid makes a very poisonous burn and therefore should be added with caution to the contents of the crucible which are how warm from the action of the sulphuric acid on the water. Care should also be exercised to avoid breathing the fumes of the hydro- fluoric acid which are given off freely when it is added to the con- tents of the crucible. ** Hildebrand, Bul. 148, U. S. G. S., pp. 38 and 40. 252 THE CLAYS OF WISCONSIN. precipitates consisting of Al(OH);, Fe(OH)., TiO, and P, O; should be washed four or five times by decantation with hot water. The washings should be placed in a ten or twelve inch evaporating dish and concentrated.* Dis- solve the washed precipitate in hydrochloric acid, add two drops of nitric acid, boil, and precipitate with ammonium hydroxide as before, adding all washings to those in the evaporating dish. If during the washing the precipitate does not settle readily add a few drops of nitric acid. It is preferable to wash by decantation, as above de- scribed, because no time is lost in boiling out the excess of nitric acid. The small amount of precipitate which may chance to be drawn over into the evaporating dish does not vitiate the results since all nitric acid is boiled out in the concentration, and the precipitate which comes over is dis- solved and re-precipitated. Some chemists prefer to wash several times by decantation and then throw on a filter and complete the washing by suction. The nature of the pre- cipitate is such, however, that, unless suspended in water, it will adhere closely to the channel, thus preventing com- ‘plete washing although the washings may show, no trace -of chlorine. When washed the precipitate is transferred to an eleven ‘centimeter filter and drained. Any particles which may adhere to the beaker are dissolved with a little hydrochloric acid and added to the washings. Add one drop of nitric acid to the washings, concentrate to 30 to 50 c. c. and wash out into a small beaker. Precipitate with ammonium hydroxide, avoiding more than a slight excess, boil, filter on a small filter, and wash, allowing filtrate and washings to run into the first portion which was drawn off by decantation. If the work has been * A very convenient instrument for these decantations is a siphon made by attaching a few inches of soft rubber tubing closed with an ordinary pinch cock to the longer arm of a bent glass tube. Use the same siphon throughout the determination. It need only be charged once for each determination. APPENDIX—EXAMINATION OF CLAY DEPOSITS. 253 carefully executed the total volume of this filtrate ought to be about 200 to 300 c. c.* The precipitate which was ob- tained may be ignited when wet but there is less danger of accident if dried first. The ignition is performed in the same manner as described above for silica. When the per- centages of Ie, O, and Al, O, are high this ought not to re- quire over one hour and a half.+ This ignited precipitate contains Fe,O,, Al,O;, P,O;, TiO., and traces of SiO. Bisulphate Fusion. To obtain the silica from this precipitate, make a second titration for Fe, O;, and determine TiO,. The precipitate should be mixed with about 6 grams of KHSO,, slowly heated and fused in the same crucible. In fifteen minutes the fusion should be liquefied. Should the precipitate float on the fluid bisulphate or adhere to the sides of the crucible, it should be washed down by rotating the crucible gently without removing the lid. Increase the heat gradually un- til the fusion has a faint red color. This will require from one to two hours, depending upon the quantity of water contained in the bisulphate. Continue heating until no black specks are visible and the fusion boils quietly. The heat should be increased very carefully owing to the ten- dency which this fusion has to boil over. If the bisulphate is satisfactory this fusion requires very little attention and ought not to consume more than three hours. Much of the bisulphate, however, is not entirely free from water and for this reason the fusion may require five or six hours and almost constant care to keep it from frothing over the sides. When looking into the crucible during fusion the lid should be kept above the crucible so that it may catch any particles which may be thrown upwards. The fusion *If the calcium oxide is low 200 c. c. is the right quantity; if high, 300 cc. + For precautions in igniting this precipitate, see Talbot’s Quantl- tative Chemical Analyses, p. 30. O54 THE CLAYS OF WISCONSIN. should be hot enough to expel the sulphur dioxide fumes when the lid is raised. After the fusion is complete the crucible is inclined about 45° and cooled. The fusion is detached from the crucible by adding a little water and then transferred to a small beaker. The crucible is washed clean with a little hot water and 60 c. c. of dilute sulphuric acid (4 of H, SO, to 4 H.O) is added to the fusion. This mixture ought to Stand over night but if used immediately should be warmed until dissolved. Tilter, ignite, weigh, and volatilize the silica with hydrofluoric acid. Add the loss of weight to silica as a correction and deduct from total weight of Fe, ‘O;, Al. Os, ete. Ferric oxide, (Fe, O:) by KMnO, titration. Add 10 c. c. of sulphuric acid to the filtrate, warm and pass through a modified Jones reductor,* which has been previously prepared by pouring a funnel full of warm di- dilute sulphuric acid and pour through the reductor. Pour 200 to 250 ¢. c. more through the reductor to wash it out and leave a little in the funnel. Titrate the iron with standard KMnO, while warm. If air is allowed to get into the reductor the result is unreliable and it must be thor- oughly washed with dilute sulphuric acid before making another determination. Determination of Titanic Acid (Ti0;). To estimate the titanium transfer the solution in which the Fe, O, was determined into a 500 c. c. flask and make up to exactly 500 c.c. Mix thoroughly and pour out 100 ¢. c. into a Nessler tube. To this portion add seven to eight ec. c. of strong sulphuric acid and about two ec. ec. of hydrogen hydroxide. Prepare a standard by taking a little less than 100 c. c. of distilled water and add seven to eight c. c. of *The modified Jones reductor is described by A. A. Biair in “ Chemical Analyses of Iron. 3rd Edition, p. 96. APPENDIX—EXAMINATION OF CLAY DEPOSITS. 9DR5 [37 strong sulphuric acid, two c. c. of hydrogen hydroxide, and sufficient standard TiO, to make the solution the same color as the sample. If necessary add distilled water un- til the volume of the solution in both tubes is the same. Compare the color with that of the solution to be estimated, taking precaution to observe both under the same condi- tions of light and depth. Add sufficient TiO, solution to bring the standard to the same color as the solution esti- mated. Observe the number of c. c. of standard solution used and calculate from this the weight of titanic oxide in the sample. If the color of the fusion shows more than a trace of manganese it will be necessary to make the first precipita- tion of iron and alumina by the basic acetate process which is as follows: Determination of Tron and Alumina as Basie Acctates. In taking up the second silica evaporation in hydro- chloric acid add three or four drops of nitric acid and 15 c. c. of dilute hydrochloric acid (3 of HCL to 2 H.0), boil, allow SiO, to settle and finally filter and wash. To the cold filtrate cautiously add solid Na.CO; keeping cover over the beaker until the appearance of a reddish brown color. Then add a solution of Na.CO;, drop by drop, un- til the precipitate which is formed is not dissolved by vigor- ous stirring and allowing to stand. Add hydrochloric acid drop by drop and stir vigorously, allowing it to stand two or three minutes between drops until the precipitate dissolves. Only two or three drops should be required for this purpose. Add one-fourth to one-half ¢. ¢. acetic acid and one to one and a half grams of sodium acetate and bring to a boil quickly. Boil briskly for not more than ten minutes taking precautions against bumping before ebolution begins. Let the precipitate settle and carefully draw off a portion of the filtrate into a beaker in which cal- cium is to be precipitated. Wash four or five times with hot water by decantation, concentrating the washings as in 256 THE CLAYS OF WISCONSIN. the case of the ammonium hydroxide precipitation. If the water becomes cold while washing a small part of the ace- tate precipitate will be taken into solution and the filtrate will become cloudy. Transfer the precipitate to an eleven: centimeter filter and wash twice with hot water. Return the precipitate to the original beaker by using a stream of hot water. Wash the filter first with dilute hydrochloric acid and then with water, turning the washings into the beaker which contains the precipitate. Preserve the filter for draining the subsequent NH, OH precipitate. Dissolve the basic acetates in hydrochloric acid and add a few drops. of HNO;. Boil and proceed in the second precipitate ac- cording to the ordinary process of precipitation of Fe (OH), and Al(OH); by NH, OH. Determination of the Oxide of Manganese. (Mn0O.) If the combined washings from the iron and alumina are more than 250 c. c. they should be concentrated to about this volume. To this cold filtrate sufficient NH,OH should be added to make it slightly alkaline. Add eight to ten drops of bromine, stir, cover, and allow to stand, adding a little bromine water from time to time until the man- ganese has separated out. Boil until all the bromine is ex- -pelled and filter, washing the precipitate thoroughly with hot water. Ignite the precipitate and weigh in a porcelain crucible as Mn, O, and calculate MnO. In this ignition as in all others here described be careful to avoid reducing conditions. In case there is from three to four per cent of manganese the precipitate should be treated as directed by Blair in “Chemical Analysis of Iron,” 3rd edition, p. 112. By this method the manganese is dissolved and re-precipitated as manganese ammonium phosphate. v APPENDIX—EXAMINATION OF CLAY DEPOSITS. 257 Determination of the Calcium. If the combined filtrates from iron, aluminum, and man- ganese are much more than 250 ¢. c. concentrate to that volume. Bring the filtrate to the boiling point and pre cipitate calcium by adding to the boiling solution 40 c. ¢. of a saturated boiling solution of (NH,)C. O, diluted with an equal volume of water. Remove the solution to a warm place and allow it to stand from five to thirty minutes. By this time all the calcium should be precipitated and the so- lution clear. If the quantity of calcium is six per cent or less the solution may be filtered, washed thoroughly in hot water, and ignited over a Bunsen burner and blast to a con- stant weight, which may require two or three hours. The calcium is then weighed as calcium oxide, CaO. On ac- count of the hygroscopic nature of calcium oxide, the weighing should be made as soon as it is cool. When re igniting the calcium oxide it should be kept over the blast at least one or one hour and a half, otherwise the weight obtained may be higher than in the first instance. If the filtrate should contain more than six per cent of calcium it should be filtered and washed with hot water. The bulk of the precipitate should be transferred with a stream of hot water to the beaker in which the precipita- tion was made. The precipitation is then dissolved by adding dilute hydrochloric acid (1:1) through the filter into the beaker containing the precipitate and the filter is thoroughly washed with hot water. To the dissolved precipitate add 5 to 10 c. c. (NH,)2 C,0, and re-precipitate with NH,OH, avoiding any excess. Filter through a weighed gooch crucible, wash with hot water, and dry at 110° to 115° C. to constant weight (1 to 1% hours). Weigh as CaC,0, H,O which contains 0.3836 CaO. As far as is known this method of weighing calcium has not been in general use by commercial chemists. Fresenius gives the composition as CaC,0, H,0 when dried at 100° C. and we have repeatedly checked to within .02¢ and closer 17 258 THE CLAYS OF WISCONSIN. by dissolving and re-precipitating, weighing both as the oxide and the sulphate. The oxalate of calcium above obtained may be converted into the sulphate and weighed as described by Professor N. W. Lord in “Notes on Metallurgical Analysis,” p. 11, or as described by W. H. Hess in the “Journal of the Amer- ican Chemical Society,” Vol. XXII, p. 477. However, the previously described method has been found to be fully as accurate and is much more rapid. Tf calcium is high it is absolutely necessary to re-precipi- tate. The first precipitate of CaC.O, always contains some magnesium which is re-dissolved as a part of the filtrate when the second precipitation is made.* Determination of Magnesium Oxide. (MgO.) The combined filtrates are rendered slightly acid by the addition of hydrochloric acid and then concentrated to 200 to 400 c. c. according to the amount of magnesium ex- pected. The filtrate is thoroughly cooled and 10 ¢. c. of strong NH,OH are added. The magnesium is then pre cipitated by adding drop by drop a saturated solution of NaHPO, at the same time stirring the filtrate. If the magnesium is under five per cent, from 4 to 6 c. c. will be ‘sufficient. If it is much higher from 9 to 11 c. c. will be required. The solution should contain about one and a half times the amount of Na,HPO, needed to precipitate the magnesium. A considerable excess of Na,HPO, tends to retard precipitation and if very great, it may even pre- vent complete precipitation. After the reagents are added the solution should be stirred vigorously until it is evi- dent that all the magnesium is precipitated. This will re- quire from three to ten minutes. Add to the solution one- tenth of its volume of strong (90¢) NH,OH, stir well, and let it stand for ten or twelve hours. Filter through a weighed gooch crucible, wash with the solution for wash- *See W. Crooks’ ‘‘ Select Methods in Chemical Analysis,” p. 51. APPENDIX—EXAMINATION OF CLAY DEPOSITS. 259 ing magnesia described under solutions, and ignite to red- ness over the Bunsen burner. Place the precipitate over the blast for ten minutes and weigh as Mg.P,0O,. If all the magnesium has not been precipitated it will show after standing for a short time. This precipitate probably acts slightly on the platinum crucible in which it is ignited, but not to such an extent as to vitiate the determinations. The magnesium ammonium phosphate may be filtered in a paper filter and ignited to Mg.P.O, in a porcelain crucible using a little HNO; to aid in oxidizing the filter paper. The weight of the MgO equals the weight of the Mg.P,0, x 0.36212. J. Lawrence Smith’s Method of Alkali Fusion. Unless it is suspected that the alkalies are very low, 0.5 grams of the clay is mixed with a trifle over 0.5 grams of NH,CL and well ground. Weigh out six grams of CaCO, coat the bottom and sides of a platinum crucible with a portion, and keep out sufficient for a thin coating on top of the clay, and mix the balance with the sample in the agate mortar. Transfer the sample to the crucible and cover with the CaCO, reserved for the purpose. A tight fitting lid is then placed on the crucible and it is heated gently un- til the excess of NH,CL is volatilized. Usually five min- utes is sufficient. The lower half of the crucible is then heated to dull redness and the temperature held at that point for about one hour. Cool and remove the sintered mass to a four inch casserole. Should the mass stick to the crucible a little water may be added to set it free. Never gouge it out. Set the fusion on a cool part of the hot plate to digest. Wash out the crucible with hot water. Add5itol0c.c. of strong hydrochloric acid, cover and warm to remove traces of iron. When the solution is complete wash the crucible into a small beaker and preserve the washings for the subsequent determination of iron. When the fusion has thoroughly disintegrated, which may be aided by using 260 THE CLAYS OF WISCONSIN. a heavy glass rod or porcelain pestle, wash five times by decantation through an eleven centimeter filter using only a small quantity of water each time and bringing it to a boil before filtering. Transfer the precipitate onto a fil- ter and wash until a five-inch casserole has been filled with the washings. Combined Chlorides. (KCl and NaCl.) Concentrate the filtrate to about half its volume and add several grams of solid(NH.). CO;.* When the solution has become quiet boil and concentrate to 30 or 40c.c. Add a few drops of NH.OH and a little more (NH,), CO; either dry or in solution. Filter through a nine centimeter filter into a four inch casserole and wash with hot water until the casserole is full. Concentrate to 5 or 10 c. c., add two drops of NH.OH and five to six drops of newly pre- pared saturated solution of (NH,). COs, and filter through a seven centimeter filter into a platinum dish. Wash with small quantities of hot water until the volume is increased to about 100 c. c. Evaporate to perfect dryness on the water bath, and ignite to expel ammonia salts, taking care to avoid snapping. Heat until the salts just fuse and not beyond a dull red. Take up in a little water and add one drop of NH.OH and three drops of (NH,), COs Filter into a tared platinum dish, wash until the volume is in- creased to 75 or 100 c. c. and add three to four drops of HCl. Evaporate to dryness on a water bath and add a lit- tle water. If all the salts do not dissolve, filter, wash, add two drops of hydrochloric acid and evaporate to dryness again. If all dissolves, filtering is unnecessary. Add two drops of hydrochloric acid and evaporate to dryness, ig- nite, expelling ammonium salts, and heat to point of fusion of the double chlorides, and weigh observing the same pre- cautions as before. Weigh as KCl and NaCl. *Owing to the marked solubility of glass in a strong solution of am- monium carbonate it is much better to use the solid for the first and largest addition of (NH,), CO, to avoid the introduction of the alkalies from the dissolved glass. APPENDIX—EXAMINATION OF CLAY DEPOSITS. 961 Determination of the Potash. (%K,0.) Wash the double chlorides into a small beaker. If not almost clear, filter and add two to four c. c. PtCl solution, depending upon the quantity of the double chlorides. Evaporate to dryness either on water bath or on a cool part of the hot plate, care being exercised to avoid spatter- ing. IT ilter through a weighed gooch crucible and wash the precipitate with eighty per cent of alcohol, the first three or four times by decantation. Dry twenty-five min- utes at 110° to 120° C., weigh as K,PtCl, and calculate K,0. Also calculate the KCl and deduct from the weight of the combined chlorides (KC1+ NaCl). This will leave the weight of the NaCl from which the Na,O is calculated. Unless the reagents used in the alkali determinations are known to be absolutely pure a blank must be run along with each determination, provided the blank is not already known. Weight of K,0 — Weight of K.PtCl, x 0.19395 Weight of KCl — Weight of IK.PtCl, x 0.30696 Weight of Na,O = Weight of NaCl = x 0.53077 Determination of Ferric Owide (Fe,03) by K,Cr.0; Titration, : Ferric oxide may be determined by removing the bulk of the fusion from the filter and dissolving in hydrochloric acid, traces from the filter being dissolved with the hy- drochlorie acid kept from the cleaning of the crucible. Wash the filter six or seven times with hot water, keeping solution as small as possible. Add 40c.c. hydrochloric acid, boil, reduce with SnCl,, cool, add thirty to forty c.c. saturated solution HgCl, and titrate with standard K.Cr.0, solution, using a one per cent potassium ferri cyanide solution as an indicator. This indicator should be freshly prepared for each set of titrations. 262 THE CLAYS OF WISCONSIN. Determination of the Sulphuric and Phosphoric Acids. To determine sulphuric and phosphoric acids it is best to make another fusion, using two grams of the clay, four- teen to fifteen grams of Na,CO; and one-half gram of KNO;. Mix a greater part of the flux in the crucible with the clay and cover with the remainder to prevent the es- cape of oxidized sulphur. Proceed with the fusion almost as before. A five-inch casserole will be better for the ex- traction of this fusion. When thoroughly disintegrated wash several times by decantation through a filter and then throw the fusion into the filter and wash five or six times with hot water. Where both sulphur and phosphoric acid are low this treatment will dissolve all but very minute traces. Divide the filtrate into two equal parts, using cal- librated, graduated flasks. Deternination of Sulphur. (S.) Place one-half of the filtrate in a casserole, “and if the ebolution is colored by Mn,Na.O,, add a few drops of alco- hol. Filter and wash well with hot water. Add hydro- chloric acid to the filtrate till just acid, and evaporate it to dryness carefully, and dry at 100° C. Now add 5c. c. of HCl first diluted with its own volume of water. Warm and add 50 c. ¢c. of H.O, heat until all is dissolved but a little SiO,, filter and wash. The filtrate should not exceed 100 c. c.; if it does, concentrate it. Now heat to boiling and add 5 to 10 c. c. of a ten per cent solution of BaCl, pre- viously diluted with 10 or 20 c. c. of water and heated. Stir and let the precipitate of BaSo, settle.”* When clear, fil- ter into a weighed gooch crucible, wash with hot water, dry, ignite and weigh as Ba SO,. Calculate the S or SO; as the case may require. A blank fusion using one-half the amount of flux above given must be run at the same time and carried through *N. W. Lord, ‘‘ Notes on Metallurgical Analyses,” p. 51. APPENDIX—EXAMINATION OF CLAY DEPOSITS. 263 just as the sulphur determination in order to get the cor- rection necessary for the sulphur in the reagents and for that absorbed by them from the gas flame during fusion. If soluble sulphates are to be determined, as will some times be the case, extract sulphates with hot water, add a few drops of HC] and BaCl, and proceed as before for sul- phur determination. Weight of Sulphur = Weight of BaSO, x 0.13756 Weight of SO; = Weight of BaSO, x 0.34352 Determination of Phosphoric Acid. (P.Os.) Place the second half of the filtrate in a casserole, neu- tralize with HCl, and evaporate to dryness on a water- bath. Add 15 c. c. of dilute hydrochloric acid (3 HCl to 2 H.O) and 60 c. ec. of water, boil, filter, and wash. The filtrate and washings from the insoluble SiO, should not exceed 150 ¢. cc. “To this add 10 c. c. of conc. HNOs, then NH,HO until a precipitate is formed which does not disappear on stirring, then 3c. c. of conc. HNO, which must redissolve the precipitate.” “The solution will now be quite warm. Add at once from a pipette in a fine stream 50 c. c. of ‘molybdic acid solution,’ stirring the liquid vigor- ously all the time, and continuing this stirring for about three minutes. Let the solution stand in a warm place un- til it is clear and the precipitate has all settled (which should not require to exceed one hour), remove a portion of the clear liquid with a pipette and test it by adding a lit- tle more molybdic acid solution and warm to see if all the P.O, is down. Filter the liquid through a seven centimeter filter, trans- fer the precipitate to the filter and wash until free from iron, with a five per cent solution of ammonium nitrate very slightly modified with HNO;.” “When the precipi- tate is washed put the beaker, in which the precipitation was made, under the funnel and redissolve the precipitate on the filter with dilute NH,HO. When dissolved and the liquid run through, wash the filter with water three or four 264 THE CLAYS OF WISCONSIN. times, then with a little dilute hydrochloric acid, and thea again with water. The filtrate should now be clear and colorless. If it is cloudy or colored (by a little iron), add HCl until the liquid is acid (the yellow precipitate usually separates), then add four or five drops of a saturated solu- tion of citric acid, then NH,HO to make the liquid strongly alkaline. This will give a clear liquid, the citric acid holding the iron in solution. Now add drop by drop a considerable excess of ‘mag- nesia mixture,’ stirring the liquid constantly. This ex- cess must be estimated from the probable amount of phos- phorus in the ore taken. Continue to stir the solution vigorously for four or five minutes, then add NH.HO until the solution smells strongly of ammonia. Let it stand until the precipitate of Mg NH,PO, has set- tled completely (one or two hours). The precipitate should be white and crystalline; if red or flaky, the results will be inaccurate. Filter on a small filter or better on a Gooch perforated crucible. Wash with water containing one-tenth of its vol- ume of conc. NH,HO and a little NH,NO,, dry, ignite and weigh as Mg.P.O,.”* Weight of P.O; = Weight of Mg.P.0, x 0.63788 REFERENCES. Bulletin 148, U. S. Geological Survey. Notes on Metallurgical Analysis, N. W. Lord. Chemical Analysis of Iron, A. A. Blair. SOLUTIONS. HCl for silica determinations— Mix 3 parts of strong HCl with two parts distilled water. * N. W. Lord, ‘‘ Notes on Matallurgical Analysis,” pp. 23-25. APPENDIX—EXAMINATION OF CLAY DEPOSITS. 265 Washing solution for magnesium ammonium phosphate— Dissolve 50 g. NH,NO, in water, filter, add 500 ec. c. strong NH,OI (Sp. G. 0.90) and make up to 5000 ¢. e. with distilled water. Mercuric Chloride solution— Make a standard solution using 60 g. to the liter of dis- tilled water. Ammonium oxalate solution— Make a saturated solution, using 40 g. to the liter of dis- tilled water, filter if necessary. Sodium Hydrogen Phosphate solution— Make a saturated solution, using 90 g. per liter of dis- tilled water, filter if necessary. Ammonium carbonate solution— Saturated solution freshly prepared for each set of de- terminations. Platinic Chloride solution— Dissolve 23 g. of PtCl, in 250 c. c. distilled water and add 2 to3c.c. HCI. Hydrogen Peroxide— 3% H.O.. Molybdic Acid solution— Dissolve 100 g. MoO; in 417 c. c. ammonium hydroxide (sp. g. 0.96). Pour this solution into 1250 c. c. HNO; (sp. gr. 1.20), with constant stirring. This solution should not be yellow. Use only a clear solution of MoO;. Magnesia Mixture— Dissolve 22 g. calcined MgO in dilute HCl, avoiding an excess of ITC]; then add an excess of MgO, and boil. Filter, wash once, and add to the filtrate 280 grammes NH,CI and 700 c. c. NH,OH (sp. g. 0.96). Dilute to 2000 ¢. ¢. 266 THE CLAYS OF WISCONSIN. SPECIFIC GRAVITIES. H.SO, Sp. Gr. 1.84 HNO, Sp.Gr. 1.42 HCl Sp. Gr. 1.18 NH,OH Sp.Gr. 0.90 STANDARD SOLUTIONS. Standard solutions of almost any strength may be used but where a number of determinations are required it is. very convenient to use solutions which will obviate the necessity of making calculations. The standard solutions. used by the Survey were made so that one cubic centi- meter of K,Cr,0, Solution=.01 g. Fe,0, of KMnO, Solution=.01 g. Fe,O, of TiO, Solution= .001 ¢. TiO, Standardization.—The solutions for iron were standard- ized against ferrous ammonium sulphate of known purity, prepared in the Survey laboratory. A standard (CO OH), solution was kept to check up the KMnO, solution before using it. The KMnO, solution was made up some time before be- ing standardized and its value did not vary appreciably from time to time. The TiO, solution was prepared by dissolving TiO, in dilute sulphuric acid (8 H,SO, to3 H,O) and diluting. It was standardized by reducing with hot nascent hydrogen, reoxidizing with standard KMnO, solution, evaporating a measured portion to dryness; igniting over a blast, and weighing as TiO,. A complete blank must always be run, including all the reagents used and the same amount of distilled water or- dinarily used in the analysis of a clay. It is very seldom that a blank does not show that corrections must be made for impurities. APPENDIX—EXAMINATION OF CLAY DEPOSITS. 267 Desirable and Necessary Apparatus. A hot plate is almost indispensable to rapid and easy work in clay analysis. A very convenient form and size is a piece of boiler iron about 12 x 16 inches, with four legs. It is a good plan to cover the top with a thin piece of as- bestos board. A tin lined copper can of about one gallon capacity, with two tubes attached near the bottom for con- necting rubber tubes, is very convenient for keeping hot water. This can be so placed that one of the rubber tubes may be used to give a jet of hot water for washing precipi- tates on the filters, using an ordinary pinch cock near the spritz end of the tube for control. The Rational Analysis. On account of the impure and highly feldspathic charac- ter of most of the clays dealt with in this report, the ra- tional analysis as ordinarily conducted would have little significance. The treatment of the sample to drive cut the clay substance may result in a loss of as much as twenty per cent of the feldspar contained in the clay. It was therefore deemed best to calculate the feldspar and kaolin from the ultimate analysis, using the following percentage compositions of feldspars: K,O, 16.9; Al.O,;, 18.4; 6SiO, 64.7; and Na,O 11.8; AJl,O;, 19.5; 6SiO,, 68.7; and kaolin Al.0O, 39.5; 2 SiO, 46.5; 2 H,O 14; as given by Dana,? as a working basis. All the potash and soda were figured to feldspar. The alumina required for the feldspar was deducted from the total alumina and the difference was taken as the starting point from which to figure the kaolinite substance. The difference between the total silica (SiO.) and that required by both feldspar and kaolin gives the quartz and the silica in silicates other than those mentioned. 1 Karl Langenbeck, ‘‘ Chemistry of Pottery,’ pp. 9-10. 2*« A Text Book of Mineralogy,”’ pp. 371, 377, and 481. 268 THE CLAYS OF WISCONSIN. These determinations will be very close except for the samples of shale from Halcyon, Grand Rapids, and Eau Claire. The microscopic examination of these clays re vealed other silicates than those considered in the calcula- tions. Therefore the volumes computed will be slightly low in the feldspathic constituent and a trifle high in kao- linite substance and quartz. The factors used for feldspar were: Al,O, for K.0 =#%K,0 x 1.0888 SiO, for K,.0 =—4%K,0 x 3.8284 Al,O, for Na,O = @Na,O x 1.6525 SiO. for Na,O = ¢Na,0O x 5.8221 For kaolin: SiO, for Al,O, = ¢ Al,O, x 1.1772 H,O for Al,O, = % Al,O, x 0.3544 Determination of the Refractory Quotient. Bischof’s refractory quotient was determined in order to show the relation existing between the quotient for these, for the most part impure clays of lower fire qualities, and the true pyrometric values which are to be determined later. Bischof’s formula is: Q = On AlO: 0 in SiO, | OimRO ~ OmAl,0, In this formula, the O in RO must be multiplied by three to make it conform to the atomic weights that he used, and the O combined with the iron must be figured as being combined in the ferrous condition as FeO. Therefore the formula is better written Oin Al,O, OinSiO, _ (Oin Al, O03)? 2=-g0im RO OMAR, (0 in RO) X (O in Si,) * APPENDIX—EXAMINATION OF CLAY DEPOSITS. Factors: O in SiO, =¢ SiO, x 0.5298 O in Al,O,=¢% Al,O, x 0.4696 Oin FeO =¢ Fe,0,; x 0.2000 Oin CaO =¢CaO x 0.2853 O in MgO =¢ MgO x 0.3971 O in MnO =¢ MnO x 0.2254 O in K,O =¢K,0 x 0.1698 O in Na,O =¢ Na,O x 0.2571 269 THE CLAYS OF WISCONSIN. 270 "sIMIOg "SG "M ‘IW 4q powmsojied sossyTeuy y SP'OOT j"OOVTL |gh°O Joe's joer jxtE jez't {o9'e [peer LUTL foo'g peo. “a “eg |" Boddy O syed eacddryD @O°OOE fo" /88°O JFo°s lep'o |egce Jeror loo'e ler'rr lte'ce Gerzg [17°90 OTLL PUue Jog woysaying |*"***"* eUpoey ore og saTpINg FO'OOL |"9981T, |oF'O Jou seo Jers |se-or lore |xe-Fr |g9-eF foun [°7°°'O OTHE Bue YONI woysurping |* ***** euroey +++ qoqSuTping HerOOr J"""""" 1080 I2e'e f9z'0 feta Jor loos !zerr jex'er loner [077777 SOMA OTHE Toastag j°""* Bqsouey |*°°""*"** TASH BeOOT pen" 09'O HF9"e Heg'o [za [er-or Jone Jex'ar los oF er-sn [T7717 STOMA OTKL Tosstngy |*°°* BISON [-"* °° TOAST BOOT f°" /9F'O eT |e9°O faa-aE frevLT sez to's lug-es lrovg [9 SFOA OUTTA | TOISUTISEAA |°*"* OTTTATOITOR 6EOOF |**"""""/88"O JoneT |g9ro |ez-ex |et-ex lege fare Ieee sresreseseeccosesss-G2TO4 UIBITITMA |“ UOISUIISE AA |°"** OTTTAUOZTOT ¥6'66 “\8F'O |Fp'e |ee'E jeo's lone |o9°p Iee-en |ze-19 lot'e |°°'°'°' CO NOMA pesserg uoso[eH |**** * UOSsyOVL [STL JeaTY A 8e°00T fOOPLL [OMON TIS S [seo |xo'2 |t9°O |xz'2 lea Lt loe'z9 los’ |°°'''**’ OO OM pessorg wodoTeH |****** wosHoL |syT TOATY AT ¥8°66 = [ean STON lf6°S les’0 j6o’e |ea't [zoe |ee'ot \zcce9 Igep [°° °°'' CO AOMA Pesserg uosoveH |****** UOSHOVL’ |STTT JOATY ATT 86°66 |S0°0 ‘86'S |2e'0 Ite" |eo't |zz’e !og-er |zs'e¢ leva [°° OO NOMA pesserg uosopeR |****** WosyoVL |sT]T.A IOATY A1 8L'66 /OOVLL /OUON €2° [070 JOST [920 |ee'0 |o'or logan lege |" °°’ OO TOMA Pessorg uodopeH |--**** osHOeL |/sTT.J JOATY TT 86°66 {19'0 = ISL'0 [90°E |gs°O |98°9 |ec’o jez’er jos‘ut lero jor'n |°°°**' CI9°ID STIeEH) pedopeaepuy |**"'** wosxoee |sqT.f 104TY AT OF QOL jeoeaL |"*"** Neue jeg'o late Teo |Fo'or lor'st |se'6s lor'y “*(Je2IQ STTPH) pedopesopug |****** uosyour Ted 208TH 1G ¥6'66 |90°0 = |S4® 46° j9L°0 069 |'sqe jco'T |10°ST jog"oL [ozs |°7"'"*"' CO HOM pessarg wosoeH |****** WosHoeL |sTT.A 164TH AIA BOOT [CORLL /€6°0 feat |#8°O jLe-L [est jxe'e [eee lozer lost |" “SOM AOLIG We Joeavog |*""""*"* eSpoq |** meq reaveg 90°00T |'e981L, |0S°0 jo8'2 |For lzg'o |es'o lose Jeg zt jog'en let's |’ “SILOM NOM weg zeavog |-""*:-: es#pog | ‘me r9Aveg eF'oor [evr joe’ lost lre-0 lepz loser loree Ieee lever leour |e coc eoppeg uyog | |guctr let-pe loge [occ pong Wee - 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OD OTTT, 3 YOIIg OnBMvYG |-""** OMBMBAG | **"" ‘OUR eYG [78 eo 5 2 & = Eg e io = = B “AUN “SIO i je ee oe Tae oa | ‘A10908,q JO OWEN ‘ON 7 a ‘NOILVOO'T ‘penuryu0g — sfinjo ussuoos74 fo sashjpun 1p01W2YY) —T ‘ON TIAV CHEMICAL ANALYSES. O75 Taste No. Il.— ational analyses and Bishof’s refractory quotient. Free SiO, | = Oxygen ra- aa Total “as othe! Feld: | Kaolin- | Oxygen ‘ina 10 3.0 ee with number | fluxes, | ,Siicutes | spathic lite baso.|Fatio SiOz jin, RO. All) “Eon” in Table I. than feld-| matter. to Als Os | Fe caleu- |quctiont. aolin. + Fev. iL cetererslsteieteas 11.31 29.58 22.88 36.76 3.706 1.152 3uL @ syeedeiees 24.78 31.10 17.51 14.43 6.198 188 -030 8 eserseaete 8.25 48.35 22.43 21.80 6.451 1.104 07 Wisco cemm otia 25.08 31.20 16.08 15.80 6.008 193 032 By saineienene 6.31 88.67 23.84 34.30 4.404 201 457 Be ccasesars orssaross 17.72 27.18 26.46 33.29 3.732 0.691 -186 T rccncsevee 23.95 19.06 23.02 34.45 3.162 0.456 144 8 eaves dances 7.74 38.53 34.34 24.56 5.079 1.453 286 D ssnssiwes 18.23 21.56 25.97 37.42 8.216 - 704 219 10 aveuxcces 13.03 35.02 26.08 29.09 4.526 7184 178 ML, .Seccdomntes: 11.20 31.36 37.57 26.18 4.445 1.059 -238 12 weoescaces 16.21 29.88 31.55 20.38 4.940 587 -119 IBS ici deSisisinrains 85.45 13.99 16.18 10.30 4.676 101 021 V4 ccccnvcoes 4.71 13.18 16.55 12.38 4.207 -116 028 TT scccanexes 24,55 15.79 25.30 24.51 3.429 831 097 1B ..ecceae C 30.34 14.20 19.35 19.22 3.610 198 055 9.50 45.65 23.79 22.41 5.893 -960 163 9.61 50.03 23.00 13.79 7.128 857 120 12.06 40.41 31.25 17.80 6.066 739 122 Bo eeenaynn . 27.39 63.85 24.23 9.99 6.232 -169 027 BS) saidoweues 14.35 34.85 29.77 20.99 5.225 -616 -118 24 icniiesccs 17.47 28.88 33.92 19.29 4.859 616 -106 De eraeastens: 19.81 32.02 28.12 18.05 5.363 404 075 DD: ssaninnaas 15.39 29.38 30.21 25 .09 4.416 639 +145 Ol weriewsien 8.70 49.59 31.07 16.02 7.003 984 141 BS: cntesecides 13.15 2.08 35.77 52.61 2.052 1.450 -706 16.00 13.94 41.29 35.40 2.989 926 -310 20.54 7.36 46.18 30.26 2.835 -666 235 4.26 2.66 6.42 86.20 1.504 6.065 4.033 44.99 35.46 8.54 1.31 2.100 037 002 BS cn ceceeeee 23.54 27.27 21.74 Tide 5.159 248 048 Bf cecaeers 24.56 26.22 20.54 16.81 6.116 229 045 BH cece eeees 31.00 16.39 18.70 16.73 4.065 170 042 276 THE CLAYS OF WISCONSIN. Tasxe No. IIl.— Rational analyses and Bishof’s refractory quotient— Continued. Number cor- ‘and SiO: tio. “aan Bishof’s cgpponding, | otal | alicates | spatiic | Klas latip S10» fa RO. ali] trae in Table I. " | than feld- | matter. to Als Us | He calou |auotiont, Eachin: FeO. 96) ve sniednone 32.34 14.10 18.75 18.75 4,222 144 +084 87 cess sassices 32.93 18.20 20.90 12.15 4,221 .138 -033 89 se euiskiniis 0.66 34.22 2.66 62.91 2.903 83.054 11.362 AD? scvcacsiine 27.27 20.49 25.54 19.19 4.187 » -268 .064 AL saxascscuse 38.99 8.32 13.35 37.44 2.251 +269 -120 BD: aisisieieisisine 6.56 36.34 18.87 40.41 3.909 2.182 645 MB cosdieeietnie 25.68 21.11 28.84 18.05 4.368 282 -065 4A ecueeeees 27.06 20.82 24,29 15.93 4.602 219 048 Cs . 27.28 19.17 26.39 14.79 4.544 218 048 4B wccceeeeee| 15.35 26.20 33.79 24.86 4,195 -726 173 AT scone cents 1.18 22.18 4.55 72.68 2.250 17.187 7.617 BB ica seine 0.38 32.87 1.84 65.47 2.717 68.350 24.610 49. 0.96 10.40 4.25 84.30 1.734 23.207 13.383 B4 24.82 14.42 9.09 29.98 2.859 -290 101 55. 27.47 18.34 22.85 19.77 3.973 238 .060 BG. exons 23.79 19.61 25.27 24.43 3.736 .363 .097 BS swisleteocee 18.84 43.44 28.68 13.16 7.282 452 .062 69) eesiescaeee 9.95 46.22 31.61 14.61 7.121 -766 -108 60. advcesaes 9.91 46.39 28.70 16.51 6.902 -795 15 GL sucienceied. 15.53 34.80 33.41 18.28 5.465 561 -108 162: sinecceawaay 15.74 33.85 34.71 16.73 5.551 555 -100 6B. ss wiasorcsiscels 15.74 34.06 29.24 21.59 5.102 .583 114 64 cneeties 15.72 19.52 52.22 19.62 4.056 860 212 GB: seeaewsices 13.63 17.01 56.11 20.36 3.857 1.223 -81T 69 .cccceecee 30.23 11.03 25.07 17.77 3.450 203 059 10 ccccens 33.72 11.27 21.98 12.86 3.892 141 036 WB i ..{ 29.80 13.41 26.45 17.77 3.688 +230 062 MD) coos ecciee 25.75 19.37 30.20 17.06 4,297 271 .068 18> rss 'sinessisinre 9.14 45.44 21.05 23.57 5.997 979 167 MAS sain baleen 10.14 43.99 26.25 20.00 6.205 .876 141 MID: Sicsaicineiorae 29.02 27.35 18.01 8.58 7.187 -118 -016 TB sacs 29.72 21.05 15.33 14.73 4.930 146 030 CHEMICAL ANALYSES. vad Tass No. II.—Rational analyses und Bishof's refractory quotient— Continued. Number cor- ‘and sie ae Bishof’ srmppondipg | Zotal | ‘eiteates | apathic Ain: actERe, lin RO. ‘ah| Petree in Table I. than fold-| matter. : 2 Og | Fe caleu- | aotiant, aolin. FeO. Th. daweetaniscos 29.30 14.65 25,04 15.87 3.975 -199 -050 1B deaen gees 24.89 18.88 21.22 15.19 4.514 177 039 19 scascvaues 22.94 31.99 20.84 13.93 6.259 0.217 035 80. czas secs 1.99 1.73 9.77 85.52 1.684 12.114 7.203 St sacneeeis 25.55 21.75 32.05 21.48 4.4115 398 | .097 BOs csian en tele 25.01 25.10 30.61 20.38 4.492 385 -086 BB nreecvasee 30.99 17.83 27.24 15.55 4.268 296 069 BB nceteccnes 28,19 24.48 |. 23.46 12.69 5.501 -184 033 BF. snewianiiee 28.09 19.86 24.33 16.69 4.420 -218 049 BB ccvceneees 31.82 16.39 21,98 11.72 4.687 145 031 89 ccs eeeeeee 29.96 21.67 19.12 9.87 5.855 «123 022 32.38 21.31 18.37 9.19 5.999 114 019 31.46 16.09 21.88 13.45 4.403 +157 036 28.45 20.08 27.60 12.28 4.933 196 040 10.29 43.56 22.84 24.43 2.661 916 162 8.27 61.86 21.23 20.69 7.001 -998 143 95 .ceseeeees{ 16.29 26.09 23.33 26.66 3.498 +738 211 99) cers 7.37 49.89 22.56 21.14 6.690 1.203 -180 TOO: cczexess . 6.64 55.07 21.97 18.36 7.738 1.138 147 OL .rrcreaeee 33.90 12.83 19.97 12.63 4.127 133 032 102 ....000e . 11.74 40.99 29.05 20.36 5.817 780 134 IOS ...ccnvees 10.89 41.00 30.41 19.91 5,852 832 142 25.04 19.59 23.50 19.12 4.191 256 -061 8.03 50.28 23.36 19.80 6.882 1.068 155 8.46 48.51 23.06 21.22 6.533 1.048 160 978 THE CLAYS OF WISCONSIN. Taste No III.—Analyses of typical 3 ; s 5 : 21/3518) ./8 a & E iss) & 3 = 3 S| 3 . oy £ i a} = a27| & | a 8 8 Location. 2 é a a 2 = 6 5 & 6 - 8 4 a= ge| 2) 24) Bal 2 | gg) 2 | & a a 4 5 = 4 4 2 VITRIFIED OR Arkansas, Fort Smith, shale.... .......| ..... 58.42) 22.50) 6.20]. 8.35!...... 1.14 Georgia, Cartersville, residual clay....]... .. 58.63) 20.4.| 7.06] 0.20) 8.58} T’ce| 1.42 Illinois, Galesburg, shale.... .. ... .J.. 68.69} 17 95) .....] 22... 7.25; 0.76) 1.47 Illinois, Streator, shale.. ...... 2... ..J... 5. 61.76) 18,32) 7.94) ..... 2.04).. ...] 1.45) Indiana, Clinton, shale..... ......-..... .e « | 48.13] 40.87] 9.48]...... 3.44) 2.01] 0.97 Iowa, Des Moines, shale... ............ 60 34! 24.26] 1.66)...... 7.73] 1.85) 0.70 Kentucky, Robbins, shale..............)....-- 70.57] 15.19) .....).... 7.97] 0.781 0.82 Kentucky, Butler county, shale ... .. |...... 51.66) 15.56] 13.44]...... 7.68; 7.27] 0.82 New York, Howelsville. .......... 06. | se. 64.45] 17.77) oa sasis 7.04] 0.58] 1.85 Ohio, Canton, shala,... 57.10) 21.29) 6.00' 1.30) 7.31] 0 29) 1.58 Ohio, Independence, shale........... «| ....- 57.40] 21.20) 7.75 6.57] 1.00] 1.40 ‘ FIRE Alabuma......... Choctaw County.... 83.30) 5.12) 6.60)...... 1.60) 0.46)...... Colorado......... Golden yecccicies vo:l|lesiw a 48.88) 35,42) 14.10)...... 1.74) 0.44) 0 20 Colorado. .......| Morrison....... 0 ..} ..... 71.80} 15.00) 8.30 T’ce| 3.80].. ... Illinois............ Wticasieosnseconseny 1.15] 56.65] 26.45) 9.80} 210} 2.10)... 0.30) Kentucky. ...... Gormon, Carter Co.| ..... 49.75] 85.16) 14 03}. ....] 0.80) 0.54) 0.15 Maryland .. .| Mt. Savage.......... ois 50.46) 85,91} 12.78)...... 1.51} 0.13] 1.02 Maryland ........ Mt. Savage. ..... . 55.75] 33.23] 10.37)...... 2 06) ..... New Jersey..... Woodbridge ........].-.... 54 9) 31.66) 10.50) 0.60) 0.74)......J..... New Jersey..... | Bonhampton........ 1.60) 75.25) 15.50} 4.90) 1.80) 1.20). ....).... OO wis saciewen ace Gaylord, Scioto Co..}.. ...| 44.34} 40.05] 14.24]...... 0.80} 0 27) T’ce Ohio........ eiseetis Sallueville .......... 59.92) 27.56) 9.70} 1.12) 1.03] T’ce| T’ce Pennsylvania,....| Johnstown... 1.55) 45.25] 38.84] 12.50] 0.70) 0.91]......]...... Pennsylvania.....| Clinton... 1,46| 63.18} 23.70] 6.87] .. 1.20) 0.17) 0.47 Pennsylvania. Woodland Mine. ...| ..... 45.29) 40.07) 18.18]...... 1.02) 0.26) 0.08 clays outside of Wisconsin. CHEMICAL ANALYSES. 279 : is g 6 . wv rel 2 leh o Mie | £ |e] 2 a A 3 a 8 Age, Authority. 3 é % ar 3 } 3 & 8 4g Se Soles PAVING BRICK. 2.18) 1.08) 8. 1.16} 13.86] 100.9} Coal Meas a ir Vol, XILI, No. 8, cago. 886) 0.14 14,00} 160.86] Paleozoic........] Georgia Geol. Surv., Geology of Paleozoic, Spencer, 1899. 2 83... 12.31] 100.00} Coal Meas...... Cy ae April, 1895 (Meade), ndiana)olis. 3.49) . 11.98) 100.00] Coal Meas, .....| As above. 0.02] . 6.44; 99.92] Coal Meas.......| As above. 8.12 12,90} 99.16) Coal Meas.......| As above. 1,15), 10.22) 100.00] Coal Meas, As above. 8.57]. 19.82} 99.98] Coal Meas..... . | As above, 2.62) 18.94] 96.16} Devoniap.. .. ..| Clay Industries of N. Y., Ries, Al- ee 8.44 13.18] 98.87] Coal Meas. . ...| Clay Worker, May, 1894, Orton, Indianapolis. 4.10 14,07) 100 42] Coal Meas..... ..| Clay Worker, May, 1894, Orton, Indianapolis, BRICK. ete vets 2.06) 100.08] Tortiary ........| Ala, Industrial and Scien. Soc., Proc., Vol. I. 1.19 8.57] 99.77] Cretaceous. .....| Tablea of Analyses of calys, Cross- oF Indianapolis, 1889, Catto 8 80} 98.90] Cretaceous......| U. 5S. Geol. Survey, Mineral Re- sources for 1592, 1,10) 3 50} 99.65] Coal Meas.... .. N. J. Geol, Survey, Report on Class, Cook, Trenton, 1878, 0.07 1.06] 100.00] Coal Meas, .| Tables of Analyses of Clays, Cross- ley, Indianapolis, 7889, T’ce 1.64] 100.79] Coal Meas....... Brickmmaker, Vol, XII, No. 3, Chi- cago. sielangeh 2.06) 101.41} Coal Meas,...... Brickmaker, Vol. XIII, No. 3, Chi- cago. 1.53) 2.27] 99.98] Creta. (Wood bridge bed)...| N. J. Geol. Surv., ar on Clays, Cook, Trenton, 1878, DAT neces rapacesae 1.87] 99.92] Creta. (Wood- | N. J. Geol. a yes eyore on Clays, bridge bed)... Cook, Trenton, 1878. T’ce.| T’ce.|........ ..| 1.07] 99.79} Coal Meas...... Clay Worker, August, 1895, (Orton) ..| Indianapolis. OF BE seins Mowers ...{ 1.70] 100 00] Coal Meas....... Clay Worker, August, 1895.,(Orton) Indianapolis. OL S5 | cciete| sere oes ee 1.26] 100.10] Coal Meas,...... N, J. Geol, Surv., Report on Clays, Cook, Trenton, 1878, BBQ eesyes $030.19] 4.55} 99.76) Coal Meas,...... Penn, Geol. Survey, Vol. L. 0 O8)...... a 1.46] 100.C0] Coal Meas (cal-| Tables of Analyses 0” Clays, Cross- cine)... 2... ley, Incianapolis, 1889. THE CLAYS OF WISCONSIN. 280 Taste No. [1l—Analyses of typical oe o z y 5 3 ° alll