THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 OF CALIFORNIA 
 
 LOS ANGELES 
 
 The RALPH D. REED LIBRARY 
 
 DEPARTMENT OF GEOLOOY 
 
 UNIVERSITY OF CALIFORNIA 
 
 LOS ANGELES, CALIF. 
 
 Robert W. Webb.
 
 ROBERT W. WEBB 
 GEOLOGY DEPT., U.C.L.A;
 
 ^
 
 ECONOMIC GEOLOGY 
 
 OP THE 
 
 UNITED STATES
 
 ECONOMIC GEOLOGY 
 
 OF THE 
 
 UNITED STATES 
 
 BY 
 
 HEINRICH RIES, A.M., PH.D. 
 
 PHOFESSOR OF ECONOMIC GEOLOGY AT CORNELL 
 UNIVERSITY 
 
 THE MACMILLAN COMPANY 
 
 LONDON: MACMILLAN & CO., LTD. 
 
 1908 
 All rights reserved
 
 COPYRIGHT, 1905, 1907, 
 BY THE MACMILLAN COMPANY. 
 
 Set up and electrotyped. Published November, 1905. 
 New edition January, 1907 ; February, 1908. 
 
 Norton oft I3rcsa 
 
 J. 8. Cashing & Co. Berwick & Smith Co. 
 Norwood, Maas., U.S.A.
 
 Library 
 
 TV 
 
 PREFACE 
 
 THE following work on the Economic Geology of the 
 United States covers essentially the ground which is gone 
 over in the elementary course in this subject in Cornell 
 University, but it is hoped that it will prove useful as a 
 text-book in other colleges. 
 
 The mode of arrangement is markedly different from that 
 found in other books on the same subject, in that the non- 
 metallic minerals are discussed first and the metallic minerals 
 last. This, to the author, seems the most desirable method 
 of treatment, for the reason that the non-metallics are not 
 only the most important, the value of their production 
 having exceeded the metallics by over one hundred and 
 fifty million dollars in 1903, but also because it leads from 
 a discussion of the simpler to the more complex forms of 
 mineral deposits. 
 
 It has not been thought desirable to include a chapter on 
 geologic and physiographic principles, since the space which 
 could be allotted to it is altogether too small, and, more- 
 over, the study of economic geology presupposes a knowl- 
 edge of geology and mineralogy on the part of the student. 
 While the references given at the end of each chapter do 
 not include every paper that has been written on the subject 
 to which they refer, still it is believed that they are suffi- 
 ciently numerous to permit one to follow out the subject in 
 considerable detail if he so desire. 
 
 In the preparation of the manuscript all available sources 
 of information have been freely drawn upon, and the num- 
 bers in parentheses in the text refer to the numbered refer- 
 ences at the end of each chapter. 
 
 562949
 
 Vi PKEFACE 
 
 All statistical figures, unless otherwise stated, are taken 
 from the reports of the United States Geological Survey. 
 
 Descriptions of mineral occurrences in foreign countries 
 are not included, except in a few cases where the deposits 
 serve as an important if not the only source of supply for 
 the United States. 
 
 The writer wishes to express his thanks to Professor R. S. 
 Tarr for examination and criticism of much of the manu- 
 script, and to W. E. McCourt, Instructor in Geology, and 
 H. Leighton, Assistant in Geology, for aid in the preparation 
 of drawings and statistical tables. For the loan of photo- 
 graphs or cuts acknowledgments are due to Messrs. H. F. 
 Bain, J. E. Spurr, J. M. Boutwell, G. H. Eldridge, W. Lind- 
 gren, F. H. Oliphant, and J. H. Pratt of the United States 
 Geological Survey ; Professor A. C. Lane, Michigan Geologi- 
 cal Survey; Dr. D. H. Newland, New York State Museum; 
 Professor C. C. O'Harra, South Dakota School of Mines; 
 Professor E. A. Smith, Alabama Geological Survey ; Pro- 
 fessor G. H. Perkins, Vermont Geological Survey ; Dr. H. B. 
 Kiimmel, New Jersey Geological Survey ; Dr. W. B. Phillips, 
 Texas Geological Survey ; Dr. G. P. Merrill, United States 
 National Museum; also to Messrs. H. W. Turner, F. S. 
 Witherbee, A. W. Sheafer, L. Martin, Wiley & Sons, Ver- 
 mont Marble Co., and Bedford Quarries Co. 
 
 CORNELL UNIVERSITY, 
 ITHACA, N.Y., June, 1905.
 
 PREFACE TO THE SECOND EDITION 
 
 THE publication of a second edition has become necessary 
 in such a comparatively short time, that it has not been 
 deemed advisable to materially alter the text. An attempt 
 has, however, been made to correct all errors of which the 
 author has knowledge. Recognizing the value of fresh 
 statistics, those for 1905 (the most recent available) have 
 been given in an appendix, and for the benefit of those who 
 make use of the bibliography, a second appendix has been 
 included, containing a list of the more important papers 
 published since the appearance of the first edition. 
 
 CORNELL UNIVERSITY, 
 
 ITHACA, N.Y., Nov. 10, 1906. 
 
 vii
 
 CONTENTS 
 
 FAGK 
 
 PREFACE v 
 
 CONTENTS vii 
 
 LIST OF ILLUSTRATIONS xv 
 
 LIST OF ABBREVIATIONS zxi 
 
 PART I 
 
 NON-METALLIC MINERALS 
 
 CHAPTER I 
 
 COAL 3-38 
 
 Kinds of coal, 3 ; Peat, 3 ; Lignite, 4 ; Bituminous coal, 4 ; Cannel 
 coal, 5 : Semi-bituminous coal, 5 ; Anthracite coal, 5 ; Proximate 
 analysis of coal, 6 ; Origin of coal, 9 ; Conditions of vegetable 
 accumulation, 10 ; Chemical changes occurring during coal forma- 
 tion, 12 ; Effect of heat and pressure, 14 ; Structural features of 
 coal beds, 15; Outcrops, 15; Associated rocks, 16; Variations in 
 thickness, 16 ; Other irregularities, 17 ; Coal fields of the United 
 States, 18; Geologic distribution of coals in the United States, 19 ; 
 Appalachian field, 20 ; Bituminous area, 21 ; Character of Appa- 
 lachian bituminous coals, 22 ; Pennsylvania anthracite field, 22 ; 
 Rhode Island field, 25 ; The Triassic field, 25 ; Eastern Interior 
 field, 26 ; Northern Interior field, 27 ; Western Interior field and 
 southwestern fields, 28 ; Western Interior field, 29 ; Southwestern 
 field, 29 ; Gulf states lignite area, 30 ; Rocky Mountain fields, 30 ; 
 The Pacific Coast fields, 31 ; Alaska, 32 ; Production of coal, 33 ; 
 Production of coke, 35; References on coal, 35; References on 
 peat, 38. 
 
 CHAPTER II 
 
 PETROLEUM, NATURAL GAS, AND OTHER HYDROCARBONS . . 39-68 
 
 History of petroleum development, 39 ; History of natural gas 
 development, 40 ; Properties of petroleum, 40; Properties of natural 
 gas, 42 ; Mode of occurrence, 43 ; Pressure of oil and gas wells, 44 ; 
 Origin, 46 ; Inorganic theory, 46 ; Organic theory, 47 ; Geological
 
 X CONTENTS 
 
 PAGE 
 
 distribution of petroleum and natural gas, 48 ; Distribution of 
 petroleum in the United States, 48 ; Appalachian field, 48 ; Ohio- 
 Indiana field, 60 ; Texas-Louisiana oil fields, 51 ; Kansas, 62 ; Cali- 
 fornia, 62 ; Wyoming, 63 ; Colorado, 53 ; Alaska, 54 ; Distribution 
 of natural gas in the United States, 54 ; New York, 64 ; Pennsyl- 
 vania, 54 ; West Virginia, 55 ; Ohio, 55 ; Indiana, 55 ; Kansas, 55 ; 
 Uses of petroleum, 66 ; Uses of natural gas, 56 ; Oil shales, 66 ; 
 Solid bitumens, 57 ; Occurrence, 57 ; Asphaltites, 58 ; Albertite, 
 59 ; Anthraxolite, 69 ; Ozokerite, 59 ; Grahamite, 59 ; Lake asphalt, 
 69 ; Uintaite or gilsonite, 59 ; Manjak, 59 ; Bituminous rocks, 60 ; 
 Analyses, 60 ; Uses, 61 ; Production of petroleum, natural gas, 
 and asphaltum, 61 ; References on petroleum, 66 ; References on 
 natural gas, 67 ; References on oil shale, 67 ; References on as- 
 phaltum, 67. 
 
 CHAPTER III 
 
 BUILDING STONES 69-91 
 
 Properties of building stones, 69 ; Color, 70 ; Texture, 70 ; Den- 
 sity, 70 ; Hardness, 71 ; Strength, 71 ; Crushing strength, 72 ; 
 Transverse strength, 72 ; Porosity and ratio of absorption, 73 ; 
 Resistance to frost, 73 ; Resistance to heat, 73 ; Structural features 
 affecting quarrying, 74 ; Bedding planes, 74 ; Granites, 75 ; Char- 
 acteristics of granites, 75 ; Distribution of granites in the United 
 States, 76 ; Eastern crystalline belt, 77 ; Central states, 77 ; West- 
 ern states, 77; Uses of granite, 77; Miscellaneous igneous rocks, 
 78 ; Limestones and marbles, 78 ; General characteristics, 78 ; 
 Varieties of limestones, 79 ; Distribution of limestones in the 
 United States, 80 ; Distribution of marbles in the United States, 
 81 ; Onyx marbles, 83 ; Serpentine, 83 ; Sandstones, 84 ; General 
 properties, 84 ; Varieties of sandstone, 85 ; Distribution of sand- 
 stones in the United States, 86 ; Uses of sandstones, 87 ; Slates, 
 87 ; General characteristics, 87 ; Distribution of slates in the 
 United States, 88; Uses of slate, 89; Production of building 
 stones, 89 ; References on building stones, 90 ; References on 
 onyx marble, 91. 
 
 CHAPTER IV 
 
 CLAY 92-108 
 
 Definition, 92 ; Residual clays, 92 ; Sedimentary clays, 93 ; 
 Marine clays, 94 ; Flood-plain clays, 94 ; Lake clays, 94 ; Glacial 
 clays, 94; jEolian clays, 94; Properties of clay, 95; Chemical 
 properties, 95; Physical properties, 96; Plasticity, 96; Tensile 
 strength, 96 ; Shrinkage, 96 ; Fusibility, 97 ; Specific gravity, 97 ;
 
 CONTENTS xi 
 
 PAOK 
 
 Chemical composition, 97 ; Classification of clay, 98 ; Kinds of 
 clay, 99 ; Geological distribution, 100 ; Distribution of clays in the 
 United States by kinds, 100 ; Kaolins, 100 ; Fire clays, 102 ; Pot- 
 tery clays, 103 ; Brick and tile clays, 104 ; Miscellaneous clays of 
 importance, 104 ; Uses of clay, 105 ; Production of clay, 105 ; 
 Eeferences on clay, 106. 
 
 CHAPTER V 
 
 LIME AND CALCAREOUS CEMENTS 109-123 
 
 Composition of limestone, 109 ; Changes in burning, 110 ; Lime, 
 110 ; Hydraulic cements, 111 ; Pozzuolano cements, 111 ; Hy- 
 draulic limes, 112 ; Natural rock cements, 112 ; Portland cement, 
 113 ; Distribution of lime and cement materials in the United States, 
 116 ; Limestone for lime, 116 ; Hydraulic limes, 117 ; Natural rock 
 cement, 117 ; Portland cements, 118 ; Uses of lime, 119 ; Uses of 
 cement, 119 ; Production of cement, 120 ; References on lime and 
 cement materials, 121. 
 
 CHAPTER VI 
 
 SALINES 124-138 
 
 Salt, 124 ; Occurrence of salt in sea and lake waters, 124 ; Rock 
 salt, 125 ; Origin of rock salt, 125 ; Natural brines, 127 ; Salt 
 marshes and soils, 127 ; Distribution of salt in the United States, 
 127; New York, 127; Michigan, 129; Other eastern states, 129; 
 Louisiana, 129 ; Kansas, 130 ; Other western states, 130 ; Extrac- 
 tion, 131 ; Uses, 132 ; Production of salt, 132 ; References on salt, 
 134; Borax, 134; Borax minerals, 134; Distribution in United 
 States, 134 ; Uses, 134 ; Production of borax, 136 ; References on 
 borax, 136 ; Sodium sulphate, 136; References, 137 ; Sodium car- 
 bonate, 137 ; References, 137 ; Soda niter, 137 ; References, 138. 
 
 CHAPTER VH 
 
 GYPSUM 139-146 
 
 Gypsum, 139 ; Anhydrite, 139 ; Origin of gypsum, 139 ; Gypsite, 
 140 ; Distribution in the United States, 140 ; Iowa, 140 ; Kansas, 
 141 ; Michigan, 142 ; New York, 142 ; Other occurrences, 142 ; 
 Analyses, 143 ; Uses, 143 ; Production of gypsum, 145 ; References 
 on gypsum, 146. 
 
 CHAPTER Vm 
 
 FERTILIZEBS . . . . . . . . . * .; . 147-167 
 
 Phosphate of lime, 147 ; Apatite, 147 ; Amorphous phosphates, 
 147 ; Florida phosphates, 148 ; Land pebble or matrix rock, 149 ;
 
 CONTENTS 
 
 PAGS 
 
 River pebble, 149 ; South Carolina phosphates, 150 ; Tennessee 
 phosphates, 160; Other phosphate occurrences, 153; Composition, 
 153 ; Uses, 154 ; Guano, 156 ; Greensand, 155 ; Production, 156 ; 
 References on fertilizers, 157. 
 
 CHAPTER IX 
 
 ABRASIVES 158-166 
 
 Introductory, 158 ; Grindstones, 158 ; Whetstones and oilstones, 
 159 ; Buhrstones and millstones, 161 ; Pumice and volcanic ash, 
 161 ; Infusorial earth and tripoli, 162 ; Crystalline quartz, 163 ; 
 Garnet, 163 ; Corundum and emery, 163 ; Artificial abrasives, 165 ; 
 Production of abrasives, 165 ; References on abrasives, 166. 
 
 CHAFIER X 
 
 MINOR MINERALS 167-203 
 
 Asbestos, 167 ; Asbestos minerals, 167 ; Distribution, 167 ; Uses, 
 169 ; Production of asbestos, 169 ; References on asbestos, 169 ; 
 Barite, 170 ; Uses, 170 ; Production, 170 ; References on barite, 
 171 ; Fluorspar, 171 ; Distribution in United States, 172 ; Uses, 173 ; 
 References on fluorspar, 174 ; Fuller's earth, 174 ; Production of 
 fuller's earth, 176 ; References on fuller's earth, 176 ; Glass sand, 
 176 ; References on glass sand, 178 ; Graphite, 178 ; Distribution 
 of graphite in the United States, 178 ; Uses, 179 ; Production of 
 graphite, 180 ; References on graphite, 181 ; Lithographic stone, 
 181 ; References on lithographic stone, 183 ; Lithium, 183 ; Mag- 
 nesite, 183 ; References on magnesite, 184 ; Mica, 184 ; References 
 on mica, 186 ; Mineral pigments, 186 ; Hematite, 186 ; Ochers, 186 ; 
 Slate, 187 ; Gypsum, 187 ; Barite, 187 ; Asbestos, 188 ; Graphite, 
 188 ; Calcium carbonate, 188 ; Other paints, 188 ; Production of 
 mineral pigments, 189 ; References on mineral paints, 189 ; Mold- 
 ing sand, 189 ; References on molding sand, 190 ; Monazite, 190 ; 
 Uses, 191 ; Production of monazite, 191 ; References on monazite, 
 191 ; Precious stones, 192 ; Diamond, 192 ; Ruby, 193 ; Sapphire, 
 193 ; Emerald, 193 ; Topaz, 194 ; Turquoise, 194 ; Garnet, 194 ; 
 Opal, 195 ; Other precious stones, 195 ; Production of precious 
 stones, 196 ; References on precious stones, 196 ; Sulphur and 
 pyrite, 196 ; Sulphur, 196 ; Solfataric type, 196 ; Gypsum type, 197 ; 
 Uses, 198; Production of sulphur, 198; References on sulphur, 
 199 ; Pyrite, 199 ; Distribution, 199 ; Uses, 200 ; References on 
 pyrite, 200 ; Strontium, 200 ; Uses, 201 ; References on strontium, 
 201 ; Talc and soapstone, 201 ; Uses, 202 ; Pyrophyllite, 203 ; 
 Production, 203 ; References on talc and soapstone, 203.
 
 CONTENTS Xlll 
 
 CHAPTER XI 
 
 PAGE 
 
 WATER 204-212 
 
 Mineral waters, 204; Distribution of mineral waters in the 
 United States, 205 ; Production of mineral waters, 206 ; References 
 on mineral waters, 207 ; Underground waters, 207 ; Ground water, 
 207 ; Artesian waters, 209 ; References on underground water, 211. 
 
 CHAPTER XII 
 
 SOILS AND ROAD MATERIALS 213-219 
 
 Soils, 213 ; Origin, 213 ; Residual soils, 213 ; Transported soils, 
 213 ; Properties of soils, 213 ; Chemical properties, 214 ; Physical 
 properties, 215 ; Distribution of soils in the United States, 216 ; 
 References on soils, 216 ; Road materials, 217 ; References on road 
 materials, 219. 
 
 PAET II 
 METALLIC MINERALS OR ORES 
 
 CHAPTER XIII 
 
 ORE DEPOSITS 223-250 
 
 Definition, 223 ; Gangue minerals, 223 ; Origin of ore bodies, 
 224 ; Ores of contemporaneous origin, 224 ; Concentration of ores 
 in rocks, 225 ; Formation of cavities, 231 ; Precipitation of metals 
 from solution, 232 ; Replacement or metasomatism, 233 ; Concen- 
 tration by eruptive after-action or pneumatolysis, 234 ; Other 
 causes of precipitation, 235 ; Forms of ore bodies, 236 ; Fissure 
 veins, 236 ; Other forms of ore deposits, 241 ; Secondary changes 
 in ore deposits, 242 ; Weathering or superficial alteration, 242 ; 
 Secondary deposition below water level, 244 ; Value of ores, 245 ; 
 Classification of ore deposits, 246 ; References on ore deposits, 249. 
 
 CHAPTER XIV 
 
 IRON 251-277 
 
 Ores of iron, 251 ; Magnetite, 254 ; Distribution of magnetites in 
 the United States, 264; Non-titaniferous magnetites, 264; Other 
 occurrences, 254 ; Titaniferous magnetites, 267 ; Magnetite sands, 
 258 ; Hematite, 259 ; Distribution of hematite ores in the United 
 States, 259 ; Lake Superior region, 259 ; Clinton ore, 266 ; Other
 
 CONTENTS 
 
 PAOH 
 
 hematite occurrences, 268 ; Limonite, 269 ; Bog ores, 269 ; Residual 
 limonites, 270 ; Other occurrences, 271 ; Siderite, 272 ; Production 
 of iron ores, 273 ; References on iron ores, 276. 
 
 CHAPTER XV 
 
 COPPER 278-302 
 
 Ores, 278 ; Impurities in copper ores, 280 ; Superficial alteration 
 of copper ores, 280; Distribution of copper ores in the United 
 States, 281 ; Montana, 282 ; Michigan, 287 ; Arizona, 290 ; Bisbee 
 or Warren district, 290 ; Jerome district,. 292 ; Clifton district, 293 ; 
 Globe district, 294 ; Appalachian region, 294 ; Utah, 296 ; Call- 
 fornia, 297 ; Other occurrences, 298 ; Uses of copper, 298 ; Produc- 
 tion of copper, 299 ; References on copper, 301. 
 
 CHAPTER XVI 
 
 LEAD AND ZINC 303-324 
 
 Ores of lead, 303 ; Ores of zinc, 303 ; Superficial alteration of 
 lead and zinc ores, 305 ; Distribution of lead and zinc ores in the 
 United States, 305 ; Lead alone, 306 ; Appalachian belt, 306 ; South- 
 eastern Missouri, 306 ; Desilverized lead, 307 ; Zinc ores alone, 
 307 ; Eastern and southern states, 308 ; Sussex County, N. J., 308 ; 
 Virginia and Tennessee, 310 ; Pennsylvania, 311 ; Lead and zinc 
 ores of the Mississippi Valley region, 311 ; Upper Mississippi Valley 
 area, 311 ; Ozark region, 314 ; Origin of the ores, 316 ; Rocky 
 Mountain states, 318 ; Uses of lead and zinc, 319 ; Uses of lead, 
 319 ; Uses of zinc, 320 ; Production of lead and zinc, 321 ; Refer- 
 ences on lead and zinc, 323. 
 
 CHAPTER XVII 
 
 GOLD AND SILVER 325-363 
 
 Ores of gold, 325 ; Ores of silver, 325 ; Mode of occurrence, 326 ; 
 Weathering and secondary enrichment, 327 ; Classification, 327 ; 
 Geological distribution, 329 ; Extraction, 329 ; Distribution of gold 
 and silver ores, 331 ; Cordilleran region, 332 ; Pacific coast Creta- 
 ceous gold-quartz ores, 332 ; Mother Lode belt, 333 ; Nevada 
 County, 334 ; Central belt of gold-silver ores, 335 ; Mercur, Utah, 
 336 ; Other occurrences, 337 ; Eastern belt of Tertiary gold-silver 
 veins, 337 ; Cripple Creek, 338 ; San Juan region, 341 ; Tonopah, 
 Nev., 343; Comstock Lode, Nev., 344; Other occurrences, 345; 
 Auriferous gravels, 346 ; Black Hills region, 350 ; Homestake belt,
 
 CONTENTS XV 
 
 PAGE 
 
 351 ; Siliceous Cambrian ores, 352 ; Michigan region, 352 ; Eastern 
 crystalline belt, 352 ; Alaska, 353; Uses of gold, 357 ; Uses of silver, 
 358 ; Production of gold and silver, 358 ; References on gold and 
 silver, 360. 
 
 CHAPTER 
 
 SILVER-LEAD 364-374 
 
 Silver-lead ores, 364 ; Lead ville District, Colo., 364 ; Aspen, Colo., 
 367 ; Other occurrences, 369 ; Park City, Utah, 370 ; Tintic District, 
 Utah, 372 ; Cceur d'Alene, Ido., 372 ; Montana, Nevada, etc., 373 ; 
 References on silver-lead ores, 374. 
 
 CHAPTER XIX 
 
 ALUMINUM, MANGANESE, AND MERCURY 375-395 
 
 Ores of aluminum, 375 ; Distribution of bauxite in the United 
 States, 376 ; Georgia-Alabama, 377 ; Arkansas, 378 ; New Mexico, 
 379 ; Uses of aluminum, 379 ; Uses of bauxite, 380 ; Production 
 of bauxite and aluminum, 380 ; References on bauxite and alumi- 
 num, 383 ; Manganese, 383 ; Manganese ores, 383 ; Origin, 384 ; 
 Distribution of manganese ores in the United States, 384 ; Eastern 
 area, 385 ; Arkansas, 387 ; Other United States occurrences, 387 ; 
 Uses of manganese, 388 ; Production of manganese, 388 ; Refer- 
 ences on manganese, 390 ; Ores of mercury, 390 ; Mode of occur- 
 rence, 390 ; Distribution in the United States, 390 ; California, 391 ; 
 Texas, 392 ; Origin, 393 ; Uses of mercury, 393 ; Production of 
 mercury, 394 ; References on mercury, 396. 
 
 CHAPTER XX 
 
 MINOR METALS 396-417 
 
 Ores of antimony, 396 ; Distribution of antimony in the United 
 States, 396 ; Uses, 397 ; Production of antimony, 397 j References 
 on antimony, 397 ; Arsenic, 398 ; References on arsenic, 398 ; Bis- 
 muth, 399; Ores, 399; Distribution, 399; Uses and production, 
 399 ; Ores of chromic iron, 399 ; Origin of chromite, 400 ; Analyses, 
 400 ; Distribution of chromic iron in United States, 400 ; Uses, 401 ; 
 Production of chromite, 402 ; References on chromic iron ore, 402 ; 
 Molybdenum, ores and occurrences, 403 ; Uses of molybdenum, 
 403 ; Production of molybdenum, 403 ; References on molybdenum, 
 403 ; Nickel and cobalt, 403 ; Ores, 403 ; Distribution, 404; Eastern 
 occurrences of nickel, 404 ; Other occurrences, 405 ; Uses of nickel, 
 405 ; Uses of cobalt, 406 ; Production, 406 ; References on nickel
 
 Xvi CONTENTS 
 
 and cobalt, 407; Platinum group of metals, 407; Platinum, 407; 
 Distribution in the United States, 407 ; Uses of platinum, 408 ; Pro- 
 duction of platinum, 408 ; References on platinum, 409 ; Palladium, 
 409 ; Osmium, 409 ; Iridium, 410 ; Tin, 410 ; Ores, 410 ; Mode of 
 occurrence, 410; Distribution in the United States, 411; Uses of 
 tin, 412; Production of tin, 412 ; References on tin, 413 ; Titanium, 
 413; Ores, 413; Occurrence, 413; Uses, 414; References on tita- 
 nium, 414 ; Tungsten, 414 ; Ores, 414; Occurrence, 415 ; Uses, 416 ; 
 Production, 415 ; References on tungsten, 416 ; Uranium and vana- 
 dium, 416 ; Ores, 416 ; Uses, 416 ; Production, 416 ; References on 
 uranium and vanadium, 417. 
 
 APPENDIX I 
 STATISTICS OF PRODUCTION FOR 1905 419-428 
 
 APPENDIX II 
 
 BIBLIOGRAPHY OF IMPORTANT PAPERS PUBLISHED SINCE APPEARANCE 
 
 OF FIRST EDITION 429-434
 
 LIST OF ILLUSTRATIONS 
 
 FIG. PAGE 
 
 1. Diagram showing changes occurring in passage of vegetable tissue 
 
 to graphite 13 
 
 2. Section in coal measures of western Pennsylvania, showing fire 
 
 clay under coal beds 16 
 
 3. Section showing irregularities in coal seam, a, split ; 6, parting of 
 
 shale ; c, pinch ; d, swell ; e, cut out 17 
 
 4. Section of faulted coal seam 17 
 
 6. Section across Coosa, Ala., coal field, showing folding and faulting 
 
 characteristic of southern end of Appalachian coal field . . 20 
 
 6. Map of Pennsylvania anthracite field 23 
 
 7. Sections in Pennsylvania anthracite field 24 
 
 8. Coal breaker in Pennsylvania anthracite region .... 25 
 
 9. Section across Eastern Interior coal field . . . ,26 
 
 10. Shaft house and tipple, bituminous coal mine, Spring Valley, HI. . 27 
 
 11. Generalized section of Northern Interior coal field . ... 28 
 
 12. Composite section showing structure of lower coal measures in Iowa 29 
 
 13. Section of anticlinal fold showing accumulation of gas, oil, and 
 
 water 43 
 
 14. Map showing oil and gas fields of United States .... 49 
 
 15. Geological section in Ohio-Indiana oil and gas field ... 60 
 
 16. Section of Spindle Top oil field near Beaumont, Tex. ... 51 
 
 17. Section in Los Angeles oil field 63 
 
 18. Map of asphalt and bituminous rock deposits of United States . 68 
 
 19. Section of Gilsonite vein, Utah 69 
 
 20. Map showing distribution of crystalline rocks (mainly granite) in 
 
 United States 76 
 
 21. Map showing marble areas of eastern United States ... 81 
 
 22. Section showing cleavage and bedding in slate .... 87 
 
 23. Section in slate quarry with cleavage parallel to bedding, a, purple 
 
 slate ; 6, unworked ; c and d, variegated ; e and /, green ; 
 
 g and A, gray green ; i, quartzite ; j, gray with black patches . 88 
 
 24. Section showing formation of residual clay 93 
 
 25. Section of a sedimentary clay deposit 93 
 
 26. Map showing distribution of salt-producing areas in United States, 
 
 compiled from various geological survey reports . . . 128 
 
 27. Map showing gypsum-producing localities of United States . . 141 
 
 28. Map of Florida phosphate deposits 148 
 
 29. Map of Tennessee phosphate areas 161 
 
 xvii
 
 Xviii LIST OF ILLUSTRATIONS 
 
 30. Vertical section showing geologic position of Tennessee phosphates 152 
 
 31. Map showing distribution of abrasives in United States . . .169 
 
 32. Section showing occurrence of corundum around border of dunite 
 
 mass 164 
 
 33. Asbestos vein in serpentine 168 
 
 34. Ideal section across a river valley, showing the position of ground 
 
 water and the undulations of the water table with reference to 
 
 the surface of the ground and bed rock 208 
 
 36. Geologic section of Atlantic Coastal Plain, showing water-bearing 
 
 horizons 210 
 
 36. Section from Black Hills across South Dakota, showing artesian 
 
 well conditions 211 
 
 37. Replacement vein in syenite rock, War Eagle mine, Rossland, B.C. 
 
 a, granular orthoclase with a little sericite ; 6, secondary biotite ; 
 
 q, secondary quartz ; c, chlorite ; black, secondary pyrrhotite 234 
 
 38. Section of vein in Enterprise mine, Rico, Colo. The right side 
 
 shows later banding due to reopening of the fissure . . .237 
 
 39. Section showing change in character of vein passing from gneiss (g} 
 
 to quartz porphyry Qj) 238 
 
 40. Tabulation of strikes of principal veins in Monte Cristo, Wash., 
 
 district 239 
 
 41. Linked veins 240 
 
 42. Gash vein with associated "flats" and "pitches" Wisconsin 
 
 zinc region 240 
 
 43. Section at Bonne Terre, Mo., showing ore disseminated through 
 
 limestone 241 
 
 44. Section through Copper Queen mine, Bisbee, Ariz., showing varia- 
 
 ble depth of weathering 243 
 
 45. Map showing distribution of iron ores in United States . . . 253 
 
 46. Map of Lake Superior iron regions, shipping ports, and transporta- 
 
 tion lines 259 
 
 47. Sections of iron ore deposits in Marquette range .... 260 
 
 48. Generalized vertical section through Penokee-Gogebic ore deposit 
 
 and adjacent rocks, Colby mine, Bessemer, Mich. . . .261 
 
 49. Generalized vertical section through Mesabi ore deposit and adja- 
 
 cent rocks . . . . 262 
 
 50. Section of Clinton ore beds, Oxmoor, Ala. a, red sandstone, 6' ; 
 
 6, yellow sandstone, 6' ; c, red sandstone, 16' ; d, ore, 22', 
 upper 2' soft; e, shale, 6' ; /, rich ore, 2' 6" . . . . 266 
 
 51. Section illustrating formation of residual limonite in limestone . 270 
 
 52. Map showing distribution of copper ores in United States . . 282 
 63. Map of Butte, Mont., district, showing distribution of veins and 
 
 geology 283 
 
 54. Section at Butte, Mont., showing mode of occurrence of the ore . 284
 
 LIST OF ILLUSTRATIONS XIX 
 
 FIG. FAGK 
 
 55. Section across Keweenaw Point 287 
 
 56. Section showing occurrence of amygdaloidal copper, Quincy mine, 
 
 Michigan 288 
 
 57. Geological section at Bisbee, Ariz 291 
 
 58. Generalized section of ore bodies at Bisbee, Ariz 292 
 
 59. Section of Morenci district. P, porphyry ; S, unaltered sediments ; 
 
 F, fissure veins ; M, metamorphosed limestone and shale ; 
 
 O, contact metamorphic ores ; R, disseminated chalcocite . 293 
 
 60. Section of ore body at Bully Hill, Calif 298 
 
 61. Map showing distribution of lead and zinc ores in United States . 305 
 
 62. Generalized section of southeastern Missouri lead region . . 306 
 6.3. Model of Franklin zinc-ore body 309 
 
 64. Section of Bertha zinc mines, Wythe County, Va., showing irregu- 
 
 lar surface of limestone covered by residual clay bearing ore . 310 
 
 65. Section showing occurrence of lead and zinc ores in Wisconsin, 
 
 with fissure ore in flats and pitches, and disseminated ore in 
 
 oil rock 312 
 
 66. Map of Ozark region 314 
 
 67. Generalized section showing occurrence of lead and zinc ore in 
 
 southwestern Missouri 316 
 
 68. A typical hoisting outfit in the southwestern Missouri zinc region . 316 
 
 69. Map showing distribution of gold and silver ores in United States . 331 
 
 70. Map and section of portion of Mother Lode district, Calif. Pgv, 
 
 river gravels, usually auriferous ; Ng, auriferous river gravels. 
 Sedimentary rocks : Jm, mariposa formation (clay, slate, sand- 
 stone, and conglomerate) ; <?c, calaveras formation (slaty 
 mica schists) . Igneous rocks : Nl, latite ; Nat, andesite tuffs, 
 breccia, and conglomerate ; mdi, meta-diorite ; Sp, serpentine ; 
 , ma, meta-andesite ; cms, amphibole schist .... 334 
 
 71. Section illustrating relations of auriferous quartz veins at Nevada 
 
 City, Calif 335 
 
 72. Section at Mercur, Utah 336 
 
 73. Map of Colorado showing location of mining regions . . . 338 
 
 74. Section of vein at Cripple Creek, Colo 339 
 
 75. Geologic map of Telluride district, Colorado, showing outcrop of 
 
 more important veins 342 
 
 76. Ideal cross section of rocks at Tonopah, Nev 343 
 
 77. Section of Comstock Lode. D, diorite ; Q, quartz ; V, vein matter 
 
 in earlier diabase (Db) ; H, earlier hornblende andesite ; 
 
 A, augite andesite 344 
 
 78. Generalized section of old placer, with technical terms, a, volcanic 
 
 cap ; 6, upper lead ; c, bench gravel ; d, channel gravel . . 347 
 
 79. Section of Homestake Belt at Lead, S.D., showing relation of 
 
 ancient and modern placers to Homestake Lode . . . 350
 
 XX LIST OF ILLUSTRATIONS 
 
 FIG. PACK 
 
 80. Typical section of siliceous gold ores, Black Hills, S.D. . . . 351 
 
 81. Map showing mineral deposits of Alaska as far as known . . 354 
 
 82. Sketch map of Douglas Island, Alaska 355 
 
 83. Cross section through Alaska Treadwell mine on northern side of 
 
 Douglas Island 356 
 
 84. Ideal section across Leadville district 366 
 
 85. Section of ore body at Aspen, Colo 368 
 
 86. Diagrammatic section across a northeasterly lode at Rico, Colo., 
 
 showing " blanket " of ore 369 
 
 87. Vein filling a fault fissure, Enterprise mine, Rico, Colo. . . 370 
 
 88. Section of lead-silver vein, Cceur d'Alene, Ido 373 
 
 89. Geologic map of Alabama-Georgia bauxite region . . . .377 
 
 90. Section of bauxite deposit, a, Residual mantle ; &, Red sandy clay 
 
 soil; c, Pisolitic ore; d, Bauxite with clay; e, Clay with 
 
 bauxite ; /, Talus ; gr, Mottled clay ; h, Drainage ditch . . 378 
 
 91. Map showing Georgia manganese areas 385 
 
 92. Section in Georgia manganese area showing geologic relations of 
 
 manganese, limonite, and ocher 386 
 
 93. Section of Batesville, Ark., manganese region, illustrating geological 
 
 structure and relation of different formations to marketable 
 
 and non-marketable ore 387 
 
 94. Map of California mercury localities 391 
 
 95. Map showing Texas mercury region 392 
 
 96. Section of cinnabar vein in limestone, Terlingua, Tex. . . .393 
 
 97. Sketch map showing location of Carolina tin belt .... 411
 
 PLATES 
 
 PLATE PAGE 
 
 I. Map showing distribution of coal in United States. Frontispiece 
 II. Fig. 1. Pit working (stripping) near Milnesville, Pa. The 
 
 mammoth seam is uncovered in bottom of pit . . . 31 
 Fig. 2. Lignite seam, Williston, N.D 31 
 
 III. Fig. 1. General view of Tuna Valley, in Pennsylvania oil field 48 
 Fig. 2. View in Los Angeles, Calif. , oil field. Such close spac- 
 ing of oil derricks tends to hasten the exhaustion of the 
 
 oil supply 48 
 
 IV. General view of Spindle Top oil field, Beaumont, Tex. . . 51 
 V. Fig. 1. Quarry of bituminous sandstone, Santa Cruz, Calif. . 60 
 
 Fig. 2. Granite quarry, Hard wick, Vt 60 
 
 VI. Quarry in limestone, Bedford, Ind. 80 
 
 VII. Marble quarry, Proctor, Vt 82 
 
 VIII. View of green slate quarry, Pawlet, Vt 88 
 
 IX. Bank of sedimentary clay, Woodbridge, N.J. This section 
 
 affords at least five kinds of clay 103 
 
 X. Fig. 1. Quarry of natural cement rock, Cumberland, Md. . 117 
 Fig. 2. Marl pit at Warners, N.Y. The dark streaks are 
 
 peat and the marl is underlain by clay . . . .117 
 XI. Fig. 1. Interior view of salt mine, Livonia, N.Y. . . .129 
 
 Fig. 2. Borax mine near Daggett, Calif 129 
 
 XII. Fig. 1. Gypsum quarry, Alabaster, Mich. Shows gypsum 
 overlain by glacial drift. The dump in foreground is over- 
 burden removed from gypsum 139 
 
 Fig. 2. Eock phosphate mine near Ocala, Fla. . . .139 
 
 XIII. Fig. 1. Grindstone quarry, Tippecanoe, Ohio . . . .159 
 Fig. 2. Corundum vein between peridotite and gneiss, Corun- 
 dum Hill, Ga 159 
 
 XIV. Fig. 1. View of open cut in magnetite deposit, Mineville, N.Y. 
 
 The pillars are ore left standing to support the gneiss 
 
 hanging wall 254 
 
 Fig. 2. General view of magnetic separating plants and shaft 
 
 houses, Mineville, N.Y 254 
 
 XV. Fig. 1. Iron mine, Soudan, Minn. Shows old open pit with 
 
 jasper horse in middle 261 
 
 Fig. 2. Outcrop of Clinton iron ore, Red Mountain, near 
 
 Birmingham, Ala 261
 
 Xxii PLATES 
 
 PLATE 1'AGB 
 
 XVL General view of Mountain Iron mine, Mesabi Eange, Minn. 
 Shows mining of ore with steam shovels and covering 
 
 of (a) glacial drift 264 
 
 XVIL Fig. 1. Pit of residual limonite, Shelby, Ala 270 
 
 Fig. 2. Old limonite mine, Ivanhoe, Va., showing pinnacled 
 surface of limestone which underlies the ore-bearing clay. 
 The level of surface before mining began is seen on either 
 
 side of excavation 270 
 
 XVIII. Anaconda group of mines, Butte, Mont 285 
 
 XIX. Fig. 1. Smelter of Clifton Copper Co., Clifton, Ariz. . . 293 
 
 Fig. '2. View of Bingham Canon, Utah 293 
 
 XX. Fig. 1. Kennedy mine on the Mother Lode near Jackson, 
 
 Calif 333 
 
 Fig. 2. Auriferous quartz veins in Maryland mine, Nevada 
 
 City, Calif 333 
 
 XXI. Fig. 1. View of Independence mine and Battle Mountain, 
 
 Cripple Creek, Colo 340 
 
 Fig. 2. General view of region around Tonopah, Nev. . . 340 
 XXII. Fig. 1. Hydraulic mining of auriferous gravel. The sluice 
 
 box in foreground is for catching the gold .... 348 
 Fig. 2. An Alaskan placer deposit 348 
 
 XXIII. Homestake mills, hoists and open cuts at Lead, S.D. . . 351 
 
 XXIV. Fig. 1. General view of Kico, Colo., and Enterprise group of 
 
 Fig. 2. Ontario mine, Park City, Utah . . . .369 
 
 XXV. Fig. 1. Bauxite bank, Eock Kun, Ala. . . . .376 
 
 Fig. 2. Furnace for roasting mercury ore, Terlingua, Tex. . 376
 
 ABBREVIATIONS USED 
 
 In the references at the end of each chapter, the volume numbers are given 
 
 in Roman numerals. Numbers following a : indicate page numbers. 
 
 The date of publication follows these, and is separated from them by a 
 
 comma. 
 Ala. Ind. and Sci. Soc., Proc. Alabama Industrial and Scientific Society, 
 
 Proceedings. 
 
 Amer. Geol. American Geologist. 
 Amer. Inst. Min. Eng., Trans. American Institute Mining Engineers, 
 
 Transactions. 
 
 Amer. Jour. Sci American Journal of Science. 
 Col. Sci. Soc., Proc. Colorado Scientific Society, Proceedings. 
 Eng. and Min. Jour. Engineering and Mining Journal. 
 Geol. Soc. Amer., Bull. Geological Society of America, Bulletin. 
 Jour. Geol. Journal of Geology. 
 Min. and Met. Mining and Metallurgy. 
 Min. and Sci. P. Mining and Scientific Press. 
 Min. Indus. Mineral Industry. 
 Min. Mag. Mining Magazine. 
 Mo. Geol. Surv. Missouri Geological Survey. 
 
 N. T. Acad. Sci., Trans. New York Academy of Science, Transactions. 
 N. Ca. Geol. Surv. North Carolina Geological Survey. 
 Sch. M. Quart. School of Mines Quarterly. 
 
 U. S. Geol. Surv., Mon. United States Geological Survey, Monograph. 
 U. S. Geol. Surv., Ann. Sept. United States Geological Survey, Annual 
 
 Report. 
 Zeitsch. f. Prak. Geol. Zeitschrift fur Praktische Geologie. 
 
 xxiii
 
 PART I 
 NON-METALLIC MINERALS
 
 CHAPTER I 
 COAL 
 
 Kinds of Coal. There is such an intimate gradation be- 
 tween vegetable accumulation now in process of formation 
 and mineral coal that it is generally admitted that coal is of 
 vegetable origin. By a series of slow changes (p. 12), the 
 vegetable remains lose water and gases, the carbon becomes 
 concentrated, and the materials assume the mineralized ap- 
 pearance of coal. To the stages of this process names are 
 given, four of which peat, lignite, bituminous coal, and 
 anthracite coal are commonly known. 
 
 Peat (79-83). This, which may represent the first stage 
 in coal formation, is formed chiefly by the growth of 
 the bog moss, sphagnum, in moist places. A section in a 
 peat bog, from the top downward, shows : (1) a layer 
 of living moss, and other plants ; (2) a layer of dead 
 moss fibers, whose structure is clearly recognizable, and 
 which grades into (3) a layer of fully formed peat, a 
 dense brownish black mass, in which the vegetable struc- 
 ture is often indistinct. 
 
 The following analyses show the difference in composition 
 of the different layers. They also show that while during 
 this change the hydrogen and oxygen diminish, the carbon 
 increases in proportion. 
 
 3
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 MATERIAL 
 
 CARBON 
 
 HYDROGEN 
 
 OXYGEN 
 
 NITROGEN 
 
 
 49 88 
 
 6 54 
 
 4242 
 
 1 16 
 
 Porous, light brown sphag- 
 
 
 
 
 
 
 50.86 
 
 5.8 
 
 42.57 
 
 .77 
 
 Porous, red brown peat . . 
 
 53.51 
 
 5.9 
 
 40.59 
 
 Heavy brown peat .... 
 
 56.43 
 
 5.32 
 
 38.25 
 
 Heavy black peat .... 
 
 59.7 
 
 5.7 
 
 33.04 
 
 1.56 
 
 Lignite. This substance, also called brown coal, repre- 
 senting the second stage in coal formation, is brownish black 
 or black in color, and often shows a brilliant luster, conchoidal 
 fracture, and brown streak. Where the lumps have formed 
 from trunks or other large, woody masses, the vegetable 
 structure is often clearly visible. It burns readily, but with 
 a long, smoky flame, and hence with lower heating power 
 than the true coal. Because of the large amount of mois- 
 ture, it often dries out on exposure to the air, and rapidly 
 disintegrates to a powdery mass. 
 
 The lignites have been found in the more recent geological periods. 
 Because of the greater age and the greater compression of the vegetable 
 matter, due to the pressure of overlying strata, lignite resembles true 
 coal more closely than peat. In fact, in favorable situations, the altera- 
 tion of Tertiary and Cretaceous coals has proceeded as far as to trans- 
 form them beyond the stage of lignite. 
 
 Jet is a coal-black variety of lignite, with resinous luster and sufficient 
 density to permit its being carved into small ornaments. It is obtained 
 on the Yorkshire coast of England, where a single seam produced 5180 
 pounds, valued at $1250. According to Phillips, jet is simply a conif- 
 erous wood, still showing the characteristic structure under the micro- 
 scope. (" Geology of England and Wales," p. 278.) 
 
 Bituminous Coal. This represents the third stage in coal 
 formation. It is denser than lignite, deep black, compara-
 
 COAL 5 
 
 tively brittle, and breaks with cubical, or sometimes con- 
 choidal, fracture. On superficial inspection it usually shows 
 no trace of vegetable remains ; but in thin sections examined 
 under the microscope, traces of woody fiber, lycopod spores, 
 etc., are commonly seen. Bituminous coal burns readily, 
 with a smoky flame of yellow color, but with much greater 
 heating power than lignite. It does not disintegrate on ex- 
 posure to air as readily as lignite does. Most bituminous 
 coal is of earlier age than lignite ; but where the two occur 
 in the same formation, as in parts of the West, the lignite 
 is commonly in horizontal strata, while the bituminous coal 
 occurs in areas of at least slight disturbance. 
 
 When freed of their volatile hydrocarbons and other gaseous constitu- 
 ents by heating to redness in an oven, many bituminous coals cake to a 
 hard mass called coke. Since some bituminous coals do not possess this 
 characteristic, it is customary to divide these coals into coking and non- 
 coking coals. 
 
 Cannel coal is a compact variety of non-coking bituminous 
 coal with a dull luster and conchoidal fracture. Owing to 
 its unusually high percentage of volatile hydrocarbons, upon 
 which its chief value depends, cannel coal ignites easily, 
 burning with a yellow flame. (See analysis No. 14.) 
 
 Semi-bituminous is a name applied to certain varieties in- 
 termediate between bituminous and anthracite coal. 
 
 Anthracite Coal. This coal is black, hard, and brittle, 
 with high luster and conchoidal fracture. It represents the 
 last stage in the formation of coal, and shows no traces 
 of vegetable structure within its mass, although plant 
 impressions are often abundant in the rocks immediately 
 above and below it. Anthracite has a lower percentage 
 of volatile hydrocarbons and higher percentage of fixed
 
 6 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 carbons than any of the other varieties (p. 8). On this 
 account, it ignites much less easily and burns with a short 
 flame, but gives great heat. 
 
 The geological distribution of anthracite is more restricted 
 than that of bituminous coal and, in fact, its occurrence 
 is often more or less intimately connected with dynamic 
 disturbances. 
 
 Proximate Analysis of Coal. An elementary analysis of 
 coal (see p. 14) is of comparatively little practical value. 
 Therefore proximate analyses are commonly employed, in 
 which the probable method of combination of the elements 
 is given. By the proximate method the elements in the 
 coal are grouped as moisture, volatile hydrocarbons, fixed 
 carbon, ash, and sulphur. 
 
 The following table gives the proximate analysis of a 
 number of coals from all parts of the United States. The 
 analyses are arranged in the following order: Peat, Lignite, 
 Bituminous Coal, Anthracite. 
 
 PROXIMATE ANALYSES OF COAL 
 
 LOCALITY 
 
 Moisture 
 
 Volatile 
 Hydro- 
 carbon 
 
 Fixed 
 Carbon 
 
 Ash 
 
 Sulph. 
 
 Fuel 
 Ratio 
 
 1. Peat 
 
 20.22 
 
 52.31 
 
 24.52 
 
 
 
 .47 
 
 Dismal Swamp 
 
 
 
 
 
 
 
 2. Newcastle .... 
 
 13.69 
 
 32.31 
 
 48.32 
 
 5.78 
 
 .164 
 
 1.49 
 
 Washington 
 
 
 
 
 
 
 
 3. Kootznaboo . . . 
 
 2.41 
 
 44.75 
 
 47.93 
 
 4.88 
 
 .67 
 
 1.07 
 
 Alaska 
 
 
 
 
 
 
 
 4. Rockdale .... 
 
 33.63 
 
 46.78 
 
 7.45 
 
 12.14 
 
 .99 
 
 .15 
 
 Texas 
 
 
 
 
 
 
 
 5. Lignite .... 
 
 22.95 
 
 23.64 
 
 43.31 
 
 5.10 
 
 
 1.51 
 
 S. Platte field, Col. 
 
 
 
 
 
 
 
 6. Lignite . . 
 
 21.11 
 
 28 55 
 
 44 98 
 
 5 01 
 
 
 1.58 
 
 E. field, Montana 
 
 
 
 
 

 
 COAL 
 
 LOCALITY 
 
 Moisture 
 
 Volatile 
 Hydro- 
 carbon 
 
 Fixed 
 Carbon 
 
 Ash 
 
 Snlph. 
 
 Fuel 
 Ratio 
 
 7 Lignite 
 
 10.80 
 
 43.10 
 
 38.57 
 
 7.53 
 
 
 .87 
 
 Corral Hollow, Cal. 
 
 
 
 
 
 
 
 8. Brookville Coal . . 
 
 1.47 
 
 17.93 
 
 75.508 
 
 4.625 
 
 .567 
 
 4.21 
 
 Conemaugh, Cam- 
 
 
 
 
 
 
 
 bric Co. 
 
 
 
 
 
 
 
 9. Pittsburg Coal . . . 
 
 1.26 
 
 31.79 
 
 67.79 
 
 7.16 
 
 .79 
 
 1.81 
 
 Connelsville, Fay- 
 
 
 
 
 
 
 
 ette Co. 
 
 
 
 
 
 
 
 10. Hocking Valley Coal 
 
 5.93 
 
 36.48 
 
 62.41 
 
 5.13 
 
 1.09 
 
 1.44 
 
 Ohio 
 
 
 
 
 
 
 
 11. Warrior 
 
 4.83 
 
 18.95 
 
 72.76 
 
 3.28 
 
 .17 
 
 3.83 
 
 Jeff. Co., Ala. 
 
 
 
 
 
 
 
 12 Jellico . . . 
 
 4.40 
 
 31.56 
 
 61.87 
 
 1.86 
 
 .31 
 
 1.96 
 
 Campbell Co., Tenn. 
 
 
 
 
 
 
 
 13. Brazil Block Coal . 
 
 13.82 
 
 35.16 
 
 49.96 
 
 1.06 
 
 1.47 
 
 1.42 
 
 Brazil, Ind. 
 
 
 
 
 
 
 
 14. Cannel Coal . . . 
 
 1.47 
 
 49.08 
 
 26.35 
 
 23.10 
 
 1.48 
 
 .53 
 
 Cannelburg, Ind. 
 
 
 
 
 
 
 
 15. Bituminous Coal . . 
 
 5.50 
 
 39.50 
 
 54.60 
 
 5.40 
 
 . . . 
 
 1.38 
 
 Belleville, 111. 
 
 
 
 
 
 
 
 16 Butler .... 
 
 
 30.66 
 
 54.94 
 
 11.00 
 
 2.544 
 
 1.71 
 
 Kentucky 
 
 
 
 
 
 
 
 17. Owasso Coal Comp'ny 
 
 7.58 
 
 35.70 
 
 52.96 
 
 3.76 
 
 1.50 
 
 1.48 
 
 Owasso, Mich. 
 
 
 
 
 
 
 
 18. Saginaw Company . 
 
 5.82 
 
 39.79 
 
 45.15 
 
 9.24 
 
 3.83 
 
 1.13 
 
 Verne, Mich. 
 
 
 
 
 
 
 
 19. Fort Dodge . . . 
 
 7.48 
 
 39.52 
 
 45.54 
 
 8.44 
 
 5.28 
 
 1.15 
 
 Iowa 
 
 
 
 
 
 
 
 20. Lexington .... 
 
 9.24 
 
 29.01 
 
 42.19 
 
 15.18 
 
 4.38 
 
 1.45 
 
 Missouri 
 
 
 
 
 
 
 
 21. Hartshorne Coal . . 
 
 1.68 
 
 41.00 
 
 51.91 
 
 5.41 
 
 2.72 
 
 1.26 
 
 Hartshorne, I.T. 
 
 
 
 
 
 
 
 22. Gwyn's shaft . . . 
 
 .892 
 
 14.57 
 
 77.09 
 
 6.24 
 
 1.19 
 
 5.28 
 
 Sebastian Co., Ark. 
 
 
 
 
 
 
 
 23. Semi-bituminous . . 
 
 1.10 
 
 il.27 
 
 72.83 
 
 12.04 
 
 2.74 
 
 6.46 
 
 Johnson Co., Ark. 
 
 
 
 
 
 
 
 24 Coal No 1 
 
 .88 
 
 31.57 
 
 56.81 
 
 8.93 
 
 1.47 
 
 1.79 
 
 Thurber, Texas 
 
 
 
 
 
 
 
 25. Coking Coal . . . 
 
 .75 
 
 31.13 
 
 57.07 
 
 11.05 
 
 . . . 
 
 1.80 
 
 Raton field, Col. 
 
 
 
 
 

 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 LOCALITY 
 
 Moisture 
 
 Volatile 
 Hydro- 
 carbon 
 
 Fixed 
 Carbon 
 
 Ash 
 
 Sulph. 
 
 Fuel 
 Ratio 
 
 26. Newcastle .... 
 
 7.992 
 
 29.031 
 
 63.806 
 
 8.023 
 
 1.148 
 
 1.85 
 
 Washington 
 
 
 
 
 
 
 
 27. Bituminous Coal . . 
 
 6.21 
 
 31.32 
 
 62.47 
 
 11.10 
 
 
 1.65 
 
 Canyon City, Col. 
 
 
 
 
 
 
 
 28. Anthracite .... 
 
 1.58 
 
 6.70 
 
 87.46 
 
 4.26 
 
 .58 
 
 13.05 
 
 Crested Butte, Col. 
 
 
 
 
 
 
 
 29. Anthracite .... 
 
 2.90 
 
 3.18 
 
 88.91 
 
 5.21 
 
 . 
 
 27.96 
 
 Cerillos field, New 
 
 
 
 
 
 
 
 Mexico 
 
 
 
 
 
 
 
 30. Mammoth .... 
 
 3.163 
 
 3.717 
 
 81.143 
 
 11.078 
 
 .899 
 
 21.83 
 
 W. Middle field, Pa. 
 
 
 
 
 
 
 
 31. Mammoth .... 
 
 3.421 
 
 4.381 
 
 83.268 
 
 8.203 
 
 .727 
 
 19.00 
 
 N. Middle field, Pa. 
 
 
 
 
 
 
 
 The moisture can be driven off at 100 C. and is usually highest in 
 peat and lignite; the volatile hydrocarbons are the easily combustible 
 elements, and decrease toward the anthracitic end of the series; the 
 fixed carbon burns with difficulty and is highest in the anthracite 
 coals. The ash represents noncombustible mineral matter and bears 
 no direct relation to the kind of coal ; and the same is true of sulphur, 
 which is present as an ingredient of pyrite or gypsum. 
 
 The value of coal for fuel or other purposes is determined mainly 
 by the relative amounts of its fuel constituents, viz. the volatile hydro- 
 carbons and the nonvolatile or fixed carbons. The fuel value, or fuel 
 ratio, is determined by dividing the fixed carbon percentage by that 
 of the volatile hydrocarbons. 
 
 The fixed carbon represents the heating element of the coal, while 
 the volatile hydrocarbons burn easily, but have little heating power. 
 The heating power and fuel ratio will, therefore, increase together. 
 This increase in the heating power of the coal is only true, however, 
 up to a certain point, after which the difficulty in making the coal 
 burn offsets the extra amount of heat developed. Coals with a high 
 percentage of fixed carbon develop great heating power, while those 
 lower in fixed carbon and high in volatile hydrocarbons lack in heating 
 power, but are free burning.
 
 COAL 
 
 9 
 
 Moisture is a nonessential constituent of coal. It not only dis- 
 places so much combustible matter, but requires heat for its evapo- 
 ration. Wheu present in large amounts it often causes the coal to 
 disintegrate while drying out. It ranges from 1 per cent in anthracite 
 to 20 or 30 per cent in lignites. 
 
 Ash also displaces combustible matter, but otherwise it is in most 
 cases an inert impurity. The clinkering of coal is commonly due to 
 a high percentage of fusible impurities in the ash, and for metallur- 
 gical work the composition of the ash often has to be considered. 
 
 The following analyses will also serve to illustrate the composition 
 
 of the ash: 
 
 ASH ANALYSES 
 
 
 8iO, 
 
 Al t O s 
 
 Fe,0, 
 
 CaO 
 
 MgO 
 3.20 
 
 MnO, 
 
 SO, 
 
 Alka- 
 lies 
 
 Chlo- 
 rine 
 
 P,0 8 
 
 2.56 
 
 Peat, average of 
 several . . . 
 
 25.50 
 
 5.78 
 
 18.70 
 
 24.00 
 
 
 7.50 
 
 1.72 
 
 .60 
 
 Lignite .... 
 Bituminous Coal 
 
 30.14 
 34.32 
 
 13.48 
 14.62 
 
 11.70 
 22.94 
 
 23.59 
 14.85 
 
 .88 
 1.42 
 
 3.32 
 1.16 
 
 14.22 
 10.97 
 
 
 
 
 Sulphur is an objectionable impurity in steaming coals on account 
 of its corrosive action on the boiler tubes. It is also undesirable in 
 coals to be used for metallurgical purposes and gas manufacture. 
 
 Origin of Coal (4). It has been shown that there are 
 gradations between unquestioned plant beds and mineral 
 coal, and that coal, besides containing the same materials 
 as plant tissue, often shows the presence of plant fibers, 
 leaves, stems, seeds, etc. Moreover, stumps or trunks of 
 trees are sometimes found standing upright in the coal, 
 with their roots penetrating the underlying bed of clay (5), 
 just as trunks of trees at present stand in bogs. While 
 these facts point unmistakably to a vegetable origin of 
 coal, it is less easy to understand the exact manner in 
 which the great accumulations of vegetable matter have 
 been made, and the changes from plant tissue to mineral
 
 10 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 coal. Each of these points, therefore, demands further 
 consideration. 
 
 Conditions of Vegetable Accumulation (4). At present 
 there are several conditions under which plant remains 
 accumulate to considerable depth over areas in some cases 
 of large size. All of these are closely associated with 
 water, either fresh or salt, because plant remains falling 
 in water have their decay so retarded by the exclusion of 
 air that accumulation is possible. Of these the following 
 are the most important : (1) accumulation due to algae on 
 the sea bottom beneath a sargasso sea ; (2) marine swamps, 
 including salt marshes and mangrove swamps; (3) delta 
 deposits; (4) peat bogs; (5) coastal plain marshes. 
 
 While accumulations made in any one of these ways 
 may form coal beds, and while individual beds may be 
 formed which are due to any of these causes, to many of 
 them there are such objections as to render them extremely 
 improbable as general explanations for the great number 
 of widely extended deposits of coal. The theory of accumu- 
 lation from deposits of algse, for example, demands deep 
 water of an open ocean for the circulation of ocean cur- 
 rents. But most coal beds are evidently formed either on 
 the land or else in shallow water of lakes, lagoons, or sea- 
 coast swamps. 
 
 To the theory of various swamps there are two serious 
 objections : (1) that in such deposits as are now forming, 
 the currents are bringing more fragmental sediments than 
 are commonly present in coal beds ; (2) that at present 
 only one kind of tree, the mangrove, is adapted to growth in 
 salt water. It is, of course, possible that in earlier ages the 
 number of trees adapted to this mode of life was far greater.
 
 COAL 11 
 
 Streams are bringing plant remains to lakes or oceans 
 and incorporating them in their deltas ; but nowhere are 
 such extensive accumulations now forming as to make large 
 coal fields in this manner. Moreover, the amount of sedi- 
 ment brought in such places would seem to exclude the 
 possibility of the deposit of large areas of vegetable mat- 
 ter free from a great admixture of sediment. The combi- 
 nation of this source of vegetable supply with that caused 
 by the growth of marine or fresh-water swamp plants in 
 the delta lagoons would increase the chances of the forma- 
 tion of coal beds by this means; but even with this addi- 
 tion, it seems impossible to accept this as a general theory 
 for the formation of extensive beds of coal. 
 
 It is a well-known fact that thick deposits of vegetable 
 matter, often covering areas of several square miles, are 
 formed in the peat bogs that in so many places represent 
 the last stage of lake or pond filling in cool, temperate 
 climates. Each of these bogs would, under favorable 
 circumstances, change to a bed of coal, and some of them 
 are extensive enough to form coal beds of large size. But 
 such bogs are, compared to our larger coal fields, far too 
 limited in area to admit of the acceptance of this explana- 
 tion to account for great coal fields without assuming far 
 more widespread bog-forming conditions than any at present 
 known. 
 
 Perhaps the most perfect resemblance to coal-forming 
 condition is that now found on such coastal plain areas as 
 that of southern Florida and the Dismal Swamp of Virginia, 
 North Carolina. Both of these areas are very level, though 
 with slight depressions in which there is either standing 
 water or swamp conditions. In both regions there is such
 
 12 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 general interference with free drainage that there are exten- 
 sive areas of swamp, and in both there are beds of vegetable 
 accumulations. In each of these areas there is a general 
 absence of sediment and therefore a marked variety of vege- 
 table deposit. If either of these areas were submerged be- 
 neath the sea, the vegetable remains would be buried and a 
 further step made toward the formation of a coal bed. Re- 
 elevation, making a coastal plain, would permit the accumula- 
 tion of another coal bed above the first, and this process 
 might be continued again and again. 
 
 In support of the theory that coal was accumulated in 
 some such situation as this, are a number of facts : (1) the 
 coal beds occur over wide areas in sediments which were 
 deposited near land borders and which may therefore have 
 been again and again raised above sea level to form extensive 
 coastal plains ; (2) there are evidences of land conditions re- 
 vealed in the workings of some mines ; (3) the enormous 
 area of some coal fields call for some such widespread condi- 
 tions as coastal plains might provide ; (4) the slight admix- 
 ture of sediment indicates the absence of conditions of 
 sediment supply, e.g. rivers, waves, tidal currents, and wind- 
 formed currents ; (5) vegetable accumulations made in such 
 situations would require but slight changes in land level to 
 be buried beneath sedimentary strata as the coal beds have 
 been. 
 
 Chemical Changes occurring during Coal Formation. 
 Dead plant tissue when exposed to the air oxidizes rapidly 
 and decays, all of the gaseous elements passing off, leaving 
 only the mineral matter which the plant tissue contained. 
 The exclusion of air caused by the presence of water, as in a 
 pond or a swamp, greatly retards oxidation ; but, as it slowly
 
 COAL 
 
 13 
 
 proceeds the oxygen, nitrogen, and hydrogen of the plant 
 tissue, together with some of the carbon pass off in the form 
 of carbon dioxide (CO 2 ), carbon monoxide (CO), marsh gas 
 (CH 4 ), and water. As a result, as the process continues 
 an increasing percentage of carbon is left behind. The 
 change is also accompanied by a change in color to deep 
 brown, and finally to black. 
 
 The changes that take place in the passage of vegetable 
 matter into coal are graphically shown in the following dia- 
 gram prepared by the late Professor Newberry : 
 
 .VEGETABLE TISSUE 
 
 FIG. 1. Diagram showing changes occurring in passage of vegetable 
 tissue to graphite. After Newberry, 
 
 In this diagram the rectangle ABCD represents a given 
 volume of fresh vegetable matter, which contains a small 
 percentage of mineral matter, the rest being organic sub- 
 stances consisting roughly of 50 per cent carbon (EFCD) 
 and 50 per cent hydrogen, oxygen, and nitrogen (ABEF). 
 In the change from fresh vegetable tissue to peat, part of 
 these four elements pass off as gaseous compounds, so that 
 the remaining volume of peat is less (BGDH) than the origi- 
 nal volume of vegetable matter (ABCD). Since, however, 
 H, O, and N have passed off in larger amounts than the 
 carbon, the percentage of the latter in the peat will be higher 
 than it was in the fresh plant tissue. (Compare BFGI and
 
 14 
 
 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 FIDH with ABEF and EFCD.) The actual weight of 
 mineral matter will be the same, but its percentage will be 
 larger. This change continued will result finally in anthra- 
 cite, the last of the coal series, in which the per cent of carbon 
 (LKMN) is high and that of the other organic elements low 
 (JKL). The amount of compression that occurs in such 
 changes as those illustrated in the diagram may be under- 
 stood when it is stated that it is estimated that from 16 to 
 30 feet of peat are required to make one foot of true coal. 
 
 The following analyses of various grades of coal from peat 
 to anthracite clearly illustrate this gradual concentration of 
 carbon by loss of volatile elements. 
 
 ELEMENTARY ANALYSES OF COALS 
 
 
 C. 
 
 II. 
 
 O. 
 
 BT. 
 
 s. 
 
 Ash 
 
 Mois- 
 ture 
 
 Peat 
 
 59.47 
 
 6.52 
 
 31.51 
 
 2.51 
 
 
 
 22 
 
 
 58 44 
 
 4 97 
 
 16 42 
 
 1 30 
 
 
 
 
 Bituminous coal . 
 
 68 13 
 
 6.49 
 
 5.83 
 
 2.27 
 
 2.48 
 
 12.30 
 
 
 Breckenridge Co., Ky. 
 Bituminous coal 
 
 73.80 
 
 5.79 
 
 16.58 
 
 1.52 
 
 .41 
 
 1.90 
 
 
 Ohio 
 Bituminous coal .... 
 
 82.70 
 
 4.77 
 
 9.39 
 
 1.62 
 
 .45 
 
 1.07 
 
 
 Clay Co., Ind. 
 Anthracite 
 
 90 45 
 
 2 43 
 
 245 
 
 
 
 467 
 
 
 East Pa. 
 
 
 
 
 
 
 
 
 Effect of Heat and Pressure. While the first stage in 
 coal formation is brought about simply by the exclusion of 
 air, for further development pressure seems necessary. 
 Even in peat beds the lower layers are under the gentle 
 pressure of the upper layers ; but peat is not changed even 
 to lignite until buried under many feet of sediments. Great 
 pressure, possibly aided by heat, seems necessary for the
 
 COAL 15 
 
 change from lignite to bituminous coal ; and long periods of 
 time are apparently required for the slow changes to take 
 place. That heat may sometimes have been present is indi- 
 cated by the evidence of rock folding that is sometimes, 
 though by no means invariably, present in bituminous coal 
 areas. 
 
 Most of the anthracite coal in the United States occurs in 
 the highly folded Appalachians of Pennsylvania. Such fold- 
 ing must have been productive of much heat and pressure, 
 and that the folding has produced the anthracite is by many 
 believed to be proved by the fact that these coal beds pass 
 into bituminous coal when traced southward or westward 
 into areas of less disturbances. This view is questioned by 
 some geologists, especially J. J. Stevenson, who has argued 
 that the anthracite has not been developed from bituminous 
 coal by metamorphism, but that the volatile constituents 
 were partly removed by longer exposure of the vegetable 
 matter to oxidation before burial (7). 
 
 There are some cases, as in the Cerillos coal field of New 
 Mexico (50), where anthracite probably has been produced 
 by heat. Here a bituminous coal has been deprived of its 
 volatile matter and converted into anthracite in those por- 
 tions of the bed near an intrusion of andesite. A similar 
 change has taken place in the Crested Butte district of 
 Colorado (29). 
 
 Structural Features of Coal Beds. Outcrops (1, 3). The 
 outcrop of a coal bed is usually easily recognizable on 
 account of its color and coaly character; but unless the 
 exposure is a rather fresh one, the material is disintegrated 
 and mellowed, the wash from it mingling with the soil, and
 
 16 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Coal 
 Fire Clay 
 
 Coal 
 Fire Clay 
 
 if the outcropping bed is on a hillside, often extending some 
 feet down the slope. This weathered outcrop has been 
 termed the "smut" or "blossom" by coal miners. In 
 areas where the beds have been tilted and the slopes are 
 steep, the outcrops of coal can usually be 
 easily traced ; but in regions where the dip 
 is low and the surface level, the search for 
 coal is often attended with difficulty, which 
 is increased if the country is covered with 
 glacial drift. In such cases boring or pit- 
 ting is commonly resorted to. 
 
 Associated Rocks. Most coal beds are 
 interbedded with shales, clays, or sand- 
 stones, though conglomerates or limestones 
 are at times also found in close proximity. 
 Coal beds are often underlain by a bed of 
 clay, which in some regions is of refractory 
 character (Fig. 2); but the widespread 
 belief that all these under clays are fire 
 clays is unwarranted. 
 
 Variations in Thickness. Coal beds or 
 Fio. 2. Section in 
 
 coal measures of "seams" are rarely of uniform thickness 
 western Pennsylva- . . . 
 
 nia, showing fire over large areas; indeed, a bed which is 
 beTs. Differ H<- of sufficient thickness to work in one mine 
 kins - may be so thin in a neighboring mine as 
 
 to be scarcely noticeable. This irregularity is in some cases 
 due to variations in thickness of vegetable accumulations, 
 in other cases to local squeezing of the coal bed subsequent 
 to its formation. These thinnings and thickenings are com- 
 monly called "pinchings" and "swellings" (Fig. 3). In 
 regions of pronounced folding, the coal beds are usually
 
 COAL 
 
 17 
 
 found in separate synclinal basins, the intervening anticlinal 
 folds having been worn away. 
 
 Other Irregularities. Splitting (Fig. 3) is a common 
 feature of many coal seams. The Mammoth bed, so promi- 
 nent in most of the anthracite basins of Pennsylvania, splits 
 
 FIG. 3. Section showing irregularities in coal seam, a, split; 
 6, parting of shale ; c, pinch ; d, swell; e, cut out. 
 
 into three separate beds in the Wilkesbarre basin. This 
 splitting is caused by the appearance of beds of shale (called 
 " slate " by coal miners), which often become so thick as 
 to split up the coal seam into two or more beds. When 
 narrow, such a bed of slate is called a parting. The Pitts- 
 burg seam of western Pennsylvania shows a fire-clay parting 
 or "horseback" (Fig. 3) 
 from six to ten inches 
 thick over many square 
 miles. 
 
 In addition to these 
 " slate " partings, which 
 run parallel with the bed- 
 ding, others are often 
 encountered which cut 
 across the beds from top 
 
 Fio. 4. Section of faulted coal seam. 
 After Keyes, la. Geol. Surv., II: 86, 1894. 
 
 to bottom. These in some cases represent erosion channels, 
 formed in the coal during or subsequent to its formation, 
 and later filled by the deposition of sand or clay. In other
 
 18 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 cases they are due to the filling of fissures formed during 
 the folding of the strata. 
 
 Faulting (Fig. 4) is not an uncommon feature of coal 
 beds, and the coal is sometimes badly crushed on either side 
 of the line of fracture. The amount of throw and the num- 
 ber and kind of faults may vary, so that one might expect 
 normal, reverse, overthrust, and even step faults. 
 
 Coal Fields of the United States (PI. I). Coal in com- 
 mercial quantities occurs in twenty-seven of the forty-seven 
 states and territories as well as in Alaska. These occur- 
 rences can be grouped into the following ten fields : 
 
 (1) Appalachian, including parts of Pennsylvania, Ohio, 
 
 Maryland, Virginia, West Virginia, Eastern Ken- 
 tucky, Tennessee, Georgia, and Alabama . . 71,291 sq. mi. 
 
 (2) Rhode Island Very small. 
 
 (3) Atlantic Coast Triassic, including parts of Virginia 
 
 and North Carolina 1070 sq. mi. 
 
 (4) Eastern Interior, including parts of Indiana, Illinois, 
 
 and western Kentucky 58,000 sq. mi. 
 
 (5) Northern Interior, including parts of Michigan . 11,300 sq. mi. 
 
 (6) Western Interior, including parts of Iowa, Missouri, 
 
 Nebraska, and Kansas . . . . . . 66,200 sq. mi. 
 
 (7) Southwestern field, including parts of Indian Terri- 
 
 tory, Arkansas, and Texas 27,876 sq. mi. 
 
 (8) Rocky Mountain field, including parts of South Da- 
 
 kota, Montana, Idaho, Wyoming, Utah, Colorado, 
 
 and New Mexico 43,610 sq. mi. 
 
 (9) Pacific Coast, including parts of Washington, Oregon, 
 
 and California 1050 sq. mi. 
 
 (10) Alaska : 
 
 The above grouping does not include the areas of lignite- 
 bearing formations, although these are shown on the map
 
 COAL 19 
 
 (PI. I). According to Hayes there are in Montana, the 
 Dakotas, and Wyoming, approximately 56,500 square miles 
 of lignite-bearing formations, chiefly of Cretaceous age. 
 A series of fields in the Tertiary of Alabama, Mississippi, 
 Louisiana, Arkansas, and Texas cover approximately as 
 large an area. 
 
 The estimates given above are of course only approximate, and some 
 of these fields may be extended in the future by the development of 
 areas now classed as unproductive. This applies especially to those in 
 which the coal lies too deep to be profitably mined at present. It is a 
 noteworthy fact that the production of the fields is by no means propor- 
 tional to their areas. (Compare above list with table, p. 34.) Proximity 
 to markets, value of the coal for fuel, and relative quantity of coal per 
 square mile of productive area, are factors of importance in determining 
 the output of a field. 
 
 Geologic Distribution of Coals in the United States. The 
 
 coal-bearing formations of the United States range in age 
 from Carboniferous to Tertiary. Carboniferous coals occur 
 east of the 100th meridian, Cretaceous coals between the 
 100th and 115th meridian, and the Tertiary coals chiefly 
 between the 120th meridian and the Pacific coast. Excep- 
 tions to this distribution are the occurrence of a small area 
 of Triassic coals in Virginia and North Carolina, and a large 
 Tertiary area of lignite in the Gulf States. This indicates 
 that during the coal-forming periods there was in North 
 America a slow westward shifting of the zone in which 
 conditions favorable to coal formation occurred, the only 
 exceptions being those mentioned above. 
 
 The Carboniferous coals are commonly grouped into 
 several well-marked and clearly separated areas; but this 
 isolation is probably the result of folding and erosion, all
 
 20 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 excepting the Michigan field having apparently been origi- 
 nally continuous. To a certain extent the same is true 
 
 1 1 
 
 1 
 
 fi.u* 
 
 of the Rocky Mountain coal fields. 
 These have often been seriously dis- 
 turbed by post-Cretaceous uplifts, 
 which in many instances have im- 
 proved the qualities of the coal. As 
 a whole, the Tertiary coals are medium 
 to low grade, though in some sections, 
 notably in Washington, they are of 
 excellent quality. 
 
 I 
 
 s 
 
 in 
 
 1-3 
 
 
 
 Appalachian Field (12, 15, 18, 55, 58, 
 60, etc.). This, the most important 
 coal field in the United States, ex- 
 tends 850 miles, from northeastern 
 Pennsylvania to Alabama, and about 
 75 per cent of its area contains work- 
 able coal. At the southern end the 
 coal measures pass beneath the coastal 
 plain deposits, and they may connect 
 with the Arkansas coal measures be- 
 neath the Mississippi embayment. 
 
 Being closely associated with the 
 Appalachian Mountain uplift, the coal 
 measures of this region partake of the 
 structural features of the Appalachian 
 belt. Thus, while the strata of the 
 western portion are either horizontal 
 or only slightly bent, those farther 
 east are often highly folded (Fig. 7), and in the southern 
 
 ril
 
 COAL 21 
 
 Appalachians the strata are both folded and faulted (Fig. 5). 
 Extensive erosion following the folding of the coal meas- 
 ures has resulted in the development of a number of 
 basins. 
 
 The coal measures of the Appalachian field consist of a 
 great thickness of overlapping lenses of conglomerate, sand- 
 stone, shale, coal, and some limestones, and owing to this 
 lenticular character of the deposits, and to local thickenings, 
 it is difficult to trace individual beds of coal over wide areas, 
 or to correlate sections at widely separated points. 
 
 The middle Carboniferous, or Pennsylvanian, includes 
 most of the coal beds of the Appalachian area, and is 
 divided into the following five major subdivisions which are 
 recognizable throughout the field : (1) Dunkard or Upper 
 Barren Measures; (2) Monongahela or Upper Productive 
 Measures ; (3) Conemaugh or Lower Barren Measures ; 
 (4) Alleghany or Lower Productive Measures; (5) Pottsville 
 or Serai Conglomerate. 
 
 This classic section was first worked out in Pennsylvania, 
 and has since been identified in other parts of the Appa- 
 lachian field. At the time it was made, the second and 
 fourth members were thought to be the only ones carrying 
 coal, and hence the name " Productive " ; but since then the 
 Pottsville has been found to be locally productive, and a few 
 seams have been found even in the Barren Measures. 
 
 The Appalachian field is divisible into two parts of very 
 unequal size : (1) the anthracite field of northeastern 
 Pennsylvania ; and (2) the bituminous area, which occu- 
 pies the balance of the field. 
 
 Bituminous Area (15, 20). In western Pennsylvania, where 
 we have the type section of the Carboniferous of eastern
 
 22 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 America, about 95 per cent of the coal mined comes from 
 the Alleghany and Monongahela groups, though beds of 
 coal are found as high as the Dunkard and as low as the 
 Pottsville. While most of the coal beds are of limited 
 extent, the celebrated Pittsburg bed, at the base of the 
 Monongahela, with an average thickness of 6 feet over 2500 
 sq. mi. of its area, has an estimated original capacity of 
 10,000,000,000 tons of available coal, thus making it one 
 of the most important bituminous coal beds in the world. 
 This same bed is recognizable and important in Ohio and 
 Maryland. 
 
 In the southern portion of the Appalachian field, the coal 
 beds lie in the Pottsville, which here is much thicker than 
 farther north, reaching a maximum thickness of 5000 to 6000 
 feet, as against 300 feet in western Pennsylvania, and most 
 of the workable coal occurs in its upper portion. 
 
 Character of Appalachian Bituminous Coals. The coals of this field 
 differ greatly from place to place. In general there is a decrease in 
 volatile hydrocarbons from the west toward the east and southeast. 
 Good coking coals are found throughout the field. Those of Maryland 
 are semi-bituminous, and have a high reputation for steaming purposes ; 
 but those of Pennsylvania include many coking coals, and are hence of 
 further value in smithing, and coke and gas manufacture. While much 
 of the coke is used locally by the great metallurgical establish- 
 ments, a large amount is also shipped to other states, even in the 
 far Northwest. 
 
 The markets for these coals are chiefly in the South where, excepting 
 along the seacoast, they come into successful competition with the Penn- 
 sylvania anthracite for domestic purposes. In the north and northwest 
 they compete less successfully with coals from the interior fields. 
 
 Pennsylvania Anthracite Meld (18). This field (Fig. 6) 
 lies in the eastern central part of the state, covering an area
 
 COAL 
 
 23 
 
 of about 3300 square miles, about one-seventh of which 
 is underlain by workable coal measures. Intense folding 
 (Fig. 7) has placed some of the coal in the synclinal troughs 
 where it has been preserved from erosion which has removed 
 the coal from the intervening anticlines. Therefore the 
 anthracite is found in a 
 number of more or less 
 separated narrow basins. 
 It has been estimated that 
 from 94 to 98 per cent of 
 the coal originally depos- 
 ited has been removed from 
 this field by denudation. 
 
 The coal measures of the 
 anthracite district consist 
 of beds of sandstone, shale, 
 and clay, with coal beds at 
 intervals varying from a 
 few feet to several hundred 
 feet, though rarely exceed- 
 ing 200 feet. The coal 
 beds, which vary in thick- 
 ness from a few inches to 50 or 60 feet, occur through- 
 out the entire section of the coal measures, but are most 
 important in the lower 300 to 500 feet. Beneath the Pro- 
 ductive Measures is the hard Pottsville conglomerate, 
 which forms an important stratigraphic horizon, recogniz- 
 able by its lithological character and bold outcrops. Local 
 variations in the coal beds, and lack of uniformity in naming 
 them, have rendered their correlation in the different fields 
 more or less difficult. 
 
 FIG. 6. Map of Pennsylvania anthracite 
 field. After Stoek, U. S. Geol. Surv., 
 22d Ann. Sept., III.
 
 24 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The position of the coal beds and physical characteristics of the coal 
 have necessitated the use of special methods of mining and of treat- 
 ment after mining. Sharpness of folding and steep dips prevail, these 
 introducing many mining problems not found in bituminous regions. 
 When brought to the surface, it consists of lumps varying in size and 
 mixed with more or less shaly coal, called " bone," so that, before ship- 
 ment to market, it is necessary to break, size, and sort it. This is done 
 
 3 jj&nu B. SkJUUlWl^S Coll Ka BuialS 
 
 Ijs^ljll -illy* 
 
 \ / 
 
 Section (C)jcroM the J&mther Creek Bwla 
 
 FIG. 7 . Sections in Pennsylvania anthracite field. After Stock, U. S. Geol. 
 Surv., 2?2d Ann. Rept., Ill: 72. 
 
 in a coal breaker (Fig. 8), in which the coal is ci-ushed in rolls, and sized 
 by screens, while the slate is separated either by hand, automatic pickers, 
 or jigs. These breakers are a prominent feature of the anthracite region, 
 and much money has been spent in increasing their efficiency. As the 
 result of years of mining, the refuse from the breakers, consisting of a 
 fine coal-dust and bone, termed "culm," has accumulated in enormous 
 piles. Much of it is now being washed to save the finer particles of 
 clean coal ; and much is also washed into the mines to support the roof, 
 so that the pillars of coal, originally left for that purpose, can be 
 extracted.
 
 COAL 25 
 
 On account of its cleanliness and high fuel ratio, anthra- 
 cite coal is much prized for domestic purposes. Most of that 
 mined is marketed in the eastern and middle states, although 
 small quantities are shipped to the western states* especially 
 those that can be reached by way of the Great Lakes. 
 
 FIG. 8. Coal breaker in Pennsylvania anthracite region. 
 
 Rhode Island Field (63, H4). A small area of metamorphosed, folded, 
 and faulted Carboniferous occurs in the Narragansett Bay region of 
 Rhode Island, extending up into Massachusetts. The inclosing strata 
 of conglomerate and clay are often changed to schist, and the coal to a 
 form of anthracite so nearly pure carbon as to be exceedingly difficult 
 to burn. In fact, in places the coal has been metamorphosed to graphite. 
 Attempts to utilize this have not met with much success on account of 
 the high percentage of impurities which the material contains. 
 
 The Triassic Field (52). This coal field which is more important 
 historically than economically, having been worked as early as 1700, 
 includes several small steep-sided basins lying in the Piedmont region of 
 Virginia and North Carolina. It is probable that the coal-bearing beds 
 of the several areas, originally horizontal, were formerly continuous, 
 having been separated by folding, faulting, and denudation. In addition 
 to this, the coal is cut by dikes and sheets of igneous rock, which have 
 locally altered it to natural coke or carbonite.
 
 26 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Eastern Interior Field (13, 32). This 
 field is an oval, elongated basin (Fig. 
 9) extending northeast and southwest, 
 with the marginal beds dipping gently 
 toward the lowest portion, which lies 
 in Illinois, where the beds are nearly 
 horizontal. 
 
 The coal-bearing rocks rest uncom- 
 formably on lower Carboniferous, Devo- 
 nian, and Silurian strata, the basal 
 member being a sandstone probably the 
 equivalent of the Pottsville. The 
 entire section of coal-bearing rocks, 
 attaining a thickness of 1200 feet, 
 belongs to the Coal Measures, although 
 the upper part may be of Permian age, 
 and the highest workable coal beds are 
 classed as Freeport or Conemaugh. 
 The coal seams occur in the lower 
 portion of the section, and hence out- 
 crop around the margin, and the mining 
 operations are confined to a narrow belt, 
 because near the center of the basin the 
 coal beds underlie too great a thick- 
 ness of unproductive strata to permit 
 of profitable working under present 
 conditions. 
 
 Great difficulty has been encountered 
 in attempts at correlation of the coal 
 beds of different parts of the field, be- 
 cause of the varying section shown
 
 COAL 
 
 27 
 
 from place to place, and lack of continuity of the beds. 
 In consequence, the custom has arisen of giving the coal 
 beds numbers instead of names. 
 
 In Indiana coal is found in at least twenty horizons with workable beds 
 in not less than eight ; but at any given point the number of workable 
 beds never exceeds three, and in places there is only one. One of the 
 Indiana coals is known as " block coal," the name arising from the fact 
 
 that the presence ^__^__ 
 
 of joint planes at 
 right angles causes 
 the coal to break 
 into blocks. 
 
 There are many 
 coal beds in Illinois 
 worked at depths 
 of from 50 to 200 
 feet or more; but 
 there is a marked 
 absence of stratigraphic knowledge regarding this part of the field. 
 In Kentucky, on the other hand, there are only two workable coal beds 
 of decided importance, and fully 75 per cent of the coal produced in the 
 strata comes from the upper of these. This bed is so persistent that it 
 underlies a part of the whole of 8 counties, with an average thickness of 
 5 feet and at a depth commonly less than 200 feet. 
 
 The coals of the eastern interior field, although varying widely in 
 quality, are all bituminous. On account of their higher percentage of 
 ash and sulphur, they are little used for coking. Most of the coal used 
 in and near this field is supplied from it ; but even within the field the 
 Appalachian coals enter into competition. The Cannel coal found near 
 Cannelsburg, Kentucky, which is the only good gas producer found in 
 this field, finds a ready market. 
 
 Northern Interior Field (43). This field forms a large 
 basin in which the coal dips irregularly from the margin 
 toward the center (Fig. 11), but on account of the heavy 
 
 FIG. 10. Shaft house and tipple, bituminous coal mine, 
 Spring Valley, 111.
 
 28 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 mantle of glacial drift it has been difficult to determine 
 its exact boundaries, and prospecting is necessarily done 
 by means of drilling. The coal measures attain a total 
 thickness of 600 to 700 feet in the center of the basin, and 
 include 7 horizons of workable coal with an average 
 thickness of 2 feet and rarely exceeding 4 feet. Coal 
 is found near the center of the basin at depths of 400 
 feet or more, though the beds that are mined are mostly 
 
 
 SO IOC I5O ZOOibct 
 
 Fia. 11. Generalized section of Northern Interior coal field. After" Lane, 
 U. S. Geol. Surv., Z2d Ann. Kept., Ill: 316. 
 
 at depths of 100 to 250 feet. All the coals are bituminous 
 and used chiefly for fuel, but some are coking, and others 
 will probably prove of value for gas manufacture. 
 
 Western Interior Field and Southwestern Fields (U). 
 These two fields form a practically continuous belt of coal- 
 bearing formations, extending from northern Iowa south- 
 westward for a distance of 880 miles into central Texas. 
 Throughout most of this area the beds lie horizontal, or 
 have a gentle westward dip averaging 10 to 20 feet per mile. 
 A notable exception is found in the beds of eastern Indian 
 Territory and Arkansas which are rather strongly folded, 
 reminding one of the Pennsylvania anthracite area.
 
 COAL 
 
 29 
 
 Western Interior Field. The coal measures, composed of 
 limestones, sandstones, shales, fireclays, and coal beds, rest 
 unconformably on the Mississippian and dip westwardly 
 under beds of Permian, Cretaceous, and Pleistocene (Fig. 12). 
 Toward the south and west the beds increase in thickness, 
 the maximum being 1000 feet in Iowa (36) and 3000 in 
 Kansas (37). 
 
 Most of the coal mined in this field comes from the lower 
 part of the coal measures where the beds are irregular in 
 
 FIG. 12. Composite section showing structure of lower coal measures of Iowa. 
 After Keyes, la. Geol. Surv., I: 105. 
 
 thickness and distribution, in consequence of deposition on 
 a very uneven surface. 
 
 All the coals of this field are essentially bituminous and used chiefly 
 for steaming and heating purposes, being of no value for either coking 
 or gas making. Some of the seams will coke, but there is no demand for 
 the product, and the sulphur and ash are too high for gas making. 
 
 Southwestern Field. While it is known that there is 
 much good coal in this field, full development has not been 
 undertaken in most parts of it. The Indian Territory 
 coals (34, 35), of which there are 7 important beds in a 
 section of 4500 feet of shales and sandstone, are both folded 
 and faulted. These coals, as well as those of Texas (69), 
 where there are three workable beds, are all bituminous;
 
 30 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 but in the eastern end of the Arkansas (25) field there is 
 anthracitic coal of probable Permian age. 
 
 The coal from this field finds its most important market 
 in the South, though some is sent North. The Texas coals 
 are of especial importance on the railways, being used as 
 far west as the Pacific coast. It has, however, found a 
 serious competitor in the Texas crude petroleum; but it 
 remains to be seen whether this competition will be lasting. 
 On account of the value for domestic purposes the anthra- 
 cite finds an important market to the northward. 
 
 Gulf States Lignite Area (9). There is a narrow lignite- 
 bearing belt extending across the lower part of Alabama 
 and Mississippi; and another much larger belt extending 
 from near Little Rock, Arkansas, southwestward across the 
 northwestern corner of Louisiana (42), and in a narrowing 
 belt across Texas. Both of these are of Eocene age. The 
 lignites are usually high in moisture and ash, the best grade 
 being that mined in the lower end of the area, near Laredo 
 on the Rio Grande. 
 
 A small field of Cretaceous lignitic coal has been devel- 
 oped around Eagle Pass on the Rio Grande (70). This 
 is an extension of the Mexican field, but is of poorer 
 quality. 
 
 Rocky Mountain Fields (17). These cover a broad area, 
 extending from the Canadian boundary southward into 
 New Mexico, a distance of about 1000 miles, and includ- 
 ing over 50 fields of various size and irregular shape. 
 Most of the beds lie within the mountainous region, but at 
 the northern end of the area, in Wyoming and the Dakotas, 
 the coal fields extend eastward under the plains for some
 
 PLATE II 
 
 FIG. 1. Pit working (Strippings) near Milnesville, Pa. The Mammoth seam is 
 uncovered in bottom of pit. 
 
 FIG. 2. Lignite seam, Williston, N.D. After Wilder photo.
 
 COAL 31 
 
 distance. The age of the coal ranges from Cretaceous to 
 Tertiary, though most of it belongs to the former. 
 
 While portions of this enormous area of coal-bearing 
 strata are only slightly disturbed, mountain-building forces 
 and igneous intrusions have affected a large proportion of 
 the region, often materially changing the character of the 
 coal. Thus, while in undisturbed portions of the field the 
 beds are lignitic (PI. II, Fig. 2), in the disturbed parts they 
 have been altered to bituminous and even to anthracite 
 coal. Some of the bituminous coals produce an excellent 
 quality of coke. 
 
 Colorado (29, 30) is the most important coal-producing state of the 
 Rocky Mountain region. This is due, not only to the quality of its 
 coals, but also to the presence within the state of extensive metal- 
 lurgical industries. The Raton field, in the southeastern part of the 
 state and extending into New Mexico (50, 51), is at present the most 
 important producer. Like many of the fields of this region the age 
 of these is Laramie, and the beds are both folded and faulted. They 
 are, moreover, crossed by igneous intrusions which have in some places 
 produced natural coke, but in others destroyed the value of the coal. 
 In a section of from 3000 to 4500 feet of Laramie strata there are 40 
 coal beds, only a few of which are, however, workable. There are 
 both coking and semi-coking coals, and some anthracite. 
 
 In Montana (45, 46, 47) the coals range in age from Triassic to Ter- 
 tiary, and in quality from lignite to bituminous. The coals of Wyoming, 
 which occupy a very large area, show the same range in quality, but 
 are more commonly lignite because found to so large an extent in re- 
 gions of slight disturbance. The Utah coals are prevailingly semi- 
 bituminous, and those of the two Dakotas lignitic. 
 
 The Pacific Coast Fields (16). Tertiary coals, partly 
 bituminous, though mainly lignitic, occur scattered over a 
 wide area in the states of California (28), Washington (75),
 
 32 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 and Oregon (56, 57). The separate fields are limited in ex- 
 tent, widely separated, and with a small total output. Of 
 the four fields recognized in Washington, the most impor- 
 tant lie directly east of Seattle arid Tacoma. The total 
 thickness of coal-bearing sandstones and strata is about 
 10,000 feet, but important coal beds are found only in the 
 lower 2000 feet. It is stated that there are 100 coal seams 
 of sufficient thickness to attract the prospector ; and in a 
 single district there may be from 5 to 10 workable beds. 
 Since the quality of the coal varies with the extent of 
 dynamic disturbance, there is considerable variation even 
 in a single field, and, in fact, in a single mine. 
 
 Both California and Oregon produce small quantities of lignitic coal 
 of Tertiary age, but show no promise of becoming important producers. 
 Indeed, the coal-trade conditions of the Pacific coast are unique. The 
 local supply is not equal to the demand, and the Rocky Mountain fields 
 are too far off to supply the Pacific coast with cheap fuel. Therefore 
 much coal is imported, bringing about a competition in San Francisco 
 from many countries, including England, Wales, Scotland, Australia, 
 Japan, and British Columbia. These foreign coals are all of better 
 quality than the Pacific coast coals, and they can be imported with 
 low freight rate as ballast in wheat-carrying vessels that come to San 
 Francisco for cargoes. These coal imports form three-quarters of the 
 total import coal tonnage of -the United States ; but since 1895 there 
 has been a steady decrease in the importation of coal and an increase 
 in the Pacific coast production. 
 
 Alaska (23,24). Although Alaskan coal was first mined 
 in 1852 at Port Graham, the resources of the region are 
 still but little known and slightly developed. The ex- 
 plorations for gold during the last few years, together 
 with the field work done by the United States Geological
 
 COAL 
 
 33 
 
 Survey, have proved that coal is widely distributed in the 
 Alaskan Territory (Fig. 81). So far as known the coal 
 beds are all in Mesozoic and Tertiary formations. While 
 most of the coal is lignitic, there is considerable bitumi- 
 nous coal and some semi-anthracite. 
 
 Coal mining has been carried on at a number of localities, especially 
 along the rivers and coast. The higher grade coals along the coast, par- 
 ticularly in the southern part where shipments can be made throughout 
 the year, will doubtless be developed with profit in the near future. 
 Coals in the Yukon Valley, though of low grade and variable character, 
 bring $15 a ton at the mines because of the local demand in the mining 
 camps. The effect of such a local demand on the coal is even more 
 strikingly shown by the fact that the semi-bituminous coal near the 
 Cape Nome gold field sold, at times, for as much as f 100 per ton. 
 
 Production of Coal. While coal mining in the United 
 States began at an early date, the figures of production for 
 the first few years are more or less incomplete. The phe- 
 nomenal growth of the coal-mining industry is well shown, 
 however, by the following figures : 
 
 YEAR 
 
 QUANTITY 
 SHORT TONS 
 
 YEAR 
 
 QUANTITY 
 SHORT TONS 
 
 1868 
 
 31 648 960 
 
 1890 
 
 157 770 963 
 
 1870 
 
 36 806 560 
 
 1895 . . . 
 
 193 117530 
 
 1875 
 
 5'} *>88 3^0 
 
 1900 
 
 959 684 0' ? 7 
 
 1880 
 
 76 157 944 
 
 1903 .... 
 
 357 356 416 
 
 1885 
 
 111 159 795 
 
 
 
 
 
 
 
 The production and value of the coal produced by the 
 12 largest producers in point of output since 1901 has 
 been as follows:
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 
 1901 
 
 1902 
 
 1903 
 
 STATE 
 
 QUANTITY 
 
 
 QUANTITY 
 
 
 QUANTITY 
 
 
 
 SHORT 
 
 VALUE 
 
 SHORT 
 
 VALUE 
 
 SHORT 
 
 VALUE 
 
 
 TONS 
 
 
 TONS 
 
 
 TONS 
 
 
 Pennsylvania : 
 
 
 
 
 
 
 
 Anthracite 
 
 67,471,667 
 
 112,504,020 
 
 41,373,595 
 
 76,173,586 
 
 74,607,068 
 
 152,036,448 
 
 Bituminous 
 
 82,305,946 
 
 81,397,586 
 
 98,574,367 
 
 106,032,460 
 
 103,117,178 
 
 121,752,759 
 
 Illinois 
 
 27,331,552 
 
 28,163,937 
 
 32,939,373 
 
 33,945,910 
 
 36,957,104 
 
 43,196,80!) 
 
 West Virginia 
 
 24,068,402 
 
 20,848,184 
 
 24,570,826 
 
 24,748,658 
 
 29,337,241 
 
 34,297,01!) 
 
 Ohio 
 
 20,943,807 
 
 20,928,158 
 
 23,519,894 
 
 26,953,789 
 
 24,838,103 
 
 31,932,327 
 
 Alabama 
 
 9,099,052 
 
 10,000,892 
 
 10,354,570 
 
 12,419,666 
 
 11,654,324 
 
 14,246,798 
 
 Indiana 
 
 6,918,225 
 
 7,017,143 
 
 9,446,424 
 
 10,399,660 
 
 10,794,692 
 
 13,244,817 
 
 Colorado 
 
 5,700,015 
 
 6,441,891 
 
 7,401,343 
 
 8,397,812 
 
 7,423,602 
 
 9,150,!U:} 
 
 Kentucky 
 
 5,469,986 
 
 5,213,076 
 
 6,766,984 
 
 6,666,967 
 
 7,538,032 
 
 7,97!),:U2 
 
 Iowa 
 
 5,617,499 
 
 7,822,805 
 
 5,904,766 
 
 8,660,287 
 
 6,419,811 
 
 10,563,910 
 
 Maryland 
 
 5,113,127 
 
 5,046,491 
 
 5,271,609 
 
 5,579,869 
 
 4,846,165 
 
 7,189,784 
 
 Kansas 
 
 4,900,528 
 
 5,991,599 
 
 5,266,065 
 
 6,862,787 
 
 5,839,976 
 
 8,871,953 
 
 Tennessee 
 
 3,633,290 
 
 4,067,389 
 
 4,382,968 
 
 5,399,721 
 
 4,798,004 
 
 5,979,830 
 
 Grouping the output by fields, the overwhelming impor- 
 tance of the Appalachian field is well seen. 
 
 PRODUCTION OF COAL IN UNITKD STATES BY FIELDS FROM 
 1901-1903 
 
 FIELD 
 
 1901 
 SHORT TONS 
 
 1902 
 SHORT TONS 
 
 1903 
 SHORT TONS 
 
 Anthracite (Pa., Colo., N. Mex.) 
 Triassic . . . 
 
 67,538,536 
 12,000 
 150 501 214 
 
 41,467,532 
 39,206 
 173, 9 74,861 
 
 74,679,799 
 35,393 
 185,600 161 
 
 Northern 
 
 1,241,241 
 
 964,718 
 
 1,367,619 
 
 
 37 450 871 
 
 46 133,024 
 
 52,130,856 
 
 Western 
 
 19,665,985 
 
 20,727,495 
 
 23,171,692 
 
 Rocky Mt . . . 
 
 14 090 362 
 
 16 149,545 
 
 16,981,059 
 
 Pacific Coast 
 
 2,799,607 
 
 2,834,058 
 
 3,389,837 
 
 The average price of anthracite coal, per short ton, in 
 1903 was $2.04, while that of bituminous was $1.24.
 
 COAL 35 
 
 The exports in 1903 amounted to 2,008,857 long tons of 
 anthracite, valued at $9,680,044, and 6,303,241 long tons of 
 bituminous, valued at $17,410,385. 
 
 PRODUCTION OF LEADING COAL-PRODUCING COUNTRIES 
 
 COUNTRY SHORT TONS 
 
 United States (1903) 357,356,416 
 
 Great Britain (1903) 257,974,605 
 
 Germany (1903) . 178,916,600 
 
 Austria-Hungary (1902) 43,518,319 
 
 France (1903) 38,583,798 
 
 Belgium (1903) 26,312,805 
 
 Russia (1902) 17,090,835 
 
 Japan (1901) 9,861,107 
 
 Production of Coke. The quantity of coke now produced 
 annually in the United States is very large, and there is 
 an extensive demand for it in smelting operations. In 
 1903 there were produced 25,262,360 short tons of coke 
 from 39,410,729 short tons of coal, which gave an average 
 yield of 64.1 per cent coke per ton of coal, with the aver- 
 age value of $2.63 per ton coke. This quantity was supplied 
 by 77,188 coke ovens, and over 50 per cent of the supply 
 came from Pennsylvania. In addition 1,882,394 short tons, 
 or 7.4 per cent of the total production, was made in by- 
 product coke ovens, the approximate percentage of by- 
 products obtained from a ton of coal being: coal tar, 12.55 
 gallons; ammonia liquor, 14.4 gallons; ammonium sulphate, 
 17.6 pounds. 
 
 REFERENCES ON COAL 
 
 GENERAL. 1. Catlett, Amer. Inst. Min. Engrs., Trans. XXX : 559, 1901. 
 (Coal outcrops.) 2. Bain, Jour. Geol. Ill: 646, 1895. (Structure 
 of coal basins.) 3. Lesley, Manual of Coal and its Topography; 
 Philadelphia, 1856. 4. Lesquereux, 2d Geol. Surv. Pa., Ann. Kept., 
 p. 95, 1885. (Origin.) 5. Lyell, Amer. Jour. Sci. CLV : 353, 1843.
 
 36 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 (Upright trees in coal.) 6. Moffat, Amer. Inst. Min. Engrs., 
 Trans. XV: 819, 1887. (Change of mine prop to coal.) 7. Steven- 
 son, Geol. Soc. Amer. Bull., V : 39, 1893. (Origin Pa. anthracite.) 
 8. Wormley, Geol. Surv., Ohio, VI: 403, 1870. (Proximate and 
 ultimate analysis.) See also Nos. 32, 32a, 37, 55. 
 
 GENERAL AREAL REPORTS. 9. Hayes, U. S. Geol. Surv., 22d Ann. 
 Kept., Ill: 7, 1902. (U. S. coal fields.) 10. MacFarlane, Coal 
 Regions of America, 700 pp., 3d ed., 1877, New York. 11. Nich- 
 olls, The Story of American Coals, 1897 (Phila.). 12. White, U. S. 
 Geol. Surv., Bull. 65. ' (Bituminous field, Pa., Ohio, and W. Va.) 
 13. Series of papers on the several coal fields of the United 
 States, in U. S. Geol. Surv., 22d Ann. Rept., Ill: 11-571, 1902, as 
 follows: Ashley, "p. 271. (Eastern Interior.) 14. Bain, p. 339. 
 (Western Interior.) lo. Hayes, p. 233. (Southern Appalachians.) 
 16. Smith, p. 479. (Pacific coast.) 17. Storrs, p. 421. (Rocky 
 Mountain field.) 18.' Stoek, p. 61. (Pa. anthracite.) 19. Taff, 
 p. 373. (Southwestern.) 20. White, Campbell, and Hazeltine, 
 p. 125. (Northern Appalachians.) Alabama: 21. Gibson, Ala. 
 Geol. Surv., 1895. (Coosa field.) 22. McCalley, Ala. Geol. Surv., 
 1900. (Warrior field.) Alaska : 23. Ball, U. S. Geol. Surv., 17th 
 Ann. Rept., I: 771, 1896. (Coal and lignite.) 24. Brooks, Ibid., 
 22d Ann. Rept., Ill: 521. Arkansas: 25. Taff, U. S. Geol. Surv., 
 21st Ann. Rept., II: 313. (Camden field.) Arizona : 26. Blake, 
 Amer. Geol., XXI : 345, 1898. 27. Campbell, U. S. Geol. Surv., 
 Bull. 225 : 240, 1904. (Deer Creek field.) California : See Pacific 
 Coast Report referred to above and also various county reports in 
 (28) llth Ann. Rept. Calif. State Mining Bureau. Colorado: 
 29. Eldridge, U. S. Geol. Surv., Geol. Atlas of the U. S., folio 9. 
 (Anthracite.) 30. Hills, U. S. Geol. Surv., Min. Res., 1892, 319. 
 Georgia: 31. McCallie, Ga. Geol. Surv., Bull. 12, 1904. (General.) 
 Iowa: 32 a. Keyes, la. Geol. Surv., II : 1894. (General.) Indi- 
 ana: 32. Ashley, Ind. Dept. of Geol. and Nat. Hist., 23d Ann. 
 Rept., 1899: 1. Illinois: 33. Also Worthen and others, 111. 
 Geol. Surv., 1 : 1866 ; III : 1868 ; IV : 1870 ; V : 1873 and VI : 1875. 
 Indian Territory : 34. Adams, U. S. G. S., 21st Ann. Rept., II : 257, 1900. 
 (Eastern Choctaw field.) 35. Taff, White, and Girty, U. S. Geol. 
 Surv., 19th Ann. Rept., Ill : 423, 1898. (McAlester-Lehigh field.) 
 Iowa: 36. Keyes, Iowa Geol. Surv., II: 536. Kansas: 37. Ha- 
 worth and Crane, Kas. Univ. Geol. Surv., Ill: 13, 1898. Ken- 
 tucky: 38. Moore, Ky. Geol. Surv., Ser. 2, IV, pt. XI: 423. (Eastern 
 border and Western field.) 39. Lesley, Ky. Geol. Surv., IV: 443, 
 1858. (Eastern.) 40. Norwood, Ann. Rept., Inspector of Mines, 
 1901-1902. (Much general information.) 41. For analyses, see
 
 COAL 37 
 
 Ky. Geol. Surv., New Series, Chem. Kept., etc., pt. I, II, and III. 
 Louisiana: 42. Harris, Prelim. Kept, on Geol. of Louisiana for 
 1899: 134. (Lignite.) Maryland: 42a. Clark, Md. Geol. Surv., Vol. 
 V, 1905. Michigan : 43. Lane, Mich. Geol. Surv., VIII: pt. 2. 
 Missouri: 44. Winslow, Mo. Geol. Surv., 1891: 19-226. Montana: 
 45. Weed, Eng. and Min. Jour., LIII: 520, 542, and LV: 197, also 
 Geol. Soc. Amer., Bull. 111:301, 1892. (Great Falls and Rocky 
 Fork fields.) 46. Rowe, Amer. Geol., XXXII: 369, 1903. 
 47. Burchard, U. S. Geol. Surv., Bull. 225:276, 1904. (Lignites, 
 Upper Missouri Valley.) Nebraska: 48. Barbour, Neb. Geol. Surv., 
 I: 198, 1903. Nevada: 49. Spurr, U. S. Geol. Surv., Bull. 225: 
 289, 1904. New Mexico: 50. Johnson, Sch. of M. Quart., XXIV: 
 456. (Cerillos.) 51. Stevenson, N. Y. Acad. Sci., Trans. XV: 105, 
 1896. (Cerillos field.) North Carolina: 52. Woodworth, U. S. 
 Geol. Surv., 22d Ann. Rept., Ill: 31, 1902. North Dakota: 
 
 53. Babcock, N. Dak. Geol. Surv., 1st Biennial Rept., 1901 : 56. 
 
 54. Wilder, Eng. and Min. Jour., 74: 674, 1902. (Lignite.) Ohio: 
 
 55. Orton, Ohio Geol. Surv., VII: 255. Oregon: 56. Diller, U. S. 
 Geol. Surv., 17th Ann. Rept., I. (N. W. Ore.) 57. Diller, Ibid., 
 19th Ann. Rept., Ill: 309. (Coos Bay.) Pennsylvania : 58. d'ln- 
 villiers, 2d Pa. Geol. Surv. Rept, 1885 and 1886. (Pittsburg re- 
 gion.) 59. McFarlane, Coal Regions of America, 3d ed. ; New 
 York, 1877. 60. Rept. MM. contains many analyses. 61. See also 
 various county reports of same survey. 62. Final Summary Rept., 
 Ill: pt. 1, and 2. Rhode Island: 63. Emmons, Amer. Inst. Min. 
 Eng., Trans. XIII : 510, 1885. 64. Stevenson, Manchester Geol. 
 Soc., Trans. XXIII: 127. (New Eng. fields.) South Dakota: 
 65. Todd, S. Dakota Geol. Surv., Bull. 1 : 159. Tennessee : 66. Duf- 
 field, Eng. and Min. Jour., LXXIV : 442, 1902. (Cumberland Pla- 
 teau.) 67. Safford, U. S. Geol. Surv., Min. Res., 497, 1892. Texas: 
 68. Dumble, Bull, on Lignites of Texas, Tex. Geol. Surv. (Lig- 
 nites.) 69. PhiUips, Univ. Tex. Mineral Surv., Bull. 3: 1902. 
 (Coal and lignite.) 70. Vaughan, U. S. Geol. Surv., Bull. 164, 
 1900. (Rio Grande fields.) Utah : 71. Forrester, U. S. Geol. Surv., 
 Min. Res., 511, 1892. Vermont : 72. Hitchcock, Amer. Jour. Sci., 
 ii, XV: 95, 1853. (Lignite at Brandon.) Virginia: 73. Camp- 
 bell, U. S. Geol. Surv., Bull. Ill, 1893. (Big Stone Gap field.) 
 74. Woodworth, U. S. Geol. Surv., 22d Ann. Rept., Ill : 31, 1902. 
 (Triassic coal.) Washington : 75. Landes and Ruddy, Wash. Geol. 
 Surv., II ; Willis, U. S. Geol. Surv., 18th Ann. Rept., Ill : 393, 1898. 
 (Puget Sound.) West Virginia : 76. White, West Va. Geol. Surv., 
 II: 1903. Wyoming : 77. Fisher, U. S. Geol. Surv., Bull. 225 : 345, 
 1904. 78. Knight, Min. Ind., Ill : 145, 1894.
 
 38 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 REFERENCES ON PEAT 
 
 79. Ries, N". Y. State Museum, 54th Ann. Kept., 1903. (N. Y., Origin 
 and uses in general, Bibliography.) 80. Carter, Ont. Bur. Mines, 
 Kept, for 1903. (General.) 81. Shaler, U. S. Geol. Surv., 12th 
 Ann. Kept., p. 311. (Peat and swamp soils.) 82. Roller, Die 
 Torfindustrie, Vienna, 1889. 83. Ries, Min. Res., U. S. Geol. Surv., 
 1901. (U. S.)
 
 CHAPTER II 
 PETROLEUM, NATURAL GAS, AND OTHER HYDROCARBONS 
 
 UNDER this head are included a number of hydrocarbon 
 compounds, of complex and variable composition, ranging 
 from the solid to the gaseous state, the series including four 
 well-marked and well-known members; viz., natural gas, 
 petroleum, mineral tar or maltha, and asphalt. The de- 
 velopment of these products, and especially the first two, 
 has been so remarkable and attended by such important 
 economic results that it seems well to preface the follow- 
 ing description by a brief outline of this history of their 
 development. 
 
 History of Petroleum Development. Petroleum has long 
 been known in many parts of the world because of its pres- 
 ence in bituminous springs or as a floating scum on the 
 surface of pools. It was used at an early date on the walls 
 of Babylon and Nineveh, and was obtained by the Romans 
 from Sicily for use in their lamps. 
 
 In the United States petroleum was mentioned by French 
 missionaries even in 1635, and the early Pennsylvania settlers 
 obtained small quantities by scooping out the oil from dug 
 wells. Its discovery at greater depth on the western slope 
 of the Alleghanies was made during the drilling of brine 
 wells; but its early use was chiefly a medicinal one until 
 1863, when attempts were made to purify it for use as a 
 
 39
 
 40 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 lubricant and illurainant. The beginning of the oil industry 
 is usually considered to date from the sinking of a successful 
 well by Colonel Drake on Oil Creek, Pennsylvania, in 1860. 
 From this center prospectors spread out in all directions mak- 
 ing valuable discoveries, until now petroleum production and 
 refining rank among the leading industries of the country, 
 the supply coming from many states. 
 
 History of Natural Gras Development. Natural gas was 
 discovered and first employed for economic purposes at 
 Fredonia, New York, in 1821. In 1841 it was used in the 
 Great Kanawah Valley _as a fuel in salt furnaces, but its first 
 extensive use began in 1872 at Fairview, Pennsylvania. It 
 was used in 1885 for iron smelting at Etna Borough near 
 Pittsburg, and in 1886 was piped nineteen miles from 
 Murrayville to Pittsburg. Now natural gas is piped long 
 distances to cities, being used as a fuel in many industries, 
 as well as for domestic heating and lighting. 
 
 Properties of Petroleum (1, 2, 7). Crude petroleum is a 
 liquid of complex composition and variable color and den- 
 sity. It consists of a mixture of hydrocarbons, the American 
 petroleum belonging usually to the paraffin series although 
 some has an asphaltic base. The Mississippi River forms 
 a rough dividing line between fields containing oil with a 
 paraffin base and those with an asphaltic base. In addition 
 to these compounds, petroleum may contain substances with 
 a small percentage of nitrogen and sulphur. 
 
 The following are analyses of several petroleums from 
 American and foreign localities :
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 41 
 ELEMENTARY ANALYSES OF PETROLEUMS 
 
 
 
 PER CENT 
 
 
 SPECIFIC 
 
 LOCALITY 
 
 
 
 
 GRAVITY 
 
 
 C. 
 
 H. 
 
 O. 
 
 H 2 O = 1 
 
 Heavy oil, W. Va 
 
 83.5 
 
 13.3 
 
 3.2 
 
 .873 
 
 Light oil, W. Va 
 
 84.3 
 
 14.1 
 
 1.6 
 
 .8412 
 
 Heavy oil Pa 
 
 84.9 
 
 13.7 
 
 1.04 
 
 .886 
 
 Light oil, Pa 
 
 82.0 
 
 14.8 
 
 3.2 
 
 .816 
 
 Parma, Italy 
 
 84.0 
 
 13.4 
 
 1.8 
 
 .786 
 
 Hanover, Germany . . . 
 
 80.4 
 
 12.7 
 
 6.9 
 
 .892 
 
 Galicia, Austria 
 
 82.2 
 
 12.1 
 
 5.7 
 
 .870 
 
 Light oil, Baku, Rus. . . . 
 
 86.3 
 
 13.6 
 
 0.1 
 
 .884 
 
 Heavy oil, Baku, Rus. . . 
 
 86.6 
 
 12.3 
 
 1.1 
 
 .938 
 
 Java 
 
 87.1 
 
 12.0 
 
 0.9 
 
 .923 
 
 Beaumont, Texas .... 
 
 86.8 
 
 13.2 
 
 
 .920 
 
 Petroleums commonly vary in specific gravity between 
 .801 and .965, the following being some of the limits shown 
 by American oils : 
 
 SPECIFIC GRAVITY OF SOME AMERICAN PETROLEUMS 
 
 STATE 
 
 SPECIFIC GRAVITY 
 
 GRAVITY BEAUME 1 
 
 Pennsylvania 
 
 .801-.817 
 
 46.2-42.6 
 
 Ohio 
 
 816 860 
 
 428-325 
 
 Kansas 
 
 .835-1.000 
 
 38.8-10.0 
 
 West Virginia 
 
 841 873 
 
 37 6-30 
 
 Beaumont, Texas 
 
 .904-.925 
 
 24.8-31.1 
 
 
 919 945 
 
 23 3 119 
 
 California 
 
 .920-.983 
 
 21.9-12.3 
 
 
 
 
 The temperature at which crude petroleum solidifies ranges 
 from 82 F., in some Burma oils, to several degrees below 
 zero in certain Italian oils. The flashing point, or the lowest 
 
 1 A specific gravity of 1, compared with water, is 10 on the Beaume scale.
 
 42 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 temperature at which inflammable vapors are given off, 
 may be as low as zero degrees in the Italian oils to as high 
 as 370 F. in an oil found on the Gold Coast of Africa, but 
 these are extreme limits. There is also a great range in the 
 boiling point, which is 180 F. in some Pennsylvania oils and 
 338 F. in oils found at Hanover, Germany. 
 
 The various liquid hydrocarbons making up crude petro- 
 leum vary in their specific gravity and boiling point. The 
 more important oils which can be separated from crude pe- 
 troleum by distillation are gasoline, benzine, heavy naphthas, 
 and residuum. Those with a paraffin base are generally 
 lighter and more valuable on account of the higher quantity 
 and quality of the naphthas, illuminating oils, and lubricating 
 oils which they produce. Those with an asphalt base are of 
 inferior quality and chiefly valuable for fuel. Their trans- 
 portation by pipe lines is also more difficult. 
 
 The percentage of the different distillates varies. 
 
 The following average percentages of distillates were 
 yielded by the oils of several fields in 1902 (Oliphant) : 
 
 
 APPALACHIAN 
 FIELD 
 
 LIMA, IND. 
 FIELD 
 
 KANSAS 
 FIELD 
 
 Naphthas . . . 
 
 201 
 
 10 9 
 
 18 
 
 Illuminating oils 
 
 61.4 
 
 488 
 
 30 
 
 Lubricating and heavy oils . . 
 
 7.1 
 63 
 
 17.2 
 
 25 
 
 Loss from uncondensed products 
 and water 
 
 51 
 
 230 
 
 27 
 
 
 
 
 
 Properties of Natural Gas. This consists chiefly of Marsh 
 gas fire damp CH 4 . It is colorless, odorless, burns 
 readily with a luminous flame, and when mixed with air,
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 43 
 
 it is highly explosive. As is shown by the following anal- 
 yses, several other gases are commonly present in small 
 quantities : 
 
 ANALYSES OF NATURAL GAS 
 
 
 HYDRO- 
 GEN 
 
 MAKSH 
 GAS 
 
 OLEFI- 
 ANT GAS 
 
 CAB- 
 
 BOKIC 
 
 OXIDE / 
 
 CAE- 
 BON DI- 
 OXIDE 
 
 OXYGEN 
 
 NlTKO- 
 GEN 
 
 SUL- 
 
 PHCBIO 
 
 HYDRO- 
 GEN 
 
 Fostoria, O. 
 
 1.89 
 
 92.84 
 
 .20 
 
 .55 
 
 .20 
 
 .35 
 
 3.82 
 
 .16 
 
 Findlay, 0. 
 
 1.64 
 
 93.35 
 
 .35 
 
 .41 
 
 .25 
 
 .39 
 
 3.41 
 
 .20 
 
 Muncie, Ind. 
 
 2.35 
 
 92.67 
 
 .25 
 
 .45 
 
 .25 
 
 .35 
 
 3.53 
 
 .15 
 
 Mode of Occurrence (4,5,6,8). Oil is rarely found without 
 gas, and saline water is likewise often present. If the con- 
 taining strata are horizontal, the oil and gas are usually 
 irregularly scattered, but if tilted or folded, they collect at 
 the highest point possible. It was the result of observa- 
 
 a GAS . b OIL WATER d CAPROCK 
 
 FIG. 13. Section of anticlinal fold showing accumulation of gas, oil, and water. 
 After Hayes, U. S. Geol. Surv., Bull. 212. 
 
 tions along this line that led I. C. White to develop what 
 is known as the " Anticlinal Theory " (8). According to 
 this theory, in folded areas the gas collects at the summit 
 of the fold, with the oil immediately below, on either side, 
 followed by water (Fig. 13). Unless there are secondary
 
 44 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 anticlines, the intervening synclines are liable to be barren 
 of oil and gas. For this theory, as for others, it is necessary 
 that the oil-bearing stratum shall be capped by a practically 
 impervious one. 
 
 Such anticlinal waves are found in the oil fields of the 
 Appalachians, Indiana, western Ohio, and many other locali- 
 ties. While this theory has been disputed, it may be con- 
 sidered established for many localities. The rival theory 
 advanced by Lesley and Ashburner, that the oil has accumu- 
 lated in porous areas of rock, perhaps ancient shore-line 
 deposits, may likewise apply in some cases. It supplies all 
 the necessary conditions of a subterranean reservoir for the 
 accumulation of oil in "pools." 
 
 In the first discovered fields, the oil and gas were 
 found in porous, sandy strata, varying from fine-grained, 
 cemented sandstone to loose gravels. These strata were 
 termed sands, and the area of porous oil sand was called 
 the pool. Later discoveries in Ohio and Indiana showed 
 that the gas and oil might occur in limestone also. 
 
 The quantity of oil which a cubic foot of apparently dense 
 rock can hold is often surprising. White (36) estimated 
 that fairly productive sands may hold from six to twelve 
 pints of oil per cubic foot, but that probably not more than 
 three-fourths of the quantity stored in the rock is obtain- 
 able. The ease with which the containing rock yields its 
 supply of oil depends largely on the openness of the pores. 
 
 Pressure of Oil and Gas Wells. Since both oil and gas 
 usually occur in the earth under pressure, any break in the 
 porous rock or reservoir which contains them allows them 
 to escape, frequently giving rise to surface indications, and 
 the force with which oil and gas oftentimes issue from a
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 45 
 
 well indicates the pressure under which they are confined. 
 It is sometimes sufficient to blow out the drilling tools and 
 casing, as well as to cause the oil to spout many feet into 
 the air. 
 
 There are several remarkable cases of the amount spouted by these 
 gushing wells. One of these is the famous Lucas well at Beaumont, 
 Texas, which in 1901 for nine days gushed a six-inch stream to a height 
 of 160 feet, at the rate of 75,000 barrels per day. This, however, is 
 small compared with the records of some Russian oil wells. Although 
 many wells flow when first drilled, this does not usually continue long, 
 and the oil then has to be brought to the surface by pumping. The depth 
 of the wells drilled in the United States ranges from 250 to 3700 feet, 
 and over 70 per cent of the total number drilled are located in Ohio 
 and Pennsylvania. 
 
 The maximum pressure which a well develops when closed 
 has been called rock pressure. As a result of his studies 
 in the Ohio-Indiana field, Orton (29) found that the rock 
 pressure was the same as that of a column of water whose 
 height was equal to the difference in elevation between the 
 level of Lake Erie and that of the oil or gas bearing stratum. 
 He therefore considered it to be hydrostatic pressure. This 
 theory, while apparently applicable in many localities, was 
 found to be inadequate to explain the great pressure shown 
 in many shallow wells. In such cases, no doubt, as in many 
 others, the pressure is due to the expansive force of the 
 imprisoned gas. 
 
 Either the drilling of additional wells or a drain by exces- 
 sive use from wells already bored commonly causes a slow 
 decrease in pressure in an oil or gas field. Thus in the 
 natural-gas region of Findlay, Ohio, the rock pressure in 
 1885 was 450 pounds per square inch; 400 in 1886; 360- 
 380 in 1887; 250 in 1889; 170-200 in 1890. Some West
 
 46 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Virginia wells have shown a measured rock pressure of 
 1110 pounds per square inch and an estimated pressure of 
 2000 pounds. 
 
 Origin. That the solid, liquid, and gaseous hydrocarbons 
 are more or less closely related is evident from the fact that 
 the gases given off by petroleum are similar to those pre- 
 dominating in natural gas, while the exposure of many 
 petroleums to the air results in a change to a viscous mass 
 and finally to a solid, asphalt-like substance. It is a well- 
 known fact that petroleum is rarely free from natural gas, 
 although this gas may sometimes form alone, as in coal 
 mines, or from decaying vegetation in stagnant pools. The 
 origin of the hydrocarbon compounds has been the subject 
 of much speculation among both chemists and geologists, the 
 former for a time arguing for an inorganic or mineral origin, 
 the latter for an organic derivation. 
 
 Inorganic Theory. Several theories have been advanced 
 to account for an inorganic origin of oil, the most important 
 of which, though not the earliest, was that of Mendeljeff, 
 the Russian chemist. According to his theory, the interior 
 of the earth contains metallic iron, as well as carbid of iron 
 like that found in meteorites. Waters percolating down- 
 ward through the earth's crust, on reaching the heated 
 interior, become converted into steam, which, attacking the 
 carbid of iron, forms hydrocarbons. These are forced to the 
 surface by the expansive force of the steam. 
 
 From a purely chemical standpoint, this theory is reason- 
 able, but it does not accord with geologic facts. If petro- 
 leum were found in this manner, we should expect to find it 
 widely distributed through the oldest rocks of the earth's
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 47 
 
 crust. On the contrary, it is known in these rocks at only 
 one locality, in Ontario, where a hard, compressed asphalt 
 is found in crystalline rocks. It is significant that this 
 material, which was probably originally petroleum, occurs 
 in rocks which show evidence of having been originally 
 stratified. 
 
 Organic Theory. This considers that petroleum has been 
 derived from either animal or vegetable matter by a process 
 of slow distillation, although the exact changes involved are 
 uncertain. There are several strong arguments in favor of 
 it. (1) Petroleum is a combustible substance, and all other 
 similar combustibles have originated organically. (2) It is 
 possible to artificially produce, from either animal or vege- 
 table substances, both gaseous and liquid compounds which 
 are closely analogous to those found in petroleum and 
 natural gas. Fish oil, for example, will on distillation yield 
 petroleum compounds, including illuminating oil, lubricating 
 oil, benzine, and paraffin. (3) These substances occur in 
 fossil-bearing rocks. (4) They are practically absent from 
 the crystalline rocks. (5) In some places these substances 
 occur in close proximity to fossils. (6) Natural gas is 
 actually generated in coal seams. 
 
 Some geologists, including Orton (4) and Newberry (Ohio 
 State Agric. Rep. 1859), have believed that the formation of 
 petroleum has taken place at low temperatures ; but others, 
 including Peckam (6), have considered heat necessary. In 
 the case of Appalachian oils, the folding of the strata is sup- 
 posed to have supplied this heat. 
 
 It seems doubtful whether either petroleum or natural gas 
 have migrated any great distance through the strata subse- 
 quent to their formation. When any movement has taken
 
 48 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 place through pores of the rock, it has probably been due to 
 gravity separation, the gas rising to the highest point of the 
 stratum while the oil settles. 
 
 Geological Distribution of Petroleum and Natural Gas. 
 Petroleum is widely distributed geologically, being found in 
 rocks whose age ranges from the Ordovician to the most 
 recent, the occurrences in Paleozoic strata being chiefly in 
 eastern United States, those in post-Carboniferous strata in 
 the western and southern states. 
 
 Natural gas may show an equally wide geological distribu- 
 tion, although in the United States the larger amount is now 
 obtained from the Paleozoic formations. 
 
 Distribution of Petroleum in the United States. The im- 
 portant petroleum occurrences of the United States, so far as 
 at present known, may be considered to belong to the seven 
 following fields (Fig. 14) : (1) the Appalachian field, includ- 
 ing New York, western Pennsylvania, eastern Ohio, West 
 Virginia, Kentucky, and Tennessee; (2) the Ohio-Indiana 
 field ; (3) the Texas-Louisiana field ; (4) the Kansas-Indian 
 Territory field ; (5) the Colorado fields ; (6) the Wyoming 
 fields; (7) the California fields. In addition to these there are 
 scattered occurrences in Michigan, etc. (See map, Fig. 14.) 
 
 Appalachian Field. This field, which supplied over 85 per 
 cent of the oil produced in the United States in 1902, extends 
 from southwestern New York (25) into West Virginia (37, 38) 
 and is subdivided into several districts, each containing sev- 
 eral "pools." The region is of interest historically and geo- 
 logically, some of the earliest discoveries of oil having been 
 made in it. The oil is obtained from sandstones and con- 
 glomerates, ranging in age from the Upper Carboniferous
 
 PLATE III 
 
 FIG. 1. General view of Tuna Valley, in Pennsylvania oil field. Photo, by F. H. 
 Oliphant. 
 
 FIG. 2. View in Los Angeles, Calif., oil field. Such close spacing of oil derricks 
 tends to hasten the exhaustion of the oil supply.
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 49 
 
 in the upper part of the field, to Middle Devonian in the 
 lower portion, which underlie an area of probably 55,000 
 
 square miles. There are often several productive beds in a 
 single formation, and 40 oil sands have been recognized in
 
 50 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 the entire section. This field, which is the most important 
 in the United States, supplies a large amount of high-grade 
 petroleum, and has a large output ; but apparently the pro- 
 duction has practically reached its maximum. The petroleum- 
 producing areas of Pennsylvania (31, 32) are divided into a 
 number of districts, this division being based partly on quality 
 and partly on county lines. Each district may be subdivided 
 into pools. In the Clarendon and Warren County district 
 is found some of the finest petroleum produced in the United 
 
 TRENTON 
 
 LIMESTONE 
 
 UTICA 
 
 SHALE 
 
 HUDSON R. NIAGARA LIMESTONE LOWER UPPER OHIO 
 
 SHALE NIAGARA SHALE HELDERBERO HELDERBERQ SHALE 
 
 MEDINA CLINTON LIMESTONE LIMESTONE LIMESTONE 
 
 FIG. 15. Geological section of Ohio-Indiana oil and gas fields. After Orton. 
 U.S. Geol. Surv., 8th Ann. Rept., II. 
 
 States, while the Franklin district is noted for the fine, natu- 
 ral lubricating oil which it yields. In Kentucky (22) and 
 Tennessee a limited amount of petroleum is obtained from 
 Silurian rocks. The total number of wells drilled in the 
 Appalachian field from 1877 to the end of 1903 was 137,679. 
 Ohio-Indiana Field (16-18, 26-30). The discovery of oil 
 and gas in the Trenton rocks of western Ohio in 1884 caused 
 considerable excitement, since it showed the existence of 
 petroleum in limestone, an exception to previously known 
 conditions, and at a much lower geological horizon than any 
 in which oil or gas had hitherto been found. This field
 
 PLATE IV
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 51 
 
 extends from Findlay in northwestern Ohio south westward 
 into Indiana. The oil, which is dark and heavy, and con- 
 tains a higher percentage of sulphur than the Pennsylvania 
 oil, is found near the top of the porous, dolomitized portions 
 of the Trenton limestones, at depths of about 1100 feet. 
 The limestone, which shows several low folds (Fig. 15), is 
 covered by the impervious Hudson River shales. 
 
 Texas- Louisiana Oil Fields (33-35). These occur in a belt 
 from 50 to 75 miles wide along the Gulf Coast from near the 
 Mississippi River in Louisiana to a point about two thirds 
 the way across Texas (Fig. 14). The nearly flat surface of 
 this coastal plain 
 is occasionally in- 
 terrupted by low 
 mounds or swells 
 which seem to in- 
 dicate favorable 
 conditions for the 
 accumulation of oil 
 below the surface. 
 Underlying this 
 area is a series of 
 
 FIG. 16. Section of Spindle Top oil field near Beau- 
 mont, Texas. After Fenneman, Min. Mag., XI: 317. 
 
 Quaternary and Tertiary clays, sands, and gravels, with 
 occasional limestones, having in general a gentle southeast- 
 ern dip interrupted by low domes. 
 
 The oil pools are all of small size, that at Beaumont, which 
 is the best known, covering an area of about 200 acres 
 (PI. IV). It was discovered in 1901, and within a year 
 and a half 280 successful wells had been drilled. The oil 
 rock, which lies from 900 to 1000 feet below the surface, is 
 a very porous, crystalline dolomitic limestone, and the cap-
 
 52 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 rock is clay. The occurrence of gypsum and salt under- 
 lying the oil rock in some of the wells is unique (Fig. 16). 
 Many of the wells in this pool were gushers, but so great was 
 the drain on this field that by the end of the first year after 
 its discovery the pressure was considerably reduced, and in 
 1903 many of the wells had practically ceased producing, 
 while others were yielding a mixture of salt water and oil. 
 The production, however, is still considerable, although the 
 supply is no doubt exhaustible. The coastal-plain oils have 
 an asphaltic base, or are "heavy," and at times contain con- 
 siderable sulphur. 
 
 In 1903 many wells were being developed in the Sour Lake district 
 about 20 miles northwest of Beaumont. The oil is heavy like that of 
 Beaumont, but runs lower in sulphur. In Louisiana active drilling 
 operations have been carried on in the region around Jennings, and one 
 well yielded 20,000 barrels per day while it was gushing. The oil re- 
 sembles that of Beaumont. 
 
 The belt of Cretaceous rocks of central Texas has yielded both oil and 
 gas at several localities, but the only important one is at Corsicana, where 
 both a light and heavy oil have been found in sands interbedded with 
 dense clay shales. The two kinds of oil occur at different horizons. 
 
 Kansas (19-21). In southeastern Kansas a dark green 
 oil is obtained from the sugar sands near the bottom of the 
 Cherokee shales, about 800 feet below the surface. A second 
 horizon is found about 300 feet lower. 
 
 California. There are a number of productive fields in 
 California (10-12), all lying south of the latitude of San Fran- 
 cisco. Altogether there are 10 or 12 horizons in the folded 
 Tertiary strata, which have a total thickness of 20,000 feet. 
 The oil which is found in conglomerates, sandstones, and 
 arenaceous shales, is, in the most productive areas, found 
 closely associated with anticlines, but the strata are in many
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 53 
 
 FIEXURE OILSAN 
 
 FIG. 17. Section in Los Angeles oil field. 
 After Watts, Calif. State Min. Bureau, 
 Bull. 11 : 7, 1897. 
 
 places extensively faulted (Fig. 17), and it is doubtless to 
 these faults that many of the California oil springs are due. 
 By adding to the porosity of the rocks, the faulting has 
 probably also increased the capacity of some of the oil 
 reservoirs. 
 
 In 1903 the Kern River field was the most productive 
 in California. It has an area of 12 square miles, the oil 
 being found at depths 
 ranging from 200 to 300 
 feet in a series of lower 
 Miocene sands inter- 
 bedded with clay. The 
 wells yield from a few 
 barrels up to 600 per 
 day, but are flowing usually for only a short period. 
 
 The California oils, like those of Texas, have an asphaltic 
 base, those found in the shale being generally lighter. 
 
 Wyoming (39-41). This state contains 18 oil districts, 
 most of which are but slightly developed and the geology 
 imperfectly known. Most of them are in the Mesozoic 
 strata, the balance in Upper Carboniferous, the oil being 
 commonly found along the axes of anticlinal folds. The 
 wells vary from 300 to 1500 feet in depth, and the oils 
 are mostly lubricating, although a few contain considerable 
 kerosene (39). 
 
 Colorado. The oil at Florence (13, 15), in this state, is 
 found in porous, sandy layers of Cretaceous age, at depths 
 of from 1000 to 2000 feet, and, unlike most other occur- 
 rences, in a synclinal trough. It is a heavy oil. Near 
 Boulder (14) there is another oil field, recently developed, 
 in which the oil is found at depths as great as 3400 feet.
 
 54 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Alaska. Petroleum has been found at several localities 
 in Alaska (Fig. 81), and the developmental work already 
 done gives promise of a supply in the future (9,10). 
 
 Distribution of Natural Gas in the United States. The 
 
 distribution of natural gas is almost coextensive with that 
 of petroleum, but the commercially important fields are 
 fewer in number. The most important producing states are 
 New York (51), Pennsylvania (54), Ohio (53), Indiana (45), 
 and Kansas (47). 
 
 New York. Gas is found in several formations, includ- 
 ing the Medina and Oswego sandstones, Utica shale, and 
 Potsdam sandstone, but the main supply is distributed 
 through the Devonic sandstones of southwestern New York. 
 A large field in Erie County obtains its supply from the 
 Medina sandstone, some of the wells having yielded as high 
 as 1,000,000 cubic feet daily. In Onondaga County gas is 
 found in the Trenton limestone. 
 
 Pennsylvania. Gas is obtained from the same forma- 
 tions that carry the oil. The Bradford district was the 
 first developed, and formerly yielded gas of high pressure. 
 Much is still obtained from McKean, Elk, and Warren 
 counties. Extensive deposits were also found about Pitts- 
 burg, and later to the south of it. Green and Washington 
 counties now produce important supplies from a pool whose 
 length is about 25 miles and width 3 to 4 miles, with pres- 
 sure ranging from 800 to 1000 pounds. Although in recent 
 years several new gas-bearing sands have been discovered 
 in southwestern Pennsylvania, the enormous demand for 
 the gas threatens exhaustion of the available supply at no 
 very distant date.
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 55 
 
 West Virginia (see Petroleum references). This state 
 is now the leading producer of natural gas in the United 
 States, and is looked to as an important source of future 
 supply for both Ohio and Pennsylvania, whose gas supply 
 is slowly falling off. The main supply is obtained from 
 the Gordon and Fifth sands of the Catskill formation, 
 this being a higher horizon than that yielding the gas in 
 the Bradford district of Pennsylvania. Immense quantities 
 are obtained from the fields 'of Wetzel and Tyler counties, 
 the wells being from 2700 to 3200 feet deep. Pipe lines 
 are now run from this district to Pittsburg, and a line 
 has been laid from Tyler County to Cleveland, Ohio. Un- 
 fortunately, by allowing it to escape with the petroleum, 
 many thousand cubic feet of gas have been wasted in this 
 state. 
 
 Ohio (52-53). The Trenton limestone, which formerly 
 supplied large quantities of natural gas, is now so nearly 
 exhausted that little gas is obtained except by pumping. 
 Some gas is obtained from the Clinton sandstone of central 
 and eastern Ohio, and small amounts from the Corniferous 
 limestone ; but many towns in this state are now supplied 
 by the West Virginia fields. 
 
 Indiana (45,46). The gas fields of this state, covering 
 about 2500 square miles, were formerly among the most 
 important in the country, the gas being obtained from the 
 Trenton limestone. The supply is, however, rapidly giving 
 out, and its complete exhaustion is probable at no very 
 distant date. 
 
 Kansas (47-50). Southeastern Kansas and northern Indian 
 Territory are underlain by what is probably an extensive 
 sandstone gas field. The supply comes from the Cherokee
 
 56 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 shale, and is now much used as a source of fuel in the local 
 metallurgical and manufacturing industries. 
 
 Some gas is obtained from eastern Kentucky. Scattered 
 pockets of high-pressure gas have also been found at several 
 localities in Texas and also in California. 
 
 Uses of Petroleum. The three most important uses are 
 for light, heat, and lubrication ; but the various distillates 
 have special uses. Rhigolene is used as a local anaesthetic, 
 gasoline is used as a fuel, and naphtha as a solvent for 
 resins in making varnish and in oilcloth manufacture, while 
 benzine is of value for cleaning and as a substitute for 
 and an adulterant of turpentine. Astral oil and mineral 
 sperm oil are special grades of illuminating oil with high 
 flashing points. Crude petroleum is now much used for 
 fuel purposes in engines, as along the Pacific coast and 
 in the southwest, where good coal is so scarce that many of 
 the locomotives are run by the use of crude oil. 
 
 The paraffin residue is placed on the market for medicinal 
 purposes under the name of vaseline, petroleum ointment, 
 and cosmoline. It is also used as an adulterant of candy 
 and for electrical insulation. 
 
 Uses of Natural Gas. Natural gas is widely employed 
 as a fuel in factories, metallurgical establishments, glass 
 works, cement plants, etc. For domestic purposes, such as 
 heating, cooking, and lighting, it is also widely used. Its 
 cheapness, cleanliness, and high calorific power, and the 
 ease with which it can be used have been important factors 
 in insuring its widespread selection for the above purposes. 
 
 Oil Shales (55 a and b) . Shale containing sufficient petro- 
 leum to permit its extraction by a process of distillation is
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 57 
 
 known as torbanite or kerosene shale. Such shales are found 
 in the Carboniferous of New South Wales, Australia, New 
 Zealand, and Scotland, and in the Cretaceous of Brazil. 
 They are almost unknown in the United States. The fol- 
 lowing analysis indicates the composition and richness of 
 shale in hydrocarbons : 
 
 
 MOIST 
 
 VOLATILE 
 HYDRO- 
 CARBON 
 
 FIXED 
 CARBON 
 
 ASH 
 
 SULPHUR 
 
 Rich shale, Joadja, N.S.W. . 
 
 .16 
 
 89.59 
 
 5.27 
 
 4.96 
 
 .384 
 
 The oil can be obtained by distillation in retorts; but in view of 
 the large available supplies of petroleum, obtainable in many parts 
 of the world, the material at present has but little commercial value. 
 It is distilled in New South Wales and also in Scotland. 
 
 SOLID BITUMENS 
 
 Occurrence (56-60, 66). Solid bitumens may be grouped 
 according to their mode of occurrence, as (1) asphaltites, 
 which represent the varieties free from sandy and clayey 
 impurities, found filling either fissures or basins ; (2) bitu- 
 minous rocks, in which the bitumen fills the pores of sand- 
 stones, limestones, or other rocks. They are found over a 
 wide range (Fig. 18), both geographically and geologically. 
 
 A study of the deposits leads to the conclusion that these 
 solid bituminous compounds have been derived from petro- 
 leum (58, 59, 60), for the following reasons : In the asphal- 
 tite deposits the solid bitumens are often associated with 
 petroleum springs, or with fissures leading down to or 
 toward petroleum-bearing strata. In some cases the asphal- 
 tite not only fills such a fissure, but impregnates the wall
 
 58 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 rock to a distance of a foot or two on ' either side of the 
 vein, indicating that the material came up through the 
 fissure in a liquid condition, filling it, and even penetrating 
 the wall rock. 
 
 The bitumen in bituminous rocks may either have origi- 
 nated from organic remains within the rock itself or have 
 seeped into it from some neighboring pool. In either case 
 the material seems originally to have been liquid petroleum 
 which later solidified. 
 
 FIG. 18. Map of asphalt and bituminous rock deposits of United States. After 
 Eldridge, U. S. Geol. Surv., 22d Ann. Kept., IX. 
 
 Asphaltites. There are several varieties of asphaltites, 
 all black or dark brown in color, commonly with a pitchy 
 odor, burning readily with a smoky flame, and insoluble in 
 water, but soluble in ether, oil of turpentine, and naphtha. 
 Their specific gravity ranges from 1 to 1.1. They are
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 59 
 
 closely related chemically and in their mode of occurrence, 
 but differ somewhat in their behavior toward solvents, as 
 well as in their fusibility. The most important varieties 
 are described below. 
 
 Albertite (61), a black bitumen with a brilliant luster and conchoidal 
 fracture, a hardness of 1 to 2 and specific gravity 1.097, is found filling 
 fissures in bituminous shales in New Brunswick. 
 
 Anthraxolite (63) is a coaly, lustrous, black mineral, with a hardness 
 of 3 to 4, and specific gravity of 1.965. It is found at Sudbury, Ontario, 
 forming veins in a black fissile slate, but has also been described from 
 other localities. 
 
 Ozokerite (67), also termed mineral wax or native paraffin, is a waxlike 
 hydrocarbon, yellow brown to green, translucent when pure, and of 
 greasy feel. Its specific gravity is .955. While known to occur in Utah, 
 the most important deposit is in Galicia. At the latter locality the 
 Ozokerite is found forming veins from a few millimeters up to several 
 feet in thickness in much-disturbed Miocene shales and sandstones. 
 
 Grahamite (66) is a vein asphalt found in the Carboniferous of West 
 Virginia. 
 
 Lake Asphalt (71) is not found in the United States, but occurs in the 
 famous pit or lake on the island of Trinidad, off the coast of Venezuela. 
 
 Uintaite, or Gilsonite (66), is a black, brilliant 
 bitumen, with conchoidal fracture, hardness 2 to 
 2.5, and specific gravity of 1.065 to 1.07. It is 
 found filling a series of fissures, termed veins, in 
 the Bridger beds of the Tertiary in eastern Utah, 
 and, to a less extent, in western Colorado. One 
 of these veins, the Duchesne, has been worked to 
 a depth of 105 feet, and is traceable for about a 
 mile, its width for half this distance being 3 to 4 
 feet. It is usually vertical and in places faulted. 
 
 Manjak is the name applied to a bitumen 
 
 Fm.l9.-SectionofGil- 
 resembhng Lintaite, found on the island of sonite vein, Utah. 
 
 Barbados. It is a hydrocarbon of high purity, A f ter Eldridge, U.S. 
 
 J Geol. Surv., VJth 
 black color, brilliant luster, and conchoidal frac- Ann. Sept., I: 932.
 
 60 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 ture, and forms seams from a quarter of an inch to 30 feet thick in 
 a blue shale. The material brings $60 a short ton in New York. 
 
 Bituminous Rocks (66). These are commonly classified 
 according to the character of the containing rock, as bitu- 
 minous sandstones, bituminous limestones, and bituminous 
 schists. They are much more widely distributed than the 
 asphaltites, being found in several geological horizons, and 
 are worked in Kentucky (66), Indian Territory (66), and 
 California (64). 
 
 As illustrative of its mode of occurrence, we may men- 
 tion the bituminous sandstone, which is extensively quar- 
 ried near Santa Cruz, California (PI. V, Fig. 1). The 
 rock, which is of blackish or brownish-black color, weather- 
 ing to gray, occurs beneath the Monterey shales, sometimes 
 resting directly on granites. The bitumen impregnates 
 the heavy bedded sandstone immediately under the shale, 
 and also the sand that fills cracks which extend up into 
 the shale. These cracks, which vary in width from very 
 minute size up to 25 or 30 feet, are sometimes traceable 
 for several hundred feet, being at times of value as guides 
 in finding the main bed. 
 
 Analyses. The variable composition of asphaltites and 
 bituminous rocks can be seen from the following table : 
 
 ANALYSES OP ASPHALTITES AND MALTHA 
 
 LOCALITY 
 
 SOLUBLE IK 
 CS 2 
 
 MINERAL 
 MATTERS 
 
 NON-BITUMINOUS 
 ORGANIC MATTER 
 
 Trinidad Lake Asphalt . 
 
 54.25 
 
 36.51 
 
 9.24 
 
 Grahamite, W. Va. . . 
 
 100.00 
 
 
 
 
 
 Gilsonite, Utah . ,' . 
 
 100.00 
 
 .10 
 
 
 
 Maltha, Kern. Co., Calif. 
 
 93.20 
 
 5.77 
 
 .54
 
 PLATE V 
 
 FIG. 1. Quarry of bituminous sandstone, Santa Cruz, Calif. After Eldridge, U.S. 
 Geol. Surv., 22d Ann. Sept., I. 
 
 FIG. 2. Granite quarry, Hardwick, Vt. Photo, by G. H. Perkins.
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 61 
 ANALYSES OF BITUMINOUS ROCKS 
 
 LOCALITY 
 
 MOISTURB 
 
 SOLUBLE 
 iNCSa 
 
 CaC0 8 
 
 MgCO, 
 
 SAND OB 
 CLAY 
 
 California 
 
 2.50 
 
 2020 
 
 3.00 
 
 
 7400 
 
 
 
 576 
 
 
 
 9422 
 
 Seyssel, France . . . 
 
 
 
 8.15 
 
 91.70 
 
 
 
 
 Limmer, Germany . . 
 
 
 
 18.26 
 
 56.50 
 
 27.01 
 
 4.98 
 
 Uses. Trinidad asphalt mixed with powdered rock and 
 tar is much in use for pavements, and the bituminous rocks 
 are employed for similar purposes. Ozokerite, known as 
 Ceresin in its purified form, is used in the manufacture of 
 candles, ointments, powders, as an adulterant of bees- 
 wax, and for bottles to hold hydrofluoric acid. 
 
 The most important use of Uintaite and Manjak is for 
 making low-grade and dipping varnishes, such as are used 
 for iron work and baking Japans. Other uses to which 
 the Uintaite at least has been put are for preventing elec- 
 trolytic action on iron plates of ship bottoms, coating 
 masonry, acid-proof lining for chemical tanks, roofing pitch, 
 insulating electric wires, as a substitute for rubber in com- 
 mon garden hose, and as a binder pitch in making coal 
 briquettes. 
 
 Production of Petroleum, Natural Gas, and Asphaltum. 
 The production of crude petroleum and natural gas for 
 several years is given below :
 
 
 3gg5 
 
 1-1 <N cc * o -f o 
 
 i 
 
 
 
 rh ^J 9 CO 
 
 co o So co ^ 
 
 1 
 
 i 
 
 oo o os og jg g g 
 
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 00 
 
 r4 
 
 assent 051 * 
 
 
 
 
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 eo -^ o ?o <N 
 
 1 
 
 
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 2 
 5s 
 
 
 
 
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 g 
 
 s 
 
 8 22 S Ss 8 S 
 
 -: *>. - - ^ 
 
 S 
 
 T-H 
 
 S 
 
 o eo co co co 
 
 i 
 
 
 CO rH CO CO 00 t- 
 
 3 
 
 g 
 
 
 r.^^0 
 
 I 
 
 
 l- O lO ^ O5 Ol (M 
 
 1 
 
 I 1 
 
 
 CO O <-l (M CO 
 
 t^ 
 o 
 
 1 
 
 |||! 8 I 8 
 
 1 
 tf 
 
 g 
 
 o 
 
 9 
 
 1 
 
 * 1 00 -^ r^ 
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 grfgof^J 
 
 1 
 
 
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 <> 
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 H 
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 IS3IS 
 
 s 
 
 i 
 
 ** o o oo eo t- 
 
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 " " oo" i-T -*" 
 
 1 
 
 
 
 a 
 
 1 
 
 s-.ss 
 
 t^- <M O C<) r-H 
 
 eo" 
 
 
 
 o<r TjT of t^" co" t>^ 
 
 TJH r-i ^ co eo 
 
 S2 
 
 45,823,572 
 
 P 
 
 u 
 
 B 
 H 
 
 g 
 
 ie 
 
 os 
 
 00 
 
 O O O O O 
 S S 
 
 ff^ o^ oo_ I-H 10 
 
 s ^ * 
 
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 g 
 
 9 
 
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 1 
 
 i 
 
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 s 
 
 Q 
 
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 s 
 
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 8 
 
 z 
 
 3 
 
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 <3 
 
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 |f:fJ::i 
 
 ^ ^ g I ^ | 
 
 I -2 8 ^ ill 
 
 I^illlll 
 
 1 
 
 
 
 ' ;lli 
 
 ! ft? 
 
 .2 o 5 02 
 
 !!!*! 
 
 1
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 63 
 VALUE OF PETROLEUM AND XATURAL GAS PRODUCED IN 1903 
 
 STATE 
 
 VALUE OF 
 PETROLEUM 
 
 VALUE OF 
 NATURAL GAS 
 
 COMBINED 
 VALUE 
 
 Pennsylvania . . . 
 Ohio 
 West Virginia . . . 
 Indiana 
 
 $18,170,881 
 26,234,521 
 20,516,532 
 10,474,127 
 
 $16,182,834 
 4,479,040 
 6,882,359 
 6 098,364 
 
 $34,353,715 
 30,713,561 
 27,398,891 
 16,572,491 
 
 
 7 399 349 
 
 104 5 9 1 
 
 7 503 870 
 
 Texas 
 
 7 517 479 
 
 21 351 
 
 7 538 830 
 
 New York 
 
 1,849,135 
 
 493 686 
 
 2 342,821 
 
 Other states .... 
 
 2,532,026 
 
 1,553,205 
 
 4,085,231 
 
 Total 
 
 $94,694,050 
 
 $35,815,360 
 
 $130,509,410 
 
 The average price per barrel of petroleum naturally 
 varies somewhat from year to year. In 1885 it was 87-|^; in 
 1890, 86f^; in 1895, $1.36f ; in 1900,11.194; in 1903, 94j 
 
 The total number of barrels of petroleum produced in the 
 United States from 1859 to the end of 1903 was 1,265,751,585, 
 while the total value of the natural gas produced in the 
 United States from 1885 to the end of 1903 was 1322,872,792. 
 
 The world's production of petroleum in 1902 and 1903 
 was as follows : 
 
 WORLD'S PRODUCTION OF PETROLEUM IN 1902 AND 1903 
 
 COUNTRY 
 
 BARRELS, 1902 
 
 BARRELS, 1903 
 
 United States 
 Russia 
 
 69,389,194 
 85,168,556 
 
 100,461,337 
 75,591,256 
 
 
 3 038 700 
 
 6 640 000 
 
 
 3 251 544 
 
 5,234,475 
 
 Roumania 
 
 1 406,160 
 
 2,763,117 
 
 
 1 430 716 
 
 9 510 259 
 
 
 1 100 000 
 
 964,000 
 
 Canada 
 
 572 500 
 
 481,504 
 
 Germany 
 
 313,630 
 
 445,818 
 
 Peru 
 
 79961 
 
 61,745 
 
 Italy . . ...... 
 
 10 100 
 
 20,000 
 
 All other countries 
 
 20,000 
 
 30,000 
 
 Total 
 
 165 773 361 
 
 195,203,511 
 
 

 
 64 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 EXPORTS OF MINERAL OILS 
 
 KIND 
 
 1895 
 
 1900 
 
 1902 
 
 1903 
 
 Crude 
 
 $5,161,710 
 
 $7,340,749 
 
 $6,331,011 
 
 $6,782,136 
 
 Naphtha .... 
 Illuminating . . 
 Lubricating and 
 Paraffin . . . 
 Residuum . . . 
 
 910,988 
 34,706,844 
 
 5,867,477 
 13,063 
 
 1,681,201 
 54,692,872 
 
 9,933,548 
 845,337 
 
 1,392,771 
 49,079,055 
 
 10,872,154 
 922,152 
 
 1,518,541 
 51,355,668 
 
 12,690,065 
 282,129 
 
 Total . . . 
 
 $46,660,082 
 
 $74,493,707 
 
 $68,597,143 
 
 $72,628,539 
 
 The petroleums reach a wider market than any of our 
 other exports, and over 38 per cent of the total quantity of 
 crude oil produced is now exported in either crude or re- 
 fined form. This was formerly sent away in cans, but it is 
 now transported largely in bulk in tank steamers, some of 
 which have a capacity of 60,000 barrels. (8 a) 
 
 The following table gives the production of the different 
 kinds of asphaltum for the last three years : 
 
 PRODUCTION OF ASPHALTUM IN THE UNITED STATES FROM 1901-1903 
 
 
 1901 
 
 1902 
 
 1903 
 
 VARIETY 
 
 SHORT 
 TONS 
 
 VALUE 
 
 SHORT 
 TONS 
 
 VALUE 
 
 SHORT 
 TONS 
 
 VALUE 
 
 Bituminous sandstone 
 
 34,248 
 
 $138,601 
 
 57,837 
 
 $156,993 
 
 38,633 
 
 $118,001 
 
 Bituminous limestone 
 
 6,970 
 
 33,375 
 
 2,869 
 
 19,817 
 
 2,520 
 
 8,800 
 
 Mastic 
 
 
 
 
 
 961 
 
 11,532 
 
 Hard and refined or 
 
 
 
 
 
 
 
 Sfum . 
 
 19,316 
 
 333 509 
 
 22321 
 
 264 817 
 
 1 896 
 
 343 799 
 
 Liquid or maltha . . 
 
 2,600 
 
 49,850 
 
 1,605 
 
 20,172 
 
 58 
 
 1,150
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 65 
 
 The production by states in 1903 was as follows : 
 
 STATE 
 
 QUANTITY 
 SHORT TONS 
 
 VALUE 
 
 California 
 
 74,578 
 
 $ 702,758 
 
 Texas 
 
 2 158 
 
 30550 
 
 Utah 
 
 5,619 
 
 188,357 
 
 
 12578 
 
 50 163 
 
 Indian Territory 
 
 5,107 
 
 28,150 
 
 
 1215 
 
 5468 
 
 
 
 
 Since deposits of the purer type, such as lake asphalt, 
 are very scarce in the United States, the supply for domes- 
 tic consumption is obtained from foreign countries. The 
 imports for the last two years are given below : 
 IMPORTS OP ASPHALTUM 
 
 
 19 
 
 02 
 
 19 
 
 03 
 
 
 LONG TONS 
 
 VALUE 
 
 LONG TONS 
 
 VALUE 
 
 West Indies 
 
 106 844 
 
 $358316 
 
 139 031 
 
 $415291 
 
 Venezuela 
 
 12,406 
 
 62028 
 
 16,445 
 
 74874 
 
 All others 
 
 375 
 
 8533 
 
 17416 
 
 95770 
 
 
 
 
 
 
 Total .... 
 
 119625 
 
 $ 428 877 
 
 17 892 
 
 $ 585 865 
 
 
 
 
 
 
 The world's production for 1902 was as follows : 
 WORLD'S PRODUCTION OF ASPHALTUM IN 1902 
 
 COUNTRY 
 
 SHORT TONS 
 
 VALUE 
 
 
 178 230 
 
 9 8 9 8 347 
 
 United States 
 
 84,632 
 
 461,799 
 
 France 
 
 284 719 
 
 390 254 
 
 Italy 
 
 70619 
 
 151,829 
 
 Germany 
 
 97415 
 
 146 470 
 
 Austria-Hungary 
 
 4,047 
 
 67,623 
 
 Spain 
 
 6 946 
 
 12356 
 
 Venezuela 
 
 10,060 
 
 
 

 
 66 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 REFERENCES ON PETROLEUM 
 
 ORIGIN, OCCURRENCE, AND TECHNOLOGY. 1. Folger, Ann. Kept. Secy. 
 of Internal Affairs, 1892, Pt. Ill, p. B. (Petroleum production and 
 products.) 2. Mineral Industry, II : 497, 1894. (Mining and Tech- 
 nology.) 3. Newberry, Ohio State Agric. Kept., 1859. 4. Orton, 
 Geol. Soc. Amer., Bull. IX: 85, 1892. (Origin and accumulation.) 
 5. Orton, Kentucky Geol. Surv., 1894. (Origin.) 6. Peckham, 
 Day, Maybery, etc., Proc. Amer. Phil. Soc., XXXVI: 93. (Origin 
 and composition.) 7. Redwood, B., Treatise on Petroleum. (Ex- 
 cellent.) London. 8. White, Geol. Soc. Amer., Bull. Ill: 187, 
 1892. (Anticlinal theory.) 8 a. Oliphant, Mineral Census, 1902, 
 Kept, on Mines and Quarries. (General and statistical.) 
 
 AREAL REPORTS. Alaska : 9. Martin, U. S. Geol. Surv., Bull. 225 : 365, 
 1904. Also U. S. Geol. Surv., Bull. 259: 129, 1905. California : 
 10. Eldridge, U. S. Geol. Surv., Bull. 213: 306, 1903. (General, 
 good.) 11. Mabery and Hudson, Amer. Acad. Arts and Sci., Proc. 
 XXVI: 255. (Composition.) 12. Watts, Bulls. Calif. State Min. 
 Bureau, No. 3 (Central Valley), No. 11 (Los Angeles, Ventura, and 
 Santa Barbara Cos.), No. 19 (General.) Colorado : 13. Eldridge, 
 Trans. Amer. Inst. Min. Engrs., XX: 442, 1892. (Florence field.) 
 14. Fenneman, U. S. Geol. Surv., Bull. 225 : 383, 1904. (Boulder 
 field.) 15. Fenneman, U. S. Geol. Surv., Bull. 260: 436, 1905. 
 (Florence.) Indiana : 16. Blatchley, Ind. Dept. Geol., 22d Ann. 
 Rept.: 155, 1898. (Trenton limestone field.) 17. Chapters on 
 petroleum in other annual reports of this series. 18. Ortou, U. S. 
 Geol. Surv., 8th Ann. Rept., II: 475, 1889. (Trenton limestone.) 
 Kansas: 19. Adams, U. S. Geol. Surv., Bull. 184, 1901. 20. Ha- 
 worth, Kansas Geol. Surv., I: 232, 1896. (General.) 21. See also 
 Volumes on Mineral Resources, issued by Kansas Geol. Surv. from 
 1897 to 1901. Kentucky: 22. Orton, Ky. Geol. Surv., 1894. (Gen- 
 eral.) Louisiana: 23. Hayes and Kennedy, U. S. Geol. Surv., Bull. 
 212, 1903. (General.) Michigan: 24. Gordon, Mich. Geol. Surv., 
 Ann. Rept., 1901; 269, 1902. (Port Huron field.) New York: 
 
 25. Orton, N. Y. State Mus., Bull. 30, 1899. (General.) Ohio : 
 
 26. Bownocker, Ohio Geol. Surv., 4th Series, Bull. 1, 1903. 27. Gris- 
 wold, U. S. Geol. Surv., Bull. 198. (Berea grit oil.) 28. Mabery, 
 Amer. Chem. Jour. ; Dec., 1895. (Composition.) 29. Orton, Ohio 
 Geol. Surv., VI : 60. 30. Orton, U. S. Geol. Surv., 8th Ann. Rept., 
 II : 475, 1889. (Trenton limestone field.) Pennsylvania : 31. Carll, 
 Ann. Rept. Pa. Geol. Surv., 1885 ; II. 1886. 32. Reports I to 1 5 of 
 the same survey. Texas : 33. Adams, U. S. Geol. Surv., Bull. 184, 
 1901. (General.) 34. Hayes and Kennedy, U. S. Geol. Surv., Bull.
 
 PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS 67 
 
 212, 1903. 35. Phillips, Tex. Univ. Min. Surv., Bull. No. 1, 1900. 
 (General.) Washington: 36. Landes, Wash. Geol. Surv., I: 207. 
 (General.) West Virginia: 37. White, W. Va. Geol. Surv., I a : 1, 
 1904. (General.) 38. White, Geol. Soc. Amer., Bull. Ill: 187, 
 1892. (Mannington field.) Wyoming: 39. Knight and Slosson, 
 Bull. 4, Wyo. School of Mines. (General.) 40. Bull. 3. (Crook 
 and Uinta Cos.) 41. Bull. 5. (Newcastle field.) 42. Bull. 1. (Salt 
 Creek field.) 
 
 REFERENCES ON NATURAL GAS 
 
 ASHBURXER. 43. Amer. Inst. Min. Engrs., Trans. XIV : 428. (Geology 
 and Distribution in the United States.) 43 a. Orton, Geol. Soc. Amer., 
 Bull. I: 87. (Rock pressure.) California : 44. Watts, Calif. Min. 
 Bureau, Bull. 3. (Central Valley.) Indiana: 45. Phinney, U. S. 
 Geol. Surv., llth Ann. Kept., I: 589, 1891. 46. See also Ann. 
 Repts. Ind. Geol. and Nat. Hist. Survey. Kansas: 47. Adams, 
 U. S. Geol. Surv., Bull. 184, 1901. 48. Haworth, Kan. Geol. Surv., 
 I: 232, 1896. (General.) 49. Orton, Geol. Soc. Amer., Bull. X: 
 99, 1899. (lola field.) 50. Volumes on Mineral Resources, issued 
 by Kan. Geol. Surv., 1897-1901. New York: 51. Orton, N. Y. 
 State Mus., Bull. 30, 1899. (General.) Ohio : 52. Orton, Ohio 
 Geol. Surv., I. 3d ser. : 55. 53. Orton, U. S. Geol. Surv., 8th Ann. 
 Rept., II: 475, 1889. Pennsylvania: 54. Carll and Phillips, Ann. 
 Kept. Pa. Geol. Surv., 1886, Pt. II, 1887. (General.) Texas : 
 55. Adams, U. S. Geol. Surv., Bull. 184, 1901. 
 
 REFERENCES ON OIL SHALES 
 
 55 a. Branner, Amer. Inst. Min. Eng., XXX: 537. Brazil.) 556. Carne, 
 Memoirs, Dept. Mines and Agric., New South Wales, Geology No. 3. 
 (General treatise.) 
 
 REFERENCES ON ASPHALTUM 
 
 GEXERAL. 56. Dow, Min. Indus., X: 51, 1902. (History of Asphalt 
 Industry.) 57. Greene, Amer. Inst. Min. Engrs., Trans. XVII : 355. 
 (Uses.) ORIGIN: 58. Adams, Amer. lust. Min. Engrs., Trans. 
 XXXIII: 340, 1903. (Origin.) 59. Day, Eng. Record, XL: 346. 
 60. Peckham, Amer. Phil. Soc., XXXVII: 108. (Genesis of 
 bitumens.) SPECIAL PAPERS: 61. Bailey and Ells, Geol. Surv.; 
 Canada, 1876-77, 384. (Albertite.) 62. Blake, Amer. Inst. Min. 
 Engrs., Trans. XVIII : 563. (Uintaite, Albertite, and Grahamite.) 
 63. Coleman, Ontario Bur. Mines, 6th Ann. Rept., 159, 1897. 
 (Anthraxolite.) AREAL: 64. Cooper, Calif. State Min. Bureau, 
 Bull. 16. (California.) 65. Crosby, Amer. Naturalist, XIII: 229.
 
 68 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 (Trinidad.) 66. Eldridge, U. S. Geol. Surv., 22d Ann. Kept., I: 
 190L (General occurrence in United States, excellent.) 67. Gos- 
 ling, Sch.M. Quart., XVI: 41. (Ozokerite.) 68. Lane, Eng. and Min. 
 Jour., LXXIII: 50. (Mich.) 69. Merivale, Eng. and Min. Jour., 
 LXVI: 790, 1898. (Barbados.) 70. Parker, U. S. Geol. Surv., 
 19th Ann. Kept., VI (ctd.) : 187, 1898. (Ozokerite.) Also Min. 
 Ind., X: 50, 1902. 71. Peckham, Pop. Sci. Mo., LVIII: 225, 1901. 
 (Trinidad and Venezuela.) 72. Phillips, Univ. of Tex. Min. Surv., 
 Bull. 3, 1902. (Texas.) 73. Vaughn, Eng. and Min. Jour., LXXIII : 
 344. (Cuba.)
 
 CHAPTER III 
 BUILDING STONES 
 
 UNDER this term are included all stones for ordinary 
 masonry construction, as well as for ornamentation, roofing, 
 and flagging. The number of different kinds used is very 
 great, and includes practically all varieties of igneous, sedi- 
 mentary, and metamorphic rocks, but a few stand out 
 prominently on account of their widespread occurrence 
 and durability. 
 
 The cost of a building stone naturally exerts decided in- 
 fluence on its use. Since the ease of splitting and dressing 
 a stone influences its cost, the texture is also of importance. 
 Color is another factor in determining the value of a build- 
 ing stone, and this, together with other considerations, some- 
 times gets a fashion leading to the widespread use of certain 
 stones. This has been well illustrated in the eastern cities 
 of the United States where, for many years, Connecticut 
 browstone was in such great demand for use in building 
 private dwellings that much inferior stone was put on the 
 market. More recently Indiana limestone and Ohio sand- 
 stone have met the popular fancy, and these two are now 
 used in vast quantities. 
 
 Properties of Building Stones -(1-6). The following prop- 
 erties have an important bearing on the value of a building 
 stone :
 
 70 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Color. The color of rocks varies greatly, and those shown 
 by common building stones include white, black, brown, 
 red, yellow, and buff, while some are green, blue, or mottled. 
 The color may vary in the same quarry. 
 
 In igneous rocks the color may be that of the prevailing mineral, as 
 in pink granite, where there is an excess of pink feldspar ; or it may be 
 a composite due to the blending of the colors of several minerals, as in 
 the case of ordinary gray granite, where the color results from the mix- 
 ture of black mica and whitish quartz and feldspar. Sedimentary 
 rocks commonly owe their color either to ferruginous cements, or to 
 carbonaceous matter. The former give brown, yellow, red, or green 
 colors -depending on the condition of oxidation of the iron, while the 
 latter produces gray, black, and bluish tints depending on the amount 
 present. Sandstone and limestone free from either of these coloring 
 agents are nearly if not quite white. 
 
 Some stones change color on exposure to the air. For example, 
 limestones or sandstones containing carbonaceous matter may bleach ; 
 some black marbles fade to a white or gray ; and many red and green 
 roofing slates, as well as many red granites, change color. Oxidation 
 of evenly distributed pyrite may change gray or bluish-gray sandstones 
 to buff color. If the minerals responsible for such change in color are 
 not uniformly distributed, the stone assumes a blotchy appearance, but 
 such changes are not necessarily an indication of deterioration. 
 
 Texture. Building stones vary in their texture from 
 coarse-grained granites and conglomerates to fine-grained 
 sandstones, limestones, and porphyries. 
 
 Texture is an important property, for it influences both the dura- 
 bility and the cost of stone. Other things being equal, a fine-grained 
 rock is not only more durable, but splits better and dresses more evenly 
 than a coarse-grained rock. Uneven texture, whether due to mineral 
 grains or cement, is undesirable since it often causes uneven weathering. 
 
 Density. On the whole, dense stones resist weather bet- 
 ter than porous ones, but there is great difference in the 
 density of building stones.
 
 BUILDING STONES 71 
 
 In general, though with some exceptions, igneous and metamorphic 
 rocks have high density because of the close interlocking of the crystal- 
 line grains. Sedimentary rocks of clastic origin, on the other hand, 
 have less closely fitting grains, and unless the latter are very small, or 
 the pores well filled with cement, they are apt to be porous. 
 
 The specific gravity of a stone indicates its density ; and from the 
 specific gravity the weight per cubic foot may often be approximately 
 estimated by multiplying it by 62.5, the weight of an equal volume of 
 water. While sufficiently accurate for very dense stones this method is 
 liable to lead to incorrect results when applied to very porous rocks. 
 Following are some average specific gravities of common building 
 stones, as given by Hermann (1): granite, 2.65; syenite, 2.80; serpen- 
 tine, 2.60; gneiss, 2.65; limestone, 2.60; dolomite, 2.80; sandstone, 
 2.10; slate, 2.70.' 
 
 Hardness. The hardness of a building stone is not neces- 
 sarily dependent on the hardness of its component minerals, 
 but is largely influenced by their state of aggregation. 
 
 For example, a sandstone composed of quartz grains, but with little 
 cementing material, may be so soft as to crumble easily in the fingers, 
 while a limestone, whose grains of soft carbonate of lime fit closely and 
 are firmly cemented, may be difficult to break with a hammer. The 
 nature of the cement in sedimentary rocks, that is whether it is lime, 
 silica, or iron, will also affect the hardness of the stone. Crystalline rocks 
 owe their great hardness to the firm interlocking of the mineral grains. 
 
 Strength. Two kinds of strength, compressive and trans- 
 verse, are to be considered in building stones. 
 
 The compressive or crushing strength, which is expressed in pounds 
 per square inch, is the resistance which the rock offers to a crushing 
 force, and is dependent chiefly on the size of the grains, state of aggrega- 
 tion, and mineral composition. Because of the close interlocking of the 
 grains of igneous rocks they are stronger than those of sedimentary 
 origin, in which the strength is due chiefly to the cement which binds 
 the grains together. Sedimentary rocks show greatest strength when 
 dry, or when pressure is applied at right angles to the bedding.
 
 72 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Few building stones are subjected to pressures even approximately 
 equal to their crushing strength. No domestic building stone at present 
 used in the eastern market has a crushing strength of less than 6000 
 pounds, yet the pressure even in the tallest buildings does not require 
 a stone with a crushing strength exceeding 314.6 pounds, and this in- 
 cludes the factor of safety of twenty usually allowed by architects. 
 Computations show that a stone at the base of the Washington monu- 
 ment sustains a maximum pressure of 6292 pounds per square inch, 
 which includes the usual factor of safety of twenty ; the crushing strength 
 of the stone used in the base of the monument is however not less than 
 10,000 to 12,000 pounds per square inch. 
 
 The crushing strength of some soft limestones or sandstones may be 
 but little above 3000 pounds per square inch, while that of diabase often 
 exceeds 30,000 pounds per square inch. The accompanying table gives 
 the crushing strength of a number of native stones. 
 
 CRUSHING STRENGTH OF BUILDING STONES 
 
 Granite, Vinal Haven, Me 13,381 
 
 Granite, East Saint Cloud, Minn. . . . 28,000 
 
 Granite, Port Deposit, Md 19,750 
 
 Dolomite marble, Tuckahoe, N.Y. . . . 13,076 
 
 Limestone, Caen, France 3,550 
 
 Sandstone, Portland, Conn 13,310 
 
 Sandstone, E. Long Meadow, Mass. . . 8,812 
 
 The published crushing tests of different stones cannot really be fairly 
 compared because all have not been tested under exactly the same 
 conditions. 
 
 Transverse Strength. The transverse strength is the load which a 
 bar of stone, supported at both ends, is able to withstand without break- 
 ing. It is measured in terms of the modulus of rupture, which represents 
 the force necessary to break a bar of one square inch cross section, rest- 
 ing on supports one inch apart, the load being applied in the middle. 
 Although stones in buildings are rarely, if ever, crushed, they are fre- 
 quently broken transversely, and therefore a knowledge of the transverse 
 strength is of more importance than the crushing strength. A high 
 crushing strength does not necessarily mean a high transverse strength. 
 Unfortunately few stones have been tested in this manner.
 
 BUILDING STONES 73 
 
 Porosity and Ratio of Absorption. The porosity of build- 
 ing stones varies widely. Most igneous rocks have little 
 pore space and hence absorb little water; but sedimentary 
 rocks, especially sandstones, are often very porous. 
 
 Many rocks, especially those of the sedimentary class, contain water 
 in their pores when first quarried. This is known to quarrymen as 
 quarry water, and it is present in some porous sandstones in sufficient 
 quantities to interfere with quarrying during freezing weather. Mineral 
 matter in solution in the quarry waters is deposited between the grains 
 when the water evaporates, often in sufficient quantities to perceptibly 
 harden the stone. 
 
 Water is also present in the joint planes, and by its passage along 
 these planes causes oxidation and rusting of the iron of the rock-forming 
 minerals. This discolors the stone along and on either side of the joint 
 planes, giving rise to a yellow color known as sap. 
 
 Resistance to Frost. Building stones show a varying 
 degree of resistance to frost. 
 
 Dense rocks, like granites, quartzites, and many limestones, and even 
 some very porous rocks, are little affected ; but many porous and lami- 
 nated rocks, like open sandstones and schists, disintegrate under frost 
 action. This is due to the fact that moisture absorbed in the warmer 
 weather, on freezing in the pores, expands, and either forces off small 
 pieces or disrupts the stones. Since clay readily absorbs water, clayey 
 rocks are sometimes similarly affected. 
 
 Resistance to Heat. All rocks expand when heated, and 
 contract when cooled, but do not shrink down to their 
 original dimensions. This permanent increase in size is 
 termed permanent swelling, and though small when figured 
 for one linear foot, is appreciable in long pieces. 
 
 The following figures give the average of a number of tests of per- 
 manent swelling in stone bars 20 inches long, heated from 32 F. to 
 212 F., and then cooled to the original temperature: granite, .009
 
 74 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 inches; marble, .009 inches; limestone and dolomites, .007 inches; 
 sandstone, .0047 inches. 
 
 The most severe test of a stone's resistance to rapid changes of 
 temperature is to heat it to about 800 C. and then immerse it in cold 
 water. Quartzites and hard sandstones withstand such treatment best ; 
 some granites crack and crumble, and the carbonate rocks change to 
 lime. 
 
 Structural Features affecting Quarrying. All rocks are traversed by 
 planes of separation of one sort or another. In sedimentary rocks these 
 consist of bedding and joint planes ; in igneous rocks, the latter alone 
 are present; and in metamorphic rocks, joint planes, a banding of 
 minerals, and, very often, cleavage planes. 
 
 Bedding Planes. These may be either an advantage or a disadvan- 
 tage to the quarryman. They are desirable because they facilitate the 
 extraction of the stone ; but if numerous and closely spaced, the layers 
 may be too thin for any purpose except nagging. They often serve 
 as a means of entrance for the agents of weathering, and the stone 
 may be disintegrated along the bedding planes while elsewhere fresh. 
 
 Incipient planes of weakness, due either to the arrangement of 
 minerals or to microscopic fractures in them, often give rise to planes 
 of easy splitting which are of great value in quarrying, notably of 
 granite. Such planes which permit splitting in approximately horizon- 
 tal directions are called lift ; the most prominent vertical plane is called 
 rift ; and a less prominent vertical plane, approximately at right angles 
 to the rift, is called the cut off. 
 
 The position of the beds exerts an important influence on the cost 
 of quarrying. When horizontal and of different quality, it may often 
 be necessary to strip off worthless rock in order to reach the beds of 
 good quality. In such cases, there is often less stripping to do in 
 quarries opened on gently sloping ground. In regions of steep dip, it 
 is sometimes possible to work the quarry as a cut, extracting the desired 
 beds and leaving useless ones standing.
 
 BUILDING STONES 75 
 
 GRANITES 
 
 Characteristics of Granites (3). As commonly used by 
 quarrymen, the term granite includes all igneous rocks 
 and gneiss ; but in this book it is used in the geological 
 sense, which is more restricted. From the geological stand- 
 point a granite is a holocrystalline, plutonic igneous rock 
 consisting of quartz, orthoclase feldspar, and either mica 
 or hornblende, or both. There are also varying but usually 
 small quantities of other feldspars, and there may be sub- 
 ordinate accessory minerals, such as pyrite, garnet, tourma- 
 line, and epidote. 
 
 Granites vary in texture from fine to coarse grained, and 
 in some cases are porphyritic. They pass into gneisses by 
 such insensible gradations that no sharp line can be drawn 
 between the two. In color they vary, being, most com- 
 monly, gray, mottled gray, red, pink, white, or green, 
 according to the color or abundance of the component 
 minerals. Most granites are permanent in their color, but 
 some of bright red color bleach on exposure to weather. 
 
 The average specific gravity of granites is 2.66, which corresponds 
 to a weight of 166.5 pounds per cubic foot. They commonly contain 
 less than 1 per cent of water, and often absorb two or three tenths 
 more. Their crushing strength varies, but is apt to lie between 15,000 
 and 30,000 pounds per square inch. 
 
 Granites are among the most durable of building stones, but there 
 is some variation in the durability of the different kinds. Other things 
 being equal, fine-grained granites are more durable than coarse-grained, 
 being less easily affected by changes of temperature. One of the 
 most beautiful granites known, the Rapikivi granite of Finland, lacks 
 in durability on this account. Pyrite and marcasite are injurious 
 minerals, since they rust rapidly and may discolor the stone in an
 
 76 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 unsightly manner. Very few granites now in use show signs of decay; 
 but in those that do, the darker silicates are rusted, the luster of the 
 feldspar is dulled, and, in some cases, the stone has begun to disinte- 
 grate. Some red granites bleach on continued exposure to sunlight. 
 
 Distribution of Granites in the United States (3). Granite 
 usually occurs in great bosses frequently forming the cores 
 of mountain chains. Removal of the overlying strata by 
 
 FIG. 20. Map showing distribution of crystalline rocks (mainly granites) in 
 United States. After Merrill. Stone for Building and Decoration. 
 
 denudation has revealed the granite, which, owing to its 
 greater durability, is often left standing as peaks or domes 
 by the farther removal of the surrounding, weaker strata. 
 Granites show a wide, geologic range, but most known 
 occurrences are associated with the older formations. 
 
 Granite forms an important source of durable building 
 stone widely distributed in the United States (Fig. 20) ; 
 but nearly 70 per cent of that quarried comes from the
 
 BUILDING STONES 77 
 
 Atlantic states. There are several areas which will be 
 briefly considered. 
 
 Eastern Crystalline Belt (3, 8, 15, 21, 25, 32, 33). From 
 northeastern Maine south west ward to eastern Alabama 
 there is an important belt of granites and gneisses, mostly 
 of pre-cambrian age. Those at the northeastern end of 
 the belt, as far south as New York, are most extensively 
 quarried, largely because of their peculiarly favorable loca- 
 tion. In this belt those of Quincy, Massachusetts, Barre, 
 Vermont, and Westerly, Rhode Island, are of value for 
 monumental work. 
 
 Central States. In these states there are several widely 
 separated areas : (1) the Minnesota- Wisconsin area (35), 
 affording many fine stones ; (2) the southeastern Missouri 
 area ; (3) east central Arkansas ; and (4) Llano County, 
 Texas, all supplying stones of excellent quality. 
 
 Western States. There are many granite areas in the 
 Cordilleras, including stone of various colors and texture; 
 but quarrying is almost entirely confined to California (12), 
 Colorado (13), Montana, Washington (34), and Oregon for 
 local use. The supply is inexhaustible. There is some 
 quarrying, also, in the enormous mass of coarse-grained 
 granite which forms the central portion of the Black Hills 
 of South Dakota. 
 
 Uses of Granite. On account of its massive character 
 and durability, granite is much employed for massive 
 masonry construction, while some of the granites that take 
 and preserve a high polish, and are susceptible of being 
 carved, are in great demand for ornamental and monumen- 
 tal work. Because of its greater durability, granite has
 
 78 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 in recent years largely replaced marble for monumental 
 purposes. 
 
 The refuse of the quarries is often dressed for paving 
 blocks or crushed for roads and railroad ballast. The size 
 of the blocks which can be extracted from a granite quarry 
 depends in part on the spacing of the joint planes, in part 
 on the perfection of development of the rift, some of the 
 monoliths that have been quarried being of immense size ; 
 for example, one from Stony Creek, Connecticut, measured 
 41 ft. x 6 ft. x 6 ft. ; one from Vinal Haven, Maine, 60 ft. 
 X 5 ft. ; one from Barre, Vermont, 60 ft. x 7 ft. x 6 ft. 
 
 Miscellaneous Igneous Rocks. Other igneous rocks than granites 
 are little used for structural work, though they are quarried in some 
 localities. For example, the diabase, or trap, so abundant in the Tri- 
 assic of the eastern states, is occasionally used for dimension blocks, 
 but its chief value is for paving blocks and road metal. The basaltic 
 rocks of the western states are often employed for similar purposes. 
 Norites of great beauty occur in New York, and syenites of excellent 
 quality have been quarried in Arkansas. Diorites are also quarried at 
 scattered localities. Some of the porphyries and rhyolites of the Atlan- 
 tic States possess considerable beauty when polished. A handsome 
 porphyry is quarried in Wisconsin (35), and in the Cordilleran region 
 both rhyolite and porphyry occur in numerous localities. A pink rhyo- 
 lite and consolidated volcanic tuffs are used, to some extent, for 
 building in Arizona. 
 
 LIMESTONES AND MARBLES 
 
 General Characteristics (1.3). A great series of sedi- 
 mentary and metamorphic rocks, composed chiefly of car- 
 bonate of lime, or, in the case of dolomite, of carbonate of 
 lime and magnesia, is included under the term limestone 
 and marble. These rocks also contain varying, but usually 
 small amounts of iron oxide, iron carbonate, silica, clay,
 
 BUILDING STONES 79 
 
 and carbonaceous matter. When of metamorphic character, 
 various silicates, such as mica, hornblende, and pyroxene, 
 may be present. 
 
 These calcareous rocks vary in texture from fine-grained, 
 earthy, to coarse-textured, fossiliferous rocks, and from 
 finely crystalline to coarsely crystalline varieties. There 
 is, also, great range in color, the most common being blue, 
 gray, white, and black, but beautiful shades of yellow, red, 
 pink, and green, usually due to iron oxides, are also found. 
 Their crushing strength commonly ranges from 10,000 
 to 15,000 pounds per square inch, while their absorption is 
 generally low. 
 
 The mineral composition of limestone exerts a strong 
 influence on its durability. Those limestones which are 
 composed chiefly or wholly of carbonate of lime are liable 
 to solution in waters containing carbon dioxide ; but dolo- 
 mite limestones, especially coarse-grained ones, disintegrate 
 rather than decompose. Streaks of mineral impurities cause 
 the stone to weather unevenly. Pyrite is an especially inju- 
 rious constituent, not only on account of its rusting, but 
 also because the sulphuric acid set free by its decompo- 
 sition attacks the stone. Black or gray limestones will 
 sometimes bleach on exposure. 
 
 Varieties of Limestones. In the geological sense limestones are of 
 sedimentary origin, while marbles are of metamorphic character, but 
 in the trade the term marble is applied to any calcareous rock capable 
 of taking a polish. In addition to the different varieties of marble 
 and the ordinary limestones there are certain kinds of calcareous rock 
 to which special names are given, as follows : 
 
 Dolomite, or dolomitic limestone, composed of carbonate of lime and 
 magnesia, and to the eye alone often is indistinguishable from lime- 
 stone.
 
 80 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 Oolitic limestone, composed of small, rounded grains of concretionary 
 character. 
 
 Travertine, or calcareous tufa, a limestone deposited from springs. 
 It is often sufficiently hard and durable for building, but rarely occurs 
 in deposits of large size. 
 
 Stalactitic and stalagmitic deposits, formed on the roofs and floors of 
 caves, respectively, are often of crystalline texture and beautifully 
 colored, and, when of sufficient solidity, are known as onyx marble. 
 
 Fossiliferous limestones is a general term applied to those limestones 
 which contain many fossil remains. Under this heading are included 
 crinoidal limestone and coral-shell marble. Coquina is a loosely 
 cemented shell aggregate, like that found near St. Augustine, Florida. 
 Chalk is a fine, white, earthy limestone, composed chiefly of forami- 
 niferal remains. 
 
 Distribution of Limestones in the United States. Lime- 
 stones are found in many states, and in all geological for- 
 mations from Cambrian to Tertiary, but those of the 
 Paleozoic, which are much used in the Eastern and Central 
 states, are more extensive and more massive than those of 
 later formations. Although many large quarries have been 
 opened to supply a local demand, the product is shipped 
 to a distance from only a few localities. At present the 
 sub-Carboniferous Bedford O 8 ) oolitic limestone of Indiana 
 (PI. VI) is, perhaps, the most widely used limestone in the 
 United States. It occurs in massive beds from 20 to 70 
 feet thick, and is said to underlie an area of more than 
 70 square miles. Although soft and easily dressed, it has 
 good strength, and has been used in many important cities 
 of the United States. 
 
 Cretaceous limestones are worked in Kansas, Nebraska, 
 and Iowa, although the most important sources are in the 
 Paleozoic formations.
 
 PLATE VI
 
 BUILDING STONES 
 
 81 
 
 Distribution of Marbles in the United States (3). While 
 some variegated marble is produced in the United States, 
 
 FIG. 21. Map showing marble areas of eastern United States. After Merrill. 
 Stones for Building and Decoration. 
 
 still most of those quarried are white, the greater part of 
 the variegated stones being imported. The main supply
 
 82 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 comes chiefly from regions of metamorplaic rock, the eastern 
 crystalline belt being the principal producer (Fig. 21). 
 Vermont (32, 33) leads all other states in marble produc- 
 tion, supplying 80 per cent of all the marble used for 
 ornamental work in the country. The most important 
 and largest quarries are those at Proctor (PL VII) and 
 West Rutland, where a thick and steeply dipping bed of 
 marble occurs between other limestones. The marble bed, 
 which has a thickness of 150 feet at the top of the quarry, 
 narrowing to 75 feet at the bottom, is divisible into a 
 series of well-marked layers of varying thickness, quality, 
 and color, white, blue, gray, and striped (33). Similar 
 marbles are quarried in Massachusetts (3, 22), New York 
 (3, 28), Maryland (21), and Georgia (15). 
 
 A variegated red and white marble of some hardness is 
 quarried at S wanton, Vermont (33), the brilliant red being 
 caused by iron oxide, the white by calcite deposited in 
 breccia cavities. 
 
 The Trenton limestone in eastern Tennessee (3) supplies 
 marbles of pinkish chocolate color with white variegation ; 
 and certain layers are rendered peculiarly beautiful by the 
 replacement of the fossils by calcite. It is used chiefly for 
 interior decoration. 
 
 Marble has been reported from various states west of the 
 Mississippi, but as yet little quarrying has been done. That 
 quarried in Inyo County, California, has attracted con- 
 siderable attention in recent years. 
 
 Most of the variegated marble used for interior decoration in this 
 country is obtained from abroad, although ornamental stones of this 
 class occur in the United States; however, up to the present time few 
 attempts have been made to place them on the market. This may be
 
 PLATE VII 
 
 Marble quarry, Proctor, Vt. Photo., Vermont Marble Co. The banding of the rock 
 is vertical. The horizontal lines are caused by the stone being quarried in 
 benches.
 
 BUILDING STONES 83 
 
 due to the fact that few quarrymen care to assume the temporary expense 
 which their introduction might involve. 
 
 Onyx Marbles (37-40). Under this term are included two types of 
 calcareous rock, one a hot-spring deposit, or travertine, formed at the 
 surface, the other a cold-water deposit formed in limestone caves in 
 the same manner as stalagmites and stalactites. Cave onyx is more 
 coarsely crystalline and less transluscent than travertine onyx. The 
 beautiful banding of onyx is due to the deposition of successive layers 
 of carbonate of lime, while the colored cloudings and veinings are 
 caused by the presence of metallic oxides, especially iron. 
 
 Neither variety of onyx occurs in extensive beds, though both are 
 widely distributed. Onyx is found in Arizona, California, and Colorado, 
 but it has not been developed in any of these states except on a small 
 scale. Most of the onyx used in the United States is obtained from 
 Mexico, though small quantities are obtained from Egypt and north 
 Algeria. 
 
 The value of onyx varies considerably, the poorer grades selling for 
 as little as 50 cents per cubic foot, while the higher grades bring $50 
 or more. The earliest-worked deposits were probably those of Egypt, 
 which were used by the ancients for the manufacture of ornamental 
 articles and religious vessels; and the Romans obtained onyx from the 
 quarries of northern Algeria. Many of the travertine onyx deposits 
 occur in regions of recent volcanic activity, and all of the known 
 occurrences are of recent geological age. 
 
 SERPENTINE 
 
 Pure serpentine is a hydrous silicate of magnesia; but beds of ser- 
 pentine are rarely pure, usually containing varying quantities of such 
 impurities, as iron oxides, pyrite, hornblende, and carbonates of lime 
 and magnesia. The purer varieties are green or greenish yellow, while 
 the impure types are various shades of black, red, or brown. Spotted 
 green and white varieties are called ophiolite or ophicalite. 
 
 Serpentine is sometimes found in sufficiently massive form for use in 
 structural or decorative work; but, owing to the frequent and irregu- 
 lar joints found in nearly all serpentine quarries, it is difficult to obtain 
 other than small-sized slabs. Its softness and beautiful color have led
 
 81 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 to its extensive use for interior decoration ; but since it weathers irregu- 
 larly and loses luster, it is not adapted to exterior work. 
 
 Though found in a number of states, most of the numerous attempts 
 to quarry American serpentine have been unsuccessful. Considerable 
 serpentine for ordinary structural work has been quarried in Chester 
 County, Pennsylvania, and a variety known as Verdolite is worked 
 near Easton, Pennsylvania. Quarrying operations are also under way 
 in the state of Washington. 
 
 SANDSTONES 
 
 General Properties (1, 3). While most sandstones are 
 composed chiefly of quartz grains, some varieties contain 
 an abundance of other minerals, such as mica, or, more 
 rarely, feldspar, which in rare cases may even form the 
 predominating mineral. Pyrite is occasionally present, and 
 varying amounts of clay frequently occur between the 
 grains, at times in sufficient quantity to materially influence 
 the hardness and dressing qualities of the stone. The hard- 
 ness of sandstones, however, usually depends on the amount 
 and character of the cement, varying from those having 
 so small an amount of silica or iron oxide cement that 
 the stone crumbles in the fingers to those quartzites whose 
 grains are so firmly bound by silica that the rock resembles 
 solid quartz. With these differences the chemical compo- 
 sition varies from nearly pure silica to sandstone with a 
 large percentage of other compounds. (For analyses, see 
 Kemp's "Handbook of Rocks.") 
 
 There are many colors among sandstones, but light gray, 
 white, brown, buff, bluish gray, red, and yellow are most com- 
 mon. In density sandstones range from the nearly imper- 
 vious quartzites to the porous sandrocks of recent geologic 
 formations, and consequently they show a variable absorption.
 
 BUILDING STONES 85 
 
 Most sandstones contain some quarry water, and those with 
 appreciable amounts are softer and more easy to dress when 
 first quarried ; but they cannot be quarried in freezing 
 weather. The average specific gravity of sandstone is 2.3, 
 and accordingly a cubic foot weighs about 140 to 150 pounds. 
 On the whole, sandstones resist heat well and are usually 
 of excellent durability, since they contain few minerals that 
 easily decompose. When they disintegrate it is commonly 
 by frost action. The injurious minerals are pyrite, mica, 
 and clay. Pyrite is likely to cause discoloration on weather- 
 ing ; the presence of mica tends to cause the stone to scale 
 off if set on edge ; and clay may cause injury to the stone in 
 freezing weather on account of its capacity for absorbing 
 moisture. The value of a sandstone is often lessened by 
 careless quarrying, or by placing it on edge in the building, 
 thus exposing the bedding planes to the entrance of water. 
 
 Varieties of Sandstone. With an increase in the size of 
 their grains, sandstones pass into conglomerates on the one 
 hand and with an increase in clay into shales. By an in- 
 crease in the percentage of carbonate of lime they may also 
 grade into limestones. 
 
 On account of these variations, as well as the difference in color and 
 the character of the cement, a number of varieties of sandstone are 
 recognized, of which the following are of economic value: arkose, a 
 sandstone composed chiefly of feldspar grains ; flagstone, a thinly bedded, 
 argillaceous sandstone used chiefly for paving purposes ; bluestone, a flag- 
 stone much quarried in New York ; freestone, a sandstone which splits 
 freely and dresses easily; brownstone, a term formerly applied to sand- 
 stones of brown color, obtained from the eastern Triassic belt, and since 
 stones of other colors are now found in the same formation, the term 
 has come to have a geographic meaning and no longer refers to any 
 specific physical character.
 
 86 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Distribution of Sandstones in the United States. Sand- 
 stones occur in all formations from pre-Cambrian to Ter- 
 tiary. They are so widely distributed that for local supply 
 there are numerous small quarries in many states, but there 
 are several areas which have been operated on an extensive 
 scale, some of them for many years. Of these, one of the 
 best known is the Triassic Brownstone belt, which extends 
 from the Connecticut Valley in Massachusetts southwest- 
 ward into North Carolina. 
 
 Among the Paleozoic strata there are many sandstones, 
 often massive, and usually dense and hard. Of these the 
 Medina and Potsdam are specially important and much 
 quarried in New York State (27, 28). The same forma- 
 tions extend southward along the Appalachians and are 
 available at several points. Devonian flagstones are ex- 
 tensively quarried at several localities in New York and 
 Pennsylvania. At the present time the Lower Carbon- 
 iferous Berea sandstone of Ohio (29) is in great demand 
 because of its light color, even texture, and the ease with 
 which it is worked. Moreover, it has the peculiar property 
 of changing to a uniform buff on exposure to the air. There 
 are numerous other Paleozoic sandstones in the central 
 states, among them the Potsdam which covers a wide area 
 in Michigan and Wisconsin (35). Some of this stone is 
 bright red in color. 
 
 The Mesozoic and Tertiary strata of the West contain an 
 abundance of sandstone strata, and quarries opened in many 
 of them yield a good quality of stone. Though usually less 
 dense and hard than the Paleozoic sandstones, they serve 
 admirably for buildings in the mild or dry climates of the 
 West.
 
 BUILDING STONES 
 
 87 
 
 Uses of Sandstones. The wide distribution of sandstones 
 makes them an important source of local structural material. 
 They are chiefly used for ordinary building work, and but 
 little for massive masonry or monuments. The thin-bedded 
 flagstones are much used for flagging, and some of the 
 harder sandstones are split up for paving blocks. For other 
 uses, see Abrasives. 
 
 SLATES 
 
 General Characteristics (3, 26). Slates are metamorphic 
 rocks derived from clay or shale or more rarely from igneous 
 rocks (11). Their value depends upon the presence of a 
 well-defined plane of splitting, called cleavage (Fig. 22), de- 
 veloped by metamorphism through the rearrangement and 
 flattening of the original 
 mineral grains and the E 
 development of mica- 
 ceous minerals. The 
 cleavage usually de- 
 velops at a variable 
 angle to the bedding 
 planes which are often 
 completely obliterated by the metamorphism. When not 
 completely destroyed the bedding planes are marked by 
 parallel bands, called ribbons, cutting across the planes of 
 cleavage, but so perfect is the cleavage in the best slates that 
 the rock readily splits into thin sheets with a smooth surface. 
 
 Slates are commonly so fine grained that the mineral com- 
 position is not evident to the eye, but the microscope re- 
 veals the presence of many of the varied mineral grains 
 found in shale, and in addition much chlorite, developed by 
 
 QUARRY FLOOR 
 
 FIG. 22. Section showing cleavage and bed- 
 ding in slate. After Dale, U. S. Geol. Surv., 
 19th Ann. Kept., III.
 
 88 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 metamorphism. Owing to the presence of carbonaceous 
 particles, most slates are black or bluish black, but green, 
 purple, and red slates are also 
 known. The specific gravity of 
 slate is about 2.7, and a cubic 
 foot weighs between 170 and 175 
 pounds. 
 
 Most slates are fairly durable, 
 ,. ~^ 7 though the presence of pyrite 
 
 FIG. 23. Section in slate quarry 
 
 with cleavage parallel to bed- their decay. Some colored slates 
 
 ding, a, purple slate; 6, un- 
 
 worked; c and d, variegated ; fade on exposure to the weather, 
 
 e and f, green; g and h, gray , , ,, . , , . , . , 
 
 green ;, quartette tf.gray with but this change, which IS due to 
 black patches. After Dale. ^ bleaching of certain mineral 
 
 grains, does not necessarily result in loss of strength or 
 disintegration. 
 
 Distribution of Slates in the United States. Since slates 
 are of metamorphic origin, they are limited to those regions 
 in which the rocks are metamorphosed, and at present the 
 greater part of our supply comes from the Cambrian and 
 Silurian strata of the eastern crystalline belt of the Atlantic 
 states. 
 
 A series of quarries producing red, green, purple, and 
 variegated slates are located in a belt of Cambrian and 
 Hudson River strata along the border of New York (PL 
 VIII) and Vermont (26,33). 
 
 Black slates are quarried in Maine (3), New Jersey (3), 
 Pennsylvania (3), Maryland (21), Georgia (3), and Virginia 
 (3). Other producing states are Minnesota, California (11), 
 and Arkansas (9).
 
 ROBERT W. WEBB 
 GEOLOGY DEPT., U.C.LA 
 
 PLATE VIII 
 
 View of green-slate quarry, Pawlet, Vt. Photo, by H. Ries.
 
 BUILDING STONES 
 
 89 
 
 Uses of Slate. Slate is best known as a roofing material, 
 but it is also used for mantels, billiard-table tops, floor tiles, 
 steps, flagging, slate pencils, acid towers, wash tubs, etc. 
 The process of marbleizing slates for mantels and fireplaces 
 is carried on at several localities. 
 
 In quarrying slate there is from 40 to 60 per cent waste, 
 which is greater than in any other building stone; but the 
 introduction of channeling machines in quarrying has done 
 much to reduce this. The discovery of a use for this waste 
 has been an important problem, which has thus far been only 
 partially solved. It is sometimes ground for paint, and 
 attempts have been made to utilize it in the manufacture 
 of bricks and Portland cement. 
 
 Production of Building Stones. The production of build- 
 ing stones by kinds for several years was as follows: 
 
 
 PRODUCTION OF BUILDING STONES IN THE 
 UNITED STATES 
 
 1900 
 
 1901 
 
 1902 
 
 1903 
 
 Granite and Trap . 
 Marble .... 
 Slate 
 
 $12,675,617 
 4,267,253 
 4,240,466 
 
 6,471,384 
 16,666,62s 1 
 
 $15,976,961 
 4,965,699 
 4,787,525 
 
 8,138,680 
 21,747,061! 
 
 $18,257,944 
 5,044,182 
 5,696,051 
 
 10,601,171 
 
 24,959,751 1 
 
 $18,436,087 
 5,362,686 
 6,256,885 
 
 11,262,259 
 26,642,551 * 
 
 Sandstone and 
 Bluestone . . . 
 Limestone . . . 
 
 Total .... 
 
 44,321,345 
 
 55,615,926 
 
 64,559,099 
 
 67,960,468 
 
 The value of the building stones produced by the several 
 more important states, together with the kind of stone pro- 
 duced chiefly in 1903, is given below. 
 
 i Does not include limestone used as flux.
 
 90 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 
 PRODUCTION OF BUILDING STONES IN MORE 
 
 
 IMPORTANT STATES IN 1903 
 
 
 TOTAL VALUE 
 
 KIND PRODUCED CHIEFLY 
 
 Pennsylvania . . 
 
 $12,589,202 
 
 Limestone 
 
 Vermont .... 
 
 5,889,208 
 
 Marble 
 
 
 3 611 140 
 
 Granite 
 
 Ohio . . . . 
 
 5,280,472 
 
 Limestone 
 
 New York . . . 
 
 5,182.850 
 
 Limestone 
 
 Massachusetts . . 
 
 4,443,601 
 
 Granite 
 
 Indiana .... 
 
 2,903,284 
 
 Limestone 
 
 Georgia .... 
 
 1,577,134 
 
 Granite 
 
 Maryland . . . 
 
 1,344,722 
 
 Granite 
 
 All others . . . 
 
 42,821,613 
 
 
 In 1903 the slate exported was valued at $628,612. 
 
 REFERENCES ON BUILDING STONES 
 
 GENERAL ON PROPERTIES. 1. Hermann, Steinbruchindustrie und Stein- 
 bruchgeologie, Berlin, 1899. Borntrager Bros. 2. Merrill, Min- 
 eral Census, 1902. (Mines and Quarries.) 3. Merrill, Stones for 
 Building and Decoration, 3d ed., New York, 1904. Wiley & Sons. 
 For general information on properties and testing see also, 4. Buck- 
 ley, Jour. Geol., VIII: 160 and 333, 1900. 5. Julien, Jour. 
 Frankl. Inst., CXLVII, 1899. 6. MerriU, Maryland Geol. Surv., II : 
 47, 1898. 7. Watson, Ga. Geol. Surv., Bull. 9-A, 1903. 
 
 AREAL REPORTS. Alabama : 8. Smith, Eng. and Min. Jour., LXVI : 398. 
 (General.) Arkansas: 9. Dale, U. S. Geol. Surv., Bull. 225: 414, 
 1904. (Slate.) 10. Hopkins, Ark. Geol. Surv., Ann. Kept., 1890; 
 IV, 1893. (Marbles.) California : 11. Eckel, U. S. Geol. Surv., 
 Bull. 225 : 417, 1904. (Slate.) 12. Jackson, Calif. State Min. Bureau ; 
 8th Ann. Kept. : 885, 1888. (General.) Colorado : 13. Lakes, 
 Mines and Minerals, XXII : 29 and 62, 1901. (General.) 14. 
 Merrill, Stones for Building and Decoration, New York, 1904. 
 Georgia: 15. McCallie, Ga. Geol. Surv., Bull. 1, 1894. (Marbles.) 
 16. Watson, Ibid., Bull. 9-A, 1903. (Granites and Gneisses.) 
 Indiana: 17. Hopkins, Ind. Geol. and Nat. Hist. Surv., 20th Ann. 
 Kept. : 188, 1896. 18. Siebenthal, U. S. Geol. Surv., 19th Ann. Kept., 
 VI : 292, 1898. (Bedford limestone.) 19. Thompson, Ind. Geol. and 
 Nat. Hist. Surv., 17th Kept.: 19, 1891. (General.) Maine : 20.
 
 BUILDING STONES 91 
 
 Merrill, Stones for Building and Decoration. Wiley and Sons, New 
 York, 1904. Maryland: 21. Matthews, Md. Geol. Sure., 11:125, 
 1898. (General.) Massachusetts: 22. Whittle, Eng. and Min. 
 Jour., LXVI : 336, 1898. (General.) Michigan : 23. Benedict, 
 Stone, XVII : 153, 1898. (Bayport district.) Missouri : 24. Buck- 
 ley and Buehler, Mo. Bur. Geol. and Mines, Vol. 2, 1904. New 
 Hampshire: 25. Hitchcock, 10th Census U. S., X : 124, 1884. New 
 York : 26. Dale, U. S. Geol. Surv., 19th Ann. Kept., Ill : 153, 1899. 
 (Slate belt.) 27. Dickinson, N.Y. State Museum, Bull. 61, 1903. 
 (Bluestone and other Devonian sandstones.) 28. Smock, N. Y. 
 State Museum, Bull. 3, 1888. Ohio: 29. Orton, Ohio Geol. Surv., 
 V : 578, 1884. (General.) Pennsylvania: 30. Hopkins, Penn. 
 State College, Ann. Kept., 1895 ; Appendix, 1897. (Brownstones.) 
 31. Lesley, Tenth Census, U. S., X : 146, 1884. (General.) 
 31 a. South Dakota: Todd, S. Dak. Geol. Surv., Bull. 3 : 81, 1902. 
 (General.) Vermont: 32. Perkins, Kept, of State Geologist on 
 Mineral Industries of Vt., 1899-1900, 1900, 1903-1904; and 33. Re- 
 port on Marble, Slate, and Granite Industries, 1898. Washington: 
 . 34. Shedd, Wash. Geol. Surv., II : 3, 1902. (General.) Wisconsin : 
 35. Buckley, Wis. Geol. and Nat. Hist. Surv., BuU. IV, 1898. 
 (General.) Wyoming: 36. Knight, Eng. and Min. Jour., LXVI: 
 546, 1898. 
 
 REFERENCES ON ONYX MARBLE 
 
 37. DeKalb, "Onyx Marbles," Trans., Am. Inst. Min. Engrs., XXV: 
 557, 1896. 38. Merrill, Stones for Building and Decoration (New 
 York), 3d ed., 1904. 39. Merrill, Ann. Kept. U. S. Nat. Mus. 
 (Washington), 1895. 40. Merrill, Min. Indus., Vol. II, "Onyx," 
 1894.
 
 CHAPTER TV 
 CLAY 
 
 Definition. Clay, which is one of the most widely dis- 
 tributed materials and one of the most valuable commercially, 
 may be denned as a fine-grained mixture of the mineral kao- 
 linite (the hydrated aluminum silicate) with fragments of 
 other minerals, such as silicates, oxides, and hydrates, and 
 also often organic compounds (sometimes classed as col- 
 loids), the mass possessing plasticity when wet and becom- 
 ing rock hard when burned to at least a temperature of 
 redness. 
 
 Residual Clays (42). Clays are derived primarily and 
 principally from the decomposition of crystalline rocks, 
 more especially feldspathic varieties, and deposits thus 
 formed will be found overlying the parent rock and grad- 
 ing down into it. From its method of origin and position 
 it is termed a residual clay (Fig. 24). 
 
 All residual clays show a variable amount of kaolinite or clay-substance. 
 This mineral, which is white in color, results from the decomposition 
 of feldspar, either by weathering, or, less often, by the action of volcanic 
 vapors. The decay of a large mass of pure feldspar would therefore 
 yield a mass of white clay, but in most instances, the feldspar is asso- 
 ciated with other minerals, such as quartz, mica, and hornblende, all 
 of which, except the quartz, decay with the greater or less rapidity, 
 and some of these, such as the hornblende, may likewise yield a 
 hydrous aluminum silicate. Any ferruginous minerals in the rock will, 
 in decomposing, form limonite, which stains the 
 92
 
 CLAY 
 
 93 
 
 Large masses of pure feldspar are rare, but feldspathic rocks, such 
 as granite or syenite, are more common, and these will also decompose 
 to clay; but, since the parent rock contains other minerals, such as 
 quartz or mica, these 
 will either remain as 
 sand grains in the 
 clay, or, by decom- 
 position, will form 
 soluble compounds, 
 or iron stains. The 
 decay of many rocks, 
 for example, lime- 
 stone and shale in FIG. 24. Section showing formation of residual clay. 
 
 After Ries, U.S. Geol. Surv., Prof. Paper, 11:16. 
 addition to the crys- 
 talline rocks, produces a residuum of clay. Kaolin is a white-burning 
 residual clay, but it is rare. 
 
 The extent of a deposit of residual clay will depend on the extent 
 of the parent rock and the topography of the land, which also influences 
 its thickness. On steep slopes much of the clay may be washed away 
 and residual clays are also rare in glaciated regions, for the reason that 
 they have been swept away by the ice erosion. They are consequently 
 wanting in most of the Northern states, but abundant in many parts 
 of the Southern states, where the older formations appear at the surface. 
 
 Sedimentary Clays (42). With the erosion of the land 
 surface the particles of residual clay become swept away 
 
 to lakes, seas, or 
 the ocean, where 
 they settle down 
 in the quiet water 
 as a fine alumin- 
 ous sediment, 
 After f rm i n g a deposit 
 of sedimentary 
 
 LOAMY CLAY 
 
 CLAY 
 
 SAND 
 
 SAND AND GRAVEL 
 
 BED ROCK' 
 
 FIG. 25. Section of a sedimentary clay 
 
 Ries, U. S. Geol. Siirv., Prof. Paper, 11:18 
 
 clay (Fig. 25). Such beds are often of great thickness and
 
 94 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 vast extent. With the accumulation of many feet of other 
 sediments on top of them, they often become solidated either 
 by pressure or by the deposit of a cement around the grains. 
 Consolidated clay is termed shale, and this upon being ground 
 and mixed with water often becomes as plastic as an uncon- 
 solidated clay. 
 
 Sedimentary clays may be divided into the following 
 groups according to their mode of origin and form of 
 deposit. 
 
 Marine Clays. Formed by the deposition on the ocean floor of 
 the finer particles derived from the waste of the land. Such ancient 
 sea-bottom clays have been elevated to form dry land in all the con- 
 tinents, in many cases forming consolidated clay strata, but elsewhere, 
 especially in coastal plains, in unconsolidated condition. Extensive 
 clay deposits are also formed in protected estuaries and lagoons along 
 the sea coast. 
 
 Flood-plain Clays. Formed by the deposition of clayey sediment 
 on the lowlands bordering a river during periods of flood. Layer 
 upon layer, this deposit builds a flood plain often of great extent 
 and depth. Such areas of flood-plain clays are most extensive along 
 the greater rivers and in the deltas which they have built in the 
 sea. 
 
 Lake Clays. Clay is deposited on the bottom of many lakes and 
 ponds in the same manner as on the ocean bottom. Where the 
 streams bring only fine particles the filling of a lake may be entirely 
 of clay. Many lakes have been either drained or completely filled 
 and their clays therefore made available. This is especially true of 
 small, shallow lakes formed during the Glacial Period. 
 
 Glacial Clays, commonly known as till or bowlder clay, a rock flour 
 ground in the glacial mill in which rock fragments were worn down to 
 clay by being rubbed together or against the bed rock over which the 
 ice moved. When the ice melted, this deposit was left in a sheet of 
 varying thickness and characteristics over a large part of the area 
 which the ice covered.
 
 CLAY 95 
 
 JEolian Clays. Wind drifts drive clay about, and in favorable posi- 
 tions causes its accumulation in beds. This is true of the Chinese loess, 
 a wind-blown deposit derived from residual soils and drifted about in 
 the arid climate of interior China. Some at least of the loess clays of 
 the Mississippi Valley seem to have a similar origin, the source of the 
 clay being glacial deposits ; in other cases loess seems to be a water 
 deposit either in shallow lakes or else in broad, slowly moving 
 streams. 
 
 Properties of Clay. These are of two kinds, physical 
 and chemical, and since they exercise an important influence 
 on the behavior of the clay, the most important ones may 
 be described. 
 
 Chemical Properties (42). The number of common ele- 
 ments which have been found in clays is great, and even 
 some of the rarer ones have been noted ; but in a given 
 clay the number of elements present is usually small, being 
 commonly confined to those determined in the ordinary 
 chemical analysis, which shows their existence in the clay, 
 but not always the state of the chemical combination. 
 The common constituents of a clay are silica, alumina, 
 ferric or ferrous oxide, lime, magnesia, alkalies, titanic acid, 
 and combined water. Organic matter, though often pres- 
 ent, is usually in small amounts, and carbon dioxide is 
 always found in calcareous clays. The effect of these 
 may be noted briefly. 
 
 Silica is most often present in the form of quartz grains; but it 
 may also be contained in grains of undecomposed minerals. It aids 
 in lowering the plasticity and shrinkage, and helps to increase the 
 refractoriness at low temperatures. A clay high in silica (70 to 80 
 per cent) is usually sandy. Alumina, which is most abundant in white 
 clays, is a refractory ingredient. Iron oxide acts as a coloring agent in 
 both the raw and burned clay, small quantities coloring a burned clay
 
 96 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 buff, and larger amounts (4 to 7 per cent), if evenly distributed, turning 
 it red. It also acts as a flux in burning. Whatever the iron compound 
 present in the raw clay it changes to the oxide in burning. Lime, 
 magnesia, and alkalies are also fluxing ingredients of the clay. The 
 combined percentage of fluxing impurities is small in a refractory clay, 
 and often high in a low grade one. Lime, if present in considerable 
 excess over the iron, will, in burning, exert a bleaching effect on the 
 iron. For this reason, highly calcareous clays, such as those in the 
 Great Lake region, burn cream or buff. When lime is present in large 
 amounts it also causes clay to soften more rapidly in firing than it 
 otherwise would. 
 
 Chemically combined water and organic matter both pass off at a 
 temperature of very dull redness (450 to 650 C.). Their loss leaves 
 the clay temporarily porous until fire shrinkage sets in. Titanic acid, 
 though rarely exceeding 1 per cent, acts as a flux at high tempera- 
 tures at least. Sulphur trioxide is rarely present in sufficiently high 
 amounts to interfere with the successful burning of the clay. 
 
 Physical Properties (42). These include plasticity, ten- 
 sile strength, air and fire shrinkage, fusibility, and specific 
 gravity. 
 
 Plasticity may be defined as the property which clay possesses of 
 forming a plastic mass when mixed with water, thus permitting it to be 
 molded into any desired shape, which it retains when dry. This is an 
 exceedingly important character of clay. Clays vary from exceedingly 
 plastic, or " fat " ones, to those of low plasticity which are " lean " and 
 sandy. Plasticity is probably due in part to fineness of grain, and in 
 part to the presence of colloids. 
 
 Tensile strength is the resistance which a mass of air-dried clay offers 
 to rupture, and is probably due to interlocking of the particles. Tests 
 show that the tensile strength of clays varies from 15 to 20 pounds per 
 square inch up to 400 pounds or more per square inch. Many common 
 brick clays range from 100 to 200 pounds. 
 
 Shrinkage, is of two kinds air shrinkage and fire shrinkage. The 
 former takes place while the clay is drying after being molded, and i.s
 
 CLAY 97 
 
 due to the evaporation of the water, and the drawing together of the 
 clay particles. The latter occurs during firing, and is due to a com- 
 pacting of the mass as the particles soften under heat. Both are 
 variable. In the manufacture of most clay products an average total 
 shrinkage of about 8 or 9 per cent is commonly desired. Excessive air or 
 fire shrinkage causes cracking or warping of the clay. To prevent this 
 a mixture of clays is often used. 
 
 Fusibility is one of the most important properties of clays. When 
 subjected to a rising temperature, clays, unlike metals, soften slowly, and 
 hence fusion takes place gradually. In fusing, the clay passes through 
 three stages, termed, respectively, incipient fusion, vitrification, and 
 viscosity. 
 
 lu the lower grades of clay, that is, those having a high percentage 
 of fluxing impurities, incipient fusion may occur at about 1000 C., 
 while in refractory clays, which are low in fluxing impurities, it may 
 not occur until 1300 or 1400 C. is reached. The temperature interval 
 between incipient fusion and vitrification may be as low as 30 C. in 
 calcareous clays, or as much as 200 C. in some others. The recognition 
 of this variation is of considerable practical importance, and vitrified 
 products, such as paving bricks and stoneware, have to be made from 
 a clay in which the three stages of fusion are separated by a dis- 
 tinct temperature interval. The importance of this rests on the fact 
 that it is impossible to control the temperature of a large kiln with- 
 in a few degrees, and there must be no danger of running into a 
 condition of viscosity in case the clay is heated beyond its point of 
 vitrification. 
 
 Specific gravity varies commonly from about 1.70 to 2.30. 
 
 Chemical Composition. As might be expected from their 
 diverse modes of origin, clays vary widely in their chemical 
 composition. There is every gradation from those which, 
 in composition, closely resemble the mineral kaolinite to 
 those, like ordinary brick clays, in which there is a high 
 percentage of impurities. This variation is shown in the 
 following table :
 
 98 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 
 
 
 
 
 
 
 
 4 
 
 * 4 
 
 3 
 
 
 
 
 
 o 
 
 jjS 
 
 5 
 
 >6 
 
 t& 
 
 jf 
 
 M S 
 
 s^ 
 
 i 
 
 
 
 I s - 
 
 ^ 
 
 Bfc 
 
 o " 
 
 Si 
 
 IT 
 
 Sj 
 
 i" 
 
 J 
 
 11 
 
 !i 
 
 g -g~ 
 
 
 1 
 
 -1 
 
 t-i 
 
 
 f| 
 
 II 
 
 i| 
 
 - ~ 
 
 o a 
 
 |i 
 
 || 
 
 B 55 
 
 
 
 
 
 g 
 
 
 t> 2 
 
 M 1 
 
 oo H 
 
 
 
 U! ^ 
 
 
 3 
 M 
 
 M 
 
 M 
 
 
 
 3*' 
 
 < 
 
 
 1= 
 
 5 to 
 
 o 
 
 pq 
 
 Si0 2 
 
 46.3 
 
 62.4 
 
 45.7 
 
 61.6 
 
 52.52 
 
 59.92 
 
 67.84 
 
 68.62 
 
 67.78 
 
 38.07 
 
 64.64 
 
 A1 2 8 
 
 39.8 
 
 26.51 
 
 40.61 
 
 28.38 
 
 31.40 
 
 27.56 
 
 21.83 
 
 14.98 
 
 16.29 
 
 9.46 
 
 14.62 
 
 Fe 2 8 
 
 
 
 1.14 
 
 1.39 
 
 .52 
 
 2.34 
 
 1.03 
 
 1.57 
 
 4.16 
 
 4.57 
 
 2.70 
 
 5.69 
 
 CaO 
 
 
 
 .57 
 
 .45 
 
 .46 
 
 .4 
 
 tr. 
 
 .28 
 
 1.48 
 
 .6 
 
 15.84 
 
 5.16 
 
 MgO 
 
 
 
 .01 
 
 .09 
 
 .36 
 
 .42 
 
 tr. 
 
 .24 
 
 1.09 
 
 .727 
 
 8.6 
 
 2.90 
 
 K 2 
 
 
 
 .98 
 
 2.82 
 
 
 
 \ 61 
 
 .64 
 
 2.24 
 
 3.36 
 
 2.001 
 
 2.76 
 
 5.89 
 
 Na 2 
 
 
 
 
 
 
 
 / 
 
 
 
 
 
 
 
 H 2 
 
 Moist 
 
 13.9 
 
 8.8 
 .25 
 
 8.98 
 .35 
 
 5.08 
 
 1 12.42 
 
 (9.70 
 11.12 
 
 5.90 
 
 .80 
 
 3.55 
 
 2.78 
 
 } 6.24 
 
 2.49 
 
 3.74 
 .85 
 
 
 
 
 
 Ti0 2 
 
 Ti0 2 
 
 
 
 MnO 
 
 Ti0 2 
 
 C0 2 
 
 C0 2 
 
 
 
 
 
 3.6 
 
 .96 
 
 
 
 .64 
 
 .78 
 
 20.46 
 
 4.80 
 
 
 
 
 
 
 
 
 
 
 
 
 MnO 
 
 
 
 
 
 
 
 
 
 
 
 
 .76 
 
 Classification of Clay. It is possible to base a classifica- 
 tion of clays either on origin, chemical and physical proper- 
 ties, or uses. But since the subdivisions which can be made 
 are not sufficiently distinct, each of these gives rise to a more 
 or less unsatisfactory grouping. The following classifica- 
 tion is based partly on mode of origin and partly on physical 
 characters : 
 
 1. Residual clays. 
 
 A. White-burning (kaolins, formed from feldspathic rocks). 
 
 B. Colored-burning (formed from igneous, metamorphic, and 
 
 many sedimentary rocks). 
 
 2. Clastic, or mechanically formed clays. 
 
 A. Water formed (of variable extent, depending on locality and 
 mode of deposit). 
 
 a. White-burning (ball and paper clays). 
 
 b. Colored-burning (brick and pottery clays).
 
 CLAY 99 
 
 B. Glacial clays (often stony ; all colored-burning). 
 
 C. Wind-formed clays (some loess). 
 
 3. Chemical precipitates (some flint clays). 
 
 Kinds of Clays. Many kinds of clays are known by 
 special names, the more important of which are the 
 following : 
 
 Adobe. A sandy, often calcareous, clay used in the west and south- 
 west for making sun-dried brick. Ball clay. A white-burning, plastic, 
 sedimentary clay, employed by potters to give plasticity to their mixture. 
 Brick clay. Any common clay suitable for making ordinary brick. 
 China clay. A term applied to kaolin (q.v.*). Earthenware clay. Clay 
 suitable for the manufacture of common earthenware, such as flower 
 pots. Fire clay. A clay capable of resisting a high degree of heat. 
 Flint clay. A peculiar flintlike, fire clay, which when ground up and 
 wet develops no plasticity. Chemically it differs but little, if at all, 
 from the plastic fire clays. Moreover, the two often occur in the same 
 bed, either in separate layers or irregularly mixed. Gumbo. A very 
 sticky, highly plastic clay, occurring in the central states, and used for 
 making burned -clay ballast (1). Kaolin. A white-burning residual 
 clay, employed chiefly in manufacture of white earthenware and por- 
 celain. Loess. A sandy, calcareous, fine-grained clay, covering thou- 
 sands of square miles in the Central states, and of wide use in brick 
 making. Paper clay. Any fine-grained clay, of proper color, that can 
 be employed in the manufacture of paper. Pipe clay. A loosely used 
 term applied to any smooth plastic clay. Strictly speaking, it refers to 
 a clay suited to the manufacture of sewer pipe. Pottery clay. Any 
 clay suitable for the manufacture of pottery. Retort clay. A plastic 
 fire clay, used in making gas retorts. The term is a local one used 
 chiefly in New Jersey. Sagger clay. A loose term applied to clays 
 employed in making saggers ; they are of value for other purposes as 
 well. Stoneware clay. A very plastic clay, which burns to a vitrified 
 or stoneware body. Terra-colta clay. Clay suitable for the manufac- 
 ture of terra cotta. The term has no special significance, as a wide 
 variety of clays are adapted to this purpose.
 
 100 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Geological Distribution. Clays have a wider distribution 
 than most other economic minerals or rocks, being found in 
 all formations from the oldest to the youngest. The pre- 
 Cambrian crystallines yield both white and colored residual 
 clays, usually the result of weathering, though more rarely of 
 solfataric action. In the Paleozoic rocks, deposits of shale, 
 and sometimes of clay, are found in many localities ; and, 
 since they are usually marine sediments, the beds are often 
 of great extent and thickness. With the exception of cer- 
 tain Carboniferous deposits, the Paleozoic clays are mostly 
 impure. The Mesozoic formations contain large supplies of 
 clays and shale suitable for the manufacture of bricks, terra 
 cotta, stoneware, fire brick, etc. 
 
 The Pleistocene clays are all surface deposits, usually 
 impure, and individually of limited extent, although they 
 are thickly scattered all over the United States. Their 
 chief value is for brick and tile making. They have been 
 accumulated by glacial action, on flood plains, in deltas, or 
 in estuaries and lakes. 
 
 Distribution of Clays by Kinds. Kaolins (59) . Since 
 kaolins are derived only from crystalline or igneous rocks, 
 their distribution is limited ; indeed, at present the only 
 deposits worked are in the eastern states. Being com- 
 monly formed by the weathering of pegmatite veins, kaolin 
 deposits have great length as compared with their width, 
 which may be anywhere from 5 to 300 feet. Their depth 
 ranges from 20 to 120 feet, depending on the depth to 
 which the feldspar has been weathered. 
 
 Quartz and white mica are often present in kaolin, and it is 
 then frequently necessary to put the clay through a washing process
 
 CLAY 
 
 101 
 
 to remove these minerals. The difference between a washed and 
 unwashed kaolin is well shown by the two following analyses, from 
 which it is seen that the quartz contents have been considerably 
 lowered, and that the washed product approaches more closely to the 
 composition of kaolinite : 
 
 
 CRUDE KAOLIN 
 
 WASHED KAOLIN 
 
 SiO 
 
 6.40 
 
 45.78 
 
 ALO, . 
 
 26.51 
 
 36.46 
 
 Fe O, 
 
 1 14 
 
 28 
 
 FeO 
 
 
 1.08 
 
 CaO 
 
 .57 
 
 .50 
 
 MgO 
 
 Alkalies 
 
 .01 
 .98 
 
 .04 
 .25 
 
 H O 
 
 880 
 
 1340 
 
 Moisture 
 
 .25 
 
 2.05 
 
 Clay substance 
 
 100.66 
 66.14 
 
 99.84 
 93.24 
 
 
 
 
 North Carolina (44) and Pennsylvania (50, 52) are the 
 most important kaolin-producing states, but deposits are 
 also worked in Connecticut, Maryland (30), and Virginia 
 (59). It is known to occur in Alabama (9). All of these 
 deposits except that in Connecticut are found south of 
 the limit of the glacial drift. 
 
 The output from the American deposits is insufficient 
 to supply the domestic pottery industry, and consequently 
 many thousand tons are annually imported from England. 
 Since this can be brought over as ballast, it is possible to 
 put it on the American market at a low price. The best 
 grades of kaolin sell for $10 to $12 per ton at Trenton, 
 New Jersey, and East Liverpool, Ohio, these being the two 
 most important pottery centers of this country.
 
 102 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Fire Clays. Fire clays are found in the rocks of all 
 systems, from the Carboniferous to the Tertiary, inclusive, 
 with the exception of the Triassic. In the Lower Creta- 
 ceous of New Jersey (42) there are many beds of refrac- 
 tory clay, variable in thickness and closely associated with 
 beds of less refractory character. They not only support 
 a thriving local fire-brick industry, but serve also as a 
 source of supply for factories in other states. Similar, 
 but less extensive and less refractory, beds occur in strata 
 of Cretaceous Age in the coastal plain of Maryland (30), 
 Georgia (17), South Carolina (53), and Alabama (9). 
 
 The most extensive, and among the most important, beds 
 of fire clay are those found in the Carboniferous strata of 
 Pennsylvania (48, 52), Ohio (46, 47), Kentucky (26, 27), Indi- 
 ana (20), and Illinois (19). Those of the first two named 
 states are on the average the most refractory. Here the 
 fire clays are usually found underlying coal seams and often 
 at well-marked horizons, especially in the Upper Productive 
 Measures. 
 
 The section given in Fig. 2 is fairly representative of 
 their mode of occurrence. 
 
 Those of Indiana and Illinois are so placed that one mine 
 shaft is often used for extracting coal, fire clay, stoneware 
 clay, and shale. 
 
 The beds of refractory clay, found in the Carbon- 
 iferous strata near St. Louis (38), are not only used in the 
 manufacture of fire brick, but are, in some cases, found 
 suitable, after washing, for mixture with imported Ger- 
 man clays for the manufacture of glass pots. The Ter- 
 tiary strata of Missouri also supply some refractory 
 clays.
 
 PLATE IX
 
 CLAY 103 
 
 Fire clays are found in the Black Hills of South Dakota (54), in 
 the Laramie beds of Colorado (13-15), and in California (12) ; but, except- 
 ing near Denver, where used for making fire brick and assayer's appa- 
 ratus, these deposits are as yet slightly developed. 
 
 Pottery Clays. Under this heading are included several 
 grades of clay, the kaolins, already described, being the 
 purest and best suited to the manufacture of high grades 
 of pottery. 
 
 A second grade of pottery clay, the ball clay, is of limited 
 distribution in the United States. A small quantity is 
 found in the Cretaceous (PL IX) of New Jersey (42), 
 and a much larger amount in the Tertiary of western 
 Kentucky (26, 27) and Tennessee (55), and southeastern 
 Missouri (38) and Florida (59). As in the case of kaolin, the 
 domestic supply is not sufficient to meet the demand, and 
 large quantities of ball clay are imported from England. 
 
 Stoneware clays form a third grade of pottery clays. 
 Being usually of at least semi-refractory character, their 
 distribution is essentially coextensive with that of fire 
 clays; indeed, the two are often dug from the same pit or 
 mine. Large quantities are obtained in New Jersey (42), 
 western Pennsylvania (48), and eastern Ohio (47). 
 
 Stoneware clays usually in the same area as the fire clays are also 
 obtained in Illinois (19), Indiana (20), Kentucky (26), Tennessee (55), 
 Georgia (17), Alabama (9), and Texas (56) ; and they occur also in 
 Missouri (38), Iowa (22), Colorado (14), and California (12), although 
 little is known about these deposits. 
 
 Many of the Pleistocene surface clays in various states 
 are sufficiently dense-burning to be used locally by small 
 stoneware factories.
 
 104 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Brick and Tile Clays (59) . None of our states lack an 
 abundant supply of good brick and tile clays, and in many 
 areas there are extensive deposits near the large markets, 
 and often near tide water. In such cases the clay beds 
 are exploited to an enormous extent. 
 
 In the northeastern states the Pleistocene surface clays 
 are found almost everywhere in great abundance, and are 
 made use of in many places, especially near the large cities. 
 
 In the Middle Atlantic states Columbian loams and clay 
 marls are an important source of brick material. 
 
 In Ohio, Illinois, and Indiana Pleistocene clays, in part 
 of glacial, and in part of flood-plain origin, are much used 
 for brick and tile. Impure Paleozoic shales are also used 
 in places, especially in the manufacture of vitrified paving 
 brick, thousands of which are made annually in Ohio. 
 Northern Illinois, Michigan, and Wisconsin draw their main 
 supply of brick clays from the calcareous lake deposits. 
 
 Although glacial clays and flood-plain deposits are much 
 used in the states west of the Mississippi, the loess which 
 occurs over a wide area is probably even more important 
 as a source of brick, while in the southwestern states loess 
 and adobe are important. Residual clays, river silts, glacial 
 clays, and other forms of clay are employed in brick making 
 along the Pacific coast. 
 
 Miscellaneous Clays of Importance. Paper clays of good quality are 
 much sought for by paper manufacturers. At present the best ones 
 are obtained from the Potomac formation of North Carolina. A small 
 amount of glasspot clay (48), comes from western Pennsylvania and 
 eastern Missouri; but our chief supply is imported. Terra-cotta clays 
 are obtained from the same areas that supply fire clays, New Jersey 
 being the principal producer.
 
 CLAY 
 
 105 
 
 Uses of Clay. So few people have even an approxi- 
 mate idea of the uses to which clays are put that it seems 
 desirable to call attention to them briefly. In the following 
 table an attempt has been made to do this : 1 
 
 Domestic. Pottery of various grades; Polishing brick, often known as 
 bath bricks; Fire kindlers; Majolica stoves. 
 
 Structural. Brick; Tiles and Terra cotta; Chimney pots ; Chimney flues ; 
 Door knobs ; Fireproofing; Copings; Fence posts. 
 
 Hygienic. Closet bowls ; Sinks, etc. ; Sewer pipe ; Ventilating flues ; 
 Foundation Blocks; Vitrified bricks. 
 
 Decorative. Ornamental pottery ; Terracotta; Majolica; Garden furniture. 
 
 Minor Uses. Food adulterants; Paint filler; Paper filling ; Electrical 
 insulations; Pumps; Filling cloth; Scouring soap; Packing horses' 
 hoofs ; Chemical apparatus ; Condensing worms ; Ink bottles ; Ultra- 
 marine manufacture; Emery wheels. 
 
 Refractory Wares. Crucibles and other assaying apparatus ; Refractory 
 bricks of various patterns ; Glass pots. 
 
 Engineering Work. Puddle; Portland cement; Railroad ballast; Water 
 conduits; Turbine wheels. 
 
 Production of Clay. Owing to the fact that clays are 
 usually manufactured by the producer, it is necessary to 
 give the value of the product, no record being kept of 
 value of the raw material. 
 
 VALUE OF CLAY PRODUCTS IN UNITED STATES, 1901-1903 
 
 
 1901 
 
 1902 
 
 1903 
 
 Ohio . . . . 
 
 $21,574,985 
 
 $24,249,748 
 
 $25 208 128 
 
 Pennsylvania . . 
 New Jersey . . . 
 Illinois .... 
 New York . . . 
 Indiana .... 
 Others 
 
 15,321,742 
 11,681,878 
 9,642,490 
 8,291,718 
 4,466,454 
 39,232,320 
 
 17,833,425 
 12,613,263 
 9,881,840 
 8,414,113 
 5,283,733 
 44,293,409 
 
 18,847,324 
 13,416,939 
 11,190,797 
 9,208,252 
 5,694,625 
 47,396,583 
 
 Total .... 
 
 $110,211,587 
 
 $122,169,531 
 
 $130,962,648 
 
 i Table compiled by E. T. Hill and modified by H. Hies.
 
 106 ECONOMIC GEOLOGY OF THE UNITED STATES 
 LEADING STATES IN PRODUCTION IN 1903 
 
 
 
 PEE CENT OF TOTAL 
 
 Common brick 
 
 Pennsylvania . 
 
 12.2. 
 
 
 Pennsylvania . 
 
 19.7 
 
 Vitrified brick 
 
 Ohio .... 
 
 28.8 
 
 Ornamental brick .... 
 Fire brick 
 
 Ohio .... 
 
 4.7 
 464 
 
 Drain tile 
 
 Ohio .... 
 
 24.7 
 
 
 Ohio .... 
 
 386 
 
 Terra cotta 
 
 Illinois . 
 
 25.6 
 
 
 New Jersey . 
 
 46.3 
 
 Hollow tile and block . . . 
 Tile, not drain 
 
 Ohio .... 
 Ohio .... 
 
 44.9 
 30.5 
 
 REFERENCES OW CLAY 
 
 TECHNOLOGY AND PROPERTIES. 1. Bain, Min. Indus., VI : 157, 1898. 
 (Clay ballast.) 2. Barber, The Pottery and Porcelain of the United 
 States, 2d ed., N. Y., 1901 (G. P. Putnam's Sons), $5.00. 
 3. Bourry, Treatise on Ceramic Arts, N. Y. (Van Nostrand & Co.), 
 London (Scott Greenwood & Co.), 1901. 4. Bischof, Die Feuer- 
 festen Thone, 2d ed., Leipzig, 1895 (Quandt & Handel), 12 Mks. 
 5. Branner, Bibliography of Clays and the Ceramic Arts, U. S. Geol. 
 Surv., Bull. 143, Washington, 1896. 7. Davis, A Practical Treatise 
 on the Manufacture of Bricks, Tiles, and Terra Cotta, 2d ed., Philadel- 
 phia, $5.00. 8. Wheeler, Vitrified Paving Brick, Indianapolis, 1895, 
 (Clayworker Pub. Co.), fl.OO. Many excellent papers in Transac- 
 tions American Ceramic Society, Vols. 1-6 of which have appeared. 
 See also Nos. 22, 30, 42, 43 for general properties and technology. 
 
 AREAL REPORTS. Alabama: 9. Smith and Ries, Ala. Geol. Surv., 
 Bull. 6, 1900. (General.) Arkansas: 10. Branner, Ark. Geol. 
 Surv., Rept. for 1888. (Many analyses.) 11. Also Amer. Inst. Min. 
 Engrs., Trans. XXVII: 42, 1898. (S. W. Ark.) California : 
 12. Johnston, Calif. State Mineralogist, 9th Ann. Rept.: 287, 1890. 
 (General.) See also scattered notices in other annual reports. 
 Colorado: 13. Eldridge, U. S. Geol. Surv., Mon. XXVII, 1896. 
 (Denver Basin.) 14. Geijsbeek, Clay Worker, XXXVI : 424, 1901. 
 (General.) 15. Ries, Amer. Inst. Min. Engrs., XXVII : 336, 1898. 
 (Clays and Clay Industry.) Delaware : 16. Booth, Geol. of Dela-
 
 CLAY 107 
 
 ware: 94 and 106, 1841. Georgia : 17. Ladd, Ga. Geol. Surv., Bull. 
 6 A., 1898. (Cretaceous clays.) 18. Spencer, Ga. Geol. Surv., Paleo- 
 zoic Group : 276, 1893. (N. W. Ga.) Illinois : 19. Many scattered 
 references in volumes on Economic Geology of Illinois Geol. Survey, 
 Resume of these in TJ. S. Geol. Sutv., Prof. Pap. 11, 1903. Indiana: 
 20. Blatchley, Ind. Dept. Geol. and Nat. Hist., 20th Ann. Kept. : 23, 
 1896. (Carboniferous clays.) 21. Same author, 22d Ann. Kept.: 
 105, 1898. (X. W. Ind.) Scattered references in other annual re- 
 ports. Iowa : 22. Beyer, Williams, and Weems, la. Geol. Survey, 
 XIV: 29, 1904. Kansas : 23. Prosser, U. S. Geol. Surv., Mineral 
 Resources, 1892: 731, 1893. 24. See also Reports on Mineral 
 Resources of Kansas, Kas. Geol. Survey, 1897-1901. Kentucky: 
 25. Crump, Eng. and Min. Jour.,LXVI: 190, 1898. 26. Ries, U. S. 
 Geol. Surv., Prof. Pap. 11, 1903. 27. Many analyses in Ky. Geol. 
 Surv., Chem. Rept. A, pts. 1, 2, and 3, 1885, 1886, 1888. Louisiana: 
 28. Clendenin, Eng. and Min. Jour., LXVI: 456, 1898. 29. Ries, 
 Preliminary Report on Geology of La., I: 264, 1899. Maryland: 
 
 30. Ries, Md. Geol. Surv., IV, Pt. Ill: 205, 1902. Massachusetts : 
 
 31. Crosby, Technol. Quart., Ill : 228, 1890. (Kaolin at Blandford.) 
 
 32. Shaler, Woodworth, and Marbut, U. S. Geol. Surv., 17th Ann. 
 Rept., 1 : 957, 1896. (R. I. and S. E. Mass.) 33. Whittle, Eng. and Min. 
 Jour., LXVI: 245, 1898. Michigan : 34. Ries, Mich. Geol. Surv., 
 VIII : Pt. I, 1903. (Clays and shales.) Minnesota : 35. Berkey, 
 Amer. Geol., XXIX : 171, 1902. (Origin and distribution.) 36. Win- 
 chell, Minn. Geol. Surv., Misc. publications, No. 8, 1881. (Brick 
 clays.) Mississippi : 37. Eckel, U. S. Geol. Surv., Bull. 213 : 382, 
 1903. (N.W. Miss.) Missouri: 38. Wheeler, Mo. Geol. Surv., XI, 
 1896. (General.) Nebraska: 39. Neb. Geol. Surv., I: 202, 1903. 
 New Hampshire : 40. Hitchcock and Upham, Report on Geology of 
 New Hampshire, V: 85, 1878. New Jersey: 41. Cook, N. J. Geol. 
 Surv., 1878. (Special Report on Clays.) 42. Kummel, Ries, Knapp, 
 N. J. Geol. Surv., Final Reports, VI, 1904. New York: 43. Ries, 
 N. Y. State Museum, Bull. 35, 1900. (General.) North Carolina: 
 44. Ries, N. Ca. Geol. Surv., Bull. 13, 1897. (General.) North 
 Dakota : 45. Babcock, N. D. Geol. Surv., 1st Rept. : 27. (General.) 
 Ohio : 46. Orton, Ohio Geol. Surv., VII : 45, 1893. (Geology.) 
 
 47. Orton, Jr., Ibid., p. 69. (Clay industries.) Pennsylvania : 
 
 48. Hopkins, Pa. State College, Ann. Repts. as follows, 1897, Ap- 
 pendix. (W. Pa.) 49. Ibid., Append, to Rept. for 1899-1900. 
 (Philadelphia and vicinity). 50. Ibid., 1898-1899. (S. E. Pa.) 
 51. Many analyses in 2d Pa. Geol.' Surv., Rept. MM. : 257, 1879, 
 and scattered references in Repts. H 5, H 4, C 4, C 5, etc. 52. Re'- 
 sume in U. S. Geol. Surv., Prof. Pap. 11 : 208, 1903. South Carolina :
 
 108 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 53. Sloane, Bull. I, S. Car. Geol. Surv. (S. Car.) South Dakota : 54. 
 Todd, S. D. Geol. Surv., Bull. 3: 101. Tennessee : 55. Eckel, 
 U. S. Geol. Surv. Bull., 213 : 382, 1903. (W. Tenn.) Texas : 56. See 
 county reports issued by First Geol. Survey. United States: 57. Hill, 
 U. S. Geol. Surv. Min. Res. 1891 : 474, 1893. 58. Ries, U. S. Geol. 
 Surv. 17th Ann. Rept., Ill : 845, 1896. (Pottery Clays.) 59. Ries, 
 U. S. Geol. Surv., Prof. Pap. 11, 1903. (Clays east of Mississippi 
 River.) Vermont : 60. Nevius, Eng. and Min. Jour. LXIV : 189, 
 1897. (Kaolin.) 61. Ries, U. S. Geol. Surv., Prof. Pap. 11 : 133, 
 1903. Washington: 62. Landes, Wash. Geol. Surv., I: 173, 1902. 
 (General.) Wisconsin: 63. Buckley, Wis. Geol. and Nat. Hist. 
 Surv., Bull. 7, Pt. I, Eco. Series 4, 1901. (General.) 64. Forth- 
 coming bulletin by Ries. Wyoming : 65. Knight, Wyo. Experiment 
 Station, Bull. 14, 1893. (General.)
 
 CHAPTER V 
 
 LIME AND CALCAREOUS CEMENTS 
 
 Composition of Limestones (35). Limes and calcareous 
 cements form an important class of economic products, 
 obtained from limestones by heating them to a tempera- 
 ture ranging from that of decarbonation to clinkering. 
 The term limestone is applied to one of the main divi- 
 sions of the stratified rocks so widely distributed, both 
 geologically and geographically, and formed under such 
 different conditions, that its composition varies greatly, 
 this range of variation becoming appreciable from an 
 inspection of the following table, which contains a few 
 selected types : l 
 
 TABLE OF LIMESTONE ANALYSES, INCLUDING THE MINERALS 
 CALCITE AND DOLOMITE 
 
 
 CaC0 8 
 
 MgC0 8 
 
 SiO 2 
 
 A1 2 8 
 
 Fe 2 8 
 
 HaO 
 
 1. Calcite .... 
 2. Dolomite . . . 
 3. White limestone, 
 Adams, Mass. . 
 4. Limestone, Lehigh 
 Valley district, 
 p a 
 
 100.00 
 54.35 
 
 99.30 
 8800 
 
 45.65 
 .49 
 
 400 
 
 .63 
 5 87 
 
 .55 
 1 
 
 59 
 
 
 5. Limestone, Coplay, 
 Pa 
 
 67.14 
 
 2.90 
 
 18.34 
 
 7 
 
 49 
 
 3.92 
 
 Kemp, " Handbook of Rocks.' 
 109
 
 110 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 
 CaCO 8 
 
 MgC0 8 
 
 SiO a 
 
 A1 2 8 
 
 Fe-A. 
 
 H 2 O 
 
 6. Limestone, Cum- 
 
 
 
 
 
 
 
 berland, Md. . 
 
 41.80 
 
 8.60 
 
 24.74 
 
 16.74 
 
 6.30 
 
 
 7. Dolomite, Pleasant- 
 
 
 
 
 
 
 
 ville, N.Y. . . 
 
 59.84 
 
 36.80 
 
 2.31 
 
 .40 
 
 .25 
 
 
 8. Magnesian lime- 
 
 
 
 
 
 
 
 stone, Rosendale, 
 
 
 
 
 
 
 
 N.Y 
 
 45.91 
 
 26.14 
 
 15.37 
 
 11.38 
 
 1.20 
 
 
 
 
 
 1 
 
 
 From this table it will be seen that limestones vary from 
 rocks composed almost entirely of carbonate of lime, or of 
 carbonate of lime and carbonate of magnesia, to others 
 which are high in clayey or siliceous impurities. The 
 presence of such impurities in large quantity usually 
 imparts an earthy appearance to the limestone, and some- 
 times even gives it a shaly structure. 
 
 Marked variations in composition may at times be found 
 even in a single quarry, while in other cases a limestone 
 formation may show remarkable uniformity of composition 
 over a wide area. 
 
 Changes in Burning (8, 35). When limestones are cal- 
 cined or "burned" to a temperature sufficiently high to 
 drive" off volatile constituents, such as carbon dioxide, 
 water, and sulphur (in part), or, in other words, to the 
 point of decarbonation, the rock is left in a more or less 
 porous condition. If heated to a still higher temperature, 
 the rock clinkers or 'fuses incipiently, but the temperature 
 of clinkering depends on the amount of siliceous and clayey 
 impurities in the rock. 
 
 Lime (5, 8). Limestone free from or containing but a 
 small percentage of argillaceous impurities is, by decarbona-
 
 LIME AND CALCAREOUS CEMENTS 111 
 
 tion, changed to quicklime, a substance which has a high 
 affinity for water, and which, when mixed with water, 
 "slakes," forming a hydrate of lime. This change is 
 accompanied by the evolution of heat and by swelling, 
 and this action becomes the more marked the higher the 
 percentage of lime carbonate in the rock, for the slaking 
 activity is retarded by the presence of magnesium carbon- 
 ate, and especially by argillaceous impurities. Limes have, 
 therefore, been divided into "fat" limes and "meager" 
 limes, depending on the rapidity with which they slake 
 and the amount of heat they develop in doing so (5). 
 
 Hydraulic Cements. With an increase in clayey and 
 siliceous impurities, the burned rock shows a decrease in 
 slaking qualities, and develops hydraulic properties, or sets 
 when mixed with water, and even under the same. Products 
 of this type are termed cements, and owe their hydraulic 
 properties to the formation during burning of silicates and 
 aluminates of lime. On mixing the burned ground rock 
 with water, these take up the latter and crystallize, thereby 
 producing the set of the cement. 
 
 Hydraulic cements can be divided into the following 
 classes : Pozzuolano cements, hydraulic limes, natural ce- 
 ments, and Portland cements. 
 
 Pozzuolano Cements (2, 9, 41). These are produced from 
 an uncalcined mixture of slaked lime and a silico-aluminous 
 material, such as volcanic ash or blast-furnace slag. 
 
 This process was known to the ancients, and is named 
 from its early use around Pozzuolano, Italy. The composi- 
 tion of an Italian Pozzuolano earth may vary between the 
 following limits (9): SiO 2 , 52-60; A1 2 O 3 , 9-21; Fe 2 O 3 ,
 
 112 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 5-22; CaO, 2-10; MgO, up to 2; alkalies, 3-16; H 2 O, 
 up to 12. 
 
 The manufacture of slag cement is now carried on at 
 several localities in the United States, and is a growing 
 industry (2). 
 
 Hydraulic Limes (9) are formed by burning a siliceous 
 limestone to a temperature not much above that of decar- 
 bonation. Owing to the high percentage of lime carbon- 
 ate, considerable free lime appears in the finished product. 
 Hydraulic limes generally have a yellow color, and a gravity 
 of about 2.9. They slake and set slowly, and have little 
 strength unless mixed with sand. This class is of little im- 
 portance in the United States, but much more so in Europe. 
 
 Natural Cements (1, 8, 9,41). These, known also as Roman 
 cement, quick-setting cement, and Rosendale cement, are 
 made by burning a silico-aluminous limestone (containing 
 from 15 to 40 per cent clayey impurities) at a temperature 
 between decarbonation and clinkering. The product shows 
 little or no free lime. The following analyses will give 
 some idea of the range in composition of natural cement 
 rocks quarried in the United States: 
 
 ANALYSES OF CERTAIN AMERICAN CEMENT ROCKS 
 
 
 CaCO 3 
 
 MgC0 8 
 
 Si0 2 + 
 INSOL. 
 
 FeaOg 
 
 A1 2 8 
 
 ALKA- 
 LIES 
 
 H 2 
 
 UN- 
 
 DET. 
 
 Rosendale, N.Y. 
 
 45.91 
 
 26.14 
 
 15.37 
 
 11. 
 
 38 
 
 
 1. 
 
 20 
 
 Utica, 111. . . . 
 
 42.25 
 
 31.98 
 
 21.12 
 
 1. 
 
 12 
 
 
 1.07 
 
 2.46 
 
 Milwaukee, Wis. 
 
 45.54 
 
 32.46 
 
 17.56 
 
 3.03 
 
 1.41 
 
 
 
 
 Fort Scott, Kas. 
 
 65.21 
 
 10.65 
 
 15.21 
 
 
 4.56 
 
 
 
 4.37 
 
 Cement, Ga. . . 
 
 43.50 
 
 22.00 
 
 22.10 
 
 1.80 
 
 5.45 
 
 .22 
 
 4.95 
 
 
 Coplay, Pa. . . 
 
 67.14 
 
 2.90 
 
 18.34 
 
 7. 
 
 49 
 
 .19 
 
 
 3.94
 
 LIME AND CALCAKEOUS CEMENTS 
 
 113 
 
 Natural cements differ from lime in possessing hydraulic 
 properties, and refusal to slake unless ground very fine. 
 They differ from Portland cements in lighter weight, lower 
 temperature of burning, quicker set, lower ultimate strength, 
 and greater latitude of composition. Magnesia is not re- 
 garded as a detrimental impurity in natural cements as it 
 is in Portland cement. 
 
 The following are some analyses of the burned material : 
 
 ANALYSES OF SOME NATURAL ROCK CEMENTS 
 
 
 CaO 
 
 MgO 
 
 Si0 2 
 
 A1 2 8 
 
 Fe 2 8 
 
 Na 2 O,K 2 O 
 
 IGNITION 
 
 Natural rock cement, 
 
 
 
 
 
 
 
 
 Rosendale, N.Y. . 
 
 34.38 
 
 18 
 
 30.5 
 
 6.84 
 
 2.42 
 
 3.98 
 
 3.78 
 
 Natural rock cement, 
 
 
 
 
 
 
 
 
 Akron, N.Y. . . 
 
 40.68 
 
 22 
 
 22.62 
 
 7.44 
 
 1.40 
 
 2.23 
 
 3.63 
 
 Natural rock cement, 
 
 
 
 
 
 
 
 
 Cumberland, Md. . 
 
 43.97 
 
 2.21 
 
 22.38 
 
 11.71 
 
 2.29 
 
 9. 
 
 2.44 
 
 Roman cement, Rii- 
 
 
 
 
 
 
 
 
 dersdorf, Germany . 
 
 56.45 
 
 4.84 
 
 27.88 
 
 6.19 
 
 4.64 
 
 
 
 Portland Cement (4, 6, 7, 10, 41). This term is applied to 
 artificial mixtures of clay and lime rock, which are burned 
 to a temperature of clinkering. Portland cement was first 
 made by Joseph Apsdin, of Leeds, England, who desired 
 to make an artificial cement that would replace natural 
 hydraulic cements. It received its name because it hard- 
 ened under water to a mass resembling the Portland stone 
 of England. 
 
 The three essentials for Portland cement are lime, silica, 
 and alumina, and it is consequently necessary to use raw 
 materials supplying these three substances in the proper 
 quantities. This is in all cases done by artificial mixture,
 
 114 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 and many of the so-called "natural" Portland cements 
 used in the United States are not strictly such. The fol- 
 * lowing six combinations of materials are at present used 
 in the manufacture of true Portland cement in the United 
 States : marl and clay ; limestone and clay, or shale ; 1 chalk 
 and clay; pure limestone and argillaceous limestone; alkali 
 waste and clay; limestone and slag. 
 
 In the first four of these combinations it is evident that the sub- 
 stances first named supply the lime and the second the silica and 
 alumina. In the fourth the argillaceous limestone supplies some lime, 
 as well as the silica and alumina. The nature of the raw materials 
 chosen depends to a large degree on the location of the plant, whether 
 in a limestone or a marl producing region. Where both of these raw 
 materials are available, as in parts of New York, questions of manipu- 
 lation in the process of manufacture govern the selection of one or 
 the other. 
 
 Marls, for example, though easier to excavate and reduce than lime- 
 stones, contain so much more organic matter and water than limestones 
 that they are more expensive to handle and prepare. Marl beds are 
 likewise apt to be of limited extent and irregular, while limestone 
 beds are, so far as the needs of a manufacturing plant are concerned, 
 practically limitless. 
 
 Comparing clay and shale, the former is often easier to excavate, 
 but, on account of the water it contains, has to be dried before it can 
 be ground and mixed. The fossils in shales are sometimes an impor- 
 tant source of calcium carbonate, and then careful grinding and mixing 
 is necessary to bring about a uniform distribution of the lime through 
 the mass. Shale is, however, used by only a few works. 
 
 Argillaceous limestone, mixed with a much smaller quantity of purer 
 limestone, as in Pennsylvania and New Jersey, is superior to a lime- 
 stone and clay mixture, because less thorough mixing and fine grinding 
 are required. In such cements, even when grinding and mixing are 
 
 1 It is probable that the refuse of many slate quarries could also be used 
 in place of shale.
 
 LIME AND CALCAREOUS CEMENTS 
 
 115 
 
 incompletely done, the particles of argillaceous limestone so closely 
 resemble the proper mixture in chemical composition as to affect the 
 result but little. 
 
 The following table gives the analyses of some of the 
 raw materials used in manufacture of Portland cement: 
 
 ANALYSES OF RAW MATERIALS USED FOR PORTLAND CEMENT 
 
 LOCALITY 
 
 MATERIAL 
 
 SiO 2 
 
 A1 2 8 
 
 Fe a 8 
 
 CaC0 8 
 
 MgCOa 
 
 H 2 O + 
 OKG. 
 MATTER 
 
 MlSCEL. 
 
 
 Calc. shale 
 
 
 
 
 
 
 
 
 Lehigh 
 
 or 
 
 
 
 
 
 
 
 CaSO 4 
 
 Valley, 
 
 cement rock 
 
 15.40 
 
 4.26 
 
 1.38 
 
 74.66 
 
 2.66 
 
 1.88 
 
 .86 
 
 Penn. 
 
 Limestone 
 
 5.87 
 
 1.59 
 
 88.00 
 
 4.00 
 
 
 
 
 Mixture 
 
 13.97 
 
 5.07| 1.88 
 
 74.1 
 
 2.04 
 
 1.82 
 
 
 Glens 
 
 
 
 
 CaO 
 
 MgO 
 
 
 S0 3 
 
 
 Limestone 
 
 3.3 
 
 1.3 
 
 52.15 
 
 1.58 
 
 
 .3 
 
 Falls, 
 N.Y. 
 
 
 
 
 CaO 
 
 MgO 
 
 
 S0 3 
 
 
 Clay 
 
 55.27 
 
 28.15 
 
 5.84 
 
 2.25 
 
 8.37 
 
 .12 
 
 Warners, 
 
 /Marl 
 
 .26 
 
 .10 
 
 94.39 
 
 .38 
 
 4.64 
 
 
 N.Y. 
 
 I Clay 
 
 40.48 
 
 20.95 
 
 25.80 
 
 .99 
 
 8.50 
 
 
 
 
 Insol. 
 
 
 
 
 
 CaSO< 
 
 Sandusky, 
 
 Marl 
 
 1.28 
 
 1.72 
 
 92.70 
 
 .50 
 
 1.13 
 
 2.06 
 
 Ohio 
 
 
 
 
 
 CaO 
 
 MgO 
 
 
 
 
 Clay 
 
 64.70 
 
 11.9 
 
 9.9 
 
 .90 
 
 .70 
 
 11.9 
 
 
 White 
 
 { Chalk 
 
 7.97 
 
 1.09 
 
 88.64 
 
 .73 
 
 
 
 Cliffs, 
 
 
 
 
 
 CaO 
 
 MgO 
 
 
 
 Ark. 
 
 I Clay 
 
 53.3 
 
 23.29 
 
 9.52 
 
 .36 
 
 1.49 
 
 5.16 
 
 
 In the selection of raw materials the aim of the manu- 
 facturers is to produce a raw mixture which runs approx- 
 imately 70 to 75 per cent lime carbonate and the balance 
 clay (U. S. Geol. Surv., 21st Ann. Kept., VI : 404, 1900). 
 The proportions of clay and lime rock used at each factory 
 are not always disclosed, and the mixture of the two in-
 
 116 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 gredients is kept under careful control by frequent chemical 
 analysis, since slight variations from the proper composi- 
 tion may injure the cement. The following analyses will 
 serve to illustrate the composition of some American Port- 
 land cements: 
 
 ANALYSES OF CEMENTS 
 
 
 SiO 2 
 
 A1 2 8 
 
 Fe 2 3 
 
 CaO 
 
 MgO 
 
 S0 8 
 
 Empire brand . . 
 
 22.04 
 
 6.45 
 
 3.41 
 
 60.92 
 
 3.53 
 
 2.73 
 
 San dusky .... 
 
 23.08 
 
 6.16 
 
 2.90 
 
 62.38 
 
 1.21 
 
 1.66 
 
 Alpha 
 
 22.62 
 
 8.76 
 
 2.66 
 
 61.46 
 
 2.92 
 
 1.53 
 
 Distribution of Lime and Cement Materials in the United 
 States. Limestone for Lime. Limestones of suitable com- 
 position for burning lime are so widely distributed that no 
 particular regions or states require special mention. 1 In the 
 New England states, crystalline limestones are the chief 
 source of supply. In the Appalachian states, from New 
 York to Alabama, there are many Paleozoic limestones of 
 high purity, notably the Trenton, Lower Helderberg, and 
 Carboniferous limestones (see state references). The same 
 series of rocks are also of importance in the Mississippi 
 Valley states from Tennessee to Michigan (27). Lime of 
 excellent quality is obtained from the Subcarboniferous in 
 Iowa (41), Kansas (21), and Missouri (41), and from the 
 Cretaceous in Texas (41). Limestones suitable for lime 
 manufacture are also found in numerous localities in the 
 Pacific coast states (41). 
 
 1 Analyses and detailed descriptions will be found in the areal reports, 
 mentioned in the list of References.
 
 PLATE X 
 
 FIG. 1. Quarry of natural cement rock, Cumberland, Md. Photo, by H. Ries. 
 
 FIG. 2. Marl pit at Warners, N.Y. The dark streaks are peat, and the marl is 
 underlain by clay. Photo, by H. Hies.
 
 LIME AND CALCAKEOUS CEMENTS 117 
 
 Hydraulic Limes. Largely because of the great abun- 
 dance of natural rock cements, which are of superior value, 
 these materials, though much used abroad, are of no im- 
 portance in the United States. 
 
 Natural Rock Cements (1, 41). Calcareous rocks of this 
 class are found at a number of points, mainly in the Paleozoic 
 formations. In 1903 they were worked in sixteen different 
 states, eleven of which are east of the Mississippi. These 
 are found at a number of points in the Appalachian region, 
 but, owing to the folded character of the beds (PL X, Fig. 
 1), their extraction is often difficult. The most important 
 natural rock cement region of the United States is that of 
 Rosendale, New York (32, 35), where the cement rocks are 
 found in the Water Lime beds at the top of the Upper 
 Silurian, being obtained from underground workings. The 
 three beds are interstratified with other limestones, and 
 often dipping at a high angle. Their thickness ranges from 
 7 to 25 feet. The great development of this region is due 
 partly to the large supply of raw material, and partly to the 
 proximity to New York City and the possibility of shipment 
 by tide-water. 
 
 Farther west, around Akron, New York, and Buffalo (31), 
 the cement rock occurs at a somewhat lower horizon. In 
 eastern Pennsylvania, especially in the vicinity of Coplay 
 and Catasauqua (39), cement rock of Trenton age occurs in 
 a region of marked folding. This region, though an im- 
 portant producer of cement rock, is even more important as 
 a producer of Portland cement (41). 
 
 The Water Lime beds again form an important source of 
 cement rock in the vicinity of Cumberland, Maryland (24) 
 (PL X, Fig. 1), where there are four beds of economic
 
 118 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 value, ranging from 6 to 17 feet in thickness, and separated 
 by calcareous shales. The entire series is highly folded, the 
 dip sometimes being as much as 90. 
 
 Cement rock is also obtained in southeastern Ohio (36); 
 at Louisville, Kentucky (23), probably the second most im- 
 portant center in the United States ; in the Hamilton rocks 
 at Milwaukee, Wisconsin (44) ; and at Utica and La Salle, 
 Illinois (17), where it is found in the Calciferous formation 
 in a bed from 6 to 8 feet thick. 
 
 Portland Cements. Clay and limestone, in one form or 
 another, are so widely distributed throughout the United 
 States, that it is possible to manufacture Portland cement 
 at many localities, and the geologic age of the materials 
 used ranges from Ordovician to Pleistocene (41). Nine- 
 teen states were making this cement in 1903, the factories 
 being spread over the country from the Atlantic to the 
 Pacific (41). 
 
 By far the most important district is the Lehigh Valley 
 in Pennsylvania, which supplies about 70 per cent of the 
 domestic product. Here the raw materials consist of beds 
 of argillaceous limestone and nearly pure limestone, this 
 being one of the few localities where such a mixture is 
 obtainable. The same beds are found in the adjacent terri- 
 tory of New Jersey (30). 
 
 In the eastern half of New York (35) the Ordovician and 
 Silurian limestones form an inexhaustible supply of material 
 to mix with Pleistocene surface clays. In the south central 
 part of New York the Tully limestone and Hamilton shales 
 are employed, while in the central and southwestern portion, 
 beds of marl (PI. X, Fig. 2), associated with surface clays, 
 are utilized.
 
 LIME AND CALCAREOUS CEMENTS 119 
 
 Ohio (36, 41), Indiana (18), and Michigan (26, 28) are 
 important Portland cement producing states. The abun- 
 dance of marl and Pleistocene clays makes them the favorite 
 materials, notwithstanding the fact that beds of Paleozoic 
 limestones occur in each of the states. Marl, although espe- 
 cially abundant in Michigan, is found in many states lying 
 east of the Mississippi and north of the terminal moraine. 
 It is precipitated from the waters of ponds through the 
 agency of minute plants, especially CTiara (26). 
 
 In Kansas Carboniferous shales and limestones are used 
 for making Portland cement (21, 22), and in Texas and 
 Arkansas the Cretaceous shales and chalky limestones are 
 employed (13, 14) ; Alabama has a Cretaceous limestone of 
 such composition that very little clay or shale has to be 
 added to it (12). Portland cement is also manufactured in 
 North Dakota (41), South Dakota (41), Utah (41), Colorado 
 (41), and California (15). 
 
 Uses of Lime. The most important single use of lime 
 is for mixing with sand to form mortar, and many thousands 
 of tons are used annually for this purpose. In addition 
 to this use, lime is employed for a great variety of pur- 
 poses, of which the following are the most important : as 
 a purifier in basic steel manufacture; in the manufacture 
 of refractory bricks, ammonium sulphate, soap, bone ash, 
 gas, potassium-dichromate, paper, pottery glazes, and cal- 
 cium carbide; as a disinfectant; as a fertilizer; as a polish- 
 ing material ; for dehydrating alcohol, preserving eggs, and 
 in tanning. 
 
 Uses of Cement. The use of hydraulic cement is con- 
 stantly increasing in the United States, this being specially
 
 120 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 true of Portland cement, which is superseding natural 
 cement to a great extent, and is finding an increasing use 
 in building and engineering operations. For pavements, 
 Portland cement is probably more extensively used in 
 America than in any other country; and as an ingredient 
 of concrete it is widely employed. Blocks weighing as much 
 as 65 to 70 tons have been made for harbor improvements 
 at New York City (37 a). 
 
 Production of Cement. The following tables give the 
 production of natural-rock and Portland cement. Those 
 given for the latter cover a greater period than those of the 
 former, and are grouped with figures of import and consump- 
 tion in order to show more clearly the tremendous growth 
 of the American Portland cement industry. 
 
 PRODUCTION OF NATURAL CEMENT IN UNITED STATES 
 
 
 1901 
 
 1902 
 
 1903 
 
 
 QUANTITY 
 
 VALUE 
 
 QUANTITY 
 
 VALUE 
 
 QUANTITY 
 
 VALUE 
 
 
 barrels 
 
 
 barrels 
 
 
 barrels 
 
 
 New York . 
 
 2,234,131 
 
 $1,117,066 
 
 3,577,340 
 
 $2,135,036 
 
 2,417,137 
 
 $1,510,529 
 
 Pennsylvania . 
 
 942,364 
 
 376,954 
 
 796,876 
 
 340,669 
 
 1,339,090 
 
 576,269 
 
 
 
 
 
 
 
 
 Kentucky/ 
 
 2,150,000 
 
 752,500 
 
 1,727,146 
 
 869,163 
 
 533,573 
 
 766,786 
 
 Wisconsin . . 
 
 481,020 
 
 182,788 
 
 437,913 
 
 162,628 
 
 330,522 
 
 139,373 
 
 Illinois . . . 
 
 469,842 
 
 187,936 
 
 607,820 
 
 156,855 
 
 543,132 
 
 178,900 
 
 Maryland . . 
 
 351,329 
 
 175,665 
 
 409,200 
 
 150,680 
 
 269,957 
 
 138,619 
 
 Others . . . 
 
 456,137 
 
 263,369 
 
 488,010 
 
 261,599 
 
 569,860 
 
 365,044 
 
 Total . . 
 
 7,084,823 
 
 $3,056,278 
 
 8,044,305 
 
 $4,076,630 
 
 7,030,271 
 
 $3,675,520
 
 LIME AND CALCAREOUS CEMENTS 121 
 
 PRODUCTION OF PORTLAND CEMENT IN UNITED STATES 
 
 
 1891 
 
 1900 
 
 1901 
 
 1902 
 
 1903 
 
 Production of United States 
 Imports 
 
 barrels 
 454,813 
 2,988,313 
 
 barrels 
 8,482,020 
 2,386,683 
 
 barrels 
 12,711,225 
 922,426 
 
 barrels 
 17,230,644 
 1,961,013 
 
 barrels 
 22,342,973 
 2,251,969 
 
 
 
 
 
 
 
 Total 
 
 3,443,126 
 
 10,868,703 
 
 13,633,651 
 
 19,191,657 
 
 24,594,942 
 
 Exports (domestic and for- 
 eign) 
 
 - 
 
 139,939 
 
 417,625 
 
 373,414 
 
 285,463 
 
 Total consumption . . 
 Percentage of domestic 
 production to total con- 
 sumption in United States 
 
 3,443,126 
 13.2 
 
 10,728,764 
 79.1 
 
 13,216,026 
 96.2 
 
 18,818,248 
 91.6 
 
 24,309,479 
 91.9 
 
 PRODUCTION OF PORTLAND CEMENT BY STATES IN 1903 
 
 
 BARRELS 
 
 VALUE 
 
 
 9,754,313 
 
 $11 205 89 9 
 
 
 2 693 381 
 
 2 944 604 
 
 
 1 955 183 
 
 2 674 780 
 
 Illinois 
 
 1 9 57 500 
 
 1 914 500 
 
 Indiana 
 
 1,077,137 
 
 1 347 797 
 
 
 1 019 68? 
 
 1 285 310 
 
 Ohio 
 
 729,519 
 
 998 300 
 
 All others 
 
 3 856 58 
 
 5 34 136 
 
 
 
 
 Total 
 
 22 349 973 
 
 $7 713 319 
 
 
 
 
 REFERENCES ON LIME AND CEMENT MATERIALS 
 
 TECHNOLOGY. 1. Cummings, American Cements, Boston, 1898. (Many 
 analyses.) 2. Eckel, Min. Indus. X : 84, 1902. (Slag cement manu- 
 facture.) 3. Eckel, Amer. Geol. XXIX: 146, 1902. (Classifica- 
 tion.) 4. Green, Portland Cement Industry of the World, Journal 
 of Association of Civil Engineering, XX: 391, 1898. 5. Gilmore, 
 Practical Treatise on Limes, Hydraulic Cements and Mortars, N. Y., 
 D. Van Nostrand, 1872. 6. Jameson, Portland Cement; its Manu- 
 facture and Use, New York, 1898. 7. Lewis, Manufacture of
 
 122 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Hydraulic Cement in United States, Mineral Industry, VI : 91, 1898. 
 8. Richardson, Series of Articles on Lime and Cement Mortars 
 in the Brickbuilder, 1897 and 1898. 9. Schoch, Die Moderne 
 Aufbereitung u. Wertung der Mortel-Materialien, Berlin, 1896. 
 10. Spalding, Hydraulic Cement; its Properties, Testing, and Use, 
 New York, 1897, John Wiley & Sons. 
 
 LOCALITY REPORTS. Alabama: 11. Meissner, Ala. Ind. and Sci., 
 Proc., IV: 12. (Birmingham district limestone.) 12. Smith, Ala. 
 Geol. Surv., Bull. 8, 1904. (Many analyses.) Arkansas: 13. Bran- 
 ner, Amer. Inst. Min. Engrs., Trans. XXVII : 42, 1898. (S. W. 
 Ark.) 14. Taff, U. S. Geol. Surv., 22d Ann. Rept., 111:687, 1902. 
 (S. W. Ark.) California : 15. Grimsley, Eng. and Min. Jour., 
 LXXII: 71, 1901. (Cement industry.) 16. Irelan, 8th Ann. Rept. 
 State Mineralogist : 865 to 883, 1888 ; also 9th Ann. Rept. : 
 309-311, 1889; 13th Ann. Rept. Calif. State Mineralogist: 627, 
 1896 ; 12th Ann. Rept. : 391, 1894. (Cements.) Illinois : 17. Free- 
 man, Amer. Inst. Min. Eng., Trans. XIII: 172, 1885. (La Salle, 
 natural rock cement.) Indiana: 18. Blatchley, 25th Ann. Rept. 
 Ind. Dept. Geol. and Nat. Res., 1900 : 323, 1901. (Bedford lime- 
 stone.) 19. Siebenthal, 25th Ann. Rept. Ind. Dept. Geol. and 
 Nat. Hist. 1900 : 331, 1901. (Silver Creek hydraulic limestone.) 
 Iowa : 20. Houser, la. Geol. Surv., 1 : 199, 1893. (Niagara lime- 
 stone.) Kansas : 21. Haworth, Kas. Geol. Surv., Ill: 31, 1898. 
 22. Haworth and Schrader, U. S. Geol. Surv., Bull. 260 : 506, 1905. 
 (Independence Quadrangle.) Kentucky : 23. Kentucky Geol. Surv., 
 New Series, IV : 404. Maryland : 24. Clark and others, Md. Geol. 
 Surv. Rept. on Allegheny Co.: 185, 1900. (Lime and cements.) 
 25. Martin, Md. Geol. Surv. Rept. on Garrett Co. : 220, 1902. 
 Michigan : 26. Hale and others, Mich. Geol. Surv., VHI, Pt. 3, 1903. 
 (Marl for Portland cement.) 27. Lane, Eng. and Min. Jour., LXXI : 
 662, 693, and 725, 1901. (Mich, limestones.) 28. Russell, U. S. Geol. 
 Surv., 22d Ann. Rept., Ill: 629, 1902. (Mich. Portland cement 
 industry.) Mississippi: 29. Crider, U. S. Geol. Surv., Bull. 260: 
 510, 1905. (N. E. Miss.) New Jersey: 30. Kiimmel, Ann. Rept. 
 N. J. State Geologist, 1900 : 9. (N. J. Portland cement industry.) 
 New York : 31. Bishop, 15th Ann. Rept. N. Y. State Geologist : 338, 
 1897. (Erie Co.) 32. Nason, Rept. of N. Y. State Geologist, 1893 : 
 375. (Ulster Co.) 33. Pohlman, Amer. Inst. Min. Eng., Trans. 
 XVIII : 250, 1889. (Cement rock at Buffalo.) 34. Ries, U. S. Geol. 
 Surv., 17th Ann. Rept., Ill (cont.) : 795, 1896. (Limestone quarries, 
 New England and New York.) 35. Ries and Eckel, Bull. N. Y. 
 State Museum, 44, 1901. (N. Y. lime and cement industry.) Ohio : 
 36. Lord, Ohio Geol. Surv., VI : 671, 1888. (Natural and artificial
 
 LIME AND CALCAREOUS CEMENTS 123 
 
 cements.) 37. Orton, Ohio Geol. Surv., VI : 703, 1888. (Lime.) 
 37 a. Eno, Ohio Geol. Surv., 4th Series, Bull. 2, 1904. (Uses of 
 cement.) 376. Bleininger, Ibid., Bull. 3. (Manufacture of cement.) 
 Pennsylvania : 38. Prime, Second Geol. Surv. of Pa., Rep. DD : 59, 
 1878. 39. Eckel, U. S. Geol. Surv., Bull. 225 : 448, 1904. (Lehigh 
 district.) 40. Clapp, U. S. Geol. Surv., Bull. 249, 1905. (Limestones, 
 S. W. Pa.) United States : 41. Eckel, U. S. Geol. Surv., Bull. 260 : 
 497, 1905. Also Bull. 243. (Cement resources and industry.) Vir- 
 ginia: 42. Catlett, U. S. Geol. Surv., Bull. 225 : 457, 1904. (Cement 
 resources, Valley of Va.) 43. Also Bassler, Ibid., Bull. 260: 531, 
 1905. Wisconsin: 44. Chamberlin, Geol. of Wis., II, Pt. 2: 395, 
 1873. (Natural rock cement.)
 
 CHAPTER VI 
 
 SALINES 
 
 Salt. Common salt, the chloride of sodium (NaCl), is 
 a widely distributed mineral, being found, (1) in solution 
 in sea water or salt lakes; (2) as solid masses termed rock 
 salt ; (3) as natural brine in cavities or pores of the rocks, 
 from which it may exude as salt springs or be tapped by 
 wells ; and (4) in marshes and soils. 
 
 Although all four of these methods of occurrence may 
 serve as commercial sources of salt, it is only the second 
 that is of great economic importance. 
 
 Occurrences of Salt in Sea and Lake Waters. Salt is 
 present in all ocean water, and also in that of most inland 
 lakes or seas having no outlet. As can be seen from the 
 following analyses, the percentage of salt is greater in some 
 salt lakes than in the ocean : 
 
 
 
 
 PEBCENTAGE OF SALTS IN SOLID MATTER 
 
 
 o 
 
 
 
 LOCALITY 
 
 S & 
 
 1 
 
 
 
 
 
 
 
 
 
 Jl 
 
 
 
 s 
 
 
 
 
 
 & M 
 
 a tt> 
 
 o 
 
 o 
 
 6 
 
 ft 
 
 
 
 
 f, 
 
 M 
 
 S 
 
 *% 
 
 5 
 
 M 
 
 a 
 
 Black Sea .... 
 
 1.77 
 
 98.23 
 
 79.39 
 
 1.07 
 
 7.38 
 
 .03 
 
 .60 
 
 8.32 
 
 3.21 
 
 Mediterranean Sea . 
 
 3.37 
 
 96.63 
 
 77.03 
 
 2.48 
 
 8.76 
 
 .49 
 
 2.76 
 
 8.34 
 
 .10 
 
 Atlantic Ocean . . 
 
 3.63 
 
 96.37 
 
 77.07 
 
 3.89 
 
 7.86 
 
 1.30 
 
 4.63 
 
 5.29 
 
 
 
 
 
 
 
 
 
 
 
 
 CaClj 
 
 Dead Sea .... 
 
 22.30 
 
 77.70 
 
 36.55 
 
 4.57 
 
 45.20 
 
 .85 
 
 .45 
 
 
 
 11.38 
 
 
 
 
 
 
 
 
 
 
 K 2 S0 4 
 
 Great Salt Lake . . 
 
 14.99 
 
 85.01 
 
 79.12 
 
 .57 
 
 9.93 
 
 
 
 .56 
 
 6.21 
 
 3.47 
 
 124
 
 SALINES 125 
 
 Salt is sometimes obtained by artificial evaporation from 
 both the ocean and salt lakes ; but in the United States this 
 plan is profitable only under exceptional conditions, as around 
 San Francisco Bay, California (6), or Great Salt Lake, Utah. 
 
 Rock Salt. Rock salt, which is the most important source 
 of commercial salt, is present in layers of variable thickness 
 and purity embedded with sedimentary rocks, such as shales 
 or sandstones. It is frequently associated with gypsum, and 
 less commonly with limestone, or easily soluble compounds 
 of magnesia, potash, and lime. The salt beds vary in thick- 
 ness from a few inches up to as much as 3600 feet (Speren- 
 berg, Germany), and while found in all geological formations 
 from the Cambrian to the Pleistocene, except the Creta- 
 ceous, the rock salt of the United States is not found in 
 formations older than the Upper Silurian. 
 
 Origin of Rock Salt (5). One of the interesting problems 
 of geology has been to find a correct theory to account for 
 salt deposits of enormous thickness and often high purity. 
 It is well known that salt is deposited in the course of 
 evaporation of inland seas, such as the Dead Sea, and this 
 is perhaps the origin of some of the salt beds found in the 
 strata. But in many cases the material was evidently de- 
 posited in close connection with the open ocean, being both 
 overlain and underlain by massive sediments with which 
 it is directly continuous. It is inconceivable that such 
 beds were precipitated in the open ocean, though they may 
 well have been formed in seas or bays more or less com- 
 pletely cut off from the ocean. 
 
 This explanation, elaborated by Ochseuius (4), assumes 
 a barrier partly shutting out the ocean water. Evaporation
 
 126 ECONOMIC GEOLOGY OF THE UNITED STATES ^ 
 
 on the inclosed area of the sea exceeds the supply of water 
 from inflowing rivers and from the open ocean. Therefore 
 the water on the surface of the sea becomes more dense and 
 settles to the bottom of the basin, being prevented from 
 escape into the open ocean by the barriers at the entrance. 
 As the surface of the bay is lowered by evaporation, ocean 
 water enters, furnishing a constant supply of salt. If the 
 barrier is complete, forming a bar, sea water may enter only 
 at times of high tide or storm. Eventually evaporation will 
 so concentrate the solution in the bay as to cause the pre- 
 cipitation of sodium chloride and other salts. So long as 
 these conditions lasted, salt would be precipitated, but beds 
 of clayey material would be deposited wherever fine-grained 
 sediment was supplied from the land. 
 
 As will be seen by reference to the sea-water analyses 
 given above, there are other salts present besides sodium 
 chloride, and these will separate out in order of their 
 solubilities, the least soluble ones being precipitated first. 
 The order of precipitation would therefore be : (1) small 
 amounts of lime carbonate and some hydrous iron oxide ; 
 (2) most of the sulphate of lime present ; (3) a mixture of 
 sodium chloride and lime sulphate ; (4) sodium chloride of 
 high purity ; (5) a mixture of sodium chloride and soluble 
 salts of magnesia, potash, bromine, and iodine. 
 
 This accounts for the frequent association of gypsum with 
 salt ; but the potash and magnesia salts, precipitated last, are 
 rare, because even after being precipitated they may, owing 
 to their easy solubility, be removed by an influx of fresh 
 water or by leaching of the deposit. The only locality 
 where the complete series is found is at Stassfurt, 
 Prussia.
 
 SALINES 127 
 
 This deposit, which is of Permian age, is one of the most interesting 
 in the world. It shows the following section : at the bottom is the 
 main bed of rock salt which is broken up into layers 2 to 5 inches thick 
 by layers of anhydrite. Above this comes 200 feet of rock salt, with 
 which are mixed layers of magnesium chloride and polyhalite (K 2 SO 4 , 
 MgSO 4 , 2 CaSO 4 , 2 H 2 O). Resting on this is 180 feet of rock salt, with 
 alternating layers of sulphates, chiefly kieserite, the sulphate of magnesia. 
 These layers are about 1 foot thick. Lastly, and uppermost, is a 135- 
 foot bed consisting of a series of reddish layers of rock salt and salts of 
 magnesia and potassium, kainite (K 2 SO 4 , MgSO 4 , MgCl 2 , 6 H 2 O), kieserite 
 (MgSO 4 ), carnallite (KC1, MgCl 2 , 6H 2 O), tachhydrite (CaCl 2 , 2MgCl 2 , 
 12H 2 O), as well as masses of snow-white boracite (Mg 7 Cl 2 B 16 O 30 ). 
 
 Natural Brines. These, sometimes found in porous layers 
 of the rocks, may result either from sea water imprisoned 
 in the layers of sediment or from the solution of rock salt 
 by percolating waters. 
 
 Salt Marshes and Soils. When away from the ocean, 
 these owe their salinity to the infiltration of brine from 
 neighboring saliferous formations. They sometimes repre- 
 sent the site of former salt lakes. 
 
 Distribution of Salt in the United States (Fig. 26). In 
 1903 most of the domestic production came from nine states, 
 either in the form of artificial brine obtained by forcing 
 water through wells to the salt, which is then brought up 
 in solution, or else as rock salt, raised through shafts from 
 underground workings. 
 
 New York (13). Salt was manufactured from brine springs 
 at Onondaga Lake as early as in 1788 ; but the presence of 
 rock-salt beds was not suspected until 1878, when a bed 
 seventy feet thick was struck in drilling for petroleum in
 
 128 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Wyoming County. Since then the development of the salt 
 industry has been so rapid that for some years New York 
 has been one of the two leading salt-producing states. 
 
 The salt occurs in lenticular masses interbedded with 
 soft shales of the Salina series, which also carry gypsum 
 deposits. The outcrop of the formation coincides approxi- 
 
 FIG. 26. Map showing known occurrences of salt in United States, compiled 
 from various geological survey reports. 
 
 mately with the line of the New York Central Railroad, 
 but owing to its soluble character, no salt is found along 
 the outcrops. The beds dip southward from 25 to 40 
 feet per mile, so that the depth of the salt beneath the 
 surface increases in this direction. 
 
 At Ithaca, salt is struck at 2244 feet, and there are seven beds. The 
 thickness of the individual beds varies, but the greatest known thickness 
 is in a well near Tully, where 325 feet of solid salt was bored through. 
 Though most of the New York product is obtained from artificial brines, 
 a small quantity is mined by shafts.
 
 PLATE XI 
 
 FIG. 1. Interior view of salt mine, Livonia, N.Y. Both roof and pillars are rock 
 
 salt. 
 
 FIG. 2. Borax mine near Daggett, Calif. Photo, loaned by G. P. Merrill.
 
 SALINES 129 
 
 Michigan (11). Salt in Michigan is obtained both from 
 natural brines and from brines obtained by dissolving rock 
 salt, as in New York. The natural brines occur in the 
 sandstones of the Subcarboniferous, the most important 
 locality being in the Saginaw Valley, where the brines are 
 found in the Napoleon or Upper Marshall sandstone. They 
 are remarkable for the large amount of bromine contained, 
 more than half the bromine produced in the United States 
 being obtained here. The vast beds of rock salt which 
 occur in the Salina (Monroe) are exploited along the Detroit 
 and St. Clair rivers and at Manistee and Ludington. The 
 salt is dissolved by lake water pumped down and then re- 
 evaporated, and soda ash (sodium carbonate) is made from 
 the salt to a very great extent, by forced reaction with 
 calcium carbonate. 1 
 
 Other Eastern States. In the Holston Valley of south- 
 western Virginia salt is obtained by wells from the Lower 
 Carboniferous shaly limestones. Part of the product is 
 marketed as salt, and the balance is used in the manufacture 
 of alkali (19). 
 
 Brine is obtained from the Salina and Salt sand of Ohio 
 (14), and from those portions of Pennsylvania and West 
 Virginia adjacent to the Ohio salt district. In the Kanawha 
 Valley of West Virginia a natural brine is obtained by wells 
 from the oil horizons. Brines are also present in the Car- 
 boniferous of Illinois. 
 
 Louisiana (8-10) . Brine occurs in springs and wells in 
 the Cretaceous area of northern Louisiana, but the most 
 important source of salt is in the extensive beds of rock salt 
 
 1 Private communications from Dr. A. C. Lane, State Geologist of 
 Michigan.
 
 130 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 found in the southern portion of the state. These occur in 
 a series of low knolls, called the Five Islands, beneath a 
 series of clay, sand, and gravel beds. Though structural 
 details are lacking, there seems in one case to be a dome 
 fold and in Petite Anse a block fault. The age of the salt 
 beds is Prepleistocene. Although the amount of rock salt 
 present is evidently great, borings in one case having re- 
 vealed a thickness of 1756 feet of solid salt, these deposits 
 yield but a small percentage of the country's output. 
 
 Kansas (7). Salt is found in this state under the follow- 
 ing conditions: (1) in the northern and central parts of Kansas 
 as brine in salt marshes derived by leaching from the salifer- 
 ous Dakota shales ; (2) a limited amount in eastern Kansas 
 from wells sunk in the Carboniferous ; (3) in the Permian 
 of south central Kansas as beds of rock salt. At the present 
 time the rock salt is the most important commercial source, 
 being obtained in part as artificial brines and in part as 
 rock salt. The thickness of the salt varies, the greatest 
 aggregate thickness recorded in any well being 324 feet. 
 The deposits thin out to the eastward, and the north and 
 south limits are fairly well known, but the western boundary 
 remains undefined. The absence of gypsum in close asso- 
 ciation with the salt is a significant fact, but farther south 
 it is found at a lower horizon, and the separation of the two 
 is explained by a shifting sea bottom during deposition. 
 
 Other Western States (16, 17). Rock salt has been found 
 at several localities in Texas, notably in Mitchell County 
 and under the oil beds at Beaumont ; but none is yet pro- 
 duced. In Utah, some salt is obtained by evaporating the 
 waters of Great Salt Lake (18). In California the main 
 supply of salt is obtained by evaporating sea water (6), an
 
 SALINES 
 
 131 
 
 elaborate system of ponds, covering thousands of acres, 
 having been built on San Francisco Bay. These are filled 
 at high tide, and the salt obtained by natural evaporation. 
 A remarkable deposit of salt is worked at Salton Lake. 
 This is a depression 27 miles long, 3^ to 9 miles wide, and 
 at its lowest point 280 feet below sea level. The deposit 
 is formed by evaporation of the lake waters, which are fed 
 by saline springs from the surrounding foothills. The salt, 
 which has accumulated to a depth of 6 inches, is gathered by 
 scrapers. Salt is also found in marshes, springs, or wells in 
 a number of other localities in California (6). 
 
 ANALYSES OF ROCK SALT FROM VARIOUS LOCALITIES 
 
 
 s 
 
 R 
 
 Ei 
 
 1$ 
 
 l! 
 
 <" 
 
 2 j 
 
 * 
 
 
 
 S3 
 
 a a 
 
 o * 
 
 3 3 
 
 9 \ * 
 
 3 3 * 
 
 \ 
 
 
 
 o 
 
 o o 
 
 So 
 
 O n 
 
 S 
 
 < 
 
 * 
 
 
 Retsof. N.Y. . . . 
 
 98.701 
 
 Tr. 
 
 _ 
 
 .446 
 
 
 
 .743 
 
 Tr 
 
 F. E. Englehardt 
 
 Pearl Creek, N.Y. 
 
 96.885 
 
 .157 
 
 .103 
 
 .437 
 
 
 
 1.21 
 
 1.21 
 
 F. E. Englehardt 
 
 Petite Anse, La. . 
 
 98.90 
 
 .146 
 
 .022 
 
 .838 
 
 
 
 .014 
 
 .08 
 
 P. Collier 
 
 Saltville, Va. . . 
 
 99.084 
 
 Tr. 
 
 
 
 .446 
 
 
 
 .47 
 
 
 
 C. B. Hayden 
 
 ANALYSES OF SOLID MATTER OF BRINES FROM VARIOUS LOCALITIES 
 
 
 
 
 * - 
 
 a 
 2 a 
 
 a 5 
 
 h 
 
 ^ 
 
 3 K 
 
 b 
 O 
 
 
 LOCALITY 
 
 y- 3 
 to 23 
 
 
 H S 
 
 S5 3 
 
 3 s 
 
 - ^ 
 
 "* -^ 
 
 Sic 
 
 ** E 
 
 ATTTHOBITY 
 
 
 z s 
 
 3 3 
 
 3 
 
 s a 
 
 9 j 
 
 ui 5 
 
 | n 
 
 -^ 
 
 
 
 
 00 
 
 ii 
 
 
 a* 
 
 4li 
 
 
 B O ffi 
 
 
 Warsaw, N.Y. 
 
 97.60 
 
 .51 
 
 .20 
 
 1.68 
 
 _ 
 
 _ 
 
 26.34 
 
 1.204 
 
 Englehardt 
 
 Syracuse, N.Y. 
 
 95.966 
 
 .90 
 
 .69 
 
 2.54 
 
 
 
 .004 
 
 18.50 
 
 1.142 IG. H. Cook 
 
 Saginaw, Mich. 
 
 82.14 
 
 12.39 
 
 5.01 
 
 .46 
 
 
 
 
 
 21.32 
 
 Ic.A.Goessman 
 
 Bay City, Mich. 
 
 91.95 
 
 3.19 
 
 2.48 
 
 2.39 
 
 
 
 
 
 16.61 
 
 
 
 C. A. Goessman 
 
 Kanawha.W.Va. 
 
 79.45 
 
 16.48 
 
 4.07 
 
 
 
 
 
 
 
 9.20 
 
 1.07H 
 
 G. H. Cook 
 
 Pittsburg, Pa. 
 
 81.27 
 
 13.93 
 
 4.80 
 
 
 
 . - 
 
 
 
 2.80 
 
 1.019 
 
 G.H. Cook 
 
 Saltville, Va. 
 
 97.792 
 
 .033 
 
 
 
 2.17 
 
 '"* 
 
 Tr. 
 
 24.60 
 
 
 
 C. B. Hayden 
 
 Extraction. When salt forms underground deposits, it 
 has to be extracted either by a process of solution or
 
 132 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 mining. In the former case water is forced down to the 
 salt bed through a well, for the purpose of dissolving the 
 salt, the brine being brought to the surface and evaporated, 
 sometimes by solar heat, but more commonly by artificial 
 means. In the latter case a shaft is sunk to the salt bed, 
 and the material mined like coal and brought to the sur- 
 face in lumps, known as rock salt. Natural brines are 
 pumped to the surface for evaporation. In the evapora- 
 tion of brine care has to be taken to separate the gypsum 
 and other soluble impurities present, which precipitate be- 
 fore the salt does. 
 
 Uses. Salt is largely used in the meat-packing business 
 and the manufacture of dairy products, as well as for 
 domestic purposes. Therefore a number of different grades 
 are called for, known under various names, such as table, 
 dairy, common, fine, packers, solar, rock, milling, etc. Large 
 quantities of salt are also consumed in the manufacture of 
 soda ash, sodium carbonate, caustic soda, and other sodium 
 salts. The chlorination of gold ores calls for an additional 
 large amount. 
 
 Production of Salt. The increase in the amount of salt 
 produced has been very marked, but it has been accom- 
 panied by a decrease in price, as shown in the statistics 
 given below : 
 
 PRODUCTION OF SALT IN UNITED STATES FROM 1880 TO 1900 
 
 YEAR 
 
 BARBELS 
 
 VALUE 
 
 YEAR 
 
 BARRELS 
 
 VALUE 
 
 1880 . . . 
 1885 . . . 
 1890 . . . 
 
 5,961,060 
 7,038,653 
 8,876,991 
 
 $4,828,566 
 4,825,345 
 4,752,286 
 
 1895 . . 
 1900 . . 
 
 13,699,649 
 20,869,342 
 
 $4,423,084 
 6,944,603
 
 SALINES 183 
 
 PRODUCTION OF SALT BY STATES FROM 1901 TO 1903 
 
 
 19 
 
 01 
 
 19 
 
 02 
 
 19 
 
 03 
 
 
 BARRELS 
 
 TALUK 
 
 BABBELS 
 
 VALUE 
 
 BABBELS 
 
 VALUE 
 
 New York 
 
 7,286,320 
 
 $2,089,834 
 
 8,523,389 
 
 $1,938,539 
 
 8,170,648 
 
 $2,007,807 
 
 Michigan 
 
 7,729,641 
 
 2,437,677 
 
 8,131,781 
 
 1,535,823 
 
 4,2! (7,542 
 
 1,119,984 
 
 Kansas . 
 
 2,087,791 
 
 614,365 
 
 2,158,486 
 
 514,401 
 
 1,555,934 
 
 564,232 
 
 Ohio . . 
 
 1,153,535 
 
 455,924 
 
 2,109,987 
 
 593,504 
 
 2,798,888 
 
 795,897 
 
 California . 
 
 601,659 
 
 133,656 
 
 682,660 
 
 253,085 
 
 629,701 
 
 198,630 
 
 Texas . 
 
 (a) 
 
 (a) 
 
 347,906 
 
 143,683 
 
 314,000 
 
 117,647 
 
 West Virginia 
 
 231,722 
 
 94,732 
 
 208,592 
 
 97,721 
 
 244,236 
 
 35,797 
 
 Utah . 
 
 324,484 
 
 326,016 
 
 417,501 
 
 270,626 
 
 212,955 
 
 181,710 
 
 Louisiana 
 
 (a) 
 
 (a) 
 
 (a) 
 
 (a) 
 
 568,93(5 
 
 178,342 
 
 Other States . 
 
 1,141,509 
 
 465,245 
 
 1,268,929 
 
 321,254 
 
 175,238 
 
 86,942 
 
 Total . . 
 
 20,566,661 
 
 $6,617,449 
 
 23,849,231 
 
 $5,668,636 
 
 18,968,089 
 
 $5,286,988 
 
 (a) Included in " Other States." 
 
 The exports in 1903 were 25,449,630 Ibs., valued at 
 95,570 ; while the imports for the same year amounted to 
 331,961,807 Ibs., valued at $495,948. 
 
 WORLD'S PRODUCTION OF SALT IN 1902 
 
 COUNTRY 
 
 SHORT TONS 
 
 VALUE 
 
 United States 
 United Kingdom 
 
 3,339,891 
 2,121,126 
 982,479 (a) 
 1,745,226 
 761,575 (rf) 
 505,401 
 575,936 
 1,913,696 (e) 
 470,057 
 1,165,291 
 63,056 
 125,467 
 
 $5,668,636 
 2,886,665 
 2,605,800 (a) 
 4,992,600 
 4,459,245 (rf) 
 711,400 
 16,071,930 
 2,767,168 (e) 
 707,424 
 1,554,914 
 288,581 
 970,522 
 
 
 
 Japan 
 
 Italy 
 
 
 Russia 
 
 
 
 Canada 
 
 Others 
 
 Total 
 
 13,769,201 
 
 $43,684,935 
 
 
 (a) Includes Algeria. 
 
 (d) Production and value, 1901. 
 
 (e) Production and value, 1901.
 
 131 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 REFERENCES OW SALT 
 
 TECHNOLOGY AND ORIGIN. 1. Chatard, U. S. Geol. Surv., 7th Ann. 
 Kept. : 491, 1888. 2. Englehardt, N. Y. State Museum, Bull. No. 
 XI : 38, 1893. 3. Hubbard, Mich. Geol. Surv., V, Pt. II : 1, 1895. 
 4. Ochsenius, Chem. Zeit., XI: 1887. (Bar theory.) 5. Wilder, 
 Jour. Geol., XI : 725, 1903. 
 
 AREAL. California: 6. Bailey, Calif. State Min. Bureau, Bull. XXIV: 
 105, 1902. Kansas: 7. Kirk and Haworth, Min. Resources of Kas., 
 1898: 67. Louisiana: 8. Lucas, Amer. Inst. Min. Engrs., Trans. 
 XXIX : 462, 1900. (Rock salt.) 9. Veatch, La. Exp. Sta., Pt. V : 
 209, 1899. (Rock salt.) 10. Veatch, ibid., Pt. VI : 47, 1902. (N. 
 La. salines.) Michigan: 11. Lane, Mich. Geol. Surv., Ann. Rept., 
 1901 : 241, 1902. New Mexico: 12. Darton, U.S. Geol. Surv., Bull. 
 260: 565, 1905. (Zuni.) New York: 13. Merrill, N. Y. State 
 Museum, Bull. XI, 1893. Ohio: 14. Root, Ohio Geol., VI: 653, 
 1888. Oklahoma : 15. Gould, Kas. Acad. Soc., Trans. XVII : 181, 
 1901. (Salt plains.) Texas : 16. Cummins, Tex. Geol. Surv., 2d 
 Ann. Rept.: 444, 1890. (Northwestern Texas.) 17. Richardson, 
 U. S. Geol. Surv., Bull. 260 : 572, 1905. (Trans-Pecos regions.) 
 Utah : 18. U. S. Geol. Surv., Min. Res., 1888: 605, 1890. Virginia: 
 19. Eckel, U. S. Geol. Surv., Bull. 213 : 407, 1903. (S. W. Va.) 
 
 BORAX 
 
 Borax Minerals (3,4). The chief minerals containing 
 boron are borax, tincal, or sodium biborate, Na 2 B 4 O 7 , 
 10 H 2 O ; colemanite, Ca 2 B 6 O n , 5 H 2 O ; ulexite, CaNaB 5 O 9 , 
 8 H 2 O ; boracite, 2 Mg 3 B 8 O 15 , MgCl 2 . These minerals are 
 found usually as incrustations in alkaline marshes, or in 
 lake waters of arid regions, or as bedded deposits. In 
 some localities boric acid is found in fumarolic vapors. 
 
 Distribution in United States (5). Deposits of borax 
 have up to the present time been discovered only in Cali- 
 fornia (1, 2), Nevada, and Oregon. Borax was originally 
 obtained by evaporation from the waters of Clear Lake, 
 north of San Francisco, being produced in commercial 
 quantities in 1864, and the solution was enriched by crys-
 
 SALINES 135 
 
 talline borax obtained from the marshes surrounding the 
 lake. This and other lakes of California were worked 
 until the discovery of large deposits of nearly pure borax 
 in alkaline marshes of eastern California and western Nevada 
 in the early seventies. Several refining plants were located 
 at these marshes, and the product was sometimes hauled a 
 hundred miles to the railroad. Increased production and 
 importation from Italy, however, reduced the price and 
 caused these plants to be abandoned. 
 
 The discovery, in 1890, that the marsh borax was a 
 secondary deposit, derived from easily accessible and ex- 
 tensive bedded deposits in the Tertiary lake beds of that 
 region, revolutionized the industry. 
 
 The most important of these beds is located near Daggett 
 (PL XI, Fig. 2), San Bernadino County, California, but 
 much larger deposits are known in Death Valley. The 
 borax, which forms a regular stratum, interbedded with 
 sands and clays, is supposed by Campbell (2) to have been 
 deposited in a series of Tertiary lakes, but the beds are 
 in many instances tilted, due to violent crustal movements, 
 which interrupted sedimentation at intervals. 
 
 Uses. The borax-bearing minerals are utilized chiefly 
 for the manufacture of borax and boracic acid. Borax is 
 used in industrial chemistry, in medicine, and as a labora- 
 tory reagent. It is also employed in the assaying of gold 
 and silver ores. 
 
 Boric acid is used in the manufacture of borax, in colored 
 glazes for decorating iron, steel, and metallic objects, in 
 enamels and glazes for pottery, in making flint glass, as 
 an antiseptic, and as a preservative for food.
 
 136 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 While several borax refineries are located on the Pacific 
 coast, the main one is at Bayonne, New Jersey. 
 
 Production of Borax. The California colemanite de- 
 posits form the main source of domestic supply, while small 
 amounts are obtained from Nevada and Oregon. 
 
 The United States production in 1903 was 34,430 short 
 tons of crude borax, valued at $661,400. The value of 
 the refined product is naturally much higher, and its total 
 value for 1903 would be 12,735,000. 
 
 WORLD'S PRODUCTION OF BORAX IN 1902 
 
 COUNTRY 
 
 QUANTITY 
 METRIC TONS 
 
 MINERAL 
 
 United States 
 
 18,148 
 
 Calcium borate 
 
 Bolivia 
 
 593 
 
 
 Chile 
 
 14,437 
 
 Calcium borate 
 
 India (1901) 
 
 162 
 
 Borax 
 
 Germany 
 
 196 
 
 Boracite 
 
 Italv 
 
 2,763 
 
 
 Peru (1901) 
 
 4,156 
 
 Calcium borate 
 
 Turkey 
 
 9000 
 
 Pander mite 
 
 
 
 
 REFERENCES ON BORAX 
 
 (T) Bailey, Calif. State Mining Bureau, Bull. 24 : 33, 1902. (Calif, and 
 general.) @ Campbell, U. S. Geol. Surv., Bull. 200, 1902. (Calif.) 
 3. Kemp, Min. Indus. I: 43, 1893. (General.) (t) Merrill, Non- 
 Metallic Minerals : 313, N. Y., 1904. 5. Struthers, Mineral Census 
 of 1902, Mines and Quarries : 885, 1905. (General.) 
 
 SODIUM SULPHATE 
 
 The hydrous sulphate, mirabilite or glaubersalt (Na 2 SO 4 
 + 10 H 2 O), is a white saline material, which is collected on or 
 near the surface of some alkaline marshes in desert regions. 
 It is known to occur at several localities in Wyoming.
 
 SALINES 137 
 
 REFERENCES ON SODIUM SULPHATE 
 
 1. Attfield, Jour. Soc. Chem. Ind., Jan. 31, 1895. 2. Knight, Min. 
 Indus., Ill : 651, 1895. 3. Knight, Wyo. Agric. Exper. Sta., Bull. 
 14, 1893. 
 
 SODIUM CARBONATE 
 
 Sodium carbonate, or natural soda, is obtained by the 
 evaporation of the waters of alkali lakes, or is found as a 
 deposit on or near the surface of alkaline marshes in arid re- 
 gions. It is usually a mixture of sodium carbonate and 
 bicarbonate in varying proportions, as well as impurities 
 such as sodium chloride, sodium sulphate, borax, and sodium 
 nitrate. 
 
 Sodium carbonate is obtained from Owens Lake in Cali- 
 fornia. An analysis of the waters by Chatard yielded : 
 SiO 2 , .220; Fe 2 O 3 , A1 2 O 3 , .038; CaCO 3 , .055; MgCO 8 , .479; 
 KC1, 3.137 ; NaCl, 29.415 ; Na 2 SO 4 , 11.080 ; Na 2 CO 3 , 26.963 ; 
 NaHCO 3 , 5.725. The soda is purified by fractional dis- 
 tillation. Soda is also known to occur in Oregon and 
 Nevada. 
 
 REFERENCES ON SODIUM CARBONATE 
 
 1. Bailey, Calif. State Min. Bur., Bull. 24 : 95, 1902. 2. Chatard, U. S. 
 Geol. Surv., Bull. 60 : 27, 1888. (Analyses.) 3. Russell, U. S. Geol. 
 Surv., Mon. XI : 73. 
 
 SODA NITER. 1 
 
 Soda niter, or Chile saltpeter (NaNO 3 , with 63.5 per cent 
 Na 2 O 5 when pure), is found in San Bernadino and Inyo 
 counties, California, along the shore lines marking the 
 boundary of Death Valley in Eocene times (1). It occurs 
 in peculiar rounded hills of Eocene clay, the niter being 
 found as a layer near the surface or distributed through the 
 1 The term niter, when used alone, refers to potash niter.
 
 138 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 clay. Very little soda niter is obtained from this source, 
 and the main supply of this country continues to come 
 from Chile, where extensive deposits are found in the 
 desert region west of Iquique. There the niter (caliche) 
 forms a bed 6 to 12 feet thick, under a cap of conglom- 
 erate (costra) 1 to 18 feet thick. The origin of this deposit 
 is interesting, and has caused considerable discussion. One 
 theory quite generally accepted is that the niter was formed 
 primarily by the slow oxidation in air of guano or other 
 nitrogenous organic matter in contact with alkali ; a second 
 theory refers its origin to the oxidation of organic mate- 
 rials and ammonia, by microscopic organisms known as 
 nitrifying germs. 
 
 REFERENCES ON SODA NITER 
 
 1. Bailey, Calif. State Min. Bur., Bull. 24 : 139, 1902.
 
 PLATE XII 
 
 FIG. 1. Gypsum quarry, Alabaster, Mich. Shows gypsum overlain by glacial 
 drift. The dump in foreground is overburden removed from gypsum. Photo., 
 A. C. Lane. 
 
 FIG. 2. Rock phosphate mine near Ocala, Fla. Photo., A. W. Sheaf er.
 
 CHAPTER VII 
 GYPSUM 
 
 G-ypsum (1), the hydrous sulphate of lime (CaSO 4 , 2 H 2 O), 
 occurs most frequently in sedimentary rocks, interbedded 
 with shales, sandstones, and limestones, and often more or 
 less closely associated with rock salt. It is also found as 
 surface deposits of sand or mixed with clay (gyp&ite), as well 
 as in limited quantities in volcanic regions, especially in lavas. 
 When occurring in bedded deposits (PL XII, Fig. 1) it is 
 massive, of finely crystalline or earthy appearance, and of 
 variable color, although most commonly white and gray. 
 Transparent, colorless forms, known as selenite, are found as 
 veins or crystals in the massive gypsum, or as plates and 
 crystals in many clays, shales, and limestones. This variety 
 by itself never forms deposits of commercial importance. 
 
 Anhydrite differs from gypsum chemically in the absence 
 of water, but changes to it on exposure to the air. 
 
 Origin of G-ypsum (3). Gypsum is widely distributed 
 both geographically and geologically, being found in vari- 
 ous horizons from the Silurian to the Recent. Most beds 
 of this substance have no doubt been formed by the evapo- 
 ration of salt water either in inland seas or else in arms 
 of the ocean, the process of precipitation having been dis- 
 cussed in the chapter on Salt. As gypsum separates from 
 sea water after 37 per cent of the water has evaporated, 
 139
 
 140 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 while salt precipitates only after 93 per cent has been 
 removed, it is evident that gypsum beds may be deposited 
 without salt. This also explains why gypsum is more 
 widely distributed than salt ; and the fact that the per- 
 centage of gypsum in salt water is much less than that 
 of salt probably accounts for its usual occurrence in the 
 thinner deposits. 
 
 Gypsum may also be formed by the decomposition of sulphides, 
 such as pyrite, and the action of the sulphuric acid thus liberated on 
 lime carbonate. Small quantities are formed in volcanic regions 
 through the action of sulphuric vapors on the lime of volcanic tuffs 
 or other rocks. 
 
 G-ypsite, or gypsum dirt, is an earthy or sandy variety 
 of gypsum forming a surface deposit in Kansas (9) and 
 other western states (16, 19), which, in spite of its impure 
 appearance, may run high in calcium sulphate. It is 
 believed to be a deposit either in the soil or in shallow 
 lakes supplied by springs whose water has dissolved the 
 calcium sulphate from gypsum beds or other rocks. 
 During its precipitation by the second method, its impure 
 character is caused by its becoming mixed with clay or 
 sand washed in from the land. 
 
 Distribution in the United States (Fig. 27). Eighteen 
 states are producers of gypsum, although four of these 
 Iowa, Kansas, Michigan, and New York supply most of 
 the output of the country. 
 
 Iowa (8). Important deposits are found in this state 
 in an area of about 25 square miles in Webster County, 
 especially near Fort Dodge. The gypsum, which is pre- 
 sumably of Permian age, rests on the Coal Measures and
 
 GYPSUM 141 
 
 is covered by glacial drift. It varies from 3 to 30 feet in 
 thickness, with an average of 16 feet, and much of it is 
 sufficiently white for stucco. 
 
 Kansas. Gypsum (9) is found occurring either as rock 
 gypsum, or as gypsite, the deposits forming a belt extend- 
 ing across the central part of the state in a northeast- 
 southwest direction, and includes three important areas. 
 
 FIG. 27. Map showing gypsum-producing localities of United States. After 
 Adams, U. S. Geol. Surv., Bull. 223. 
 
 The beds of rock gypsum are of Permian age, interbedded 
 with red shales, those at the southern end of the belt being 
 stratigraphically 1000 feet higher than those at the northern 
 end. 
 
 The gypsite or gypsum dirt, which is of more recent age, 
 is found in the central area, as well as at a number of 
 other localities. The spring waters which have supplied it 
 have leached the calcium sulphate either from the gypsum
 
 142 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 beds or the red shales. The product is used for fertilizer 
 and cement plaster. 
 
 Deposits of gypsum earth are found to the south of 
 Kansas in Oklahoma (16) and northern Texas (16), as well 
 as to the northwest in Wyoming 1 (19, 20). 
 
 Michigan (10) contains two important occurrences of gyp- 
 sum, one in the vicinity of Grand Rapids, and the other at 
 Alabaster on Saginaw Bay (PI. XII, Fig. 1), both in beds 
 of Lower Carboniferous age. That at Grand Rapids runs 
 from 6 to 12 feet in thickness, forming several beds inter- 
 stratified with shale and limestone. A third possibly pro- 
 ductive area is near St. Ignace on the upper peninsula, where 
 it occurs in the Salina. 
 
 New York (11, 12). Gypsum occurs in the Salina shales 
 of central and west central New York. Most of the product 
 is gray and used for land plaster ; but in recent years some 
 whiter deposits, suitable for stucco, have been worked near 
 Batavia. 
 
 Other Occurrences. Gypsum is also found in beds of 
 Lower Carboniferous age in the Holston Valley of south- 
 western Virginia (18). The rock is mined partly by under- 
 ground workings, and some of the beds are fully 30 feet 
 thick. The product is used for land and wall plaster. In 
 Ohio gypsum has been obtained from the lower Helderberg 
 beds of Ottawa County, 10 miles west of Sandusky. The 
 material occurs at different horizons, the beds being bent 
 into rolls, the main ones having a thickness of about 12 feet 
 (13, 16). Additional occurrences are known in Wyoming 
 ( 19, 20), Utah (17), Arizona (5), Nevada (16), California (6), 
 lontana (16), Idaho (16), Colorado (7, 16), and South Da- 
 , >ta (H-16).
 
 GYPSUM 
 
 143 
 
 Analyses. The following analyses indicate the com- 
 position of gypsum from different localities in the United 
 
 States : 
 
 ANALYSES OF GYPSUM FROM UNITED STATES 
 
 
 CaO 
 
 80s 
 
 H,0 
 
 Insolu- 
 ble 
 
 CaCOa 
 
 Al,0 3 
 
 Fe,0. 
 
 MgO 
 .54 
 
 .16 
 .42 
 
 CO, 
 2.03 
 
 Pure Gypsum . 
 
 Onondaga, N.Y. 
 Sandusky, O. . 
 Upper layer, 
 Fort Dodge, la. 
 Michigan . . . 
 Medicine Lodge, 
 Kas. ... 
 Gypsite, Salina, 
 Kas. . . . 
 Gypsite, Quanah, 
 Tex. . . . 
 Plastercoj Va. . 
 
 32.60 
 
 46.50 
 
 20.90 
 
 4.64 
 .91 
 
 .65 
 
 .19 
 12.13 
 
 7.43 
 .10 
 
 21.44 
 5.07 
 
 .60 
 
 .1 
 . 
 
 .] 
 
 .7 
 
 , ' 
 
 
 9 
 
 2 
 
 
 32.35 
 
 73.92 
 46.38 
 
 19.70 
 
 20.76 
 20.98 
 
 20.46 
 16.75 
 
 8.49 
 19.40 
 
 78 
 32.88 
 
 32.53 
 29.14 
 
 44 
 
 45.79 
 
 45.73 
 37.49 
 
 78 
 33.20 
 
 66 
 46.04 
 
 Uses (1). Gypsum is sold either in the ground, uncal- 
 cined condition, or after calcining and screening. In the 
 former state its chief value is as a fertilizer, it being marketed 
 under the name of land plaster, which is also used as a dis- 
 infectant. Though the softness of gypsum prevents its 
 general employment as a building material, the pure white, 
 massive varieties, known as alabaster, have been used for 
 statuary, basins, vases, and other objects for interior decora- 
 tion. Gypsum is also used to weight fertilizers, and as an 
 absorbent of organic materials in them; as a flux in the 
 manufacture of glass and porcelain; and, under the name 
 of ''terra alba" as an adulterant of foods and medicinal 
 preparations.
 
 144 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 In its calcined form, gypsum is known as plaster of 
 paris and has the following uses, dependent on its prop- 
 erty of hardening or setting when mixed with water : 
 stucco, plastering for walls, whitewash, pottery molds, 
 statuary, and dental purposes, as a deodorizer, for crayons, 
 and as a retarder of fermentation and absorbent of water 
 in wines. 
 
 Calcining Gypsum. When heated to 250 F., gypsum loses a portion 
 of its water of hydration, but if finely ground has the property of 
 recombining with it. If heated to 300 F. to 400 F., it loses this power 
 and is said to be dead-burned. In addition to dehydration, burning also 
 breaks up the crystals into minute particles. The set is due to the for- 
 mation of a crystalline network of the rehydrated grains. 
 
 Since calcined gypsum sets in from 6 to 10 minutes, some retarding 
 material, such as organic matter from slaughter-house refuse, is often 
 added to it, and thus the setting process may be delayed from 2 to 6 
 hours. Those plasters which set slowly are termed cement plasters. 
 
 The following analyses show the composition of (1) uncalcined gyp- 
 sum ; (2) the calcined rock ; and (3) the plaster after it has taken up 
 water and set. From these it will be seen that the plaster takes up the 
 amount of water lost in calcination. 
 
 SERIES OF ANALYSES SHOWING CHANGES IN GYPSUM DURING 
 BURNING AND AFTER SETTING 
 
 
 CRUDE 
 
 FINISHED 
 
 SET 
 
 SiO 2 and Insol. res 
 Fe 2 O 3 and A1 2 O 3 
 CaO 
 
 12.29 
 2.27 
 2967 
 
 14.31 
 2.16 
 3353 
 
 12.03 
 1.62 
 3005 
 
 MeO 
 
 78 
 
 91 
 
 61 
 
 SO 3 
 
 3487 
 
 3985 
 
 35.73 
 
 CO 
 
 3 52 
 
 4 11 
 
 355 
 
 ^^2 
 H 9 O 
 
 1607 
 
 481 
 
 16.38 
 
 
 

 
 GYPSUM 
 
 145 
 
 Production of Gypsum. Michigan, New York, Iowa, and 
 Kansas are the four leading producers, but many other states 
 contribute small amounts as seen below. 
 
 PRODUCTION OF GYPSUM IN UNITED STATES FROM 1901-1903 
 
 
 1901 
 
 1902 
 
 1903 
 
 
 SHORT 
 TONS 
 
 VALUE 
 
 SHORT 
 TONS 
 
 VALUE 
 
 SHORT 
 TONS 
 
 VALUE 
 
 California, Ohio, 
 
 
 
 
 
 
 
 and Virginia 
 
 18,7861 
 
 $49,3441 
 
 101,545 
 
 $290,393 
 
 103,392 
 
 $467,113 
 
 Colorado and 
 
 
 
 
 
 
 
 Wyoming . 
 
 17,394 
 
 76,435 
 
 16,051 
 
 73,372 
 
 33,549 
 
 133,347 
 
 Iowa, Kansas, 
 
 
 
 
 
 
 
 and Texas . 
 
 213,419 
 
 629,336 
 
 295,769 
 
 807,355 
 
 307,102 
 
 1,087,045 
 
 Michigan . . 
 
 185,150 
 
 267,243 
 
 240,227 
 
 459,621 
 
 269,093 
 
 700,912 
 
 New York . . 
 
 119,565 
 
 241,669 
 
 110,364 
 
 259,170 
 
 137,886 
 
 462,383 
 
 Oklahoma . . 
 
 15,930 
 
 66,031 
 
 34,156 
 
 111,215 
 
 69,158 
 
 234,621 
 
 Other states . 
 
 63,547 
 
 176,583 
 
 18,366 
 
 88,215 
 
 121,524 
 
 707,522 
 
 Total . . . 
 
 633,791 
 
 $1,506,641 
 
 816,478 
 
 $2,089,341 
 
 1,041,"04 
 
 $3,792,943 
 
 The imports for 1903 amounted to 269,484 short tons, 
 valued at 1378,597. 
 
 WORLD'S PRODUCTION OF GYPSUM, 1902 
 
 
 SHORT TONS 
 
 VALUE 
 
 France 
 
 1,975,513 
 
 83,318,070 
 
 United States 
 
 816 478 
 
 2 089 341 
 
 
 332 045 
 
 356 317 
 
 Great Britain 
 
 251 6 9 9 
 
 384263 
 
 
 34 944 
 
 12732 
 
 Algeria 
 
 6889 
 
 59953 
 
 
 7 874 
 
 17 443 
 
 
 
 
 Total 2 
 
 3 425 372 
 
 ^6 230 419 
 
 
 
 
 1 Ohio, none reported. 
 
 L 
 
 2 India not available.
 
 146 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 REFERENCES ON GYPSUM 
 
 PROPERTIES AND TECHNOLOGY. 1. Grimsley, Mich. Geol. Surv., IX, 
 Ft. 2, 1904. 2. Grimsley and Bailey, Kas. Geol. Surv., V, 1899. 
 3. Wilder, Eng. and Min. Jour., LXXIV: 276, 1902. 
 
 AREAL. 4. Adams and others, U. S. Geol. Surv., Bull. 223, 1904. 
 (United States.) Arizona : 5. Blake, Amer. Geol., XVIII: 394, 
 1896. California: 6. Crawford, Calif. State Mining Bureau, XII : 
 323, 1894. Colorado : 7. Lee, Stone, XXI : 35, 1900. (Larimer Co.) 
 Iowa : 8. Wilder, la. Geol. Surv., XII : 99, 1902, and Jour. Geol., 
 XI : 723, 1903. Kansas : 9. Grimsley and Bailey, Kas. Univ. Geol. 
 Surv., V, 1899. Michigan : 10. Grimsley, Mich. Geol. Surv., IX, 
 Pt. 2, 1904. New York : 11. Merrill, N. Y. State Museum, Bull. 
 11 : 70, 1893. 12. Parsons, N. Y. State Geologist, 20th Ann. Kept. : 
 r 177, 1902. Ohio: 13. Orton, Ohio Geol. Surv., VI: 696, 1888. 
 South Dakota: 14, U. S. Geol. Surv., Geol. Atlas Folios 85: 6. 
 15. Todd, S. D. Geol. Surv., Bull. 3: 99, 1902. United States: 16. 
 Adams and others, U. S. Geol. Surv., Bull. 223, 1904. Utah: 17. 
 Boutwell, U. S. Geol. Surv., Bull. 225: 483, 1904. Virginia: 
 
 18. Eckel, U. S. Geol. Surv., Bull. 213: 406, 1903. Wyoming : 
 
 19. Knight, Wyo. Exper. Station, Bull. 14 : 189, 1893. 20. Slosson 
 and Moody, Wyo. Coll. Agric. and Mech., 10th Ann. Kept., 1902.
 
 CHAPTER VIII 
 FERTILIZERS 
 
 UNDER this term are included a number of mineral sub- 
 stances, limestone, marl, gypsum, phosphate of lime, green- 
 sand, and guano, which are of value for adding to the soil to 
 increase its supply of plant food. Since the first three of 
 these have other uses as well, they have already been dis- 
 cussed in Chapters III, V, and VII. 
 
 Phosphate of Lime. This occurs both as crystalline phos- 
 phate of lime, or apatite, and amorphous phosphate of lime, 
 or rock phosphate. 
 
 Apatite (5, 6). This mineral, which theoretically contains 
 42.3 per cent P 2 O 6 , is widely distributed in some igneous 
 and metamorphic rocks, but rarely occurs in sufficient quan- 
 tity, or in sufficiently concentrated masses, to render its 
 extraction profitable, at least while the supply of amorphous 
 phosphate lasts. No commercial^ valuable deposits have 
 thus far been discovered in the United States; but in the 
 provinces of Quebec and Ontario, Canada, apatite occurs in 
 veins or pockets in metamorphic rocks, though little is now 
 mined. 
 
 Amorphous Phosphates. These, though composed chiefly 
 of phosphate of lime, also carry variable quantities of other 
 substances. (See table, p. 154.) They occur (1) as con- 
 cretionary bodies in consolidated rocks ; (2) as beds ; (3) as 
 147
 
 148 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 irregular rocklike masses ; and (4) as nodular masses of 
 varying size, often scattered through unconsolidated beds. 
 As is shown in the following descriptions, amorphous phos- 
 phates occur in various geological horizons, from the Silurian 
 to Tertiary, and in several states in the Union, though 
 most of the domestic supply comes from Florida, Tennessee, 
 and South Carolina. 
 
 Florida Phosphates (10). This state is at present the 
 most important phosphate producer, although the full extent 
 and value of the deposits were unsuspected until the dis- 
 covery of large beds along 
 the Peace River in 1887. 
 The phosphate deposits 
 which are associated with 
 Tertiary limestones of vari- 
 ous horizons from the Eocene 
 to the Pliocene form a curved 
 belt, beginning west of the 
 
 Appalachicola River and ex- 
 tending east and then south 
 through Dunnellon, and ap- 
 proximately as far as Punta 
 Gorda (Fig. 28). The to- 
 pography varies from gently 
 FIG. 28. Map of Florida phosphate rolling to flat pine lands and 
 
 "eas, the general 
 elevation being under 75 feet. 
 
 Eldridge recognizes four types of phosphates in this area, 
 viz. hard rock, soft rock, land pebble, and river pebble. Of 
 these the hard rock phosphate (PL XII, Fig. 2) is the richest, 
 and has had most influence in the rapid development of the
 
 FERTILIZERS 149 
 
 district. It is a hard, massive, close-textured rock, of vari- 
 able color, and often containing irregular cavities which 
 show a secondary deposition of phosphate. Accompanying 
 this in some places is a second type, the soft phosphate, 
 which is evidently a disintegration product. Bowlders of 
 hard phosphate are frequently embedded in a matrix of soft 
 phosphate, and also in sands and clays overlying the Eocene 
 limestone. While the hard rock has an average of a little 
 over 36.65 per cent of phosphoric acid, the soft phosphate 
 rarely averages over 22.90. 
 
 The land pebble or matrix rock is made up of pebbles of 
 varying size, shape, and color, and composed either (1) of 
 earthy material with fossils, quartz grains, and pisolitic 
 grains of phosphate, or (2) of pebbles closely resembling 
 the hard-rock phosphate. To render it marketable, the 
 pebbles, which average 32.06 per cent phosphoric acid, have 
 to be freed from the matrix by washing and screening. The 
 unit composition of sale for land pebble is 68 per cent of the 
 bone phosphate and 3 per cent of the combined oxides of 
 iron and alumina, with moisture at 2 per cent. 
 
 The river pebble consists of phosphate pebbles, having a 
 blue, black, or dark gray surface, and mixed with sand, 
 bones, and teeth. It is found in the present as well as in 
 ancient river channels, in the latter case being covered by 
 coastal sands. That found in the Peace River district 
 averages 28.40 per cent phosphoric acid. 
 
 All of the above-mentioned types, with the exception 
 of the soft phosphates, are found underlying more or less 
 separate regions (Fig. 28). 
 
 The origin of the Florida phosphates has been a puzzling 
 problem to geologists. Eldridge (10) has proposed two
 
 150 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 theories : (1) that they have been derived by the leaching 
 of guano and bone beds, and the deposition of the phosphate 
 in the underlying limestone, either by precipitation in its 
 pores or replacement of the lime carbonate ; (2) that they 
 are due to the solution of the limestone and consequent 
 concentrations of the less soluble phosphate of lime which 
 was originally disseminated through the rock. Later solu- 
 tions removed the limestones from around the phosphate 
 deposits, leaving them as bowlders, which, at a still later 
 date, were rounded by water currents which also deposited 
 sand around them. 
 
 The land pebble and river pebble probably represent 
 nodules of a highly phosphatized marl, formed in limestone 
 pebbles, shell casts, or by segregation of the contained lime 
 phosphate, and subsequently set free by the solution of the 
 lime carbonate. 
 
 South Carolina Phosphates. Phosphate is found both on 
 the land and in the river bottoms in a belt about 60 miles 
 long lying inland from Charleston and Beaufort (6, 17, 18). 
 The phosphate, which rarely averages much over one foot in 
 thickness, is commonly of nodular character, and often con- 
 tains many bones and teeth. The presence of these animal 
 remains, including both land and marine forms, has given 
 rise to the belief that the deposits were caused by the accu- 
 mulation of bones and excrements along a shore line, prob- 
 ably of Upper Miocene age. Leaching of these remains 
 may have permitted a later replacement of limestone or the 
 formation of phosphatic concretions in swamp bottoms. 
 
 Tennessee Phosphates (11,12,13,16,19). Since the recogni- 
 tion, in 1893, of considerable quantities of high-grade phos- 
 phates in western middle Tennessee (Fig. 29), there have
 
 FERTILIZERS 
 
 151 
 
 been important developments of the deposits. Three types 
 are recognized. The first is brown phosphate occurring in 
 terraces along Duck River, Maury County. It is evidently 
 
 Black Phosphate 
 
 White Phosphate 
 Brown Phosphate 
 
 F^a Area in which Black 
 ^-^ Phosphate may be found 
 
 FIG. 29. Map of Tennessee phosphate areas. Compiled from data in U. S. Geol. 
 Surv., Columbia Atlas folio, and papers by Hayes. 
 
 derived from the weathering of near-by phosphatic limestone 
 of Ordovician age. 
 
 A second type, of black or blue color, occurs either in 
 nodules or in beds. The bedded phosphate is underlain
 
 152 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 either by gray Devonian sandstone or by blue Silurian lime- 
 stone, and capped by black carbonaceous shale ; the nodular 
 
 form occurs higher 
 up in the section. 
 Both are believed 
 to be chemical pre- 
 cipitates on the 
 floor of the Devo- 
 nian sea. 
 
 The third group 
 includes white 
 phosphates occur- 
 ring in three con- 
 ditions: stony, 
 brecciated, and 
 lamellar, inti- 
 mately associated 
 with Carbonifer- 
 ous strata, but 
 some occur in Si- 
 lurian limestones. 
 In the stony phase, 
 the phosphate has 
 been deposited in 
 a siliceous lime- 
 stone, replacing 
 the lime. It al- 
 ternates with beds 
 
 FIG. 30. Vertical section showing geologic position f stony chert and 
 of Tennessee phosphates. After Hayes. contains under 50 
 
 per cent of bone phosphate. The brecciated form, which 
 
 NCONFORMITY 
 
 FERNVALE FORMATION 
 SHALES AND LIMESTONE 
 TV
 
 FERTILIZERS 153 
 
 is the most abundant, consists of angular chert fragments in 
 a phosphate matrix deposited between chert fragments of a 
 limestone. The lamellar variety was deposited in caverns 
 in the Silurian limestones, which, since the deposition of the 
 phosphate, has weathered to a residual clay in which the 
 phosphate masses occur. 
 
 Hayes has advanced the .theory that the lime phosphate 
 of the white phosphates was originally extracted from sea 
 water by organisms, and accumulated on the bottom either 
 as nodules or disseminated through the sediments. Later, 
 when these strata were lifted above sea level and subjected 
 to erosion and the action of percolating waters charged with 
 acids from the soil, the phosphate was leached out and 
 carried to lower levels where it was redeposited either in 
 ca\dties or by replacing limestone. 
 
 Other Phosphate Occurrences, Phosphate, in the form of 
 nodules, white vesicular rock, and in limestone fragments, 
 occurs along the contact of Oriskany sandstone and Lower 
 Helderberg limestone, in Juniata County, Pennsylvania (14). 
 It contains 30 to 54 per cent bone phosphate. Nodular phos- 
 phate, although not worked, is known to occur in Devonian 
 strata in Arkansas (7), and in Cretaceous and Tertiary strata 
 in Alabama (20), Georgia (15), and North Carolina (8). 
 
 Composition. The following analyses will serve to show 
 the composition of some native phosphates. Of the impuri- 
 ties present, lime carbonate is undesirable, since it neutral- 
 izes the acid used in phosphate manufacture. Iron oxide, 
 alumina, and silica are inert impurities displacing just so 
 much phosphate of lime. 
 
 The richness of a phosphate is usually expressed in terms 
 of the tribasic-calcic phosphate, commonly termed bone
 
 154 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 phosphate. Of this about 45.80 per cent is phosphoric 
 
 acid. 
 
 ANALYSES OF PHOSPHATE ROCK 
 
 
 I 
 
 $ 
 
 4 
 
 S 
 
 0* 
 
 | 
 
 1 
 
 3 
 
 
 
 o 
 5 
 
 + s 
 
 Ej 
 
 i 1 
 
 MISCKL. I 
 
 TENNESSEE 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Mt. Pleasant . . 
 
 1.05 
 
 34.69 
 
 2.39 
 
 3.36 
 
 1.40 
 
 3.18 
 
 4.05 
 
 2.64 
 
 46.76 
 
 1.39 
 
 76.42 
 
 S 
 
 Swan Creek, 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Hickman Co. . 
 
 .50 
 
 28.27 
 
 3.14 
 
 2.93 
 
 1.15 
 
 
 13.24 
 
 
 40.50 
 
 
 
 2.80 
 
 White phosphate, 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Stone Quarry 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Hollow, Perry 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Co 
 
 
 15.30 
 
 
 
 
 8.23 
 
 54.88 
 
 
 22.76 
 
 
 
 
 FLORIDA 
 
 
 
 
 
 
 
 
 
 
 
 
 .30 
 
 Hard rock . . . 
 
 .07 
 
 38.84 
 
 .96 
 
 3.07 
 
 .65 
 
 
 .49 
 
 2.96 
 
 50.08 
 
 2.46 
 
 
 
 Washed land peb- 
 
 
 
 
 
 
 
 
 
 
 
 
 .21 
 
 ble 
 
 .63 
 
 34.72 
 
 1.35 
 
 2.53 
 
 2.19 
 
 
 4.34 
 
 2.72 
 
 47.95 
 
 3.15 
 
 
 .44 
 
 River pebble . . 
 
 .56 
 
 28.33 
 
 1.05 
 
 2.01 
 
 3.99 
 
 
 12.23 
 
 4.90 
 
 42.75 
 
 2.44 
 
 
 
 SOUTH CAROLINA 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Average, S. C. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Analysis . . . 
 
 3.68 
 
 25.61 
 
 
 
 4.68 
 
 
 11.55 
 
 4.78 
 
 
 
 55.91 
 
 
 Uses. Fertilizers are used either in their raw condition 
 or after undergoing proper preparation. Lime carbonate is 
 commonly calcined before being spread on the soil, while 
 gypsum is first pulverized before being sold as land plaster. 
 
 Phosphate rock is treated with sulphuric acid to produce superphos- 
 phate or acid phosphate, and in this treatment ammoniates, or potash, or 
 both, are sometimes added to the material. Concentrated phosphate is 
 made by treating the phosphate rock with enough sulphuric acid to 
 entirely decompose it, converting all the lime into sulphate, the phos- 
 phoric acid solution being drawn off and further treated with additional 
 quantities of high-grade phosphate. Since this form of phosphate there- 
 fore requires raw materials of a high grade, and is much more exten- 
 sively manufactured in Europe than in the United States, most of the 
 high-grade Florida rock is exported.
 
 FERTILIZERS 155 
 
 Guano. Under this name are included surface deposits 
 of excrement, chiefly of birds. Penrose (25) recognizes two 
 classes : (1) soluble guano, of recent origin, which still con- 
 tains most of its soluble ingredients; (2) leached guano, 
 which has lost its soluble constituents by the action of rain 
 or sea water. Most of the soluble guano of commerce was 
 formerly obtained from Peru, where, it is said, the Incas, as 
 well as the early Spaniards, valued it so highly that a death 
 penalty was imposed for killing the birds which produced it. 
 These deposits, from which many thousand tons have been 
 obtained, are now exhausted. No large deposits of bird 
 guano are known in the United States. Leached guanos occur 
 on islands in the southern Pacific and in the West Indies. 
 
 Bat guano has been found in the caves of Kentucky, 
 Texas (26), and many other states, but few of the deposits 
 have proved large enough to work, and none are of great 
 extent, although one cave in Texas was known to yield 
 1000 tons. The following analysis is representative: am- 
 monia, 9.44 per cent; available phosphoric acid, 3.17 per 
 cent; potash, 1.32 per cent. 
 
 Greensand. This term is applied to beds of marine 
 origin, made up in large part of the green sandy grains of 
 glauconite, the hydrated silicate of iron and potash. It 
 also contains small amounts of phosphoric acid. Green- 
 sands (23) are found at many localities in the Cretaceous 
 and Tertiary formations of the Atlantic Coastal Plain, but 
 New Jersey (22) and Virginia are the two important pro- 
 ducers. The New Jersey greensand is spread on the soil 
 in its raw condition, but that from Virginia is dried and 
 ground for use in commercial fertilizers.
 
 156 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The following analyses show its variable composition, and 
 the comparatively small amount of P 2 O 5 and K 2 O neces- 
 sary to make it of value as a fertilizer. 
 
 ANALYSES OF GREENSAND 
 
 
 P.O. 
 
 SO, 
 
 SiO, 
 
 CO, 
 
 K,0 
 
 Na,O 
 
 CaO 
 
 MgO 
 
 Al,0 8 
 
 Fe,0 
 
 H,0 
 
 Pemberton, 
 
 
 
 
 
 
 
 
 
 
 
 
 N. J. . . . 
 
 1.02 
 
 .27 
 
 50.23 
 
 
 
 6.32 
 
 1.59 
 
 1.40 
 
 3.45 
 
 7.94 
 
 20.14 
 
 9.00 
 
 Aquia Creek, 
 
 
 
 
 
 
 
 
 
 
 
 
 Va. . . . 
 
 .09 
 
 
 
 21.58 
 
 29.79 
 
 .37 
 
 .59 
 
 36.78 
 
 1.05 
 
 7.70 
 
 
 .76 
 
 Production of Fertilizers. The production of phos- 
 phate in the United States for several years was as 
 follows : 
 
 
 1901 
 
 1902 
 
 1903 
 
 LONG TONS 
 
 VALUE 
 
 LONG Toxs 
 
 VALUB 
 
 LONG TONS 
 
 VALUE 
 
 Florida . . 
 South 
 Carolina . 
 Tennessee . 
 Others . . 
 
 Total . . 
 
 751,996 
 
 321,181 
 409.653 
 893 
 
 $3,159,473 
 
 961,840 
 1,192,090 
 3,000 
 
 785,430 
 
 313,365 
 390,799 
 720 
 
 $2,564,197 
 
 919,725 
 1,206,647 
 2,875 
 
 860,336 
 
 258,540 
 460,530 
 2,125 
 
 $2,986,824 
 
 783,803 
 1,543,567 
 4,600 
 
 1,483,723 
 
 85,316,403 
 
 1,490,314 
 
 $4.693,444 
 
 1,581,576 
 
 $5,319,294 
 
 The imports of crude phosphates, guano, and fertilizers 
 in 1903 were valued at $985,324. The world's production 
 in 1902, exclusive of Norway and Russia, was 2,766,253 
 metric tons, valued at $9,778,950. The production of gyp- 
 sum is given under that head. Greensand statistics are 
 not available.
 
 FERTILIZERS 157 
 
 REFERENCES ON FERTILIZERS 
 
 GENERAL. 1. Adams, Amer. Inst. Min. Engrs., Trans. XVIII: 649, 1890. 
 (List of Commercial Phosphates.) 2. Davidson, Eng. and Min. Jour., 
 LIU: 499, 1892. (Deep Sea Formations.) 3. Davidson, Amer. Inst. 
 Min. Engrs., Trans. XXI : 139, 1893. (United States and Canada.) 
 4. Matthew, N. Y. Acad. Sci., Trans. XII: 108, 1893. (Nodules 
 of Cambrian.) APATITE: 5. Ells, Can. Rec. Sci., VI: 213, 1895. 
 (Canada.) 6. Penrose, U. S. Geol. Surv., Bull. 46, 1888. (General.) 
 PHOSPHATES: 7. Branner, Amer. Inst. Min. Engrs., Trans. XXVI: 
 580, 1897. (Arkansas.) 8. Carpenter, N. Ca. Agric. Exper. Station, 
 Bull. 110, 1894. (North Carolina marls and phosphates.) 9. Eckel, 
 U. S. Geol. Surv., Bull. 213: 424, 1903. (Decatur County, Tenn.) 
 10. Eldridge, Amer. Inst. Min. Engrs., Trans. XXI: 196, 1893. 
 (Florida.) 11. Hayes, U. S. Geol. Surv., 21st Ann. Kept., Ill: 473, 
 1901. 12. Also 17th Ann. Kept., II: 513,1896. 13. Hayes, 16th Ann. 
 Kept., IV : 610, 1895. (Tennessee white phosphates.) 14. Ihlseng, 
 U. S. Geol. Surv., 17th Ann. Kept., III. (ctd.) : 955, 1896. (Penn- 
 sylvania.) 15. McCallie,Ga. Geol. Stirv., Bull. 5-A, 1896. (Georgia.) 
 16. Memminger, U. S. Geol. Surv., Min. Res., 1893: 709, 1894. 
 (Tennessee.) 17. Penrose, U. S. Geol. Surv., Bull. 46, 1888. 
 18. Reese, Amer. Jour. Sci. iii, XLIII : 402, 1892. (South Caro- 
 lina.) 19. Phillips, Eng. and Min. Jour., LVII : 417, 1894. (Hick- 
 man County, Tennessee.) 20. Smith, Ala. Geol. Sur., Bull. 2 : 9, 
 1892. (Alabama.) GREENSAND : 21. Clark and Martin, Md. Geol. 
 Surv., Rept. on Eocene, 1901. (Maryland.) 22. Cook, Geol. of N. J., 
 1868: 261, 1868. 23. Parsons, U. S. Geol. Surv., Min. Res., 1901: 
 823, 1902. (General.) 24. Wilber, U. S. Geol. Surv., Min. Res., 
 1882: 522, 1883. (United States.) GUANO: 25. Penrose, U. S. 
 Geol. Surv., Bull. 46 : 117, 1898. 26. Phillips, Mines and Minerals, 
 XXI : 440, 1901. (Texas Bat Guano.)
 
 CHAPTER IX 
 ABRASIVES 
 
 Introductory. Under this heading are included natural 
 products employed for abrasive purposes; but brief refer- 
 ence will also be made to some artificial compounds which 
 come into serious competition with the natural ones. 
 
 The natural abrasives may be divided into the three fol- 
 lowing groups : (1) Those, like grindstones, whetstones, 
 and buhrstones, which occur in the form of massive rock, 
 and which can consequently be cut and manufactured 
 directly into the desired shape; (2) those, like garnet, 
 emery, quartz, and corundum, which occur usually as 
 grains in a rock or vein, and which have to be separated 
 mechanically from the rock; and (3) those, like infusorial 
 earth, quartz sand, and pumice dust, which occur in more 
 or less unconsolidated condition. 
 
 While some abrasive substances occur as constituents of 
 veins, the great majority form a part of rocks of either 
 sedimentary, igneous, or metamorphic origin. That they 
 are widely distributed both geologically and geographically 
 is shown in the following description of the individual 
 groups, and the map (Fig. 31) : 
 
 Grindstones (2, 3). These are made from sandstones of 
 homogeneous texture and sufficient cementing material to 
 hold the quartz grains together, but not enough to so fill 
 158
 
 PLATE XTIT 
 
 FIG. 1. Grindstone quarry, Tippecanoe, Ohio. J. H. Pratt, photo. 
 
 FIG. 2. Corundum vein between peridotite and gneiss, Corundum Hill, Ga. 
 After Pratt, U. S. Geol. Surv., Bull. 180.
 
 ABRASIVES 
 
 159 
 
 the pores as to make the rock wear smooth under use. 
 Most of the grindstones produced in the United States are 
 obtained from the Berea grit of Ohio (PL XIII, Fig. 1) and 
 Michigan, certain layers of which are highly prized for 
 this purpose. 
 
 FIG. 31. Map showing distribution of abrasives in United States. 
 
 Pulpstones, which have a diameter of 48 to 56 inches, a thickness 
 of 16 to 26 inches, and a weight of 2300 to 4800 pounds, are a thicker 
 variety of grindstone. They are used for grinding wood pulp in paper 
 manufactui'e, and hence have to withstand continual exposure to hot 
 water. On account of their superior quality, pulpstones from New- 
 castle-upon-Tyne, England, supply most of the American demand ; but 
 it is probable that certain beds of the Ohio sandstones will be found 
 suited for this purpose (3). 
 
 Whetstones, Oilstones (2, 3, 10, 11), etc. The term "whet- 
 stone " includes those stones used for sharpening tools, the 
 term "oilstone" being often applied when oil is placed on 
 the stone to prevent heating and clogging of the pores by
 
 160 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 grains of steel. The stones used for making whetstones 
 are either sedimentary or metamorphic in character, and 
 include sandstone, quartzite, mica schist, and novaculite. 
 The stone selected will naturally vary somewhat with the 
 exact use to which it is to be put, but even texture and 
 comparatively fine grain are essentials. A small amount 
 of clayey matter adds to the fineness of grinding, but an 
 excess lowers the abrasive efficiency of the stone. In the 
 schists used, abrasive action is due to the grains of quartz, 
 or sometimes garnet, which are embedded among the fine- 
 grained scales of mica. 
 
 Rocks suitable for whetstone manufacture are found in 
 many states, especially east of the Mississippi (2, 3), but, on 
 account of keen competition and limited demand, only the 
 better grades from the best-located deposits are employed. 
 Most of the supply is therefore obtained from a few states, 
 especially Arkansas, Indiana, Ohio, New York, Vermont, 
 and New Hampshire. 
 
 Among the whetstones quarried in the United States, the Hindostan 
 or Orange stone of Indiana and the Deerlick oilstone of Ohio are much 
 used for oilstones. Scythestones are made from schistose rock in Graf- 
 ton County, New Hampshire, and Orleans County, Vermont. 
 
 The novaculite, quarried in Garland and Saline counties, 
 Arkansas (10), represents a unique type, much prized for 
 high-grade oilstones for sharpening small tools, and in 
 demand both at home and abroad. It is an extremely fine 
 grained sandstone made up of finely fragmental quartz 
 grains, visible under the microscope. The rock is chertlike 
 in superficial appearance and has a conchoidal fracture. 
 While the deposits, which are stratified, have a total thick- 
 ness of over 500 feet, the commercial novaculite is found
 
 ABRASIVES 161 
 
 only in .thin beds varying from a few inches to 15 feet in 
 thickness. The beds have a steep dip, and are cut by 
 several series of joints, which greatly interfere with the 
 extraction of large blocks, and sometimes even with small 
 ones. There are also structural irregularities and almost 
 invisible flaws, so that much waste is caused in quarrying 
 the rock. The rock has been variously regarded as a meta- 
 morphosed chert, a siliceous silt, or a silicified limestone. 
 
 Buhrstones and Millstones (2, 3) are stones of large diame- 
 ter used for grinding cereals, paint ores, cement rock, barite, 
 fertilizers, etc. The American stones are either coarse sand- 
 stone or quartz conglomerate, and are quarried at several 
 points along the eastern side of the Appalachian Mountains 
 from New York to North Carolina. The most important 
 beds are in the Oneida conglomerate, which is quarried in 
 the Shawangunk Mountains of eastern New York and far- 
 ther south in Pennsylvania. Some is also quarried in 
 North Carolina. 
 
 Many buhrstones are imported from France, Belgium, and Germany. 
 Those from the first two localities are hard, cellular rocks, consisting 
 of a mixture of fine quartz particles and calcareous material ; but the 
 German buhrstone is basaltic lava. 
 
 Pumice and Volcanic Ash. The term "pumice," as used 
 in the geological sense, refers to the light spongy pieces of 
 lava, whose peculiar texture is due to the rapid and violent 
 escape of steam from the molten lava. It is put on the 
 market either in lump form, or ground to powder, or in 
 compressed cakes of the ground-up material. In the com- 
 mercial sense the term "pumice" includes volcanic ash as 
 well as true pumice.
 
 162 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Most of the pumice used in the United States is obtained from the 
 island of Lipari, north of Sicily. The stone, after being freed from the 
 volcanic ash with which it is mixed, is sorted according to color, weight, 
 and size, before it is shipped to market. 
 
 Deposits of volcanic ash are abundant in many western 
 states, for example in Nebraska (12) and Utah (13), but 
 owing to inaccessibility these materials cannot compete with 
 Lipari pumice, which is imported as ballast, and sells in its 
 prepared form for 2 to 2| cents per pound. 
 
 Infusorial Earth and Tripoli. These include all porous 
 siliceous earths, composed of organic fragments, such as 
 infusoria or diatom tests, which have accumulated either 
 on the ocean bottom or in ponds. Such deposits are quite 
 common in the coastal plain area of Maryland, Virginia (8), 
 Georgia and Alabama, where they form beds several feet in 
 thickness, generally interstratified with the Tertiary sands 
 and clays. In New England and New York (7) infusorial 
 earth is frequently found in swamps formed by the filling of 
 ponds. A deposit of tripoli worked near Carthage, Missouri 
 (9), differs from those mentioned above in being the re- 
 sidual silica left by the leaching of an impure limestone. 
 It makes an excellent substitute for infusorial earth as an 
 abrasive. Infusorial earth is known in other parts of the 
 country, for example, Nevada and California, but is worked 
 only to a small extent. 
 
 The largest and best-known deposits of infusorial earth are in north- 
 ern Germany, where it is found from 15 to 18 feet below the surface, in 
 a bed varying from 18 to 45 feet in thickness. This is exported to all 
 parts of the world. 
 
 Infusorial earth and tripoli are used chiefly for polishing 
 powders and scouring soaps. The porous character of
 
 ABRASIVES 163 
 
 infusorial earth also renders it valuable as an absorbent for 
 nitroglycerine. As a nonconductor of heat it is of value for 
 steam boiler packing, for wrapping steam pipes, and for fire- 
 proof cement. The tripoli of Missouri is used for water filters. 
 
 Crystalline Quartz (3). Much of the vein quartz quarried 
 in the United States is pulverized and put on the market 
 under the name of tripoli. Considerable quartz sand is used 
 by stone cutters as an abrasive in sawing stone, and a small 
 quantity is employed in making sandpaper. 
 
 Garnet (3) . Although this is a common mineral in many 
 metamorphic rocks, and of some value as an abrasive, it is 
 produced at but few localities. Most of the supply comes 
 from North Carolina, but some is obtained in New York, 
 Connecticut, and Tennessee. It is used in the manufacture 
 of garnet paper, and sometimes as a substitute for corundum 
 in the manufacture of emery wheels, for, although softer, it 
 possesses the advantage of having a splintery fracture, which 
 prevents it from wearing smooth. The price varies from $20 
 to 160 per ton when cleaned for the market. 
 
 Corundum and Emery (4, 5, 6). Corundum (A1 2 O 3 ) is, 
 next to diamond, the hardest of the natural abrasives known, 
 having a hardness of 9. It varies slightly in hardness, and 
 also in chemical composition, being rarely pure alumina ; it 
 also shows variable behavior when heated, some forms 
 crumbling when exposed to a high temperature. Such 
 kinds are worthless for the manufacture of emery wheels, 
 since it is necessary to fire these in order to fuse the clay 
 cement used in their manufacture. Emery is a mechanical 
 mixture of corundum and magnetite or hematite, and is 
 much more abundant than corundum. Its efficiency as an
 
 164 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 abrasive depends on the percentage of corundum which it 
 contains. 
 
 Most of the commercially valuable deposits of corundum 
 have been found in the eastern United States, in a belt of 
 basic magnesian rocks, extending from Massachusetts to 
 Alabama. These rocks reach their greatest development 
 in North Carolina (Fig. 31) and Georgia, and most of the 
 corundum is found there, in veins on the border of a peri- 
 dotite mass which has been intruded into the gneiss. It 
 
 is believed that 
 the corundum, 
 which was one 
 of the earliest 
 minerals to crys- 
 tallize out from 
 the cooling peri- 
 dotite, was con- 
 centrated around 
 the borders of 
 the mass by con- 
 vection currents. 
 This zone of co- 
 rundum sent off 
 tongues toward the interior of the mass, and now that erosion 
 has removed the main zone of corundum, these tongues remain 
 as apparently separate veins within the peridotite (Fig. 32). 
 The most important emery deposit is that at Chester, 
 Massachusetts ; but some is also worked near Peekskill, 
 New York. The emery of Chester occurs in a local widen- 
 ing of a belt of amphibolite schists, and forms a vein 
 traceable for nearly five miles. The emery-bearing vein 
 
 FIG. 32. Section showing occurrence of corundum 
 around border of dunite mass. After Pratt, U. S. 
 Geol. Surv., Bull. 180: 16, 1901.
 
 ABRASIVES 
 
 165 
 
 varies in width from a few feet up to 10 or 12 feet, while 
 the emery streak in it averages about 6 feet, it being 
 bordered on both sides by chlorite seams. The emery is 
 in pockets, but these are traceable by a small vein of chlorite. 
 After mining, both corundum and emery need to be cleaned 
 and concentrated by special mechanical processes. The 
 chief use of this material is as an abrasive, and for this 
 purpose it is used in the form of wheels and blocks, emery 
 paper, and powder. 
 
 Artificial Abrasives. Several artificial abrasives are now much manu- 
 factured. Prominent among these is Carborundum, which is produced 
 by fusion in the electric furnace of a mixture of silica, coke, and saw- 
 dust ; the reaction being SiO 2 + 3 C = CSi + 2 CO. The sawdust is 
 added to give porosity to the mixture. 
 
 Artificial corundum or alundum, whose introduction is of more recent 
 date, is made by fusing bauxite in the electric furnace. It is put on the 
 market in the form of wheels, while carborundum is either made into 
 wheels or sold in powdered form. 
 
 Production of Abrasives. The value of the abrasives pro- 
 duced in the United States during the last three years, together 
 with the imports and artificial abrasives, was as follows : 
 
 KIND OF ABRASIVES 
 
 1901 
 
 1902 
 
 1903 
 
 Oilstones and scythestones . . 
 Grindstones 
 
 $158,300 
 580,703 
 
 $221,762 
 667,431 
 
 $366,857 
 721,446 
 
 Buhrstones and millstones . . 
 
 57,179 
 
 59,808 
 2,750 
 
 52,552 
 2,665 
 
 Infusorial earth and tripoli . . 
 Crystalline quartz 
 
 52,950 
 41,500 
 
 53,224 
 84,335 
 
 76,273 
 76,908 
 
 
 158 100 
 
 \y> 820 
 
 132,500 
 
 Corundum and emery .... 
 
 146,040 
 
 104,605 
 
 64,102 
 
 Total . 
 
 $1,194,772 
 383 386 
 
 $1,326,755 
 390 45 
 
 $1,493,303 
 493,815 
 
 Imports 
 
 490,712 
 
 426,736 
 
 621,585 
 
 Grand total 
 
 $2,068,870 
 
 $2,143,736 
 
 $2,608,603 
 
 
 

 
 166 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 REFERENCES ON ABRASIVES 
 
 GENERAL. 1. King, Ga. Geol. Surv., Bull. 2 : 119, 1894. 2. Pratt, U. S. 
 Geol. Surv., Min. Res., 1900: 787, 1901. 3. Pratt, Mineral Census, 
 1902, Mines and Quarries: 876, 1905. CORUNDUM AND EMERY: 
 4. Eckel, Mineral Industry, IX : 15, 1901. (N. Y. emery.) 5. King, 
 Ga. Geol. Surv., Bull. 2 : 73, 1894. (Georgia corundum.) 6. Pratt, 
 U. S. Geol. Surv., Bull. 180, 1901. (U. S. occurrence, mining and 
 concentration.) TRIPOLI AND DIATOMACEOUS EARTH : 7. Cox, 
 N. Y. Acad. Sci., Trans. XII : 219, 1893, and XIII : 98, 1894. (Diat. 
 earth, N.Y.) 8. Michels, Science, 1 : 222, 1880. (Va.) 9. Quimby, 
 Mineral Industry, VI: 17, 1898. (Mo.) WHETSTONES, GRIND- 
 STONES, AND MILLSTONES: 10. Griswold, Ark. Geol. Surv., Ann. 
 Kept. 1890, III, 1892. (Ark. novaculite.) 11. Kindle, Ind. Dept. 
 Geol. and Nat. Res., 20th Ann. Rep. : 329, 1896. (Ind.) PUMICE 
 AND VOLCANIC ASH: 12. Barbour, Neb. Geol. Survey, I: 214, 1903. 
 13. Merrill, Non-Metallic Minerals : 398, N. Y., 1904.
 
 CHAPTER X 
 MINOR MINERALS ASBESTOS 
 
 Asbestos Minerals. Two different minerals are mined 
 and sold under this name, one a variety of amphibole, the 
 other a fibrous variety of serpentine known as chrysotile. 
 The first, which forms pockets or veins in gneissic or schis- 
 tose rocks, is white, gray, or greenish white in color. Chryso- 
 tile usually occurs in seams of varying width in serpentine 
 rocks (Fig. 33), its color being greenish white, green, or 
 yellow, and its luster silky. 
 
 In both forms of asbestos the fibers are easily separated, 
 but the amphibole variety often contains gritty impurities 
 which are difficult to remove. The fibers of chrysotile are 
 shorter than those of the amphibole asbestos, rarely exceed- 
 ing 2^ inches in length, but they have greater strength. 
 Since the amphibole asbestos can be mined more easily, it 
 is cheaper than the chrysotile variety, which, nevertheless, 
 is in greater demand because more constant in character and 
 suited to more uses. The two varieties are equal in value 
 as nonconductors of heat. 
 
 Distribution. Amphibole asbestos is found at a number 
 of localities in the crystalline belt of the Appalachians, but 
 at present Sail Mountain in White County, Georgia, is the 
 only producer, although promising deposits are known in 
 Polk County, North Carolina, and Bedford County, Virginia, 
 and are worked occasionally. 
 
 167
 
 168 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The limited supply of chrysotile asbestos has naturally 
 stimulated prospecting, and deposits of promise have been 
 found in Vermont (4), Wyoming, California, Montana (8), 
 
 and Arizona (9). 
 The Vermont de- 
 posits, discovered 
 in 1900, occur in 
 Lamoille and Or- 
 leans County, oc- 
 cupying a rather 
 limited area in a 
 large serpentine 
 belt (4). Two 
 types of chryso- 
 tile are found, one 
 forming branch- 
 ing veins similar 
 in character and 
 quality to the 
 Canadian fiber, 
 the other, of inferior quality, occurring as short fibers on 
 slickensided surfaces. 
 
 The main supply of chrysotile used in the United States 
 is obtained from Black Lake and Thetford, Quebec. The 
 serpentine is blasted out and the lumps bearing chrysotile 
 separated from the barren rock by hand picking. These 
 are crushed and screened and the fibres then separated from 
 the rock by air currents. It is stated that 100 tons of rock 
 yields two tons of commercial asbestos (5, 8). 
 
 There has been some difficulty in explaining satisfactorily 
 the origin of the chrysotile veins in serpentine, for we have 
 
 FIG. 33. Asbestos vein in serpentine. Photo, by G. P. 
 Merrill.
 
 MINOR MINERALS 169 
 
 here two quite different forms of the same mineral. Pratt, 
 in attempting to explain the origin of the vein filling, 
 believes that the fissures represent contraction cracks formed 
 around the edge of the serpentine mass while cooling, and 
 which were then filled by aqueous solutions from which the 
 chrysotile crystallized. Merrill, on the other hand, believes 
 the fissures to have been caused by shrinkage incident to a 
 partial dehydration of the rocks and subsequent filling by 
 crystallization extending from the walls inward (6). 
 
 Uses. Asbestos is used in fireproof paints, boiler cover- 
 ing, for packing in fire safes, and for other purposes where 
 non-conductivity of heat is required. Chrysotile is also 
 used in making fireproof rope, felt, tubes, cloth, boards, 
 blocks, and other objects. Asbestic is a name given to 
 short-fibered chrysotile mixed with serpentine. 
 
 Production of Asbestos. The production of asbestos for 
 the last three years was as follows : 
 
 YEAR 
 
 SHORT TONS 
 
 VALUE 
 
 1901 
 
 747 
 
 f 13,498 
 
 1902 
 
 1005 
 
 16,200 
 
 1903 
 
 887 
 
 16,760 
 
 The imports in 1903 were valued at $689,327. 
 
 REFERENCES ON ASBESTOS 
 
 1. Ells, Amer. Inst. Min. Engrs., XVIII: 320, 1890. (Ontario.) 
 2. Jones, Asbestos and Asbestic : Their Properties, Occurrence, and 
 Use (London), 1897. 3. Pratt, U. S. Geol. Surv., Min. Res., 1904. 
 
 4. Kemp, U. S. Geol. Surv., Min. Res., 1900: 862, 1901. (Vt.) 
 
 5. Merrill, National Museum Guide to Study of Non-metallic Min- 
 erals, 296: 1901. (General.) 6. Merrill, Geol. Soc. Amer., Bull. 
 XVI, 1905. (Origin.) 7. Pratt, U. S. Geol. Surv., Min. Res., 1901 : 
 887, 1902. 8. Pratt, Mineral Census, 1902, Report on Mines and 
 Quarries : 973, 1904.
 
 170 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 BARITE 
 
 Barite, the sulphate of barium, is abundant at many 
 localities, and in a few places in sufficient quantity to be 
 of commercial value. Its usual mode of occurrence is as a 
 series of pockets or lenses, which conform to the dip of the 
 inclosing rock, often limestones. Galena is a common asso- 
 ciate. Deposits of commercial value are found in Connecti- 
 cut, North Carolina, Tennessee, Virginia, and Missouri (2). 
 At Evington, Virginia (3), where the mines have been worked 
 since 1874, the barite forms lenticular pockets in limestone. 
 The barite-bearing stratum has a total length of about 4 
 miles and a width of 100 to 200 feet or more. The pockets 
 dip from 20 to 30 to the east, and are sometimes separate 
 or may be connected by thin stringers of barite. Limestone 
 is associated with the Tennessee and Missouri deposits, but 
 in North Carolina barite lenses 3 to 6 feet thick occur in a 
 decomposed schist. 
 
 The following analysis of barite from Fulton County, Pennsylvania, 
 shows the impurities which it may contain : BaSO 4 , 95.22 ; Fe 2 O 3 , A1 2 O 3 , 
 .38; MnO 2 , .05; CaO, .59; MgO, .18; CO 2 , .65; H 2 O, .23; SiO 2 , 2.45. 
 
 Uses. Barite, which is pulverized, and sometimes puri- 
 fied by washing, is used in the manufacture of paper, rubber, 
 paints, and for coating canvas ham sacks. It is also used in 
 pottery glazes and in the manufacture of barium hydroxide. 
 Its white color and great weight (sp. gr. 4.3) make it of 
 value as an adulterant of white lead. Lithophone paint is a 
 mixture of barium sulphate (68 per cent), zinc oxide (7.28 
 per cent), and zinc sulphide (24.85 per cent). 
 
 Production. The production of barite for several years 
 has been as follows :
 
 MINOR MINERALS 
 
 171 
 
 PRODUCTION OF CRUDE BARITE IN THE UNITED STATES FROM 
 1901 TO 1903 
 
 
 1901 
 
 1902 
 
 1903 
 
 Quantity 
 Short 
 
 Value 
 
 Quantity 
 Short 
 
 Value 
 
 Quantity 
 Short 
 
 Value 
 
 
 tons 
 
 
 tons 
 
 
 tons 
 
 
 Missouri 
 
 20,950 
 
 $73,814 
 
 31,334 
 
 $104,677 
 
 23,178 
 
 $77,712 
 
 North Carolina 
 
 7,390(6) 
 
 22,615 
 
 14,679 
 
 44,130 
 
 6,835 
 
 21,347 
 
 Tennessee . . 
 
 10,460 
 
 30,155 
 
 3,255 
 
 14,647 
 
 14,684(a) 
 
 32,691 
 
 Virginia . . 
 Total . . . 
 
 20,950 
 
 31,260 
 
 12,400 
 
 39,700 
 
 5,700 
 
 20,400 
 
 49,070 
 
 $157,844 
 
 61,668 
 
 $203,154 
 
 50,397 
 
 $152,150 
 
 (a) Includes the small production of Kentucky. 
 (6) Includes the small production of Georgia. 
 
 The imports of crude barites in 1903 amounted to 7105 
 pounds, valued at $22,777, while those of manufactured 
 barites were 5716 pounds, valued at $48,726. 
 
 REFERENCES ON BARITE 
 
 1. McCallie, Ala. Indus, and Sci. Soc., Proc. V : 25, 1895. (Ala.) 2. Eng. 
 and Min. Jour., LXXIII : 762, 1902. (Mo.) 3. Pratt, U. S. Geol. 
 Surv., Min. Res., 1901 : 915, 1902. (General.) 
 
 FLUORSPAR 
 
 Fluorspar or fluorite (CaF 2 ), a widely distributed mineral 
 of variable colors, including white, green, and purple, is com- 
 monly found in veins, including limestones, sandstones, slates, 
 and gneisses, but seems to favor metamorphic rocks. It is not 
 an uncommon constituent of many igneous rocks, and enters 
 into the composition of some minerals, such as apatite, cer-
 
 172 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 tain micas and topaz. Fluorite has also been observed in con- 
 nection with some volcanic outbursts. (See Cripple Creek, 
 under Gold.) Calcite and galena are sometimes found in 
 the same vein. Fluorite is also noted, though rarely in 
 economic quantities, in the gangue of many metallic minerals, 
 especially lead. 
 
 Distribution in United States. In the United States fluorite 
 is found at a number of points in the Piedmont and Ap- 
 palachian areas from Maine to Virginia, and is likewise noted 
 in small amounts in many metalliferous veins of the West, 
 but it is rarely found in the Mississippi Valley. In unaltered 
 limestone it is exceedingly rare, and the only commercially 
 important deposits found in this kind of rock are in areas of 
 igneous intrusions. 
 
 Until 1898 the mines of Hardin and Pope counties, Illi- 
 nois, were the only domestic source (1), and this area con- 
 tinues to be the most important producer. There the deposits 
 fill fault fissures in Lower Carboniferous limestone or sand- 
 stone. Dikes of mica peridotite and lamprophyre also occur 
 in the district, but not in contact with the veins. These 
 latter in some places attain a width of 45 feet and a proven 
 depth of 200 feet. This great width is due partly to enlarge- 
 ment of the fissure by solution, and partly to a replacement 
 of the limestone walls. In the limestone footwall, the fluor- 
 spar sometimes forms a solid mass from 2 to 12 feet thick, but 
 that on the hanging wall is less pure. The vein filling is 
 chiefly fluorite and calcite, while associated with these are 
 smaller amounts of galena, sphalerite, and occasionally pyrite 
 or chalcopyrite. It is significant that the galena is slightly 
 argentiferous.
 
 MINOR MINERALS 173 
 
 The origin of the fluorite is somewhat doubtful, but 
 Bain (1) believes that it has probably been derived from 
 heated waters of either meteoric or magmatic origin which 
 leached the mineral from some large mass of low-lying 
 igneous rocks of which the dikes are offshoots. These 
 heated ascending solutions are thought to have carried 
 fluosilicates of zinc, lead, copper, iron, barium, and calcium. 
 The dissolved compounds were probably broken up by cold 
 descending waters, which possibly also furnished the sulphur 
 to combine with the metals. 
 
 Fluorspar deposits are also known in Kentucky (5), Ten- 
 nessee (6), and Arizona (6), in the latter state occurring as a 
 common gangue mineral of the metalliferous veins in Yum a 
 County. 
 
 Uses. Fluorspar was formerly used chiefly for making 
 hydrofluoric acid, but not more than 5 to 10 per cent of the 
 domestic product is now employed for this purpose, while in- 
 creasing quantities are sold for the manufacture of opalescent 
 glass. The greatest demand for it, however, is as a flux in 
 iron manufacture, since it saves from 3 to 5 per cent more iron 
 than limestone flux, reduces the sulphur and phosphorus 
 contents, and increases the tensile strength of the metal. 
 On account of its valuable reducing properties, it is also 
 used in making spiegeleisen, in foundry work, and in cupola 
 furnaces. One objection to the more widespread use of 
 fluorspar as a flux has been its high cost as compared with 
 limestone. 
 
 Fluorspar is divided into 6 grades for the market, the first- 
 grade lump bringing $14.40 per ton in 1903. 
 
 The production of fluorspar for 1903 was as follows :
 
 174 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 PRODUCTION OF FLUORSPAR IN UNITED STATES IN 1903 
 
 STATE 
 
 QUANTITY 
 SHORT TONS 
 
 VALUE 
 
 Arizona and Tennessee 
 
 275 
 
 $2037 
 
 
 30885 
 
 153 960 
 
 Illinois 
 
 11 413 
 
 57 620 
 
 
 
 
 Total 
 
 42 523 
 
 <$213 617 
 
 
 
 
 REFERENCES ON FLUORSPAR 
 
 1. Bain, U. S. Geol. Surv., Bull. 255, 1905. (111.) 2. Burk, Min. Ind., 
 IX : 293, 1901. (Ky.) 3. Emmons, Amer. Inst. Min. Engrs., Trans. 
 XXI: 51, 1893. (111.) 4. Min. Indus., IX: 203, 1901. 5. Fohs, 
 Min. Ind., XII: 131, 1904. (Ky.-Ill.) 6. Pratt, U. S. Geol. Surv., 
 Min. Res. 1901 : 879, 1902. (Gen.) 
 
 FULLER'S EARTH 
 
 Fuller's earth is a term applied to a claylike mate- 
 rial which has the property of absorbing greasy sub- 
 stances. It was first used for fulling cloth or fur and 
 hence the name, but in more recent years it has been found 
 of great value for the clarification of mineral and vege- 
 table oils, being used with the former as a substitute for 
 charcoal. 
 
 While fuller's earth resembles clay superficially, it usually 
 differs from it in having lower plasticity, and a higher per- 
 centage of combined water as compared with the alumina 
 contents. It is often, though not invariably, high in mag- 
 nesia. In color, fracture, and texture, it varies considerably, 
 and the only satisfactory way of determining its value is by 
 a practical test.
 
 MINOR MINERALS 
 
 175 
 
 Fuller's earth is not confined to any particular formation, 
 but the known deposits occur in sedimentary rocks ranging 
 from the beginning of the Mesozoic up to the Pleistocene. 
 In Gadsden County, Florida, and in Decatur County, 
 Georgia (1, 3), it is obtained from the Upper Oligocene of the 
 Tertiary, the former locality being the most important in the 
 country. The earth from this region is used for bleaching 
 mineral oils. 
 
 Earth of at least fair quality has been found at other localities in 
 the southern coastal plain district. Small quantities of fuller's earth 
 are also produced in Arkansas, eastern Colorado, and central New York 
 (2). The last-mentioned occurrence has been used for cleansing cloth and 
 also in the manufacture of soap. It is known to occur in Nebraska, 
 South Dakota (2), and Alabama. 
 
 Before the development of the Florida deposits, in 1893, much fuller's 
 earth was imported from England, and even now a considerable amount 
 is imported for use by the refiners of cotton-seed oil, since it bleaches 
 better than most of the American earth. 
 
 The following analyses indicate the composition of Ameri- 
 can fuller's earth, and to these are added some analyses of 
 the English material, for purposes of comparison, although 
 chemical composition is of little value as a guide to the 
 quality of the material. 
 
 
 SiO 2 
 
 A1 2 8 
 
 Fe 2 8 
 
 CaO 
 
 MgO 
 
 H 2 
 
 Na 2 o| K 2 
 
 Moist. 
 
 Quincy, Fla. . . . 
 
 62.83 
 
 10.35 
 
 2.45 
 
 2.43 
 
 3.12 
 
 7.72 
 
 .20 1 .74 
 
 6.41 
 
 Decatur Co., Ga. . 
 
 67.46 
 
 10.08 
 
 2.49 
 
 3.14 
 
 4.09 
 
 5.61 
 
 < . ' 
 
 6.41 
 
 Fairburn, S. D. . . 
 
 58.72 
 
 16.90 
 
 4.00 
 
 4.06 
 
 2.56 
 
 8.10 
 
 2.11 
 
 2.20 
 
 Sumter, S. C. . . 
 
 74.20 
 
 10.10 
 
 1.80 
 
 1.90 
 
 2.10 
 
 5.70 
 
 1.60 
 
 2.50 
 
 Yellow earth. 
 
 
 
 
 
 
 
 
 
 Woburn Sands, Eng. 
 
 47.10 
 
 16.27 
 
 10.66 
 
 2.63 
 
 3.15 
 
 5.73 
 
 
 15.12
 
 176 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Production of Fuller's Earth. The domestic output has 
 never been large, and much is still imported from England. 
 
 PRODUCTION OF FULLER'S EARTH IN UNITED STATES 
 FROM 1901 TO 1903 
 
 
 SHORT TONS 
 
 VALUE 
 
 1901 
 
 14 112 
 
 $96 835 
 
 1902 . . . ... 
 
 11 492 
 
 98144 
 
 1903 
 
 20,693 
 
 190,277 
 
 REFERENCES ON FULLER'S EARTH 
 
 1. Ries, U. S. Geol. Surv., 17th Ann. Kept., Ft. Ill (cont.) : 876, 1896. 
 
 2. Ries, Amer. Inst. Min. Engrs., Trans. XXVII: 333, 1898. (S. Dak.) 
 
 3. Vaughan, U. S. Geol. Surv., Bull. 213 : 392, 1903. (Fla. and Ga.) 
 
 GLASS SAND 
 
 Glass sand is obtained from quartzose sands, sandstones, or 
 quartzites, usually having at least 98 per cent of silica and 
 a very low percentage of iron oxide, as seen from the analyses 
 given below. When sand is employed, it is sometimes 
 necessary to put it through a washing process in order to 
 separate the impurities, while in the case of quartzite or sand- 
 stone a preliminary crushing and screening are necessary. 
 Clay is undesirable since it tends to cloud the glass, while 
 iron oxide imparts an undesirable color; but this may be 
 counteracted to some extent by the addition of arsenic. 
 
 Sands for glass making are sometimes obtained from 
 Pleistocene deposits, but those from the Tertiary and 
 Cretaceous formations are of better quality. Quartz rock 
 (sandstone and quartzite) is found at various localities in 
 the Paleozoic strata.
 
 MINOR MINERALS 
 
 177 
 
 Much sand is obtained from Silurian sandstones in La Salle 
 and Randall counties, Illinois (5), for use in the plate glass 
 works at Chicago. In New Jersey there are extensive pits 
 in the Tertiary, around Bridgeton (4), the material being 
 used by the glass works of southern New Jersey and south- 
 eastern Pennsylvania. Large pits are also opened in the 
 Raritan formation of the Cretaceous along the Severn River in 
 Maryland (5). Of the quartz rocks, the Cambrian quartzites 
 in Berkshire County, Massachusetts (5), the Oriskany sand- 
 stone of West Virginia, and those of Pennsylvania (7) are all 
 of importance. In Iowa the St. Peters sandstone is used (2). 
 
 The following analyses taken from several American lo- 
 calities will serve to show the composition of the materials 
 employed : 
 
 LOCALITY 
 
 SiO 2 
 
 A1 2 8 
 
 Fe 2 8 
 
 CaO 
 
 MgO 
 
 MISCEL- 
 LANEOUS 
 
 GEOLOGICAL 
 AGE 
 
 Ottawa, 111. . . 
 
 99.45 
 
 
 .30 
 
 .13 
 
 Tr 
 
 
 Silurian 
 
 Hanover, N. J. . 
 
 97.705 
 
 .755 
 
 .150 
 
 .955 
 
 .442 
 
 
 Tertiary 
 
 Berkeley Springs, 
 
 
 
 
 
 
 Moist. 
 
 
 W. Va. . . . 
 
 99.37 
 
 .33 
 
 .04 
 
 
 
 .17 
 
 Oriskany 
 
 
 
 
 
 
 
 Loss, etc. 
 
 
 Columbia, Pa. 
 
 99.5044 
 
 .1337 
 
 .2998 
 
 
 
 .062 
 
 Oriskany 
 
 Cheshire, Mass. . 
 
 99.46 
 
 .48 
 
 
 .06 
 
 
 
 Cambrian 
 
 
 
 
 
 
 
 Ignition 
 
 
 Lewiston, Pa. . . 
 
 98.84 
 
 .17 
 
 .34 
 
 Tr 
 
 Tr 
 
 .23 
 
 Oriskany 
 
 
 
 
 
 
 
 Loss, etc. 
 
 
 Clayton, la. . . 
 
 98.85 
 
 .46 
 
 .095 
 
 .21 
 
 
 .384 
 
 Ordovician 
 
 The total production of glass sand in 1903 is given by the 
 United States Geological Survey as 823,044 short tons valued 
 at 8855,828, and came from twelve states. It is doubtful, 
 however, whether all this was used in glass manufacture. 
 Ohio is credited with being the largest producer and Illinois 
 second.
 
 178 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 ON GLASS SAND 
 
 1. Broadhead, Mo. Geol. Surv., 1872: 289, 1873. (Mo.) 2. Calvin, 
 la. Geol. Surv., I: 24, 1893. (la.) 3. Collett, Geol. and Nat. 
 Hist. Surv. of Ind., 12th Ann. Kept. : 22, 1883. (Ind.) 4. Cook, 
 Geology of New Jersey, 1868 : 690, 1868. (N. J.) 5. Coons, U. S. 
 Geol. Surv., Min. Res., 1902 : 1007; 1903. (General.) 6. DeGroot, 
 Calif. State Min. Bur., 9th Ann. Kept. : 324, 1890. (Calif.) 7. D'ln- 
 villiers, Second Pa. Geol. Surv., F, 1878. (Pa.) 8. Fuller, Stone, 
 XVIII : 1, 1898. (General.) 
 
 GRAPHITE 
 
 Graphite, or black lead as it is often termed popularly, is 
 a form of carbon, and occurs in two forms, the crystalline 
 and amorphous. The first type is commonly found in granular 
 or foliated masses, while the latter lacks crystalline struc- 
 ture and is often shaly in its character. On this account 
 some carbonaceous schists which resemble the latter in 
 appearance, but contain no graphite whatever, are put 
 on the market under its name. Even the best grades of 
 crystalline graphite are, however, never pure carbon, as 
 the following analysis shows: 
 
 
 C 
 
 ASH 
 
 VOLATILE MATTER 
 
 Ceylon graphite . . . 
 
 98.87 
 
 .28 
 
 .90 
 
 Distribution of Graphite in United States. Crystalline 
 graphite is widely distributed in the United States, occur- 
 ring in contact zones between igneous and sedimentary 
 rocks, in metamorphosed rocks, etc., but the known de- 
 posits of commercial value are few in number. Most of 
 the domestic supply has been obtained from the mines
 
 MINOR MINERALS 179 
 
 near Ticonderoga (3), Essex County, New York, where the 
 mineral occurs in a gray quartzite, which is interbedded 
 with gametiferous and micaceous gneiss and a quartzite. 
 The rock contains about 10 per cent graphite, but not 
 more than 50 per cent of this is saved in the process of 
 extraction or concentration. Crystalline graphite is also 
 mined in Chester County, Pennsylvania, where it forms 
 two layers from 4 to 6 feet thick in decomposed mica schist 
 (2, 4). Deposits are also known in Alabama, Georgia, 
 North Carolina, New Hampshire, and Montana (4), but none 
 of the localities have been important producers. Amor- 
 phous graphite occurs in Rhode Island (4) in metamor- 
 phosed carboniferous rocks, and the locality has attracted 
 attention for many years, but its production has been very 
 irregular, due partly to the fact that most attempts to 
 utilize it have been unsuccessful. The material is some- 
 what scaly, but does not as a rule carry more than 55' per 
 cent carbon, the balance being siliceous impurities. That 
 produced in Michigan (4) and Wisconsin is simply car- 
 bonaceous schist, containing no graphite whatever. 
 
 Most of the graphite used in the United States is obtained from 
 Ceylon, where it occurs as veins in granulite and associated with 
 feldspar, rutile, pyrite, biotite, and calcite. Weinschenk believes these 
 deposits to have been formed by the decomposition of vapors carry- 
 ing carbonic oxide and cyanogen compounds. Styria, Bohemia, and 
 Bavaria are also important foreign sources of supply. All of these 
 localities supply the American market, but Ceylon is the most impor- 
 tant source by far. 
 
 Uses. On account of its refractoriness and high heat 
 conductivity, graphite is employed in the manufacture of 
 crucibles, for which purpose it is mixed with clay and
 
 180 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 some sand. In addition it is employed for making stove 
 polish, foundry facings, paint, lead pencils, lubricating 
 powder, glazing, electrotyping, steam piping, etc. 
 
 Graphite is also made artificially from anthracite coal, 
 but its introduction has not seriously affected the market 
 for the natural product. 
 
 Crystalline graphite is put through a concentrating process before 
 shipment to market. This is necessary in order to free it from the 
 associated minerals. Both wet and dry methods of separation are 
 employed, while more recently air separation has been tried with 
 some success. 
 
 Production of Graphite. The domestic production of 
 crystalline graphite does not form more than a small pro- 
 portion of the entire consumption, and has shown but a 
 slight increase, whereas the output of amorphous graphite 
 has shown great expansion, as can be seen by the figures 
 given below. 
 
 PRODUCTION OF GRAPHITE IN UNITED STATES FROM 1901 TO 1903 
 
 1901 
 
 1902 
 
 1903 
 
 Amor- 
 phous 
 
 Crystalline 
 
 Value of 
 both 
 
 Amor- 
 phous 
 
 Crystalline 
 
 Value of 
 both 
 
 Amor- 
 phous 
 
 Crystalline 
 
 Value of 
 both 
 
 Short 
 tons 
 809 
 
 Lbs. 
 3,967,612 
 
 $167,714 
 
 Short 
 tons 
 4,739 
 
 Lbs. 
 3,936,824 
 
 $182,108 
 
 Short 
 tons 
 16,591 
 
 Lbs. 
 4,538,155 
 
 $225,554 
 
 The exports in 1903 were valued at $133,651, while the 
 imports were valued at $1,207,730. The total domestic 
 consumption for that year was 37,758 short tons, valued 
 at $1,598,589. 
 
 The world's production in 1902 is given below :
 
 MINOR MINERALS 181 
 
 WORLD'S PRODUCTION OF GRAPHITE IN 1902 
 
 
 METRIC TONS 
 
 VALUE 
 
 Ceylon 
 
 Austria 
 
 25,593 
 29527 
 
 $3,505,455 
 368 186 
 
 United States 
 
 6,085 
 
 182 108 
 
 
 5023 
 
 41 755 
 
 Italy . 
 
 9210 
 
 35934 
 
 Canada 
 
 994 
 
 28300 
 
 Mexico 
 
 580 
 
 3 176 
 
 
 63 
 
 1 900 
 
 France 
 
 150 
 
 1 140 
 
 India 
 
 4,648 
 
 (*) 
 
 Total 
 
 81,873 
 
 $4,167,954 
 
 (&) Statistics not available. 
 
 REFERENCES ON GRAPHITE 
 
 1. Downs, Iron Age, Apr. 19 to June 14, 1900. 2. Frazer, Amer. Inst. 
 Min. Engrs., Trans. IX : 730, 1881. (Pa.) 3. Nason, N. Y. State 
 Museum, Bull. 4: 12, 1888. (N. Y.) 4. See also various volumes 
 of the Mineral Industry, especially XI : 343, 1903, and XII : 183, 1904. 
 
 LITHOGRAPHIC STONE 
 
 Lithographic stone (1, 3) is a very fine-grained, homo- 
 geneous limestone, used for lithographic purposes. It may 
 be either pure lime carbonate or magnesian limestone, but so 
 far as known this difference in composition exerts no impor- 
 tant influence on its physical character. The two following 
 analyses will serve to indicate this difference in composi- 
 tion, No. 1 being the standard Bavarian stone and No. 2 
 the Brandenburg, Kentucky, rock: 
 
 INSOLUBLE IN HC1 SOLUBLE IN HC1 
 
 SiO, (AlFe) 2 3 CaO A1,O, 
 
 1. 1.15 .22 Trace .23 
 
 2. 3.15 .45 .09 .13 
 
 FeO MgO CaO Na,O K 2 O Moist. H,O CO, 
 
 .26 .56 53.80 .07 .23 .69 42.69 
 
 .31 6.75 44.76 .13 .41 .47 43.06
 
 182 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The physical character of the stone is of prime impor- 
 tance, for in order to yield the best results it should be 
 fine-grained, homogeneous, free from veins or cracks, of 
 just sufficient porosity to absorb the grease holding the 
 ink, and soft enough to permit its being carved with the 
 engraver's tool. Owing to these strict requirements but 
 few localities have produced good stone. Lithographic 
 stone is not confined to any one geologic formation, and 
 deposits have been reported from many states both east 
 and west. Some of these appear to be of inferior quality, 
 while others are too far from railroads. The most prom- 
 ising developed deposit is that found at Brandenburg, Ken- 
 tucky (2, 6), at which locality a bed of blue-gray stone 
 three feet thick is quarried and used by some establish- 
 ments in the south and southwest. Another bed of good 
 quality has also been described from Iowa (1). 
 
 The main source of the world's supply is obtained from the Jurassic 
 limestone of the Solenhofen district in Bavaria (4), in which the quarries 
 have been worked for a number of years, but the supply is said to be 
 becoming unsatisfactory and unreliable. The stones are trimmed at the 
 quarries, and sizes of 22 or 28 by 40 inches are in the greatest demand. 
 From these they range up to sizes 40 by 60 inches. The best quality 
 stones sell for 22 cents per pound. 
 
 The domestic demand is not large, and it is probable 
 that one or two well-developed and well-managed native 
 quarries could no doubt satisfy it. 
 
 The successful substitution of zinc or aluminum plates 
 for certain classes of lithographic work is said to have had 
 a noticeable influence on the demand for lithographic stone. 
 Onyx has also, in some cases, been found to make a good 
 substitute.
 
 MINOR MINERALS 183 
 
 REFERENCES OW LITHOGRAPHIC STOKES 
 
 1. Hoen, la. Geol. Surv., XIII : 339, 1902. (la. also general.) 2. Kiibel, 
 Eng. and Min. Jour., LXXII: 668, 1901. (Ky.) 3. Kiibel, Min. 
 Resources, U. S. Geol. Surv., 1900 : 869, 1901. (Excellent general 
 article.) 4. Merrill, Non-Metallic Minerals: 146, 1904. 5. Mo. 
 Geol. Surv., Bull. 3 : 38, 1890. (Mo.) 6. Ulrich, Eng. and Min. 
 Jour., LXXIII : 895, 1902. (Ky.) 
 
 LITHIUM 
 
 The two minerals most commonly used as a source of 
 lithium are lepidolite (KLi[Al(OH 1 F 2 )]Al(SiO 3 ) 3 ) and 
 spodumene (LiO 2 , A1 2 O 3 , 4 SiO 2 ). The largest deposits of 
 lepidolite at present known in the United States are found 
 near Pala, California. Spodumene occurs in some quan- 
 tities in the Black Hills of South Dakota and in Connecti- 
 cut and Massachusetts, but none of these occurrences have 
 yet been worked to supply lithium. 
 
 In the last few years there has been a great demand for 
 lithium minerals for use in the manufacture of lithium car- 
 bonate. Since most of this substance now in use is made 
 in Germany, nearly all the American mineral has been 
 shipped to that country. The American supply of carbon- 
 ate is imported from Germany, selling in New York for 
 $4.20 a pound. The chief use of lithium salts is in the 
 preparation of mineral waters. 
 
 The production of lithium minerals in the United States 
 in 1903 amounted to 1155 short tons, valued at $23,425. 
 
 MAGNESITE 
 
 This mineral (1), which is a carbonate of magnesium with 
 47.6 per cent of magnesia, usually occurs as a decomposi- 
 tion product in the form of irregular veins in serpentine, 
 talcose schists, or other magnesian rocks. Its color is
 
 184 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 white or yellowish, and when massive it resembles unglazed 
 porcelain, but is quite brittle. Most of the magnesite used 
 in the United States is imported from Styria and Greece ; 
 but some is obtained in California (3), where a commercially 
 valuable deposit is known. 
 
 Magnesite is employed in the preparation of magnesium 
 salts and in the manufacture of paint and of paper. Since 
 it is a nonconductor of heat, it finds extensive use for this 
 purpose ; in fact, its most important use is as a refractory lin- 
 ing for open-hearth furnaces and converters in the steel indus- 
 try, and for the brick lining of rotary Portland cement kilns. 
 
 The domestic production is obtained entirely from Cali- 
 fornia, and has been as follows : 
 
 PRODUCTION OF MAGNESITE IN UNITED STATES FROM 1901 TO 1903 
 
 YEAR 
 
 QUANTITY 
 SHORT TONS 
 
 VALUE 
 
 1901 .... 
 
 3500 
 
 $10,500 
 
 1902 
 
 2830 
 
 8,490 
 
 1903 . ... 
 
 3744 
 
 10,595 
 
 
 
 
 The total value of crude and calcined magnesite imported 
 in 1903 was $461,398. 
 
 REFERENCES ON MAGNESITE 
 
 1. Struthers, U. S. Geol. Surv., Min. Res., 1902 : 983, 1903. 2. Yale, Eng. 
 and Min. Jour., LXXVIII : 292, 1904. (Calif.) 3. Yale, U. S. Geol. 
 Surv., Min. Res., 1903 : 1131, 1904. (Calif, and general.) 
 
 MICA 
 
 There are few minerals more widely distributed in crystal- 
 line rocks than mica, and yet deposits of economic value 
 are rare because the mica flakes are either too small, or too
 
 MINOR MINERALS 185 
 
 intimately mixed with other minerals for profitable extrac- 
 tion. Only two of the several known varieties of mica, mus- 
 covite (H 2 KAl 3 Si 3 O 12 ) and phlogopite (HgKgMgyAl^SiO^, 
 are of economic value, the former being more valuable than 
 the latter. The commercial deposits are usually found in 
 pegmatite veins, cutting granites, gneisses, and schists. In 
 these veins, which are of variable width, the mica is asso- 
 ciated with quartz and feldspar, being found in rough 
 crystals, called blocks or books, and which are either dis- 
 tributed evenly through the vein or collected near its sides. 
 The best mica is obtained from the more coarsely crystalline 
 rocks ; but the widest veins do not necessarily contain the 
 largest blocks. As a rule the mica does not form more 
 than 10 per cent of the vein, and usually not more than 10 
 or 15 per cent of that mined can be cut into plates, the rest 
 being classed as scrap mica. 
 
 Mica has been mined in a number of states both east and 
 west, and in 1902 seven states were producers, of which 
 North Carolina was the most important. 
 
 The use of mica for stove doors and chimneys is decreas- 
 ing, but there is a growing demand for small sheets which 
 can be stamped out into circular or rectanglar forms and 
 used for insulating purposes in electrical apparatus. Scrap 
 mica, obtained by trimming larger sheets, is ground for use 
 in wall papers, lubricants, boiler coverings, etc. Micanite is 
 sheet mica obtained by cementing small clear pieces of scrap 
 together under pressure. The value of the sheet mica ranges 
 from 2 cents to $3 per pound, depending on the size of the 
 sheet. Scrap mica sells for $8 to $10 per ton, and after 
 grinding for $40 to $60 per ton. 
 
 The production of mica in 1903 amounted to 1968 short
 
 186 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 tons, valued at $143,128. Most of the supply is imported from 
 Canada and India, and this in 1903 amounted to 2,251,856 
 pounds, valued at $466,332. 
 
 REFERENCES OW MICA 
 
 1. Fuller, Stone, XIX : 530, 1899. (Occurrences and uses.) 2. Hender- 
 son, Eng. and Min. Jour., LV: 4, 1893. (General.) 3. Holmes, 
 U. S. Geol. Surv., 20th Ann. Kept., VI (ctd.) : 691, 1899. (U. S. 
 deposits.) 4. Hoskins, Min. Industry, X: 458, 1902. (N. H.) 
 5. Pratt, Mineral Census 1902, Mines and Quarries: 1031, 1904. 
 (General.) 
 
 MINERAL PIGMENTS 
 
 Under this head are included a number of mineral sub- 
 stances which are used in the manufacture of paints (5). In 
 most cases they are put through some form of preparation 
 after mining, such as grinding or washing. Roasting is some- 
 times resorted to for improving the color. 
 
 The substances commonly used are iron oxides, barite, 
 gypsum, slate, graphite, asbestos, and soapstone. 
 
 Hematite. Certain kinds of hematite, such as the 
 Clinton ore (see Iron Ores), are ground and sold under 
 the name of metallic paints, and much used for coating 
 wooden surfaces and coloring mortar. The ores are some- 
 times roasted before grinding to improve their color and 
 durability. Although iron-ore deposits are widespread, 
 and often of large size, the quantity of material suitable 
 for metallic paint is small. The chief supply comes from 
 Pennsylvania, Tennessee, and New York, and smaller 
 amounts from a number of other states. 
 
 Ochers (2, 6). This name is applied to powdery limonite 
 deposits or clays, which, in their natural state, contain suf- 
 ficient ferric oxide or hydroxide to impart a bright red or
 
 MINOR MINERALS 187 
 
 yellowish-red tint to the mass. Ocher may occur as a 
 residual product resulting from the decay of limestone, 
 shale, or other rocks, as a replacement deposit, or as a sedi- 
 mentary deposit. The last-mentioned form probably con- 
 tains more clay. Ocher sometimes contains as much as 
 50-75 per cent iron oxide (6), and often gritty impurities, 
 which have to be removed by washing. Uniformity of 
 color in the product is necessary. 
 
 Ochers are classified according to shade of color, thus: 
 yellow ocher is colored by hydrous iron oxide; red ocher 
 owes its color to ferric oxide, and hence can be produced 
 by roasting yellow ocher ; brown ocher or umber is colored 
 by manganese, and sienna is a yellowish-brown variety. 
 
 The most extensive series of ocher deposits found in the 
 United States is associated with the Cambro- Silurian strata 
 of the Appalachians from Vermont to Alabama, the chief 
 production coming from Pennsylvania and Georgia. Both 
 umber and sienna are produced in small quantities in Illinois 
 and Pennsylvania, and sienna in addition is obtained from 
 New York. 
 
 Few paints are more free from adulteration than ochers, 
 for the reason that any adulterant that could be used is 
 more costly than the ocher itself. 
 
 Slate. The refuse from slate quarries is sometimes 
 ground and sold as a pigment. 
 
 G-ypsum, 1 known also as terra alba or mineral white, is 
 used to some extent as a pigment for printing wall paper. 
 
 Barite, 1 or barium sulphate, which is used as an adulter- 
 ant of white lead, is purified after mining by grinding and 
 washing. 
 1 For mode of occurrence and distribution see these minerals, pp. 139 and 170.
 
 188 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Asbestos 1 is used to some extent in paint manufacture 
 for the so-called non-inflammable or fireproof paints, but the 
 total quantity thus utilized is small. 
 
 Graphite, 1 either natural or artificial, supplies a black 
 pigment of permanent color, which, on account of its 
 resistance to the atmosphere and ordinary chemicals, is of 
 much value for coating oxidizable metals, such as iron and 
 steel. 
 
 Calcium carbonate, in the form of chalk, known commer- 
 cially as whiting or paris white, is used as a pigment to alter 
 the shade of other pigments and as a basis for whitewash. 
 
 Other paints. Paints sometimes classed as mineral paints 
 are made from other crude minerals, as follows : zinc white 
 from zinc ore; white lead, red lead, and orange mineral 
 from lead; Venetian red from iron sulphate; vermilion or 
 artificial cinnabar from quicksilver; chrome yellow from 
 chromite ; cobalt blue from cobaltite. 
 
 PRODUCTION OF MINERAL PAINTS IN THE UNITED STATES FROM 
 1901 TO 1903 
 
 
 1901 
 
 1902 
 
 1903 
 
 
 QUANTITY 
 
 
 QUANTITY 
 
 
 QUANTITY 
 
 
 
 SHORT 
 
 VALUE 
 
 SHORT 
 
 VALUE 
 
 SHORT 
 
 VALUE 
 
 
 TONS 
 
 
 TONS 
 
 
 TONS 
 
 
 Ocher . . . 
 
 16,711 
 
 $177,779 
 
 16,565 
 
 $145,708 
 
 12,524 
 
 $111,625 
 
 Umber . . . 
 
 Sienna . . . 
 
 759 
 305 
 
 11,326 
 9,304 
 
 480 
 189 
 
 11,236 1 
 4,316 J 
 
 666 
 
 15,367 
 
 Metallic paint 
 
 15,915 
 
 204,397 
 
 19,020 
 
 313,390 
 
 25,103 
 
 213,109 
 
 Mortar color . 
 
 9,346 
 
 112,943 
 
 8,355 
 
 98,729 
 
 10,863 
 
 101,792 
 
 Soapstone . . 
 
 50 
 
 350 
 
 1,100 
 
 2,200 
 
 
 
 
 
 Slate. . . . 
 
 4,865 
 
 41,211 
 
 4,071 
 
 39,401 
 
 7,106 
 
 59,029 
 
 1 For mode of occurrence and distribution see these minerals, pp. 167 and 178.
 
 MINOR MINERALS 189 
 
 The imports of ochers in 1903 amounted to 9,960,334 
 pounds, valued at $100,447; of umber, 2,168,570 pounds, 
 valued at $18,172 ; and of sienna, 1,875,369 pounds, valued 
 at $28,570. France is the largest producer of ocher. 
 
 REFERENCES ON MINERAL PAINTS 
 
 1. Benjamin, U. S. Geol. Surv., Min. Res. 1886 : 702, 1887. 2. Hayes 
 and Eckel, U. S. Geol. Surv., Bull. 213 : 427, 1903. (Georgia ocher.) 
 3. Hill, 2d Pa. Geol. Surv., Kept, for 1886, IV : 1386, 1887. 4. Min- 
 eral Industry, IV : 491, 1896, and VII : 532, 1899. 5. Struthers, 
 Mineral Census, Kept, on Mines and Quarries, 1902 : 955, 1905. 
 (General.) 6. Watson, Amer. Inst. Min. Engrs., Trans. XXXIV : 
 643, 1904. (Georgia ocher and analyses.) 
 
 MOLDING SAND 
 
 Certain fine-grained sands and loams are employed in 
 making molds for castings. Molding sand must be suf- 
 ficiently fine grained and aluminous to permit molding into 
 the required form ; strong enough to hold its shape ; re- 
 sistant to heat ; and porous enough to permit the escape of 
 gases, but not to admit the melted metal. An excess of 
 clay is undesirable, as it causes the sand to shrink and bake 
 when the metal is poured in it. Molding sands are obtained 
 from surface deposits at many localities, especially in the 
 states east of the Mississippi River. The analysis of one 
 from Manchester, England, may serve as a type, it containing 
 SiO 2 , 92.913; A1 2 O 3 , 5.85; Fe 2 O 3 , 1.249; CaO, trace. This 
 high silica percentage accounts for its refractoriness, and its 
 porosity is due to a low clay content. The mechanical 
 composition of molding sands is probably as important, if 
 not more so, as their chemical constitution, but it has been 
 little investigated. Many thousands of tons of molding 
 sand are used annually by foundrymen, but no statistics
 
 190 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 have been collected. The region around Albany, New York, 
 supplies enormous quantities of a fine-grained molding sand. 
 Ohio, Kentucky, and New Jersey are also important pro- 
 ducers. 
 
 REFERENCES ON MOLDING SAND 
 
 1. Eckel, N. Y. State Geologist, 21st Ann. Kept., 1901. 2. Merrill, U. S. 
 National Museum, Guide to Study of Non-metallic Minerals : 474, 
 1901. 3. Merrill, Eng. and Min. Jour., LXXVIII : 341, 1904. 
 4. See also forthcoming reports, Wis. Geol. Surv. and Va. Geol. 
 Surv. 
 
 MONAZITE 
 
 This mineral is an anhydrous phosphate of the rare 
 earth metals, cerium, lanthanum, and didymium, but its 
 economic value is due chiefly to the small amount of 
 thoria which it contains. Although grains of it are found 
 scattered through many granites and gneisses, still no oc- 
 currences of this type are of any commercial value. The 
 economically valuable deposits are all found in stream 
 gravels, derived from the disintegration of monazite-bearing 
 rocks. Monazite is usually light yellow to honey yellow, 
 red, or brown in color, has a resinous luster, and a specific 
 gravity of 4.64 to 5.3. Its gravity and color aid in its ready 
 determination. 
 
 In the United States deposits of monazite sand have been 
 found in the granite and gneiss areas of North Carolina (2) 
 and South Carolina (3), and these, together with deposits 
 found in Brazil (1), supply nearly the entire world's demand. 
 A small quantity is also obtained from southern Norway, as 
 a by-product in feldspar mining. The following analyses 
 indicate the composition of monazite :
 
 MINOR MINERALS 
 ANALYSES OF NORTH CAROLINA MONAZITE 
 
 191 
 
 
 P 2 5 
 
 Ce 2 8 
 
 La 2 8 
 
 ThO 2 
 
 SiO 2 
 
 H 2 
 
 Burke Co., N. C. . . 
 
 29.28 
 
 31.28 
 
 30.88 
 
 6.49 
 
 1.40 
 
 .20 
 
 Alexander Co., N. C. . 
 
 29.32 
 
 37.26 
 
 31.60 
 
 1.48 
 
 .32 
 
 .17 
 
 Uses. Monazite is usually separated from the gravels by 
 a washing process, and in addition magnetic separation has 
 in some cases been employed to separate it from the asso- 
 ciated garnet, magnetite, and quartz. 
 
 The value of monazite lies in the incandescent properties 
 of the oxides of the rare earths, cerium, lanthanum, didym- 
 ium, and thorium, which it contains, and which are utilized 
 in the manufacture of mantles for incandescent lights. 
 
 Production of Monazite. The production of monazite for 
 several years was as follows : 
 
 PRODUCTION OF MONAZITE IN THE UNITED STATES FROM 
 1901 TO 1903 
 
 YEAR 
 
 QUANTITY 
 
 VALUE 
 
 1901 
 
 Pounds 
 
 748,736 
 
 $59,262 
 
 1902 
 
 802000 
 
 64160 
 
 1903 
 
 862,000 
 
 64,630 
 
 This quantity represents washed sand containing 85 to 99 
 per cent monazite. The crude sand brings from 2 to 6 
 cents per pound, depending on the percentage of thoria 
 it contains. 
 
 REFERENCES ON MONAZITE 
 
 1. Dennis, Min. Indus., VI : 487, 1898. (General). 2. Nitze, N. C. 
 Geol. Surv., Bull. 9, 1895. 3. Pratt, U. S. Geol. Surv., Min. Res., 
 1902 : 1003, 1903 ; and 1903 : 1163, 1904. (N. C. and S. C.)
 
 192 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 PRECIOUS STONES 
 
 The names gems and precious stones (1, 2) are applied 
 to certain minerals, which on account of their rarity, as 
 well as hardness, color, and luster are much prized for 
 ornamental use. The hardness is of importance as in- 
 fluencing their durability, while their color, luster, and 
 even transparency affect their beauty. A distinction is 
 sometimes made between the more valuable stones, or gems 
 (such as diamond, ruby, sapphire, and emerald), and the less 
 valuable, or precious, stones (such as amethyst, rock crystal, 
 garnet, topaz, moonstone, opal, etc.). 
 
 Most gems are found in un consolidated surface deposits 
 representing either residual material, or alluvium derived 
 from it, and in the latter their concentration and preserva- 
 tion is due to their weight and hardness. When found in 
 solid rock, the metamorphic and igneous types are more 
 often the source than the sedimentary ones. 
 
 Many different minerals are used as gems (1, 2), but only 
 a few of the important ones can be mentioned here, and 
 the number of the more valuable kinds found in the United 
 States is very limited (7, 8, 9). 
 
 Diamond. This mineral, which is the hardest of all 
 known substances, is pure carbon, crystallizes in the iso- 
 metric system, and has a specific gravity of 3.525. It occurs 
 in many different colors, of which white is the commonest, 
 and is 'found either in basic igneous rocks, or in alluvial 
 
 The massive forms, known as bort or carbonado, have little 
 or no cleavage, and are of value only as an abrasive. 
 
 The greatest number of diamonds come from South Africa,
 
 MINOR MINERALS 193 
 
 but other deposits of commercial value occur in India, Borneo, 
 and Brazil. 
 
 In the United States a few scattered diamonds have been 
 found in the southern Alleghanies, California, Wisconsin, 
 and Indiana, but they are all small (3, 4, 5, 7, 8, 9). 
 
 Ruby. A red, transparent variety of corundum (A1 2 O 3 ), 
 having a hardness of 9 and a specific gravity of 4. The 
 most valuable color in ruby is a deep, clear, carmine red. 
 Rubies of large size are scarce, so that a three- carat stone of 
 good color and flawless is worth several times as much as a 
 diamond of the same size. The best ones come from Bur- 
 ma. In the United States they have been found in the 
 stream gravels of Macon County, North Carolina. Those 
 found in Arizona and other Western states are not true rubies, 
 but a variety of garnet (7, 8, 9). 
 
 Sapphire is a blue, transparent variety of corundum 
 (A1 2 O 3 ). It is of slightly greater hardness and specific 
 gravity than the ruby, though of similar composition. 
 Sapphires of good color and size are more common than 
 rubies and cheaper. The best sapphires come from Siam. 
 In the United States they have been found in the gravels of 
 Co wee County, North Carolina, but Yogo Gulch, Montana, 
 where they are found in an igneous dike, is now the main 
 source of domestic supply. They range in weight from 
 under one up to four or five carats (7, 9, 10). 
 
 Emerald. This gem is a variety of beryl, essentially a 
 glucinum aluminum silicate. Its hardness is 7.5 to 8, and 
 its specific gravity 2.5 to 2.7. Its brilliant green color is 
 attributed by some to chromium, by others to organic mat- 
 ter. Brazil, Hindostan, Ceylon, and Siberia are all important 
 sources. In the United States a few have been found in
 
 194 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 western North Carolina (7, 9). Flawless emeralds are very 
 rare, and equal in value to diamonds. 
 
 Aquamarine and oriental cat's-eye are also varieties of 
 beryl. Brazilian emerald is a green variety of tourmaline, 
 and lithia emerald an emerald-green spodumene. 
 
 Topaz. This is a fluosilicate of alumina, crystallizing 
 in the orthorhombic system, with a hardness of 8, specific 
 gravity of 3.5, vitreous luster, and yellow, green, blue, red, 
 or colorless. It occurs in gneiss or granite, as well as in 
 other metamorphic or igneous rocks, and is associated with 
 beryl, mica, tourmaline, etc. It is also found in alluvial de- 
 posits. The best gem stones come from Ceylon, the Urals, 
 and Brazil. In the United States they have been found in 
 small quantities in Maine, Colorado, and California (7). 
 
 Turquoise is a massive hydrated aluminum copper phos- 
 phate, of waxy luster, blue to green color, and opaque. Its 
 hardness is 6, and specific gravity 2.75. It usually occurs in 
 streaks and patches in volcanic rocks. The best varieties 
 are obtained from Persia, but it is also obtained from Asia 
 Minor, Turkestan, and Siberia. In the United States tur- 
 quoises are found in the Los Cerrillos Mountains near Santa 
 Fe, New Mexico, and Turquoise Mountain, Arizona. 
 
 It is interesting to note that turquoise was hardly known in 
 the United States in 1890, but now the bulk of the world's sup- 
 ply comes from the Southwestern states and territories (6, 7). 
 
 Garnet. Of the several varieties of garnet, three are well 
 known as gem stones, viz., the precious garnet or alman- 
 dite, Bohemian garnet or pyrope, and manganese garnet or 
 spessartite. The first two are of deep crimson, the last of 
 orange-red or light red-brown color. India is the main 
 source of supply. All three varieties mentioned are found
 
 MINOR MINERALS 195 
 
 in the United States, but there is a regular production only 
 of the pyrope from Arizona and New Mexico, and a purple- 
 red garnet known as rhodonite from North Carolina (7, 9). 
 
 Opal, which is hydrous silica chemically, is amorphous, 
 with conchoidal fracture, yellow, red, green, or blue color, 
 and often showing considerable iridescence. The varieties 
 recognized are the precious opal, fire opal, girasol, and com- 
 mon opal. The finest examples of precious opal are obtained 
 from Hungary. Others are also found at Queretaro, Mexico, 
 and in Oregon and Washington. The United States pro- 
 duction is small, although it is thought that there are many 
 scattered occurrences in the igneous rocks of Washington, 
 Idaho, Oregon, California, Nevada, and Utah (7, 9). 
 
 Other Precious Stones. Among the other precious stones 
 obtained in this country and their sources of supply may be 
 mentioned : 
 
 Tourmaline Maine and California. 
 
 Kunzite California. 
 
 Californite California. 
 
 Chlorastrolite Isle Royale. 
 
 Fluorspar Illinois. 
 
 Rock crystal California. 
 
 Amethyst Scattered localities. 
 
 Chrysoprase Oregon. 
 
 Moss agate Wyoming. 
 
 Production of Precious Stones. The production of gems in 
 the United States is not large, and for the last three years 
 was as follows : 
 
 YEAH VALUE 
 
 1901 $289,050 
 
 1902 328,450 
 
 1903 321,400 
 
 The imports of diamonds and other precious stones in 
 1903 were valued at $26,522,523.
 
 196 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 REFERENCES ON PRECIOUS STONES 
 
 1. Bauer, Edelsteinkunde. (Leipzig, 1896.) 2. Farrington, Gems and 
 Gem Minerals. (Chicago, 1903.) 3. Hobbs, Amer. Geol., XIV : 31, 
 1894. (Wis. diamonds.) 4. Hobbs, Min. Indus., IX: 301, 1901. 
 5. Hobbs, Jour. Geol., VII : 375, 1899. (Wis.) 6. Johnson, Sch. of 
 Mines Quart., XXIV: 493, 1903. (N. Hex. Turquoise.) 7. Kunz, 
 Mineral Census, 1902, Mines and Quarries. (General on United 
 States Gems.) 8. Kunz. See Chapters on Precious Stones in Min- 
 eral Resources, issued annually by U. S. Geol. Surv. 9. Kunz, Gems 
 and Precious Stones of N. Amer. (New York, 1892.) 10. Pratt, 
 U. S. Geol. Surv., Bull. 180, 1901. (Sapphire.) 11. Reid, Eng. 
 and Min. Jour., LXXV: 786, 1903. (Burro Mtn. Turquoise dist.) 
 12. Streeter, Precious Stones and Gems (London), 1892. 
 
 SULPHUR AND PYRITE 
 
 These two minerals are discussed in the same chapter 
 because they both serve as sources of sulphur. 
 
 Sulphur. The occurrences of native sulphur are of two 
 types (4) : (1) the Solfataric type and (2) the Gypsum type. 
 
 Solfataric Type. Sulphur is often found in fissures of 
 lava and tuff around many active and also extinct volcanic 
 vents, being deposited by the oxidation of hydrogen sulphide, 
 or by the sulphuretted hydrogen and sulphur dioxide, in the 
 presence of moisture, yielding water and sulphur. Ferric 
 chloride is sometimes deposited under the same conditions, 
 and might, owing to its similar color, be at first mistaken 
 for sulphur. 
 
 Deposits of the solfataric type are rarely of commercial 
 importance, but in foreign countries they are worked in 
 Japan, and also in the crater of Popocatepetl, in Mexico. 
 
 In the United States a deposit is known to exist in Beaver 
 County, southwestern Utah (4, 5). The sulphur is found 
 impregnating volcanic tuffs, sand (the product of decom-
 
 MINOK MINERALS 197 
 
 position), or in the fissures in trachyte and carboniferous 
 limestone. The deposit is said to be 30 feet thick and the 
 deposition still continues. Small amounts are mined in 
 Oregon and Nevada (l), but the output is irregular. 
 
 G-ypsum Type. This is formed by the action of bitumi- 
 nous matter on gypsum, the former having a reducing effect. 
 It is, therefore, always found in sedimentary rocks, in which 
 marls, limestones, and shales are prominent. 
 
 The change involved is a reduction of the calcium sul- 
 phate of the gypsum, to calcium sulphide, with the produc- 
 tion also of carbon dioxide and water. The sulphide then, 
 by reaction with the carbon dioxide of the air, and water, 
 yields calcium carbonate, native sulphur, and hydrogen 
 sulphide. 
 
 This type of sulphur is often of great economic value, and 
 deposits are found in a number of countries. The beds are 
 mostly of Tertiary age, but Jurassic ones are also known. 
 
 In the United States the richest and best known is found 
 in southwestern Louisiana (6, 8). Here a bed of sulphur 
 over 100 feet thick was discovered in boring for oil. It 
 is underlain by gypsum and salt, and covered by 300 to 400 
 feet of wet clay, quicksand, and gravel, which has presented 
 great difficulties in all attempts to mine the material. Its 
 extraction is now accomplished by means of superheated 
 steam. 
 
 Sicily is the most important source of supply for the United States. 
 There the sulphur is found in veinlets and cavities in a cellular Miocene 
 limestone, which underlies and overlies gypsum. The sulphur-bearing 
 beds are generally from 3 to 10 feet thick, and vary in their thickness 
 as well as dip, the latter being from 25 up to 70. The percentage of 
 sulphur varies from 8 to 25 per cent, the first figure representing the
 
 198 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 lowest economic limit. The mines contain more or less petroleum and 
 bitumen, and sometimes even explosive gases, while barite and celestite 
 are associated minerals. Owing to improper methods of mining there 
 is much waste. 
 
 Uses. The most important use of sulphur is for the 
 manufacture of sulphuric acid, and in paper manufacture. 
 Some is also used in making matches, for medicinal purposes, 
 and in making gunpowder, fireworks, insecticides, for vul- 
 canizing india rubber, etc. 
 
 In recent years pyrite has largely replaced sulphur for 
 the manufacture of sulphuric acid, and the increase in price 
 of Sicilian sulphur has helped this. 
 
 The greater portion of the world's supply of sulphur is 
 obtained from Sicily, the United States consuming the 
 largest amount. 
 
 Production of Sulphur. The value of the domestic pro- 
 duction and imports of sulphur for several years, as well 
 as total domestic consumption, which includes sulphur 
 obtained from pyrite, are given in the following table : 
 
 IMPORTS AND PRODUCTION OF SULPHUR IN THE UNITED STATES 
 
 
 DOMESTIC 
 PRODUCTION 
 
 IMPORTS 
 
 TOTAL 
 CONSUMPTION 
 
 1893 
 
 Long tons 
 1,071 
 
 Long tons 
 
 105,823 
 
 Long tons 
 
 228,709 
 
 1895 
 
 1,607 
 
 122,096 
 
 254,196 
 
 1900 . . . 
 
 3 147 
 
 167 696 
 
 408 038 
 
 1901 
 
 6806 
 
 175,210 
 
 469,415 
 
 
 
 
 
 The sulphur imported into the United States comes 
 chiefly from Sicily and Japan, with very small quantities 
 from Mexico and Chile.
 
 MINOR MINERALS 199 
 
 REFERENCES ON SULPHUR 
 
 1. Adams, U. S. Geol. Surv., Bull. 225 : 497, 1904. (Nevada.) 2. Eng. 
 and Min. Jour., XLVI: 174, 1888. (Sicily.) 3. Eng. and Min. 
 Jour., LXXVII : 523, 1904. (Sicily.) 4. Kemp, Min. Indus., II : 585, 
 1894. (General.) 5. Russell, Trans., N. Y. Acad. Sci., 1 : 168, 1882. 
 (Utah and Nevada.) 6. Preussner, Zeitschr. d. d. Geol. Gesell., 
 XL: 194, 1888. (La.) 7. Richardson, U. S. Geol. Surv., Bull. 
 260 : 589, 1905. (El Paso Co., Tex.) 8. Anon., Eng. and Min. 
 Jour., LXXVIII: 592, 1904. (La.) 
 
 Pyrite. Pyrite, the sulphide of iron, is widely distrib- 
 uted in nature, being found in many kinds of rocks and 
 in all formations. It occurs in a variety of forms, such 
 as disseminations,- contact deposits, concretionary masses, 
 fissure veins, and lenticular deposits, the last form being 
 characteristic of most of those occurrences which are of 
 commercial value. As mined, pyrite usually contains small 
 quantities of other metallic minerals as well as silica and 
 alumina ; but if its sulphur content falls below 50 per cent, 
 it is not salable. The following analysis of pyrite from 
 Louisa County, Virginia, will serve as illustration. It is: 
 S, 47.76; Fe, 43.99; Cu, 3.69; Zn, .24; SiO 2 , 1.99; As, 
 .63; Pb, .10. If chalcopyrite is present and exceeds 3 or 
 4 per cent, the rock may be used as copper ore. Pyrrhotite 
 is abundant in some of the Virginia deposits. 
 
 Distribution. The most important domestic occurrences 
 are found in a belt of metamorphic rock extending from 
 New Hampshire to Alabama (4), in which the pyrite is 
 found forming lenses in metamorphic rocks. Massachusetts 
 and Virginia are the most important producers. New York 
 also contributes. In Louisa County, Virginia (2), the pyrite 
 lenses occur in Cambro-Silurian slates and schists. The
 
 200 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 deposits are known to be over 2 miles in length, and have 
 been exploited to a depth of 600 feet, while their average 
 thickness is 18 feet. Their origin is somewhat obscure 
 and depends on the character of the original rock. 
 
 Some pyrite is obtained from Indiana and Ohio, from 
 "coal brasses" obtained as a by-product in coal mining (3). 
 
 Uses. Pyrite is used chiefly and in increasing quanti- 
 ties for the manufacture of sulphuric acid and sulphate of 
 iron, while small amounts are consumed in the manufac- 
 ture of mineral paint. It is not used as an ore of iron. 
 Recent experiments have demonstrated the possibility of 
 saving the sulphuric acid gas from the roasting of zinc 
 ores, and the utilization of pyrrhotite for making sulphur 
 and sulphuric acid. 
 
 REFERENCES ON PYRITE 
 
 1. Adams, Trans. Amer. Inst. Min. Engrs., XII: 527, 1883. (Va.) 
 2. Nason, Eng. and Min. Jour., LVII : 414, 1894. (Va.) 3. Struthers, 
 Min. Indus., XI : 577, 1903. 4. Wendt, S. of M. Quart., VII : 218, 
 1885. (Alleghanies.) 
 
 STRONTIUM 
 
 The two minerals serving as sources of strontium salts are 
 celestite (SrSO 4 ) and strontianite (SrCO 3 ). Of these two 
 the former is the more important, but the latter is the more 
 valuable, as the strontium salts can be more easily extracted 
 from it. 
 
 Both celestite and strontianite have been found at a num- 
 ber of localities in the United States, but seldom in large 
 quantities. One important deposit of celestite has been 
 found in limestone caves near Put in Bay, Strontian Island,
 
 MINOK MINERALS 201 
 
 in Lake Erie, and in opening up the cave 150 tons of the 
 mineral were taken out. Similar occurrences have been 
 found in limestones in other states, but none of them have 
 any commercial value. 
 
 Nearly all the strontium salts now used in the United 
 States are imported from Germany, the crude material being 
 obtained in part from Westphalia, Germany, and also from 
 Thuringia, Germany, and Sicily. 
 
 Uses. Strontium salts are used in sugar refining, in fire- 
 works manufacture, and to a small extent in medicine. 
 
 REFERENCES ON STRONTIUM 
 
 1. Pratt, U. S. Geol. Surv., Min. Res., 1901 : 955, 1902. 
 
 TALC AND SOAPSTONE 
 
 Talc, a silicate of magnesia, is a widely distributed mineral, 
 but rarely occurs in large quantities. It commonly repre- 
 sents the alteration product of other magnesian minerals, 
 such as tremolite, actinolite, pyroxene, or enstatite, and is 
 therefore often associated with talcose or chlorite schists, 
 serpentine, and such basic igneous rocks as peridotite. It is 
 also found associated with dolomite. In the southern Ap- 
 palachians the alteration of enstatite rocks into talcose rocks 
 has given rise to extensive soapstone deposits, soapstone 
 being an impure massive form of talc. 
 
 Large deposits of pure talc, usually massive, though in 
 places with a fibrous structure, are found in North Caro- 
 lina (1). These beds, which are associated with marble and 
 quartzite, have apparently been formed by the alteration of 
 bands of tremolite bedded with the other rocks. Those 
 portions discolored by iron oxide, or containing tremolite
 
 202 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 crystals, are of no value. A fibrous talc formed by the 
 alteration of tremolite or enstatite occurs in St. Lawrence 
 County, New York (3), where it is bedded with limestone 
 and tremolite or enstatite schist. From these two regions 
 most of the talc of the country is derived ; but soapstone is 
 obtained from a number of states, of which Virginia is the 
 most important producer. 
 
 The following analyses from several localities show the 
 kind and quantity of impurities which good talc may con- 
 tain : 
 
 ANALYSES OF COMMERCIAL TALC 
 
 
 
 
 
 
 
 
 
 H 2 O 
 
 LOCALITY 
 
 Si0 2 
 
 A1 2 8 
 
 FeO 
 
 CaO 
 
 MgO 
 
 Na 2 O 
 
 K 2 O 
 
 Loss on 
 Igni- 
 
 
 
 
 
 
 
 
 
 tion 
 
 Kinsey Mine, 
 
 
 
 
 
 
 
 
 
 N.C. . . 
 
 63.07 
 
 1.56 
 
 .67 
 
 .30 
 
 28.76 
 
 .78 
 
 Tr 
 
 4.36 
 
 St. Lawrence 
 
 
 
 
 
 
 
 MnO 
 
 
 Co.,N.Y. . 
 
 62.10 
 
 
 1.30 
 
 
 32.40 
 
 
 2.15 
 
 2.05 
 
 Uses. Talc is marketed as rough talc, sawed slabs, or 
 ground talc. Its peculiar physical character, extreme fine- 
 ness, softness, and freedom from grit, adapt it to a number of 
 uses, of which the following are most important : fireproof 
 paints, electric insulators, foundry facings, boiler and steam- 
 pipe coverings, soap adulterants, toilet powders, dynamite, 
 in wall plasters, for dressing skins and leather, as a base for 
 lubricants, and as a filling for paper. Most of the New 
 York fibrous talc is used for the last purpose, being better 
 suited for it than the North Carolina product. The com- 
 pact varieties of pure talc are employed for pencils, and 
 for coal- and acetylene-gas tips.
 
 MINOR MINERALS 
 
 203 
 
 Pyrophyllite differs from talc chemically, being a hydrous 
 aluminum silicate, instead of a magnesium silicate, but when 
 sufficiently free from grit it is put to the same use as talc. 
 It is sometimes incorrectly called agalmatolite, because of 
 its resemblance to the true mineral of that name. Deposits, 
 more extensive than those of talc, are found near Glendon, 
 North Carolina (1). It varies from green and yellowish 
 white to white, but in all cases becomes nearly white when 
 dried. 
 
 Production of Talc and Soapstone. The production for 
 the last three years has been as follows : 
 
 PRODUCTION OF TALC AND SOAPSTONE FROM 1901 TO 1903 
 
 
 1901 
 
 1902 
 
 1903 
 
 
 Short 
 tons 
 
 Value 
 
 Short 
 tons 
 
 Value 
 
 Short 
 tons 
 
 Value 
 
 New York (6) . . 
 
 69,200 
 
 $483,600 
 
 71,100 
 
 $615,350 
 
 60,230 
 
 $421,600 
 
 
 693 
 
 4 717 
 
 (c) 
 
 (c) 
 
 1 012 
 
 9042 
 
 North Carolina . . 
 
 5,819 
 
 77,824 
 
 5,239 
 
 88,962 
 
 5,330 
 
 76,984 
 
 N. Jersey and Pa. . 
 
 2,552(a) 
 
 19,132(a) 
 
 7,082 
 
 52,812 
 
 5,412 
 
 44,058 
 
 Indiana and Virginia 
 
 12,511 
 
 232,900 
 
 13,221 
 
 372,163 
 
 13,118 
 
 243,552 
 
 Other states (d) . . 
 
 7,068 
 
 90,315 
 
 1,312 
 
 11,220 
 
 1,799 
 
 44,824 
 
 (a) Pennsylvania alone. (6) Fibrous talc, (c) California, Maryland, 
 Massachusetts, New Hampshire, New Jersey, and Vermont in 1901 ; Cali- 
 fornia, Massachusetts, and Georgia in 1902 ; California, Massachusetts, and 
 Vermont in 1903. 
 
 The imports in 1903 amounted to 1791 short tons, valued 
 at $19,677. 
 
 REFERENCES ON TALC AND SANDSTONE 
 
 1. Pratt, N. C. Geol. Surv., Econ. Papers, No. 3, 1900. (N. Ca.) 2. Rand, 
 Philadelphia Acad. Nat. Sci., Proc. 1894: 455. 3. Smyth, School 
 of Mines Quart., XVII: 333, 1896. (N. Y. and bibliography.) 
 4. Waldo, Mineral Industry, II : 603, 1894.
 
 CHAPTER XI 
 MINERAL WATERS 
 
 THIS term is commonly applied to those spring waters 
 containing a variable amount of dissolved solid matter of 
 such character as to make them of medicinal value. Their 
 origin, although often regarded as curious, is simple, the 
 dissolved substances having been derived from the rocks 
 through which the spring waters have circulated. Many 
 mineral waters contain carbonic and even other acids, and 
 alkalies, which further increase their powers of solution. 
 There is apparently some connection between hot mineral 
 springs and geological structure, as they are more abundant 
 in regions of faulting or recent volcanic activity. Mineral 
 waters derived from sedimentary rocks usually show a 
 greater quantity of dissolved material than those occur- 
 ring in igneous rocks. 
 
 Springs whose temperature is above 70 F. are termed 
 thermal, those between 70 F. and 98 F. being classed as 
 tepid, and those hotter than this as hot springs. The fol- 
 lowing will serve as examples to show the temperature of 
 different thermal springs : Sweet Springs, West Virginia, 
 74 F. ; Warm Springs, French Broad River, Tennessee, 95; 
 Washita, Arkansas, 140 to 156; San Bernardino Hot 
 Springs, California, 108 to 172; Las Vegas, New Mexico, 
 110 to 140. 
 
 The volume of discharge shown by mineral springs is 
 204
 
 MINERAL WATERS 205 
 
 quite variable. The famous Orange Spring of Florida 
 discharges 5,055,000 gallons per hour, while others are 
 as follows : Champion Springs, Saratoga, New York, 2500 
 gallons ; Roanoke Red Sulphur Springs, Virginia, 1278 gal- 
 lons ; Warm Sulphur Springs, Bath, Virginia, 360,000 gal- 
 lons ; Glen Springs, Waukesha, Wisconsin, 45,000 gallons. 
 
 While a classification of mineral waters may be geo- 
 graphic, geologic, therapeutic, or chemical, that prepared 
 by A. C. Peale is perhaps as satisfactory as any. He sub- 
 divides mineral waters into the following classes : 
 
 Alkaline 
 
 Sulphated 
 
 Alkaline-saline . . 
 
 ( Muriated 
 
 ( Sulphated 
 Saline . . . \ . 
 
 I Muriated 
 
 ( Sulphated 
 
 Acid . . . | Muriated 
 
 { Sulphated 
 I Siliceous \ , 
 
 I Muriated 
 
 The springs falling in the above groups may be either 
 thermal or non-thermal, and may be either free from gas 
 or contain CO 2 , H 2 S, N, or CH 4 . 
 
 Distribution of Mineral Waters in the United States. 
 There are, according to Peale, between eight and ten thou- 
 sand mineral springs in the United States, and of this 
 number 725 were producing in 1903. The majority of the 
 commercially valuable mineral springs are located in the 
 eastern United States and Mississippi Valley. West of 
 the 101st meridian they are confined chiefly to the Pacific 
 coast. No thermal springs are known in the New England
 
 206 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 states. Among the American springs, those at Saratoga, 
 New York, have an international reputation, and compare 
 well with many of the foreign ones. Others of importance 
 are the Hot Springs of Virginia and the Hot Springs of 
 Arkansas. 
 
 The following table contains the analyses of several types 
 of mineral waters from the United States : 
 
 ANALYSES OF AMERICAN MINERAL WATERS 
 
 
 
 s 
 
 I 
 
 J 
 
 * 
 
 1 
 
 
 
 i^l 
 
 1 
 
 02 
 
 || 
 
 1 H - 5 g 
 
 |gl 
 
 fl| 
 
 CHEMICAL CONSTITUENTS 
 
 ! g g 
 
 < 
 pj ,"1 
 
 s ^ 
 
 f! 
 
 gfcoS | 
 
 
 I a'o 
 
 
 111 
 
 
 HP 
 
 OQ K 
 
 Jill 
 
 ij | 
 
 III 
 
 
 1*1 
 
 P! 
 
 ^ o 
 
 2 * 
 
 gig! 
 
 t-5 < 
 
 M < 
 
 
 gr. per 
 
 gr. per 
 
 gr. per 
 
 gr. per 
 
 gr. per 
 
 gr. per 
 
 gr. per 
 
 
 gal. 
 
 gal. 
 
 gal. 
 
 gal. 
 
 gal. 
 
 gal. 
 
 gal. 
 
 Sodium carbonate .... 
 
 
 
 
 
 
 5.00 
 
 
 Sodium bicarbonate . . . 
 
 10.77 
 
 8.75 
 
 
 
 
 
 .49 
 
 _ 
 
 1.26 
 
 Sodium sulphate .... 
 
 
 
 
 
 
 
 
 
 
 
 16.27 
 
 .54 
 
 Calcium carbonate .... 
 
 
 
 
 
 5.22 
 
 
 
 
 
 Magnesium carbonate . . 
 
 
 
 
 
 
 3.17 
 
 
 
 11.41 
 
 
 
 Calcium bicarbonate . . . 
 
 143.40 
 
 41.32 
 
 
 
 12.66 
 
 12.93 
 
 
 
 17.02 
 
 Magnesium bicarbonate . . 
 
 121.76 
 
 29.34 
 
 
 
 
 
 .69 
 
 
 
 12.39 
 
 Lithium bicarbonate . . . 
 
 4.76 
 
 
 
 
 
 
 
 
 
 Trace 
 
 
 
 Iron bicarbonate .... 
 
 .34 
 
 3.00 
 
 
 
 2.17 
 
 
 
 
 
 .04 
 
 Magnesium sulphate . . . 
 
 
 
 2.15 
 
 
 
 
 
 18.96 
 
 
 
 
 
 Potassium sulphate . . . 
 
 .89 
 
 
 
 1.38 
 
 
 
 
 
 
 
 
 
 Sodium chloride .... 
 
 400.44 
 
 166.81 
 
 
 
 
 
 .33 
 
 27.34 
 
 .46 
 
 Potassium chloride . . . 
 
 8.05 
 
 
 
 
 
 
 
 
 
 
 
 1.16 
 
 Potassium bromide . . . 
 
 
 
 1.57 
 
 
 
 
 
 
 
 
 
 
 
 Sodium bromide .... 
 
 8.56 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Sodium iodide 
 
 .14 
 
 4.67 
 
 
 
 
 
 
 Silica 
 
 .84 
 
 .53 
 
 1.72 
 
 .38 
 
 .45 
 
 2.51 
 
 .74 
 
 Calcium sulphate .... 
 
 
 
 
 
 14.53 
 
 2.54 
 
 96.64 
 
 
 
 
 Production of Mineral Waters. The production of 
 mineral waters in the United States for the last three 
 years was as follows :
 
 MINERAL WATERS 
 
 207 
 
 PRODUCTION OF MINERAL WATERS IN UNITED STATES FROM 1901 
 TO 1903 
 
 YEAR 
 
 QUANTITY 
 GALLONS 
 
 VALUE 
 
 1901 
 
 55,771,188 
 
 $7,586,962 
 
 1902 . 
 
 64,859,451 
 
 8,793,761 
 
 1903 
 
 51,242,757 
 
 9,041,078 
 
 
 
 
 The production of the more important states in 1903 was 
 as follows : 
 
 PRODUCTION OF MINERAL WATERS IN SEVERAL STATES IN 1903 
 
 STATE 
 
 QUANTITY 
 GALLONS 
 
 VALUE 
 
 New York 
 
 1 827 408 
 
 $1,432,801 
 
 
 1 293 777 
 
 1 058 954 
 
 
 1,862,855 
 
 706,372 
 
 Virginia 
 
 2 561 502 
 
 477 410 
 
 
 1 522,860 
 
 357,579 
 
 
 
 
 REFERENCES ON MINERAL WATERS 
 
 1. Bailey, Kas. Geol. Surv., VII, 1902. (Kas.) 2. Branner, Ark. Geol. 
 Surv., Kept., I, 1891. (Ark.) 3. Crook, Mineral Waters of United 
 States and their Therapeutic Value. (N. Y. 1899.) 4. Lane, U. S. 
 Geol. Surv., Water Supply Bull. XXXI, 1899. 5. Peale, U. S. Geol. 
 Surv., 14th Ann. Kept., 11: 51. (U.S.) 6. Schweitzer, Mo. Geol. 
 Surv., Ill, 1892. (Mo., also general.) 
 
 UNDERGROUND WATERS 
 
 While much of the water used for supplying towns and 
 cities, for irrigation purposes, etc., is obtained from below 
 the surface, all of it originates in rainfall. The rain water 
 falling on the surface is disposed of in part by evaporation 
 and surface run-off, but a variable and sometimes large per- 
 centage seeps into the ground.
 
 208 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Ground Water (22). Of this portion soaking into the 
 ground, a small part is retained by capillarity in the surface 
 soil, to be returned again to the atmosphere either by direct 
 evaporation or through plants, but most of it finds its way 
 into the deeper layers of the soil, which it completely 
 saturates. 
 
 The water in this saturated zone, which is termed the ground 
 water, forms a great reservoir of supply for lakes, springs, and 
 wells, and its upper surface, known as the water table, agrees 
 somewhat closely with that of the land surface, but is nearer 
 
 FIG. 34. Ideal section across a river valley, showing the position of ground 
 water and the undulations of the water table with reference to the surface 
 of the ground and bed rock. After Schlichter, U. S. Geol. Surv., Water 
 Supply Bull. 67 : 1. 
 
 to it under valleys, and farther from it under hills (Fig. 34). 
 The depth of the water table is quite variable, being but a 
 few feet below the surface in moist climates, while in arid 
 regions it may be 100 feet or more. In any area, however, 
 the water table may show periodical fluctuations. In all 
 ground water there is a slow but constant movement from 
 higher to lower levels, just as in the case of surface waters, 
 so that the ground water flows towards the valleys. There 
 it may discharge into the streams, but in some instances 
 it follows the valley bottom below the river bed, separated 
 from the river water by a more or less impervious layer (22). 
 The composition of the ground water also shows a somewhat 
 close relation to the rocks or soils in which it accumulates.
 
 MINERAL WATERS 209 
 
 Artesian Water. In some areas much of the water which 
 percolates through the soil is caught up by porous beds of 
 sandstone, gravel, or in rarer instances limestone, and where 
 these are between impervious beds such as shale, the absorbed 
 water may follow them for some distance, especially if the 
 porous stratum is inclined. Water thus confined is under 
 pressure, and tends to rise towards the surface along any 
 path of escape open to it, such as joint or fault planes, or 
 where the water-bearing bed is cut into by a stream. A drill 
 hole bored to tap the water-bearing bed serves the same pur- 
 pose ; and when the pressure is sufficient to force the water 
 upward so that it flows from the tube, it is called an arte- 
 sian well. The term is however rather loosely used now and 
 applied to many deep wells which are not flowing. 
 
 The requisite conditions (1) for a supply of artesian water 
 are : (1) a porous stratum ; (2) an impervious bed below and 
 above the water-bearing bed ; (3) inclined beds, so that the 
 point of intake or fountain head can be higher than the well ; 
 (4) a sufficient area of outcrop or collecting area to obtain a 
 large enough supply this may be many miles from the 
 well ; (5) adequate rainfall ; (6) absence of escape for the 
 water at a lower level than the surface at the well. Artesian 
 water was formerly looked for only in synclinal basins, but 
 it is now known that sedimentary beds may be water bear- 
 ing in areas of monoclinal dip. 
 
 Artesian wells vary greatly in their capacity and depth. 
 Some are not more than 100 feet deep, while others are 2000 
 or more feet deep. 
 
 Though the most productive artesian wells are found in 
 pre-Pleistocene sedimentary rocks of regular structure (Fig. 
 35), still, flowing artesian wells even of large capacity are
 
 210 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 at times found in the glacial drift where water-bearing 
 lenses of sand or gravel are overlain or surrounded by 
 clay. 
 
 Even in areas of igneous and metamorphic rocks the water 
 seeps in along joint planes, and collects at times in sufficient 
 quantities to serve as a source of supply which may even be 
 under pressure (6, paper by G. O. Smith). 
 
 
 FIG. 35. Geologic section of Atlantic Coastal Plain, showing water-bearing 
 horizons. After Barton, Amer. Inst. Min. Engrs., Trans. XXIV: 375. 
 
 Artesian wells are to be distinguished from ground water 
 wells by their greater constancy, absence of relation to sur- 
 rounding climatic conditions, and, in moist climates at least, 
 of a high constituent of mineral matter. 
 
 There are many areas in the United States in which the 
 conditions are favorable to an artesian water supply, as the 
 various state and government reports will show. A few of 
 the more important may be briefly referred to. 
 
 Along the Atlantic and Gulf Coastal Plain an abundant 
 supply of artesian water is obtained from the Cretaceous 
 and Tertiary beds, at depths varying from 50 feet along
 
 MINERAL WATEKS 211 
 
 the inland border, to 1000 feet and over along the coast (4) 
 (Fig. 35). 
 
 A second area is that of the upper Mississippi Valley (19), 
 in which an abundant supply of potable water is obtained 
 from the St. Croix and St. Peters sandstone, whose outcrop 
 in Minnesota and Wisconsin covers some 14,000 square miles. 
 
 In the Great Plains (2) region water is obtained from the 
 Dakota sandstone, whose collecting area is around the border 
 of the Black Hills (Fig. 36). This source is available in 
 
 FIG. 36. Section from Black Hills across South Dakota, showing artesian well 
 conditions. After Darton. 
 
 South Dakota and eastern Nebraska and Kansas. The chief 
 use of the water in this region is for irrigation. 
 
 For the arid regions of the West this source of supply has 
 been of inestimable value, and has been the means of reclaim- 
 ing many an area of hitherto useless land. 
 
 REFERENCES ON UNDERGROUND WATER 
 
 1. Chamberlin, U. S. Geol. Surv., 5th Ann. Kept. : 125, 1885. (Artesian 
 water supply.) 2. Darton, U. S. Geol. Surv., Prof. Paper 32, 1905. 
 (Central Great Plains.) 3. Darton, U. S. Geol. Surv., Water Supply 
 Bulls. 57 and 161. (List of deep borings in United States.) 4. Darton, 
 U. S. Geol. Surv., Bull. 138, 1896. (Atlantic Coastal Plain.) 5. El- 
 dridge, U. S. Geol. Surv., Mon. 27. (Denver basin.) 6. Fuller and 
 others, U. S. Geol. Surv., Water Supply Bull. 114, 1905. (Under- 
 ground waters, E. United States.) 7. Fuller, U. S. Geol. Surv., 
 Water Supply Bull. 100, 1905. (Hydrography E. United States.) 
 8. Gilbert, U.S. Geol. Surv., 17th Ann. Kept., II: 557, 1896. (Arkansas
 
 212 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Valley, Col.) 9. Hall, Ala. Geol. Surv., Bull. 7. (Ala.) 10. Hill, U.S. 
 Geol. Surv., 21st Ann. Rept.,VII : 387, 1901. (Tex.) 11. Holmes, Amer. 
 Inst. Min. Engrs., Trans. XXV: 936, 1896. (Piedmont plateau.) 
 12. King, U. S. Geol. Surv., 19th Ann. Kept., II : 59, 1899. (Under- 
 ground water circulation.) 13. Knight, Wyo. Univ. Exp. Sta., Bull. 
 45, 1900. (Wyo.) 13 a. Lane, U. S. Geol. Surv., Water Supply Bulls. 
 30 and 31, 1899. (Mich.) 14. Leverett, U. S. Geol. Surv., 17th Ann. 
 Kept., II: 701, 1896. (111.) 15. Leverett, U. S. Geol. Surv., Water 
 Supply Bulls. 26 and 21. (Ind.) 16. Singley, Texas Geol. Surv., 4th 
 Ann. Kept. : 87. (Galveston well.) 17. McCallie, Ga. Geol. Surv., 
 Bull. 7, 1899. (Ga.) 18. McGee, U. S. Geol. Surv., 14th Ann. Kept., 
 II : 1. (E. United States.) 19. Norton, la. Geol. Surv., VI : 115, 
 1897. (Iowa.) 20. Orton, U.S. Geol. Surv., 19th Ann. Kept., IV: 640, 
 1899. (Ohio rock waters.) 21. Ruddy, Wash. Geol. Surv., 1 : 296, 
 1901. (Wash.) 22. Slichter, U. S. Geol. Surv., Water Supply Paper 
 No. 67, 1902. (General on underground waters.) 23. Woolman, see 
 various annual reports N. J. Geol. Surv. Many other papers in 
 Water Supply and Irrigation bulletins issued by U. S. Geol. Surv.
 
 CHAPTER XII 
 SOILS 
 
 THE term soil is applied to the upper few inches of the 
 mantle of unconsolidated material (regolitTi) which covers 
 the earth's surface, and which is composed of a mixture of 
 rock, sand, and clay fragments in all stages of decay ; with 
 it there is usually mixed a variable amount of decayed and 
 decaying organic matter (humus). 
 
 Origin. Soils are classed, according to their mode of 
 origin, as residual and transported. 
 
 Residual Soils are those formed by rock weathering (see 
 Residual Clay, under Clay, Chapter IV), and are found 
 resting on the parent rock from whose decay they have 
 originated; they consequently, in most instances, show a 
 gradual transition from the surface soil to the solid rock 
 beneath. Such soils are often of great extent in the 
 unglaciated areas of the South, and their clayey character 
 and brilliant coloring is a marked feature. 
 
 With this class there is sometimes grouped the humus, or 
 peaty soil, formed by the accumulation of vegetable matter 
 in bogs or swamps (see Peat, under Coal, Chapter I). 
 
 Transported Soils. The materials of residual areas are 
 frequently carried away by the agency of water, ice, or wind 
 and deposited elsewhere, commonly at lower levels, giving 
 rise to transported soils. These are classified either accord- 
 ing to their mode of origin or texture. 
 213
 
 214 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The former grouping recognizes : Alluvial soils, deposited by water on 
 the lowlands bordering rivers or on their deltas ; these form one of the 
 most important soil types, and the fertile soils of the Nile Valley and the 
 Mississippi bottoms are of this character. Their continued high fertility 
 is due to the fact that the soil layer is added to annually or of tener during 
 periods of flood. Glacial drift soils, representing the debris of decayed 
 rocks of various kinds brought down from the north during the glacial 
 period. They are made up of a mixture of many different rock types in 
 all stages of decay; the continual decomposition of their component min- 
 eral grains gives them a more or less permanent fertility. sEolian soils, 
 or those formed by wind action, include : (1) Sand dunes heaped up by 
 the action of wind along the shores of many oceans or inland seas. 
 When anchored by systematic planting, they develop an abundant plant 
 growth. (2) Ash soils, representing the accumulations of ash thrown 
 out over a region during outbursts of volcanic activity ; these are some- 
 times of high productivity, for although at first barren and sandy they 
 rapidly decompose to a good soil. 
 
 Properties of Soils. The productivity of a soil depends 
 largely on its chemical and physical properties, and to a 
 lesser extent on climatic conditions. 
 
 Chemical Properties. The chemical analysis of a soil 
 shows a variable percentage of nitrogen, silica, phosphoric 
 acid, chlorine, alumina, lime, magnesia, iron oxide, potash, 
 and soda, all of which, with the exception of the first, are 
 derivable from mineral grains present in the soil. When 
 there is a deficiency of any one of these, it is commonly 
 remedied by adding fertilizers to the soil; but the value of 
 the latter for plant maintenance depends not so much on the 
 total quantity of each of these present, but upon the amount 
 existing in soluble form. While soils vary in their composi- 
 tion from place to place, there is a most marked difference 
 between the soils of humid and arid regions, those of the 
 latter showing a much larger proportion of fertilizing con-
 
 SOILS 215 
 
 stituents because they have been subjected to less leaching 
 action by rain water. Soils in arid regions are often covered 
 by a whitish crust termed " alkali" which is composed chiefly 
 of sulphates and carbonates of soda, and is formed by the 
 soil water bringing these to the surface, where it escapes by 
 evaporation. An excess of alkali is injurious to plants. 
 
 Physical Properties, which are of equal importance to the 
 chemical ones, include texture, structure, color, weight, and 
 temperature ; a proper physical condition may often make 
 up for a deficiency in plant food. The physical characters 
 of a soil are produced to a large extent by natural processes, 
 and can be modified but slightly by man. 
 
 The texture of a soil refers to the size of its grains, those 
 recognized being clay, silt, sand, and gravel; depending on 
 the amount of each of these present, we have clay soils, silt 
 soils, loams, sandy soils, and gravelly soils. Texture is of 
 importance because it affects the retentive power of the soil 
 for moisture and gases. Clay soils hold much water and 
 hence are wet and cold, whereas sandy soils, on account of 
 the coarseness of their particles, have large pores and hold 
 little water, and warm up easily. Loamy soils stand inter- 
 mediate between these. 
 
 The structure of the soil refers to the arrangement of the 
 particles. If compacted, the pores are small and the soil 
 holds more water, while if loose the soil behaves like sand, 
 retaining little moisture. A puddled soil is one in which 
 the grains are single, while in a flocculated soil the particles 
 are bunched together, forming compound grains, and all good 
 soils show this structure ; it increases the pore space and 
 hence facilitates the circulation of air and water through the 
 mass. Lime encourages flocculation.
 
 216 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The temperature of soils depends on their color and 
 position with relation to the sun's rays. 
 
 In moist climates the clay particles are washed out of the 
 upper layers of the soil and settle in the lower ones, produc- 
 ing a differentiation known as soil and subsoil. This is not 
 found in arid regions. 
 
 Distribution of Soils in the United States. So varied are 
 the soils of the United States that it would require many 
 pages to describe them even partially ; nevertheless, there 
 are a few well-marked types underlying extensive areas 
 which may be briefly referred to. The residual soils occupy 
 a large area throughout the southern states, and in the 
 Appalachian belt are especially prominent, being easily recog- 
 nized by their clayey character and bright colors. Glacial 
 soils are prominent in the northern United States, and their 
 high fertility has been noted by various writers. The alluvial 
 soils are prominent in all parts of the country. In the cen- 
 tral states the prairie soil is a peculiar silty type, heavily 
 impregnated with humus. The loess is a silty soil, low in 
 organic matter, covering many square miles of the Great 
 Plains, and needs but irrigation to make it blossom with har- 
 vests. Marsh soils and dune soils both cover many thousands 
 of acres along the Atlantic coast ; and the latter are also ex- 
 tensive around the Great Lakes as well as along the Pacific 
 coast. Although reclaimable they are rarely cultivated. 
 
 REFERENCES ON SOILS 
 
 Hilgard, U. S. Dept. Agric., Weather Bur., Bull. 3, 1892 (Relations of 
 Soil to Climate) ; King, The Soil, Wiley & Sons (New York, 1898) ; 
 Merrill, Rocks, Rock Weathering, and Soils, Macinillan Co. (New 
 York, 1897); Kamann, Forstliche Boden-kunde und Standortslehre
 
 SOILS 217 
 
 (Berlin, 1897) ; Shaler, U. S. Geol. Surv., 12th Ann. Kept., 1 : 213, 
 1891 (Origin and Nature) ; Warrington, Physical Properties of Soils 
 (Oxford, Eng., 1900). See also bulletins U. S. Dept. Agric., Bur. of 
 Soils, especially Nos. 4, 10, 15, 17, 18, 19, 22, and the Reports on 
 Field Operations published annually. 
 
 ROAD MATERIALS 
 
 Under this term are included clay, sand, gravel, and differ- 
 ent kinds of consolidated rock, used for covering the surface 
 of a highway. In former years but little consideration was 
 given to the proper selection of these materials, but now 
 the subject is receiving an increasing amount of attention 
 from engineers, with the results that certain required 
 standards have been set up, and in many localities carefully 
 adhered to. Such standards can however be applied only 
 to consolidated materials. 
 
 In many parts of the United States the roads have natural 
 beds, whose character depends on that of the local formations. 
 The road, therefore, may consist of clay, sand, loam, gravel, 
 or bare rock, and such a road surface is unfortunately used 
 even when better materials are at hand, but are overlooked 
 through indifference or ignorance. 
 
 Clay makes a hard road in dry weather, but becomes very 
 sticky in wet, or even dusty after prolonged drought. Sand 
 packs well if wet, but makes hard pulling when dry. Gravel, 
 if ferruginous, will often cement to a good road surface, 
 which wears well under light traffic. Shale will also make 
 a good road. Natural road beds are, however, unsatisfactory 
 at best, and artificial ones of crushed stone (macadam roads) 
 are rapidly superseding them. 
 
 For this purpose a number of different kinds of rock are
 
 218 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 employed, including trap, granite, limestone, dolomite, and 
 sandstone. 
 
 The essential qualities of a stone for macadamizing are : 
 (1) Hardness to resist crushing under traffic. (2) Sufficient 
 abrasion to permit the formation of some dust which when 
 moistened will form a cement to bind the particles together. 
 (3) Freshness of the mineral grains. (4) Cheapness. Great 
 variation is found to exist among the different stones with 
 respect to these requirements, and even stones of the same 
 kind lack uniformity. 
 
 While the most practical test for road material is actual 
 use, this is not always a cheap or rapid method, and conse- 
 quently a series of physical tests has been adopted, which 
 is in use in most highway laboratories. The two important 
 tests are the abrasive test and impact test. In the former 
 the abrasive resistance of the stone is determined, in the 
 latter the cementing power of the powdered stone is meas- 
 ured, by forming it into briquettes, which are broken by a 
 series of blows. The same powder is remolded and again 
 broken to determine its recementing power. Stones with a 
 small amount of argillaceous and calcareous impurities often 
 appear to have good cementing power ; but in every case the 
 qualities of each stone have to be determined separately. 
 
 Since, however, stone for road building will not bear the 
 cost of long transportation, it becomes necessary to make a 
 careful selection of the best that the vicinity affords. Trap 
 rock and hard argillaceous limestone are perhaps more used 
 than any other materials. 
 
 Good stones for road building are more or less widely 
 distributed in most parts of the United States, so that any 
 detailed mention of localities is not needed.
 
 SOILS 219 
 
 REFERENCES ON ROAD MATERIALS 
 
 Merrill, N. Y. State Museum, Bull. 17, 1897 (N. Y.) ; Reid and Johnson, 
 Md. Geol. Surv., I and IV; Shaler, U. S. Geol. Surv., 16th Ann. 
 Kept., II : 227, 1895 (Mass.). See also bulletins issued by Highway 
 Division of Dept. of Agric., Wash., and Reports of Massachusetts 
 Highway Commission.
 
 PART II 
 
 METALLIC MINERALS
 
 CHAPTER XIII 
 ORE DEPOSITS 
 
 Definition. The term ore deposits is applied to concen- 
 trations of economically valuable metalliferous minerals 
 found in the earth's crust, while under the term ore are 
 included those portions of the ore body of which the metallic 
 minerals form a sufficiently large proportion to make their 
 extraction profitable. A metalliferous mineral or rock 
 might therefore not be an ore at the present day, but 
 become so at a later date, because improved methods of 
 treatment or other conditions rendered the extraction of 
 its metallic contents profitable. 
 
 A few metallic minerals serving as ores, such as gold, 
 copper, platinum, or mercury, sometimes occur in a native 
 condition ; but in most cases the metal is combined with 
 other elements, forming sulphides, hydrous oxides, carbon- 
 ates, sulphates, silicates, chlorides, phosphates, or rarer 
 compounds, the first five of these being the most numer- 
 ous. A deposit may contain the ores of one or several 
 metals, and there may also be several compounds of the 
 same metal present. 
 
 Gangue Minerals. Associated with the metallic minerals 
 there are usually certain common non-metallic ones which 
 carry no values worth extracting. These are termed the 
 gangue minerals. They often form masses in the ore deposit
 
 224 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 which can be avoided or thrown out in mining, but at other 
 times they are so intermixed with the valuable metalliferous 
 minerals that the ore is crushed and the two separated by 
 special methods. 
 
 Quartz is the most abundant gangue mineral, but calcite, 
 barite, fluorite, and siderite are also common, while dolo- 
 mite, hornblende, pyroxene, feldspar, rhodochrosite, etc., are 
 found in some ore bodies. 
 
 Origin of Ore Bodies. The fact that ores form masses 
 of greater or less concentration is explainable in two ways : 
 either they have been formed contemporaneously with the 
 inclosing rock; or else they have been formed by a process 
 of concentration at a later date. The first theory is found 
 to be applicable to some ores in igneous rocks, and probably 
 some sedimentary ones, while the second applies to most ore 
 deposits regardless of the character of the inclosing rock. 
 
 Ores of Contemporaneous Origin. If the ore in an igneous 
 rock were formed at the same time as the rock, it would 
 indicate a crystallization of metallic minerals from the 
 igneous magma during cooling ; and this, in some cases, is 
 true, it being found that the metallic elements in many 
 basic rocks tend to segregate during cooling, sometimes 
 forming masses of considerable size and of high purity. 
 This mode of origin, termed magmatic segregation (18, 34, 35,^ 
 36), was shown by Vogt to apply to the titaniferous ores of 
 Scandinavia; and although the importance of the theory 
 was not at first generally appreciated in America, where 
 deposits of this type are rare, still it is now generally 
 accepted. The best-known American examples of this 
 class are the titaniferous magnetites and the chromite ores.
 
 ORE DEPOSITS 225 
 
 Spurr has suggested (34) that certain ores found in acid 
 rocks, such as quartz veins, have also been formed by mag- 
 matic segregation. He believes that siliceous rocks, such 
 as granites, may originate by differentiation from a more 
 basic magma. A further development of this process 
 yields quartz -feldspar rocks, and after the minerals of 
 these have crystallized out, only pure silica is left, which 
 forms quartz veins. Examples of this type have been 
 noted by Spurr from Alaska, and by Turner from Silver 
 Peak, Nevada. 
 
 If ores in sedimentary rocks are of contemporaneous 
 origin, then the deposit must be a bedded one conforming 
 to the stratification of the rock, and this explanation more- 
 over requires the presence of metalliferous minerals in and 
 their deposition from sea water. While certain metallic 
 elements are found in the waters of the ocean, their quan- 
 tity is extremely small and not to be compared with what 
 may be found in disseminated or concentrated form in 
 sedimentary and igneous rocks. It has been shown, how- 
 ever, that some metallic minerals, such as limonite, pyrite, 
 or manganese, are occasionally precipitated on the ocean 
 floor. While economic geologists have assigned a contem- 
 poraneous origin to certain ores found in sedimentary strata, 
 and in certain instances their theories have been quite 
 generally regarded as correct (iron ores, ref. 36), still the 
 majority at the present day believe that most ore deposits 
 are of later date than the inclosing rock, and must have 
 been formed by a process of concentration, aided in the 
 majority of cases by circulating water. 
 
 Concentration of Ores in Rocks. In order to demonstrate 
 this, it is necessary to show: (1) the presence of disseminated
 
 226 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 minerals in the earth's crust ; (2) the existence of a solvent 
 or carrier; and (3) the presence in most cases of cavities 
 in which the precipitation of the ore can occur. 
 
 It is well known that metallic minerals in small quanti- 
 ties are widely distributed, in both igneous and sedimentary 
 rocks. Sandberger (31), for example, has shown by analyses 
 the presence of nickel, copper, lead, tin, and cobalt in such 
 minerals as hornblende, olivine, and mica ; and Curtis has 
 found traces of silver, gold, and lead in the quartz-porphy- 
 ries at Eureka, Nevada (U. S. Geol. Surv., Mon. VII : 80), 
 and silver, arsenic, lead, copper, gold, and silver in the 
 granite at Steamboat Springs, Nevada (U. S. Geol. Surv., 
 Mon. XIII : 350). Winslow has pointed out the presence 
 of small quantities of lead and zinc in the limestones of 
 Missouri and Wisconsin (lead and zinc, ref. 17), and 
 Wagoner has made similar tests on California sediments 
 (42). Since, however, the sediments were originally derived 
 from the igneous rocks, it follows that the latter must be 
 the original source of the minerals. It is interesting to 
 note that even in the igneous rocks the metals are not 
 impartially distributed, but that certain metals seem to 
 favor certain rocks (De Launay, Ann. d. Min., August, 
 1897, and ref. 34). Tin seems to favor granite, and chro- 
 rnite, peridotite. 
 
 As regards the second point, it is now generally admitted 
 that water is an important agent in the concentration of 
 many ores. While cold water, free from impurities, has 
 comparatively little solvent power, the presence of acids or 
 alkalies materially increases its capacity for solution, and 
 heat and pressure have also a great influence. Analyses of 
 mine, spring, and surface waters have shown the presence
 
 ORE DEPOSITS 
 
 227 
 
 of many dissolved alkalies and other salts (24), and occa- 
 sionally small quantities of metals. 
 
 The following two analyses, which will serve as examples, 
 give the calculated composition of (1) vadose, or shallow 
 water, from the 500-foot level of the Geyser silver mine, 
 Silver Cliff, Colorado, and (2) deep water from the 2000- 
 foot level of the same mine. The ore occurs in rhyolite. 
 The figures are grams per 1000 liters: 
 
 SiO a 25.90 
 
 A1 2 3 
 
 A1 2 3 ,PA . 
 
 FeC0 3 1.50 
 
 MnCOg 1.70 
 
 CaC0 3 93.50 
 
 Ca 3 P 2 8 
 
 CaF 2 
 
 SrCO 3 
 
 MgC0 3 42.85 
 
 K 2 SO 4 4.20 
 
 KCL 16.60 
 
 KBr, KI 
 
 Na 3 CO 3 38.70 
 
 Na 2 SO 4 60.50 
 
 NaNO 3 
 
 Na 2 B 4 7 
 
 LiCl 
 
 CO, 37.20 
 
 PbCO 3 Tr 
 
 CuC0 3 Tr 
 
 ZnCO 3 .40 
 
 24.42 
 1.06 
 
 7.25 
 1.19 
 
 Tr 
 
 Tr 
 
 3.29 
 
 621.84 
 
 19.18 
 
 361.34 
 
 Tr 
 
 1489.67 
 
 223.53 
 
 2.19 
 
 Tr 
 
 17.30 
 
 1418.61 
 
 1.74 
 
 .04 
 
 The higher percentage of dissolved substances in the deep 
 water is quite marked. 
 
 While the importance of hot waters as an agent in the
 
 228 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 formation of ore deposits is clearly recognized by many, and 
 traces of metals in solution are sometimes found, still ex- 
 amples of such deposits now forming are rare. Weed has 
 described a hot spring near Boulder, Montana (49), which is 
 depositing auriferous quartz, and the deposit is pointed out 
 by him to be identical with silver and gold bearing quartz 
 veins of the region between Butte and Helena, Montana. At 
 Steamboat Springs, Nevada, it has been found that the allu- 
 vial gravels underlying the hot spring sinters are cemented 
 by stibnite and pyrite (Lindgren, Amer. Inst. Min. Eng., 
 Trans. 1905 : 275). Of still more interest is the collection 
 by evaporation of copper from certain Javan hot springs, 
 in which the metal occurs as iodide of copper (Stevens, 
 Copper Handbook, IV : 156, 1904). 
 
 Water is known to be widely (11, 39) but not uniformly 
 distributed in the rocks of the earth's crust, and much of it 
 is in slow but constant circulation. While it is admitted by 
 most geologists that this water has been an important ore 
 carrier, collecting the disseminated metals in the rocks and 
 concentrating them in localities favorable to deposition, 
 still, there exists a difference of opinion regarding its 
 source, one class maintaining that it is largely of meteoric 
 origin, the other that it is derived chiefly from igneous 
 intrusions. 
 
 The chief exponent of the former theory is Van Hise, who 
 points out that the earth's crust may be divided into three 
 zones : (1) an upper zone of fracture, beginning at the sur- 
 face ; (2) a zone of combined fracture and flowage ; and 
 (3) a zone of rock flowage, or of no fracture. In the zone 
 of no fracture the pressure is so great that any dynamic 
 disturbances will cause flowage instead of fracturing, and no
 
 ORE DEPOSITS 229 
 
 cavities of appreciable size can exist. The depth of this zone 
 will depend on the kind of rock, Van Hise having figured 
 that cavities probably cannot exist in soft shales at depths 
 below 1625 feet (500 meters), and in firm granites below 
 32,500 ft. (10,000 meters). 
 
 Into this zone of no fracture, water from the surface can- 
 not penetrate, but above it there may be active percolation 
 by water. It is well known that rain water, falling on the 
 earth's surface, seeps through the soil into the underlying 
 rocks, permeating them to a variable depth, and forming a 
 more or less saturated zone, whose upper limit, lying at a 
 variable depth, is known as the ground- water level. In 
 this zone of more or less complete saturation there is a slow 
 but continual circulation, from areas of high to areas of low 
 pressure, along irregular winding routes, often leading back 
 to the surface and giving rise to springs. According to 
 Van Hise this percolating meteoric water obtains its load of 
 metallic elements from the rocks, which it traverses in its 
 passage through the zone of fracture, depositing some of it 
 in the trunk channels, but being incapable of entering the 
 zone of no fracture. 
 
 The opponents (6, 18, 20, 21) of Van Hise's theory point 
 to the following facts as evidence that waters of igneous 
 origin are more important as ore carriers, and are the 
 ones involved in deep circulation. Meteoric waters do 
 not reach great depths, in fact probably not more than 
 2000 feet or sometimes less from the surface, and when 
 they do penetrate to a greater distance from it, it is be- 
 cause they have followed some fissure. The lower levels 
 of many deep mines are so dry as to be dusty. Ores have 
 been concentrated at a much greater depth than that reached
 
 230 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 by surface waters. It is perfectly reasonable to regard 
 igneous rocks as an important source of water, and the 
 experiments of Daubree have shown that a molten granite 
 contains a large amount of water vapor which it retains 
 while at great depths, but gives off on approaching the 
 surface and cooling. While the temperature and pressure 
 are still high this water escapes as vapor, and later, with 
 decrease in temperature and pressure, as a liquid. Under 
 favorable conditions this water may force itself upwards 
 aud finally mingle with meteoric waters, carrying metals 
 obtained both from the liberated waters and, to a less extent, 
 from the leaching of cooled igneous rock. 
 
 It is an undeniable fact that most metalliferous veins are 
 found in areas of igneous rocks, and Lindgren (see refer- 
 -ences on gold, 79) has shown that in the case of the gold de- 
 posits of North America the periods of vein formation agreed 
 closely with those of igneous activity. It is also a noteworthy 
 fact that, with the exception of the deposits of commoner 
 metals, such as iron, and some copper, lead, and zinc, ores 
 are found in close association with igneous intrusions, which 
 seems to postulate a close connection between igneous rocks 
 and ore deposits, as advocated by such authorities as Weed, 
 Kemp, Lindgren, and Emmons; and although opposed by 
 Van Hise, it is now held by many economic geologists that 
 most metalliferous deposits, aside from ores of iron, have 
 resulted by deposition from ascending waters in regions of 
 igneous intrusions, the waters being probably in large part 
 at least of igneous origin. This much should be said. The 
 metalliferous minerals as originally deposited have not 
 always been sufficiently concentrated to serve as ores, but 
 they have become concentrated at a later date by meteoric
 
 ORE DEPOSITS 231 
 
 waters, as at Bisbee, Arizona. (See Ransome, under copper 
 references.) Posepny (24), in his work on the Genesis of 
 Ore Deposits, distinguishes between descending surface 
 waters, or vadose circulations, and ascending waters from 
 great depths. It is the former that have been active in 
 the secondary concentration of ores. 
 
 Formation of Cavities. The deposition of ores in the 
 rocks is greatly facilitated by the presence of cavities along 
 which the ore-bearing solutions freely pass, and consequently 
 a great many ore deposits occur in such spaces. There are 
 a number of different ways in which cavities may be formed 
 in rocks. The percolation of surface water through certain 
 ones, such as limestones, often results in the formation of 
 solution cavities, these in many instances attaining the size 
 of veritable caverns ; a soluble rock may contain more or 
 less insoluble material, such as clay or chert, which collapses 
 when the surrounding rock is dissolved, and partly fills the 
 cave thus formed. At times the more resistant parts are so 
 bound together that they remain in their original position, 
 forming a porous mass, in the cavities of which mineral 
 matter is later deposited. 
 
 Dynamic disturbances produce cavities of variable extent 
 in many different rocks. These range from microscopic 
 cracks, like the rift planes of granite, to enormous faults 
 of great depth and linear extent, and include the joint 
 planes so common in the rocks of almost all regions. Fault 
 fissures form one of the most important types of passage- 
 ways for ore-bearing solutions. They are often irregular, 
 branching, and partly filled by fault breccia, caused by the 
 breaking of the rock during the movement along the fault 
 plane. A third important group of cavities in the rocks are
 
 232 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 those resulting from shrinkage of the mass, which may be 
 due to (1) shrinkage during cooling, as in igneous rocks ; 
 (2) shrinkage during certain forms of replacement. For 
 example, the change of carbonate of lime to dolomite is 
 accompanied by a shrinkage of the mass, which renders the 
 dolomite more porous than the original rock; and in the 
 alteration of siderite to limonite there is a shrinkage of 
 fully 20 per cent (25). A fourth type of channel way for the 
 passage of underground water is the contact plane between 
 two quite different kinds of rock, one of them fairly dense 
 and impervious ; for example, the contact plane between a 
 granite mass and a series of sedimentary strata. 
 
 Precipitation of Metals from Solution. The conditions 
 which increase the solvent power of water have already been 
 referred to. To this should be added the statement that 
 solution generally takes place out of contact with the air. 
 
 When the ore-bearing solutions approach the surface or 
 enter a cavity, the load of dissolved minerals is deposited 
 wholly or in part, due to cooling of the solution, release of 
 pressure, or by oxidation, which converts certain soluble 
 salts into an insoluble form. Chemical reactions between 
 two different solutions meeting in a cavity or at the inter- 
 section of fissures may also cause precipitation. Iron com- 
 pounds, for example, may go into solution in the form of 
 carbonate, but on exposure to the air the latter is rapidly 
 changed to limonite, which is insoluble. 
 
 While the deposition of the ore often takes place in cavi- 
 ties below the surface, there are cases in which it is not 
 precipitated until it reaches the surface, as in a pond or in 
 the soil. Certain special conditions of deposition should 
 also be noted.
 
 ORE DEPOSITS 233 
 
 Replacement or Metasomatism (22). It is a well-known 
 fact that under favorable conditions mineral-bearing solu- 
 tions may attack the minerals of the rocks which they pene- 
 trate, dissolving them wholly or in part, and depositing 
 some of the original burden in place of the material re- 
 moved. This replacement, termed "metasomatism," is an 
 important factor in the formation of many ore deposits, and 
 may involve a total or partial loss of certain constituents of 
 the rock attacked and a gain of others, even to the extent 
 of introduction of entirely new compounds and elements. 
 The change takes place molecule by molecule, a grain of 
 vein material being deposited for each grain of replaced 
 rock dissolved. The ' ore-bearing solutions penetrate the 
 rock first along the smallest cracks, and then work their 
 way into the individual mineral grains along their cleavage 
 planes, until they finally permeate the entire mass. 
 
 Metasomatic processes show great variety, and are not 
 confined to one kind of rock or mineral. In its simplest 
 form the result of metasomatism may often be seen in fossil- 
 iferous rocks, where organic remains have been replaced by 
 common mineral compounds, as in the replacement of the 
 lime carbonate of corals by quartz, or the replacement of 
 molluscan shells by pyrite. From such simple conditions 
 there is every gradation to the complete replacement of 
 extensive areas of rock by ore, or to the extensive operation 
 of metasomatism along the walls of fissure veins. In most 
 cases the changes are believed to be due to the action of 
 underground water ; but in some instances it seems probable 
 that the processes of pneumatolysis (see below) were in- 
 volved. Moreover, high temperature, pressure, and concen- 
 tration seem to have been present in replacement, especially
 
 234 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 in the case of ore deposits in fissure veins. It is rarely 
 possible, without examination of a thin section with the 
 microscope, to decide whether minerals present are due to 
 replacement or to simple interstitial filling. Fig. 37 shows 
 a replacement vein in syenite. 
 
 Some minerals are more easily replaceable than others, 
 consequently the rocks in which such predominate might 
 
 be more widely affected than 
 others. (See Butte, Mon- 
 tana, and Clifton, Arizona, 
 under Copper.) 
 
 The theory of metasoma- 
 tism was first applied in 
 America by Pumpelly in 
 1871, in explanation of the 
 copper deposits of Michigan; 
 but the ore bodies of Lead- 
 
 FIG. 37. -Replacement vein in Syenite v iH e Colorado, and Eureka, 
 Rock, War Eagle Mine, Rossland, 
 
 B. c. (a) granular orthociase with Nevada, were the first large 
 
 a little sericite ; (b) secondary biotite ; . 
 
 (q) secondary quartz ; (c) chlorite ; deposits whose origin was 
 
 explained by it. Since then 
 the great importance of 
 metasomatism has been widely recognized, and it has become 
 evident that preexisting cavities are not necessary to the 
 formation of ore bodies. 
 
 Concentration by Eruptive After-action (45) (Pneumatolysis*). 
 The term pneumatolysis was first used by Bunsen to 
 describe the combined action of gases and water. This 
 assumes that during cooling many magmas give off watery 
 vapor, heated above its critical temperature (365 C.) and 
 under high pressure. With this there are also mineralizing 

 
 ORE DEPOSITS 235 
 
 vapors and metals, combined to form volatile compounds. 
 These materials, together with any other elements given off, 
 may then be deposited either at the contact between the 
 intrusive and the surrounding rocks, forming a true contact 
 deposit, or, as in the case of the tin veins of Cornwall, Eng- 
 land, in fissures formed in the surrounding rocks by the 
 intrusions. Though the great importance of this class of 
 ore deposits has been but recently recognized, it is now 
 being found that a number of known deposits are of this 
 origin. They are usually found in calcareous rocks at or 
 near the contact with granitic intrusions. The ore minerals 
 are specularite, magnetite, bornite, chalcopyrite, pyrite, pyr- 
 rhotite, and more rarely galena and blende; while asso- 
 ciated with them are characteristic contact minerals, such 
 as epidote, wollastonite, garnet, vesuvianite, and hematite. 
 The sulphides sometimes carry gold and silver, and tellu- 
 rides are not rare (51). A characteristic feature, however, 
 is the association of iron oxides and sulphides, an almost 
 unknown thing in fissure veins. Since these minerals are 
 sometimes found in limestones of great purity, it is consid- 
 ered as quite evident that in such cases, at least, most of the 
 foreign matter has been derived from the igneous mass. 
 Examples of contact deposits are South Mountain, Idaho, 
 Seven Devils District, Idaho, and Clifton, Arizona (in part). 
 
 Other Causes of Precipitation. Some fifty years ago not 
 a few geologists, prominent among them De la Beche, advo* 
 cated the theory of ore precipitation by galvanic action (1, 9), 
 and a number of experiments were made attempting to prove 
 the existence of such action ; now little weight is attached 
 to this theory. 
 
 More recently Gillette (13) has expressed the view that
 
 236 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 osmotic pressure is an important factor in ore deposition, 
 aiding to spread the dissolved metals through the water in 
 the rocks, toward centers of crystallization. 
 
 Forms of Ore Bodies. Ore bodies vary greatly in their 
 form, and this character has at times been used as a basis 
 of classification by some writers ; but the more modern tend- 
 ency is to use genetic characters instead, making form of 
 secondary importance in the grouping. Certain forms of 
 ore bodies are so numerous as to deserve special mention. 
 
 Fissure Veins (8, 12, 16, 29, 47). A fissure vein may be 
 defined (22) as a tabular mineral mass occupying or closely 
 associated with a fracture or set of fractures in the inclosing 
 rock, and formed either by filling of the fissures as well as 
 pores in the wall rock, or by replacement of the latter (meta- 
 somatism). When the vein is simply the result of fissure 
 filling, the ore and gangue minerals are often deposited in 
 successive layers on the walls of the fissure (Rico, Colorado), 
 the width of the vein depending .on the width of the fissure 
 and the boundaries of the ore mass being sharp. In most 
 cases, however, the ore-bearing solutions have entered the 
 wall rock and either filled its pores or replaced it to some 
 extent, thus giving the vein an indefinite boundary. There- 
 fore the width of the fissures does not necessarily stand in any 
 direct relation to the width of the vein (47) (Butte, Montana). 
 
 Veins formed by the simple filling of a fissure often show 
 a banded structure of varying regularity termed (Trustification l 
 by Posepny (Fig. 38), which may sometimes be brecciated 
 by later movements along the fissure. Secondary bands 
 may be formed after reopening of the fissures (Fig. 38), 
 and such a movement may cause brecciation of the vein 
 
 1 The replacement of certain layers only in a bed of stratified rock may 
 also produce a banded structure.
 
 ORE DEPOSITS 
 
 237 
 
 material, or allow the ingress of the weathering agents 
 which decompose the wall rock, giving rise to a layer of 
 clay known as selvage. Where the fissure has not been com- 
 pletely filled, thus leaving a central space into which the 
 crystals of gangue 
 project, a comb 
 structure is formed. 
 The bands in a 
 filled fissure may 
 consist of gangue 
 and ore alternat- 
 ing, or of different 
 ores. Among the 
 commonest ores 
 seen in these fis- 
 sure veins are py- 
 rite, chalcopyrite, 
 galena, blende, and 
 sulphides of silver. 
 Some regions af- 
 ford especially fine 
 examples of banded 
 veins, notably those 
 of Grass Valley, California, and Rico, Colorado. Abroad 
 the mines of Freiberg, Saxony, and Clausthal, Prussia, also 
 often yield magnificent specimens. Even in a single vein 
 the ore may follow certain streaks which are termed shutes, 
 or again it may be restricted to pockets of great richness, 
 which are known as bonanzas. 
 
 Fissure veins in which metasomatic action has predom- 
 inated show great irregularity of width and an absence of 
 
 FIG. 38. Section of vein in Enterprise mine, Rico, 
 Colo. The right side shows later banding due to 
 reopening of the fissure. After Ransome, U. S. 
 Geol. Surv., 22d Ann. Kept., 11 : 262.
 
 238 
 
 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 well-defined boundaries ; they also lack as a rule the sym- 
 metrical banding and the breccias cemented by vein material. 
 There are all gradations between these two types of fissure 
 veins; and even in a single vein, simple filling may occur 
 in one part and replacement in another. 
 
 Veins often split (PI. XX, Fig. 2), or intersect, and at the 
 point of intersection or splitting the ore is apt to be richer. 
 There are other reasons for variations in richness, among 
 the most important being the character of the wall rocks, 
 some kinds being more easily replaceable or more porous 
 than others. Their physical character will moreover exer- 
 cise considerable influence on the shape and size of the 
 fissure. Tough rocks like gneiss, for example, give a clean- 
 
 cut fissure, but in brittle rock 
 the fissure is apt to split fre- 
 quently, and therefore a vein 
 may be workable in one kind 
 of rock, but becomes worth- 
 less when passing to another, 
 since the profuse branching 
 interferes with economical 
 
 . . . 
 
 After Beck, Lehre von der Erzla- mining (* Ig. 39). A dike 
 gerstatten: 135, 1901. 
 
 FIG. 39. Section showing change in 
 character of vein passing from 
 
 gneiss (</) to quartz porphyry (p). 
 
 larities, and in a given region the fissures not uncommonly 
 show great variation in their direction. Thus at Butte, 
 Montana, east-west veins predominate (Fig. 53), while in 
 the Silverton district of Colorado they cut the rocks in all 
 directions, but the majority show a north of east trend. In 
 the Monte Cristo, Washington, district the veins with north- 
 east trend are predominant (Fig. 40). 
 
 Fissure veins vary considerably in their width, swelling
 
 ROBERT W. WEBB 
 
 GEOLOGY DEPT., U.C.LA. 
 
 ORE DEPOSITS 
 
 239 
 
 at some points and pinching or narrowing at others. They 
 also at times show lateral enrichment ; for instance, where 
 the ore cuts through stratified beds, into which the ore- 
 bearing solutions have spread out laterally along the planes of 
 stratification or other 
 planes. It has been 
 noticed in some veins, 
 especially those formed 
 by replacement, that 
 the filling varies with 
 the wall rock, at times w 
 changing suddenly ; 
 but where the vein is 
 formed wholly by the 
 filling of an open fis- 
 sure, the rock exerts 
 no influence on the FIG. 40. Tabulation of 
 character of the ore 
 (47). If the vein is 
 inclined, the lower wall is spoken of as the foot wall and the 
 upper one as the hanging wall. 
 
 Parallel fissures are not uncommon, but the several veins 
 do not necessarily show an equal degree of richness. Where 
 the vein is of composite character, that is, consisting of 
 closely spaced parallel fissures accompanied sometimes by a 
 mineralization of the intervening rock, it is termed a lode. 
 The top of the vein is called the apex, and is occasionally 
 traceable for a long distance. 
 
 Linked veins represent a type in which the parallel fissures 
 are connected by diagonal ones (Fig. 41), giving a series 
 resembling the links of a chain. 
 
 trikes of principal 
 veins in Monte Cristo, Wash., district. After 
 Spurr, U. S. Geol. Surv., 22d Ann. Kept., 
 II : 810, 1902.
 
 240 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 FIG. 41. Linked veins. After Ordonez. 
 
 Crash veins are a special type of fissure vein, formed by 
 the enlargement of joint planes and sometimes bedding 
 
 planes. They 
 are characteris- 
 tic of the up- 
 per Mississippi 
 Valley lead and 
 zinc region, but 
 are usually of 
 limited extent 
 and local impor- 
 tance. In the 
 simplest form 
 
 they are a vertical fissure, but develop into types shown 
 in Fig. 42. 
 
 Filling of Fissure Veins (16). The manner in which 
 fissure veins have been filled, and the source of the metals 
 which they contain, formed a most fruitful subject of dis- 
 cussion among the earlier geologists. Four general theories 
 were advanced at an early date (2). They are: (1) Con- 
 temporaneous formation, a 
 theory no longer advocated 
 by any one. (2) Descension, 
 which likewise no longer has 
 many adherents. (3) Lateral 
 secretion, in which the vein 
 contents are supposed to have 
 been leached from the wall 
 rock, usually in the immediate vicinity of the fissure, but 
 at variable depths below the surface ; some geologists hold- 
 ing this view believe that the area leached was very exten- 
 
 Fio. 42. Gash vein with associated 
 "flats" (a) and "pitches" (6). 
 Wisconsin zinc region. After Grant, 
 Wis. Geol. and Nat. Hist. Surv., 
 Bull. IX : 62.
 
 ORE DEPOSITS 241 
 
 sive and not confined to the immediate vicinity of the 
 walls. (4) Ascension, the material being deposited by infil- 
 tration, sublimation with steam, sublimation as gas, or 
 igneous injection. The several arguments for or against 
 these theories are well set forth in Kemp's paper (ref. 16), 
 and it will suffice here to state that of the various ones 
 those of lateral secretion and ascension by infiltration are 
 the most rational. It is probable that the majority of geol- 
 ogists now believe in a modified theory of lateral secretion, 
 in which the area of supply extends beyond the immediate 
 walls of the fissure, and that the ore-bearing solutions have 
 either ascended the fissure or entered through the walls. 
 
 'B 
 
 FIG. 43. Section at Bonne Terre, Mo., showing ore disseminated through 
 limestone. 
 
 limestone. 
 
 Other Forms of Ore Deposits. Impregnations represent 
 deposits in which the ore has been deposited in the pores of 
 the rock, or the crevices of a breccia (Keweenaw Point, 
 Michigan). Fahlband is a belt of schist impregnated with 
 sulphides. Ore channels include those ore bodies formed 
 along some path which the mineral solutions could easily 
 follow, as the boundary between two different kinds of rock 
 (Leadville, Colorado, Mercur, Utah). Bedded deposits, found 
 parallel with the ; stratification of sedimentary rocks, and 
 sometimes of contemporaneous origin (Clinton iron ore). 
 Contact deposits, as now understood, represent ore bodies 
 formed along the contact of a mass of igneous and sedimen- 
 tary rock (usually calcareous), the ore having been derived
 
 242 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 wholly or in part from the intrusive mass (Clifton, Arizona, 
 in part). Chamber deposits, whose ore has been deposited in 
 caves of solution (Missouri lead and zinc ores). Dissemina- 
 tions, deposits in which the ore is disseminated through the 
 rock (Southeastern Missouri lead ores). 
 
 Secondary Changes in Ore Deposits. Ore deposits may be 
 changed in their upper parts by weathering agents, while the 
 lower-lying portions, below the ground water level, are often 
 enriched by secondary processes. 
 
 Weathering or Superficial Alteration (25) . This involves 
 both chemical and physical changes similar to the decay and 
 disintegration of common rocks, but the great number of 
 mineral compounds involved, including many with metallic 
 base, give rise to a large number of intricate chemical reac- 
 tions. Since many of the minerals in ore deposits are more 
 easily decomposed than the common rock-forming minerals, 
 the alteration is quite rapid and extends to a greater depth 
 than in the country rock. There is, however, marked varia- 
 tion in the rate at which the different ore-forming minerals 
 decay, and this variation exists even in a single group, like 
 the sulphides in which the order or rate of decomposition is 
 arsenopyrite, pyrite, chalcopyrite, blende, galena, chalcocite, 
 and tetrahedrite (41). 
 
 The altered portion of the ore deposit is known as the 
 gossan, or iron hat (French, chapeau-de-fer ; German, eisener 
 Hut}, because the deposit is usually stained by iron minerals, 
 such as limonite, which may sometimes completely mask the 
 true nature of the ore. 
 
 The first chemical changes are oxidation or hydration, or 
 both, and these, together with other changes, produce many
 
 ORE DEPOSITS 
 
 243 
 
 soluble compounds, which can be, and often are, leached out 
 of the gossan by percolating waters. An example of oxida- 
 tion is the alteration of pyrite to ferrous and ferric sulphate, 
 and by hydration and further oxidation to limonite. Chal- 
 copyrite oxidizes to copper sulphate, and by hydration and 
 further oxidation to copper carbonate, silicate, or oxide. We 
 see therefore that the first change in each of the above cases 
 is the same, sulphates being formed from sulphides, but the 
 later changes are different, the iron sulphate changing to 
 hydrous oxide, while the copper forms a different set of com- 
 
 No.3 L...I Cur .nd Ilolbrook 
 
 No. 4 L...I Car .ad Hoi brook 
 
 No.9 L...1 Holbnok 
 
 FIG. 44. Section through Copper Queen Mine, Bisbee, Ariz., showing variable 
 depth of weathering. After Douglas, Amer. Inst. Min. Engrs., Trans. 
 XXIX., 1900. 
 
 pounds. Reduction may, however, occur, as when, for ex- 
 ample, two partly oxidized salts of iron and copper react 
 with each other, giving ferric salts and metallic copper, owing 
 to the stronger affinity of iron for oxygen. 
 
 The porosity of the gossan is sometimes due to leaching, 
 sometimes to shrinkage, as when siderite or pyrite change to 
 limonite. Hydration, on the contrary, causes expansion. 
 
 The depth of weathering depends on topographic condi- 
 tions, chemical nature and porosity of the deposits, and 
 climate ; but in any event it is liable to vary in the same 
 deposit, owing to variation in the permeability of different 
 parts of the mass (Fig. 44). In Arizona many copper de-
 
 244 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 posits have been changed from sulphides to carbonates, to a 
 depth ranging from 100 to 700 feet; the oxidized ores of 
 the Appalachian region average about 100 feet in depth ; 
 while those of the Rocky Mountain area range from 50 to 
 700 in depth. 
 
 The ferric sulphate produced by the weathering of pyrite 
 is a most important factor in the alteration of ore deposits. 
 When formed it attacks pyrite and other sulphides, convert- 
 ing them into sulphates, at the same time being itself reduced 
 to ferrous sulphate, which is in part changed to limonite and 
 sulphuric acid. That portion remaining unreduced begins 
 anew the scale of change. Ferric sulphate is thus the main 
 agent by which the sulphides are dissolved. Moreover it 
 also acts as a solvent of free gold. 
 
 All the metallic contents are not, however, leached from 
 the gossan, for some minerals are either difficult to dissolve 
 or remain unattacked. Thus in some cases the leaching 
 produces an enrichment by the removal of worthless con- 
 stituents and a consequent increase per ton of valuable 
 minerals. The soluble compounds produced by weathering 
 are often carried downward by percolating water and de- 
 posited in an irregular zone between the gossan and the 
 unweathered ore below. In many copper deposits there is 
 found a rich zone of black copper between the gossan and 
 unaltered sulphides. 
 
 Secondary Deposition below Ground Water Level (4, 41). 
 If the body of unaltered sulphides below is broken by 
 fissures, the solutions containing the various metallic sul- 
 phates and sulphuric acid will enter them, penetrating at 
 times to considerable depths. 
 
 If pyrite or pyrrhotite are present at these depths, a reac-
 
 OKE DEPOSITS 245 
 
 tion occurs between the ferric sulphate, the dissolved metallic 
 sulphides, and the pyrite. This may result in the precipita- 
 tion of new sulphides on the walls of the fracture, forming 
 rich patches of ore or bonanzas (28) . The association of these 
 fractures formed after the primary sulphides is an important 
 character of value to the mining engineer, and from what has 
 been said above, it can be seen what an important role py- 
 rite plays in the secondary enrichment process. It has been 
 noticed, however, that pyrite is not the only reducing and pre- 
 cipitating agent in ore deposits. Carbon is a strong reducer, 
 and other minerals also exert a variable influence (14). (See 
 deposition of lead and zinc in Wisconsin and Ozark region, 
 Chap. XVII.) 
 
 Value of Ores. The terms rich and poor, as applied to 
 ores, are used with great frequency, although most indefinite 
 and often meaningless. Under very favorable conditions it 
 is possible to profitably work an ore of given value at one 
 locality, while if found under other less favorable conditions 
 at another point it might be almost worthless. 
 
 Those who have not given special study to ore deposits 
 often fail to realize that in the majority of ores the per- 
 centage of metal contained in the ore falls considerably 
 below the theoretic percentage of the metallic contents in 
 the ore-bearing minerals, due of course to the presence of 
 a greater or less quantity of gangue minerals which tend to 
 dilute the metallic values of the vein. Lake Superior copper 
 ores contain as little as .65 per cent native copper ; and many 
 sulphide ores running as low as 5 or 6 per cent metallic 
 copper or even less are successfully worked. Many low- 
 grade lead ores are profitably mined because their gold and
 
 246 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 silver contents more than pay the cost of metallurgical treat- 
 ment. Gold ores alone, running as low as $2 or $3 per ton, 
 can likewise be successfully worked at times. In many cases 
 the metallic contents of the ore is increased by mechanical 
 concentration or by roasting (in the case of sulphides), or 
 both, before the ore is smelted. 
 
 Classification of Ore Deposits. Many attempts have been 
 made to develop a suitable classification of ore deposits, and 
 many schemes have been suggested (17). These are usually 
 based either on form, mineral contents, or mode of origin. 
 The first is perhaps the most practical from the miner's 
 standpoint, the second is undesirable because several kinds 
 of ore may often be found in the same ore body, while the 
 third is the most scientific, and is of value to the mining 
 geologist and engineer. 
 
 Those desiring to look into this phase of the subject in 
 more detail are referred to the bibliography at the end of this 
 chapter, especially the papers by Kemp (17), Posepny (24), 
 and Van Hise (40). 
 
 Only one classification is given here, viz. that of W. 
 H. Weed, not because it is considered entirely satisfactory 
 or especially simple, but because it embodies the results of 
 the more modern studies of ore deposits and their genetic 
 character. 
 
 CLASSIFICATION OF ORE DEPOSITS (AFTER WEED) 
 
 A. Igneous, magmatic segregation. 
 (a) Siliceous. 
 
 1. Masses, Aplitic masses. Ehrenberg, Shartash. 
 
 2. Dikes, Beresite or Aplite. Berezovsk. 
 
 3. Quartz veins. Alaska, Randsburg, Black Hills.
 
 OKE DEPOSITS 247 
 
 (6) Basic. 
 
 1. Peripheral masses. Copper, iron, nickel. 
 
 2. Dikes, titaniferous iron. Adirondacks, Wyoming. 
 
 B. Igneous emanations. Deposits formed by gases above or near 
 
 the critical point, e.g. 365 C. and 200 atmospheres for 
 H 2 O. 
 (a) Contact metamorphic deposits. 
 
 1. Deposits confined to contact. Magnetite deposits, chalcopy- 
 
 rite deposits, Kristiania type, gold ores, Bannock type. 
 
 2. Deposits impregnating and replacing beds of contact zone. 
 
 Chalcopyrite deposits, pyrrhotite ores, magnetite ores, Can- 
 anea type, Gold tellurium ores, Elkhorn type, Arsenopyrite 
 ores, Similkameen type. 
 (6) Veins closely allied to magmatic veins and to Division D. 
 
 1. Cassiterite. Cornwall. 
 
 2. Tourmaline copper. Sonora. 
 
 3. Tourmaline gold. Helena, Mont., Minas Geraes, etc. 
 
 4. Augite copper, etc. Tuscany. 
 
 C. Fumarolic deposits. 
 
 (a) Metallic oxides, etc., in clefts in lava. No commercial impor- 
 tance. Copper, iron, etc. 
 
 D. Gas-aqueous or pneumato-hydato-genetic deposits, igneous emana- 
 
 tions, or primitive water mingled with ground water, 
 (a) Filling deposits. 
 
 1. Fissure veins. 
 
 2. Impregnation of porous rock. 
 
 3. Cementation deposits of breccia. 
 (6) Replacement deposits. 
 
 1. Propylitic. Comstock. 
 
 2. Sericitic kaolinic, calcitic, Copper silver, Silver lead. Clausthal. 
 
 3. Silicic dolomitic, silver lead, aspen. 
 
 4. Silicic calcitic, cinnabar. 
 
 5. Sideritic silver lead. Coeur d'Alene, Slocan, Wood River. 
 
 6. Biotitic gold copper. Rossland. 
 
 7. Fluoric gold tellurium. Cripple Creek. 
 
 8. Zeolitic.
 
 248 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Structure Types of Above 
 Fissure Veins. 
 
 Volcanic stocks, Nagyag. Cripple Creek. 
 Contact chimneys. Judith. 
 Dike replacements and impregnations. 
 Bedding or contact planes. Leadville, Mercur. 
 Axes of folds, synclinal basins, anticlinal saddles. Bendigo, 
 Elkhorn. 
 
 E. Meteoric waters. Surface derived, 
 (a) Underground. 
 
 1. Veins. 
 
 2. Replacements. Iron ores, Michigan ; copper ores, Michigan ; 
 
 lead, zinc. 
 
 3. Residual. Gossan iron ores, manganese deposits. 
 (6) Surficial. 
 
 1. Chemical. Bog iron ores, copper ores, sinters. 
 
 2. Mechanical. Gold and tin placers. 
 Sedimentary beds, iron ores, etc. 
 
 F. Metamorphic deposits. Ores concentrated from older rocks by 
 
 metamorphism, dynamo or regional. 
 
 Igneous ore deposits, forming the first division, are those 
 in which the metallic minerals have crystallized directly 
 from the igneous magma during cooling. 
 
 The pneuinatolytic deposits include those formed along 
 igneous contacts, the material being supplied by the in- 
 trusive, as explained on an earlier page. 
 
 The gas-aqueous deposits include those which have been 
 deposited from a mixture of water and steam, probably under 
 pressure and at high temperature. They may either fill true 
 fissures or porous deposits, or replace the wall rock lining 
 a narrow fissure. It will be seen that the types mentioned 
 under B and C might pass into each other. The same 
 igneous mass could at great depths give off metallic min-
 
 ORE DEPOSITS 249 
 
 erals under conditions mentioned under B, while higher 
 up the emission from it would yield a deposit, classifiable 
 under C. 
 
 Fumarolic deposits include those in which metallic com- 
 pounds are deposited from volcanic vapors or gases in clefts 
 in lavas. They are of no commercial importance. 
 
 The last class is the result of meteoric circulation, the 
 waters having collected the ore particles from the rocks 
 through which they moved, and deposited them under favor- 
 able conditions, either on the surface or below it. 
 
 REFERENCES ON ORE DEPOSITS 
 
 GENERAL. 1. Barus, Amer. Inst. Min. Engrs., Trans. XIII : 417, 1885. 
 (Electrical activity in ore bodies.) 2. von Cotta-Prime, Ore De- 
 posits (English translation by Prime, N. Y., 1870). 3. Don, Amer. 
 Inst. Min. Engrs., Trans. XXVII : 564, 1898. (Genesis of gold.) 
 4. Emmons, Amer. Inst. Min. Engrs., Trans. XXX : 177, 1901. (Sec- 
 ondary enrichment ore deposits.) 5. Emmons, Amer. Inst. Min. 
 Engrs., Trans. XXII : 53, 1894. (Geol. distribution useful metals.) 
 6. Emmous, Geol. Soc. Amer., Bull. XV : 1, 1904. (Theories of ore 
 deposition.) 7. Emmons, Amer. Inst. Min. Engrs., Trans. XVI: 804, 
 1888. (Structural relations of ore deposits.) 8. Emmons, Colo. Sci. 
 Soc.. Proc. II : 189. 1885-7. (Origin of fissure veins.) 9. Fox, 
 Amer. Jour. Sci. i, XXXVII : 199 ? 1839. (Vein formation by gal- 
 vanic agency.) 10. Fuchs et De Launay, Traite des Gites Mineraux 
 et Metallif eres, Paris, 1893. 11. Finch, Colo. Sci. Soc., Proc. VII : 193, 
 1904. (Underground waters and ore deposition.) 12. Glenn, Amer. 
 Inst. Min. Engrs., Trans. XXV : 499, 1896. (Fissure walls.) 13. Gil- 
 lette, Amer. Inst. Min. Engrs., Trans. XXXIV: 710. (Osmosis 
 theory.) 14. Jenney, Amer. lust. Min. Engrs., Trans. XXXIII: 445, 
 1904. (Chemistry of ore deposition.) 15. Kemp, S. of M. Quart., 
 X: 54,116, 326, 1889; XI: 359,1890; XII : 218, 1891. (Literature 
 on ore deposits.) 16. Kemp, S. of M. Quart., XIII : 20, 1892. (Fill- 
 ing of veins.) 17. Kemp, S. of M. Quart., XIV : 8, 1893. (Classifi- 
 cation of ore deposits.) 18. Kemp, Min. Indus., IV: 755, 1896. 
 (Theories of origin of ores.) 19. Kemp, Ore Deposits of United 
 States and Canada, N. Y., 1903. 20. Kemp, Amer. Inst. Min. Engrs., 
 Trans. XXXIII : 699, 1903. (Relation of igneous rocks to ore 
 deposition.) 21. Kemp, Amer. Inst. Min. Engrs., Trans. XXXI : 169,
 
 250 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 1901. (Igneous rock and vein formation.) 22. Lindgren, Amer. 
 Inst. Min. Engrs., Trans. XXX : 578, 1901. (Metasomatic processes 
 in fissure veins.) 23. Lindgren, Amer. Jour. Sci. iv, V : 418, 1898. 
 (Orthoclase gangue.) 24. Posepny, Amer. Inst. Min. Engrs., Trans. 
 XXIII: 197, 1894. (Genesis of ore deposits.) 25. Penrose, Jour. 
 Geol., II : 288, 1894. (Weathering of ore deposits.) 26. Phillips, 
 Treatise on Ore Deposits, London, 1884. 27. Rickard, Eng. and 
 Min. Jour., LXXIII : 106, 1902. (Recent advances in study of ore 
 deposits.) 28. Rickard, Amer. Inst. Min. Engrs., Trans. XXXI : 198, 
 
 1902. (Bonanzas in gold veins.) 29. Rickard, Amer. Inst. Min. 
 Engrs., Trans. XXVI : 193, 1897. (Vein walls.) 30. Rickard, Eng. 
 and Min. Jour., LXV : 494, 1898. (Minerals accompanying gold.) 
 
 31. Sandberger, Untersuchungen iiber Erzgange, Wiesbaden, 1882. 
 
 32. Suess, Eug. and Min. Jour., LXXVI : 52, 1903. (Hot springs.) 
 
 33. Spurr, Eng. and Min. Jour., LXXVI : 54, 1903. (Relation of 
 rock segregation to ore deposition.) 34. Spurr, Amer. Inst. Min. 
 Engrs.. Trans. XXXIII : 288, 1903. (Magmatic segregation of rocks 
 and ores.) 35. Vogt, Zeitsch. f. Prak. Geol., 1 : 4, 125, 257, 1893. 
 (Magmatic segregation of ores.) 36. Vogt, Min. Indus., IV : 743, 
 1896. (Formation of eruptive ore deposits.) 37. Vogt, Zeitsch. 
 f. Prak. Geol., VI : 225, 314, 377, 413, 1898 ; VII : 10, 1899. (Dis- 
 tribution of elements and concentration of metals in ore bodies). 
 38. Vogt, Amer. Inst. Min. Engrs., Trans. XXXI : 125, 1902. (Prob- 
 lems in geology of ore deposits.) 39. Van Hise, Amer. Inst. Min. 
 Engrs., Trans. XXX: 27,1901. (Deposition of ores.) 40. Van Hise, 
 U. S. Geol. Surv., Mon. XLVII, 1905. (Metamorphism.) 41. Weed, 
 Amer. Inst. Min. Engrs., Trans. XXX : 424, 1901. (Enrichment, gold 
 and silver veins.) 42. Wagoner, Amer. Inst. Min. Engrs., Trans. 
 XXXI : 798, 1902. (Gold and silver in sedimentary rocks.) 43. Weed, 
 Eng. and Min. Jour., LXXVI: 193, 1903. (Cross vein ore shoots.) 
 44. Weed, Eng. and Min. Jour., LXXIV: 545, 1903. (Vein en- 
 richment by ascending alkaline waters.) 45. Weed, Eng. and Min. 
 Jour., LXXIV: 513, 1902. (Contact deposits.) Also Lindgren. 
 46. Weed, Amer. Inst. Min. Engrs., Trans. XXXIII: 747, 1903. 
 (Vein enrichment by ascending hot waters.) 47. Weed, Amer. 
 Inst. Min. Engrs., Trans. XXXI : 634, 1902. (Influence of wall rock 
 on mineral veins.) 48. Weed, U. S. Geol. Surv., Bull. 260, 1905. 
 (Hot spring deposits.) 49. Weed, U. S. Geol. Surv., 21st Ann. 
 Rept., II : 227, 1900. (Hot springs depositing gold.) 50. Whitney, 
 Metallic wealth of U. S., Phil., 1854. 51. Weed, Amer. Inst. Min. 
 Engrs., Trans. XXXIH : 731, 1903. (Contact deposits.)
 
 CHAPTER XIV 
 IRON ORES 
 
 IRON is an abundant constituent of the earth's crust, and 
 yet few minerals are capable of serving as ores of this metal, 
 because they do not contain it in the right combination or 
 in sufficient quantity to make its extraction possible or 
 profitable. 
 
 The iron ores having the greatest commercial value at the 
 present day are usually those which are favorably located, 
 of high quality, in considerable quantity, and possessing a 
 structure such as to render their extraction easy. These 
 four requirements have been met to such an eminent degree 
 by the deposits located in the Lake Superior district that 
 they now form the main source of supply for furnaces in 
 the Eastern and Central states, many of the iron mines in 
 the eastern part of the United States having been forced to 
 shut down, although it is true that a number of small 
 deposits are worked to supply local demand, owing to their 
 proximity to furnace, flux, and coal, or because they possess 
 certain desirable characteristics. 
 
 Ores of Iron. The ores of iron, together with their com- 
 position and theoretic percentage of metallic iron, are : 
 
 MAGNETITE. Magnetic iron ore. Fe 3 O 4 . . . . . 72.4 per cent. 
 HEMATITE. Specular iron ore, red hematite, fossil ore, 
 
 clinton ore. Fe 2 O 3 70 per cent. 
 
 251
 
 252 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 LIMONITE. Brown hematite, bog iron ore, ocher. 
 
 2 Fe 2 O 3 , 3 H 2 O 59.89 per cent. 
 
 SIDERITE. Spathic ore, blackband, clay ironstone, 
 
 kidney ore. FeCO 8 48.27 per cent. 
 
 PYKITE. FeS 2 46.7 percent. 
 
 Of these hematite is the most valuable by far, chiefly on 
 account of its easier reduction,- but also because of the 
 greater richness of the known important deposits. The 
 deficiency in iron contents shown by many ores is due to 
 the presence of common rock-forming minerals in the 
 gangue, the impurities yielded by them being : alumina, 
 lime, magnesia, silica, titanium, arsenic, copper, phosphorus, 
 and sulphur. 
 
 The effect of the last six is to weaken the iron in general. 
 While silica in high amounts is not desirable, still some fur- 
 naces turn out iron for foundry purposes containing 10 or 
 more per cent. Pyrite is the source of the sulphur, and 
 apatite of the phosphorus. Titanium, a common but injuri- 
 ous ingredient, is found in many magnetite deposits (see 
 Titaniferous magnetites ; also refs. 20, 21), and up to the 
 present time has rendered them practically useless, not 
 because it interferes with the quality of the iron, but 
 because it makes the ore highly refractory, and drives 
 much of the iron into the slag. Experiments have been 
 undertaken looking towards the utilization of these titan- 
 iferous magnetites for the manufacture of ferro-titanium. 
 Manganese, when present, is found mostly in the limonite 
 ores, and for certain purposes is desirable. It is also promi- 
 nent in some of the Lake Superior hematites. 
 
 As phosphorus cannot be eliminated in either the blast furnace or the 
 acid converter used in making Bessemer steel, and as the allowable limit
 
 IRON ORES 
 
 253 
 
 of phosphorus in pig iron used for this purpose is T J a percent, a distinction 
 is usually made between Bessemer and non-Bessemer ores, the maximum 
 amount of phosphorus permissible in iron ore to be used for this purpose 
 being ^^ of the percentage of metallic iron contents of the ore. The 
 phosphorus content of many high-grade ores, however, falls considerably 
 below the allowable limit. 
 
 With the exception of iron ores formed by magmatic 
 segregation, gas-aqueous action, and some deposits of sedi- 
 
 FIG. 45. Map showing distribution of iron ores in the United States. Adapted 
 from Ransome, Min. Mag., X : 1. 
 
 mentary character, most iron ores owe their concentra- 
 tion to the action of circulating meteoric waters, which 
 have leached the iron out of the rocks and deposited it 
 under favorable conditions either in cavities or by replace- 
 ment. 
 
 The ore most commonly formed in this manner is limonite, 
 and the deposits are of surficial character, but hematite bodies 
 of similar origin are known. Deposits of siderite formed
 
 254 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 by replacement are frequently changed to limonite by 
 weathering. Iron-ore bodies may show a variety of form, 
 but most of those known in this country are lens-shaped 
 or basin-shaped in outline. 
 
 The iron ores found in the United States are widely dis- 
 tributed (Fig. 45), and their age ranges from pre-Cambrian 
 to recent. The occurrence and distribution of the different 
 kinds of ore are best discussed separately. 
 
 MAGNETITE 
 
 Magnetite occurs in the United States, (1) as lenticular 
 masses commonly in metamorphic rocks; (2) as more or 
 less lens-shaped bodies in igneous rocks; (3) as sands on the 
 shores of lakes and seas; and (4) as contact deposits. 
 
 The first class includes the most important deposits now 
 worked in this country. The second and third groups run 
 too high in titanium to have any commercial value at the 
 present time, but the second may become of importance in 
 the future, and moreover some of the deposits of this group 
 are of large size. Undoubted representatives of the fourth 
 class of commercial value are not worked. There are some, 
 it is true, which occur along the contact of an intrusive and 
 sedimentary rock, but their origin is ascribed to meteoric 
 circulations. 
 
 Distribution of Magnetites in the United States. Non- 
 Titaniferous Magnetites. These are usually found in the 
 form of lenticular deposits in metamorphic rocks. The 
 most important series of occurrences is found in the crys- 
 talline belt of rocks extending from New York into Alabama, 
 deposits being known in New York, New Jersey, Pennsyl- 
 vania, Virginia, and North Carolina.
 
 PLATE XIV 
 
 FIG. 1. View of open cut in magnetite deposit, Mineville, N.Y. The pillars are 
 ore left to support the gneiss hanging wall. After Witherbee, Iron Age, Dec. 17, 
 1903. 
 
 FIG. 2. General view of magnetic separating plants and shaft houses, Mineville, 
 N.Y. After Witherbee, Iron Age, Dec. 17, 1903.

 
 IRON OKES 255 
 
 The lenses, which are interbedded with the gneisses of 
 either acid or basic character and often conform with the 
 latter in dip and strike, are of variable size, and may 
 occur either singly or in series, the ore body commonly 
 showing pinching and swelling, or even faulting. Well- 
 defined boundaries are sometimes wanting. Feldspar, 
 hornblende, and quartz are common gangue minerals, 
 while apatite is prominent in some. Although the ore 
 as mined is frequently of sufficient purity to be shipped 
 direct to the blast furnace, in some instances it is so lean as 
 to require concentration by magnetic methods. This same 
 plan has been adopted at Mineville, New York, to treat the 
 high phosphorus magnetite, thereby yielding a rich con- 
 centrate (68 per cent Fe) for iron manufacture, a fairly 
 pure apatite used in making fertilizers, and a hornblende 
 tailings or waste product. 
 
 The magnetites have been extensively worked on the 
 northern and eastern side of the Adirondacks, notably at 
 Mineville (19), where one lens has been traced for a distance 
 of 2000 feet. Many ore bodies have also been mined in 
 New Jersey, where they are disposed in more or less 
 parallel belts. 
 
 The origin of these magnetites has been a subject of 
 much discussion, but their interfoliation with the gneisses 
 is thought by some to indicate that the ores and rock had a 
 common origin. Those believing the gneisses to be meta- 
 morphosed sediments thought the magnetites were originally 
 limonite, but if the gneisses are metamorphosed igneous 
 rocks, then the ore may represent magmatic segregations. 
 The North Carolina magnetites have been suggested by 
 Keith (18 a) to be replacement deposits, while Kemp be-
 
 256 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 lieves that the ore bodies at Mineville (19) have been formed 
 by iron-bearing magmatic waters, which were given off 
 from the neighboring gabbros and penetrated the gneisses, 
 while the latter were probably still at great depths and 
 before their metanaorphism was complete. The presence 
 of apatite and fluorite shows that mineralizing vapors also 
 played a part. A similar origin has recently been suggested 
 by Spencer (23) to explain some of the New Jersey magnetites. 
 Other theories advanced are that the magnetite deposits were 
 formed as beach sands or even river bars, but such an as- 
 sumption would require the gneisses to be metamorphosed 
 sediments. 
 
 A somewhat unique deposit and one of the largest ever 
 worked occurs at Cornwall (17), Pennsylvania, where a bed 
 of soft magnetite with some pyrite is found between Cam- 
 brian limestone and Triassic shales, and against igneous 
 dikes. Their age has been placed .as both Cambro-Silurian 
 and also Triassic, and whether they represent metamor- 
 phosed pyritiferous shale or limonites is also unsettled. 
 The ore runs from 40 to 55 per cent Fe and usually 
 under .02 P, but is rather high in S and SiO 2 . 
 
 Other Occurrences. Magnetite occurs sparingly in the 
 Marquette range of Michigan, where it is found in the 
 schists. Other western occurrences include Colorado (6), 
 Utah (32), Wyoming (la), New Mexico (la), and California. 
 
 In the table given below there will be found the analyses 
 of a number of magnetite samples from eastern mines. 
 
 These it will be seen show considerable variation in their 
 metallic iron contents, and are not all to be regarded as a 
 strict average of the region which they represent.
 
 IRON ORES 
 
 257 
 
 ANALYSES OF MAGNETITES 
 
 
 Fe 
 
 810, 
 
 P 
 
 Mn 
 
 Al,0 8 
 
 CaO 
 
 MgO 
 
 8 
 
 TiO, 
 
 Alk 
 
 u,o 
 
 FeS, 
 
 Belvidere, N.J. . 
 Little Mine, N.J. . 
 
 51.42 
 67.54 
 
 8.85 
 1.20 
 
 1.048 
 .02 
 
 .17 
 .90 
 
 3.86 
 .74 
 
 1.68 
 .31 
 
 .18 
 .51 
 
 .08 
 
 Tr 
 
 
 
 
 McKtiightstown, 
 Adams Co., Pa. . 
 
 46.90 
 
 17.054 
 
 P*0, 
 .128 
 
 MnO 
 .896 
 
 4.424 
 
 1.868 
 
 4.198 
 
 
 
 .953 
 
 5.00 
 
 .05 
 
 Dillsburg, York Co. 
 Pa 
 
 45.00 
 
 20.33 
 
 P0 5 
 .107 
 
 MnO 
 .036 
 
 3.775 
 
 5.604 
 
 4.129 
 
 80, 
 1.105 
 
 
 
 1.14 
 
 1.605 
 
 Cornwall, Pa. . . 
 
 42.70 
 
 
 P 
 .135 
 
 
 3.411 
 
 
 
 .62 
 
 
 
 
 
 Mineville, N.Y. 
 (Mine 21) . . . 
 
 62.10 
 
 
 P 
 
 1.198 
 
 
 
 
 
 
 
 
 
 
 Titaniferous Magnetites. These form a peculiar class by 
 themselves, and with only one or two exceptions are found 
 always associated with rocks of the gabbro family. The 
 ore bodies occur in the midst of igneous intrusions, and 
 according to Kemp (19, 20, 21), seem to have been formed 
 by the segregation of fairly pure titaniferous iron oxide, 
 either before or during the process of cooling and con- 
 solidation. 
 
 Mineralogically they may contain both ilmenite, FeO, 
 TiO 2 (FeO, 46.75 ; TiO 2 , 53.25), and titaniferous magnetite, 
 which is of variable composition. The gangue minerals 
 may be pyroxene, brown hornblende, hypersthene, enstatite, 
 olivine, spinel, garnet, and plagioclase. The ores are usu- 
 ally low in phosphorus and sulphur, but Va, Cr, Ni, and 
 Co are almost always present. In the United States they 
 are found in New York, New Jersey, Colorado, Minnesota, 
 and several other states, but are not worked. 
 
 The following analyses illustrate their composition :
 
 258 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 AXALYSES OF TlTANIFEROUS MAGNETITES 
 
 
 1 
 
 2 
 
 3 
 
 4 
 
 FeO 
 
 | 
 
 
 f 27 95 ] 
 
 
 Fe 2 O 3 
 
 70.50 J 
 
 80.78 
 
 | 15 85 J 
 
 79.78 
 
 Ti0 2 
 SiO 2 
 
 14.00 
 8.60 
 
 12.09 
 2.02 
 
 15.66 
 1790 
 
 12.08 
 .75 
 
 Al O 
 
 400 
 
 258 
 
 1023 
 
 462 
 
 Cr,O 3 
 
 
 2.40 
 
 .51 
 
 .32 
 
 V..O* 
 
 
 
 55 
 
 Tr 
 
 MnO 
 
 
 
 Tr 
 
 .28 
 
 CaO 
 
 1.60 
 
 
 286 
 
 .13 
 
 MgO 
 
 230 
 
 
 604 
 
 204 
 
 H 2 O 
 
 
 
 04 
 
 
 PoO 
 
 
 03 
 
 14 
 
 
 
 
 
 
 
 
 101.00 
 
 99.90 
 
 99.05 
 
 100.00 
 
 1. Grape Creek, Colo. 
 
 2. Mayhew Range, Minn. 
 
 3. Split Rock, N.Y. 
 
 4. Greensboro, N.C. 
 
 Magnetite Sands. These are found in those regions 
 where the beach sands are composed of weathering 
 products of metamorphic and igneous rocks. The sorting 
 action of the waves serves to carry the heavy mineral 
 grains high up on the beaches, where they form black 
 streaks, composed mostly of magnetite (usually titanifer- 
 ous), mixed with monazite, apatite, and other heavy min- 
 erals. 
 
 Deposits are known in this country on the shores of 
 Lake Champlain, Long Island, etc., but they are of small 
 extent as well as lacking in quality. 
 
 New Zealand and Brazil are said to possess magnetite 
 sands of commercial value.
 
 IRON ORES 
 
 259 
 
 HEMATITE 
 
 This is by far the most important ore of iron in the 
 United States, having in 1903 formed 86.6 per cent of 
 the total production. Its distribution, however, is rather 
 restricted, and about five sixths of the total quantity mined 
 came from the Lake Superior region. The varieties mined 
 in the United States include the earthy, specular, oolitic, 
 and fossiliferous. Most of the deposits belong to the 
 replacement type and are basin-shaped, while bedded and 
 contact deposits are also known, but the last are not worked. 
 
 Fio. 46. Map of Lake Superior iron regions, shipping ports, and transportation 
 lines. After Grant, Min. Mag., X: 175. 
 
 Distribution of Hematite Ores in the United States. At 
 the present day there are but two very important hematite 
 producing regions, viz. the Lake Superior region and the 
 Birmingham, Alabama, area. 
 
 Lake Superior Region Under this head are included a great 
 series of deposits lying in the region surrounding the south 
 and west sides of Lake Superior (13). The rocks are of remote 
 geological age, as can be seen from the following section:
 
 260 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Cambrian. Lake Superior sandstone. 
 
 J Upper sedimentary, or copper series. 
 
 \ Lower igneous, with interstratified sediments. 
 
 f Sedimentaries with local volcanics, and cut by Upper 
 Upper Huronian. \ . 
 
 [ Huronian and Keweenawan intrusions. 
 
 Lower Huronian. Sediments with some volcanics, cut by intrusives. 
 Archaean or f Mainly ancient igneous rocks and some sediments. 
 
 Basement com- I These igneous intrusions pierced by many others 
 plex. [ of later date. 
 
 Each of the above series is separated from its neighbor 
 by a great unconformity, due to intervals of elevation 
 
 above the sea level and 
 periods of erosion. 
 
 The rocks of the iron- 
 bearing formations are 
 cherty iron carbonates; 
 ferrous silicate rocks ; 
 pyritic quartz rocks 
 (Archaean); ferrugin- 
 ous slates ; ferruginous 
 cherts; jaspilites; am- 
 phibolites and magne- 
 tite schists ; iron ore 
 deposits; detrital fer- 
 ruginous rocks from 
 foregoing. Since their 
 formation they have 
 been folded, faulted, 
 
 FIG. 47. Sections of iron-ore deposits in Mar- 
 
 and sometimes brec- 
 
 111 111*11- 
 
 quette range. After Van Hise. ciated, and it IS in the 
 
 troughs formed by folding that the ore usually occurs 
 (Fig. 47).
 
 PLATE XV 
 
 FIG. 1. Ircm mine, Soudan, Minn. Shows old open pit with jasper horse in middle. 
 
 FIG. 2. Outcrop of Clinton iron ore, Red Mountain, near Birmingham, Ala. 
 Photo, from Tennessee Coal and Iron Company.
 
 IRON ORES 261 
 
 The Archaean, Lower Huronian, and Upper Huronian are 
 the most productive iron-bearing formations, the last men- 
 tioned containing the ore at two horizons, viz. near its base 
 and in its central portion. 
 
 Six districts, or ranges, are recognizable in the Lake 
 Superior region, viz. Marquette (13) and Crystal Falls (27) 
 in Michigan ; Menominee (25) in Wisconsin ; Penokee- 
 Gogebic (37) on the Michigan- Wisconsin boundary; Mesabi 
 
 FIG. 48. Generalized vertical section through Penokee-Gogebic ore deposit 
 and adjacent rocks ; Colby mine, Bessemer, Mich. After Leith. 
 
 (31) and Vermilion (28) in Minnesota. The general mode 
 of occurrence of the ore in several of these is shown in 
 Figs. 47, 48, and 49. 
 
 The ore is not found at the same horizons in all the districts, the 
 Marquette being the only one where all the iron-bearing formations 
 of the series are found. Of these, the Archaean iron-bearing forma- 
 tions are unproductive, the chief ore bodies lying within the Lower 
 Huronian and at the base of the Upper Huronian. In the Crystal 
 Falls district, the iron-bearing horizon of the Lower Huronian carries 
 the ore as well as the horizon within the Upper Huronian. In both the
 
 262 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Penokee and Mesabi districts the conditions are similar to those in 
 the western part of the Crystal Falls district, the ore being found in a 
 single formation in the Upper Huronian, while the same one in the 
 Marquette region is thin and of little consequence. 
 
 The smaller deposits are associated with plications, folding, brecci- 
 ations, etc., but the larger masses of ore occur at the contact of the 
 iron-bearing formations with others or between different members of 
 the iron-bearing formations. These contacts were favorable for con- 
 centration of ore, because they are planes or horizons of slipping, and 
 the effect of this movement would be to loosen the rock, thus making 
 channels for the percolating water. Underlying the deposits of first 
 
 Fio. 49. Generalized vertical section through Mesabi ore deposit and adjacent 
 rocks. After Leith. 
 
 magnitude there occur impervious formations which are bent into 
 troughs. Slate, quartzite, limestone, or igneous rock may all serve as 
 floors, or two may combine, as in the Penokee-Gogebic district, where 
 the trough is formed by the intersection of quartzite and dikes. The 
 ore bodies are often U-shaped in section, being thickest at the bottom. 
 
 The origin of these ores has for years been a puzzling 
 problem to geologists (37). Foster and Whitney considered 
 them eruptive, while Brooks and Pumpelly looked upon them 
 as altered limonite beds. In recent years the studies of 
 Irving and Van Hise (37), aided by others, have demon- 
 strated that the ores owe their origin partly to a replace- 
 ment of the chert. The trough-shaped location shows that
 
 IRON OKES 263 
 
 the deposits were formed after the rocks had been folded, 
 and it is also noticed that these troughs are even still the 
 lines of underground waters. That they have been produced 
 by descending waters is shown by the fact that they are on 
 the upper side of the impervious bed, and because the ores 
 are oxidized ones, viz., hematite and limonite. 
 
 The chemistry of the process is thought to be as follows : Part of the 
 ferric oxide was deposited as an original sediment containing silica and 
 other impurities, or in some cases as sulphides or carbonates. This was 
 later enriched by the addition of iron carbonate. These were originally 
 contained in the rocks near the surface, and became oxidized by perco- 
 lating waters, which took up the carbon dioxide liberated, and were thus 
 able to dissolve iron carbonates or silicates, which they came in contact 
 with in their downward course toward the troughs in which the ore is 
 found. 
 
 The precipitation of the ore was then caused by these solutions 
 meeting with others which had filtered in by a more open and direct 
 path from the surface, and hence contained some free oxygen, which 
 converted the dissolved iron compounds into oxides. 
 
 The same solutions, carrying carbon dioxide, dissolved the alkalies 
 out of the basic igneous rocks and these waters were then able to dis- 
 solve silica. In some cases the solution of silica proceeded faster than 
 the deposition of the iron ore, and made the rock quite porous. The 
 general result was therefore a concentration of the iron and removal 
 of silica. 
 
 The ores of the Lake Superior region vary from hard 
 blue ores to soft earthy ones. They are mostly hematite, 
 with small quantities of limonite, but some magnetite is 
 known in the Marquette district. The following table taken 
 from Birkenbine's report gives a number of typical analyses 
 (la). Many additional ones can be found in the reports on 
 Mineral Resources issued annually by the United States 
 Geological Survey.
 
 264 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 TYPICAL ANALYSES OF LAKE SUPERIOR IRON ORES 
 
 CONTENT 
 
 MARQUETTE 
 RANGE 
 
 MENOMINEE 
 RANGE 
 
 GOGEBIC 
 
 RANGE 
 
 VERMILION 
 RANGE 
 
 MESABI 
 RANGE 
 
 Iron 
 
 56.5 
 
 55.2423 
 
 56.308 
 
 61.36 
 
 56.0990 
 
 Phosphorus . . . 
 Silica .... . 
 
 .0353 
 4.584 
 
 .0594 
 6.7693 
 
 .0338 
 3.3961 
 
 .0373 
 4.2545 
 
 .0365 
 
 3.4867 
 
 Sulphur .... 
 Moisture .... 
 
 .0089 
 11.85 
 
 6.525 
 
 10.828 
 
 4.5649 
 
 12.3158 
 
 ANALYSES OF SILICEOUS ORES 
 
 CONTENT 
 
 MARQUETTE 
 RANGE 
 
 MENOMINEE 
 RANGE 
 
 VERMILION 
 RANGE 
 
 
 4227 
 
 42 199 
 
 51 1938 
 
 Phosphorus 
 
 .0316 
 
 .0244 
 
 .0498 
 
 Silica . 
 
 35834 
 
 34.141 
 
 22.3642 
 
 Sulphur 
 
 .0099 
 
 
 
 Moisture 
 
 1.23 
 
 2.2 
 
 3.21 
 
 
 
 
 
 Most of the rich ores are found above the 1000-foot 
 level, except in the Mesabi district where the deposits are 
 shallow, as compared with their horizontal extent, some, 
 however, being over 400 feet deep. 
 
 In the early period of mining many of the Lake Superior 
 bodies were worked as open cuts, but with depth underground 
 working has been resorted to. There are many deposits 
 in the Mesabi district which are worked as open pits from 
 which the granular ore is dug with a steam shovel and 
 loaded directly on to the ore cars, which are run along the 
 working face (PI. XVI). 
 
 The development of the Lake Superior region has ad-
 
 PLATE XVI
 
 IRON OKES 265 
 
 vanced with phenomenal strides. The Marquette range 
 was developed as early as 1849, and the Mesabi as late 
 as 1892. 
 
 The total yield of the Lake Superior region from 1850 
 to 1902 was 246,558,896 long tons. Between 1891 and 1903 
 it was 191,646,959 long tons, or 77.75 per cent of the total 
 amount mined. Van Hise, in estimating the available quan- 
 tity of high-grade ore still in the ground, believes that 
 even if it approached 1,000,000,000 long tons, mining at 
 the rate of 20,000,000 tons per year would exhaust the 
 supply in the first half of the twentieth century. Indeed, 
 it will not be many years before lower grades of ore, 
 hitherto thrown aside, will be shipped to market. Already 
 ore carrying 40 per cent iron, but low in phosphorus and 
 high in silica, has been sold for mixing in with high- 
 grade Mesabi ores, and Van Hise believes that ores below 
 40 per cent in iron will be marketed before another 
 generation. 
 
 The market value of the ores is based on the iron contents, percentage 
 of water, and amount of phosphorus, and at times the manganese contents 
 is taken into consideration. Some objection has been raised in the last 
 few years to the fine character of the Mesabi ore and its tendency to clog 
 the blast furnace, therefore requiring the admixture of lump ore from 
 the other ranges ; but this objection is rapidly disappearing, and some 
 furnaces now use over 75 per cent of Mesabi ore in their charge. 
 
 The Lake Superior iron ore region is not only the most important in 
 the world, but the production of some of the individual mines is star- 
 tling. This enormous output can, perhaps, be best appreciated by some 
 comparative figures. Thus, for example, the production of 15,371,396 
 long tons of ore mined in Minnesota in 1903 is about three quarters of 
 the total amount extracted from the famous magnetite deposits of 
 Cornwall, Pennsylvania, since they were opened in 1740, or of the total
 
 266 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 quantity of New Jersey magnetites mined since they were first worked in 
 1710. The production even of single mines is often great, six mines in 
 1903 producing over 1,000,000 long tons of ore each (1 a). 
 
 Clinton Ore (35, 36, 30). This ore, which is also called 
 fossil, pea, or dyestone ore, was given the first name on 
 account of the ore bed having been originally discovered at 
 Clinton, New York. It is one of the most persistent iron- 
 ore deposits that is known, for it occurs wherever rocks 
 belonging to the Clinton stage of the Silurian are found, 
 
 f e 
 
 Fia. 50. Section Clinton ore beds, Oxmoor, Ala. a, red sandstone, 5'; 
 b, yellow sandstone, 6'; e, red sandstone, 15'; d, ore, 22', upper 2' soft; 
 e, shale, 6' : /, rich ore, 2' 6". After Smyth, Amer. Jour. Sci., June, 1892. 
 
 including many localities, therefore, along the line of the 
 Appalachians from New York to Alabama, as well as in 
 Ohio and Wisconsin. In Pennsylvania there are several 
 belts of the ore, owing to the presence of many eroded folds 
 carrying the Clinton rocks. 
 
 The ore is interstratified with sandstones and shales, varies 
 in thickness from a few inches to ten or twenty feet, is at 
 times oolitic in its structure, and at others is made up of a 
 mass of small fossils. At Birmingham, where the greatest 
 development has occurred, the ore occurs in a ridge known 
 as Red Mountain, the bed having a shale roof and sandstone
 
 IRON ORES 267 
 
 floor, while the thickness of the main bed varies from twelve 
 to twenty feet. The beds dip gently to the east, and the 
 iron ore is worked by means of slopes, although the early 
 workings at some of the mines were open cuts, on account 
 of the thin overburden. The prominence of this locality is 
 due to peculiar conditions, the ore being bordered on the 
 west by Cambrian limestone which forms the valley floor, 
 while on the western side of the valley the coals of the 
 Warrior Field outcrop. Thus the three essential elements 
 for iron manufacture are brought in close contact by folding 
 and faulting. East of the iron range are two additional 
 coal basins. 
 
 The great development of this ore in Alabama is due 
 partly to favorable local conditions and partly to its re- 
 moteness from the Lake Superior region. 
 
 The origin of these ore bodies has been argued from 
 different standpoints, some holding that they represent 
 altered limestone beds (35 a), because of the presence of 
 fossils in them, while the concentric nature of the oolites, 
 with a nucleus of worn quartz grains, has led others, espe- 
 cially Smyth, to ascribe a concretionary origin (36) to them. 
 The former theory is strengthened by finding at many 
 places an increase of the lime contents of the ore with the 
 depth. Thus at Attalla, Alabama, the Clinton limestone at 
 250 feet from the surface carries only 7.75 per cent of iron, 
 while at the outcrop it has 57 per cent of iron. 
 
 The Clinton iron ores usually run high in phosphorus and also silica. 
 Of the two following analyses, No. 1 is soft ore and No. 2 hard ore. The 
 latter runs higher in lime. A difference also appears to exist between 
 the composition of the fossil or upper ore bed and the oolitic or lower 
 ore bed, as represented by analyses 3 and 4 (30) of the following table:
 
 268 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 
 1 
 
 2 
 
 3 
 
 4 
 
 Fe 
 Fe 2 O 3 
 
 52.87 
 
 37.00 
 
 30.24 
 
 46.04 
 
 p 
 
 .43 
 
 .37 
 
 
 
 PoO. 
 
 
 
 .75 
 
 1.29 
 
 S 
 
 .11 
 
 07 
 
 
 
 so s 
 
 SiO 2 
 A1A 
 CaO 
 
 13.66 
 6.13 
 1 26 
 
 13.44 
 3.18 
 16 20 
 
 .15 
 8.71 
 3.67 
 20 64 
 
 .20 
 16.82 
 3.54 
 9.96 
 
 MgO 
 MnO 
 
 .37 
 30 
 
 
 7.84 
 
 3.41 
 
 H 2 
 CO 
 
 1.62 
 
 08 
 
 .50 
 12 24 
 
 24 78 
 
 13.62 
 
 
 
 
 
 
 Other Occurrences. Extensive deposits of hematite in 
 Carboniferous limestone are found in Laramie County, Wyo- 
 ming (1). The ore carries 60 to 67 per cent iron, 2^ to 5 per 
 cent silica, and is low in phosphorus. In New Mexico, near 
 Hanover, a deposit carrying about one quarter hematite and 
 three quarters magnetite, along the contact of granite and 
 limestone, is also extensively worked. Deposits of hematite 
 in brecciated Carboniferous limestones, and formed proba- 
 bly by replacement, are known in Iron and Washington 
 counties of southwestern Utah, and are probably the largest 
 iron-ore deposits in the West. Other deposits are found 
 in the Wasatch Mountains, along the contact of andes- 
 ite and limestone. The ore here consists of hard black 
 crystallized hematite and magnetite, associated with chal- 
 cedony and crystalline quartz. Leith (32) considers it to be 
 a replacement deposit. While much of the ore is of good 
 quality, it is mostly non-Bessemer. The Utah deposits are
 
 IRON ORES 269 
 
 at present too far from the railroad to be of much value, 
 but are to be looked on as an important future source of 
 supply. Specular hematites also occur at Pilot Knob, Mis- 
 souri, interstratified with breccias and porphyry sheets, and 
 were formerly much worked. 
 
 LIMONITE 
 
 Limonite (41-52) or brown hematite is, like magnetite, of 
 comparatively little importance in the United States as 
 compared with hematite, having yielded an average of but 
 12.2 per cent of the total iron production of the United 
 States in the last fifteen years, and but 8.8 per cent of the 
 total domestic iron ore production in 1903. 
 
 Although deposits of limonite are widely scattered over 
 the United States, about nine tenths of the total quantity 
 comes from the deposits located in western New England 
 and the Appalachian belt. 
 
 Owing to their mode of origin, limonites are rarely of 
 high purity, being commonly associated with more or less 
 ferruginous clay, which has to be separated from the ore by 
 
 Limonite may occur under a variety of conditions and 
 associated with different kinds of rocks, but two impor- 
 tant types are recognized, viz. bog ores, and residual 
 limonites. 
 
 Bog Ores. The bog ores are formed by the precipitation of 
 limonite in swamps, ponds, or lakes. The iron is dissolved 
 from the rocks or soil by percolating waters charged with 
 carbon dioxide or organic acids, either in the form of ferrous 
 carbonate or ferrous sulphate. As these iron-bearing waters
 
 270 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 discharge into the ponds the iron compounds are oxidized 
 to hydrous ferric oxide or limonite, which settles on the 
 bottom. Such ores are usually impure from an admixture of 
 sand or clay which has been deposited at the same time, and 
 are rarely of any thickness. They are of no commercial 
 value in the United States, but in foreign countries are 
 worked in Sweden, in which kingdom they have been known 
 to accumulate in ponds to the depth of 18 inches or more 
 every 15 to 30 years. The ore is collected periodically 
 by dredging. Bog ore is also obtained in Quebec, Can. 
 
 Residual limonites. The residual limonites are a much 
 more important class, and form (1) by the weathering of 
 
 Fio. 51. Section illustrating formation of residual limonite in limestone. After 
 Hopkins, Geol. Soc. Amer., Bull. XI : 485. 
 
 pyritiferous veins (see gossan, Chapter XIII), or (2) more 
 often from the weathering of ferruginous rocks. The sec- 
 ond process results in the formation of deposits of iron- 
 stained clay scattered through which are nodules and 
 irregularly shaped masses of limonite, these making up 
 from 5-10 per cent of the entire mass. 
 
 The limonite may accumulate first by deposition in the 
 cracks of the rock, or by impregnation or replacement, and 
 prior to the breaking down of the rock to a mass of residual 
 clay. Since these deposits often represent the concentra- 
 tion of iron from a great thickness of rock, it is not
 
 PLATE XVII 
 
 Fio. 1. Pit of residual limonite, Shelby, Ala. After McCalley, Ala. Geol. Surv. 
 Report on Valley Regions, Pt. II: 11, 1897. 
 
 FIG. 2. Old limonite pit, Ivanhoe, Va., showing pinnacled surface of limestone 
 which underlies the ore-bearing clay. The level of surface before mining 
 began is seen on either side of excavation. H. Ries, photo.
 
 IRON OEES 271 
 
 necessary that the parent material contain a high percentage 
 of iron. 
 
 An important belt of residual limonites of Cambro-Silurian 
 age, and associated with slates, schists, or limestone, is found 
 extending from Vermont to Alabama, along the Great Valley, 
 and consisting of beds of residual clay carrying limonite 
 nodules (42, 44-48 a). This type of deposits is worked from 
 Vermont to Alabama, and some of the larger mines in the 
 latter state have an annual production of over 100,000 tons. 
 Those found in Georgia are associated with manganese. 
 Plate XVII, Fig. 2, shows the irregular surface of the 
 Cambro-Silurian limestone in one of the Virginia pits. 
 
 In addition to these, important deposits are found in Vir- 
 ginia, representing the weathered portion of a great belt of 
 pyrite bodies. This extends for over 20 miles and is known 
 as the "Great Gossan Lead," its contents averaging from 
 40 to 41 per cent metallic iron (48 J, see also Copper, Duck- 
 town, Tennessee). 
 
 The Oriskany formation also carries large deposits of 
 limonite to the westward of the Cambro-Silurian belt, and 
 these are actively worked in Virginia (49). 
 
 Other Occurrences. Limonites of more or less distinctly 
 bedded character are found in the Tertiary of northeastern 
 Texas (50, 52), where they occur as thin beds capping the hills 
 and are mined for local use (50). Others are found at the same 
 horizon in Arkansas but promise to be of little commercial 
 value. In the former case they are closely associated with 
 greensands, and may have formed by weathering either from 
 these or from pyrite grains. Small deposits are known in 
 Iowa (41), Wisconsin, Minnesota, and Oregon (3 a). Much 
 limonite, at times manganiferous and containing even small
 
 272 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 quantities of silver, is obtained from the gossan of the Lead- 
 ville ore bodies. Its chief use is as a flux. 
 
 The following analyses give the composition of limonites 
 from several localities. 
 
 ANALYSES OF LIMONITES 
 
 
 Fe 
 
 P 
 
 8 
 
 SiO, 
 
 AliOs 
 
 CaO 
 
 MgO 
 
 H0 
 
 Moist. 
 
 MnO, 
 
 Average composition Alabama 
 
 
 
 
 
 
 
 
 
 
 
 limonite 
 
 48.54 
 
 .38 
 
 .O'J 
 
 11.22 
 
 8.61 
 
 .84 
 
 
 6.00 
 
 7.00 
 
 
 Average of 29 commercial 
 
 
 P,0 B 
 
 
 
 
 
 
 
 
 
 analyses, Pa., Cambro-Silurian 
 
 43.4T 
 
 1.10 
 
 .06 
 
 18.9T 
 
 2.39 
 
 .48 
 
 .42 
 
 
 11.62 
 
 2.85 
 
 ores 
 
 
 
 SO, 
 
 
 
 
 
 
 
 
 Rusk, Cherokee Co., Texas . . 
 
 44.68 
 
 .09 
 
 .20 
 
 ttM 
 
 "5776^ 
 
 -48 
 
 Tr 
 
 11.03 
 
 
 
 Allamakee County, la. ... 
 
 54.32 
 
 1.8 
 
 
 
 
 
 
 
 
 
 
 Those of the Appalachian belt are much used by pig-iron 
 manufacturers because, owing to their siliceous character, 
 they can be mixed in with high-grade Lake Superior ores 
 which are deficient in silica. They are also cheaper, and 
 their mixture with other ores seems to facilitate the reduc- 
 tion of the iron in the furnace. 
 
 SIDERITE 
 
 Siderite (53-58) is the least important of all the ores of 
 iron mined in the United States, both on account of the 
 small quantity and its low iron contents. When of con- 
 cretionary structure, with clayey impurities, it is termed 
 clay ironstone, and these concretions are common in many 
 shales and clays. In some districts siderite forms beds, 
 often several feet in thickness, but containing much bitumi- 
 nous and argillaceous matter, and known as blackband ore. 
 This is found in many Carboniferous shales.
 
 IKON ORES 273 
 
 Eastern Ohio (54) and Kentucky (53) and western Penn- 
 sylvania (55) are the most important producing states. The 
 ore is obtained chiefly from the Lower Coal measures, 
 although known in the other stages of the Pennsylvania 
 series. Another important occurrence is at the Burden 
 Mines, near Hudson, New York (56), where lens-shaped 
 beds of clay ironstone are found in the Hudson River 
 shales and sandstones. The beds have been folded and 
 faulted, so that the ore bodies lie in basins. The ores 
 are rather magnesian, and on this account it has been 
 suggested by Kimball that they have been formed in shore 
 waters receiving drainage from the Archaean Highlands ; 
 they are also high in phosphorus. Siderite is of far greater 
 importance in foreign countries, and large quantities are 
 shipped to the United States from Spain. It is roasted 
 for use, thereby expelling the carbonic acid and raising 
 the iron contents. 
 
 Production of Iron Ores. The iron ore mining industry 
 in the United States has progressed with phenomenal 
 strides, and this country now leads the world in the pro- 
 duction of iron ore. Indeed, so great has the production 
 become that in 1903 it was equal to the combined output 
 of Germany and Luxemburg and the British Empire for 
 1902. Moreover, the average iron content of the ore 
 mined in the United States is higher than that mined 
 in foreign countries, thereby resulting in the production 
 of a greater amount of pig iron from a given quantity of 
 ore. 
 
 The Lake Superior region is now producing at least three 
 quarters of the iron ore used in the United States, and it
 
 274 
 
 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 has much the largest reserves of high-grade ores, but even 
 these may be exhausted in fifty years or less at the present 
 rate of consumption. The low-grade ores of this region 
 and others will, however, be available for a much longer 
 time. 
 
 While there is not danger of the present supply of 
 ore soon becoming exhausted, still with the present con- 
 sumption it is well to consider possible sources of the 
 future. 
 
 In the United States the Utah and some other western 
 deposits will no doubt be drawn upon, and many ores now 
 looked upon as too low grade to work will also be con- 
 sidered. Aside from domestic sources of supply there are 
 foreign ones which may perhaps be eventually turned to, 
 such as those from Canada, Newfoundland, and Brazil on 
 this side of the Atlantic, or even those of Scandinavia on the 
 European side. In the last-mentioned country especially 
 attention has been drawn in the last few years to mag- 
 netite deposits located well within the Polar circle and of 
 stupendous size. 
 
 The production of iron ores in the United States from 
 1889 to 1903 was as follows : 
 
 TOTAL PRODUCTION OF IRON ORES IN THE UNITED STATES 
 
 YEAR 
 
 LONG TONS 
 
 YEAR 
 
 LONG TONS 
 
 1889 
 
 14,518,041 
 
 1895 
 
 15,957,614 
 
 1890 
 
 16,036,043 
 
 1896 
 
 16,005,449 
 
 1891 
 
 14,591,178 
 
 1897 
 
 17,518,046 
 
 1892 
 
 16,296,666 
 
 1898 
 
 19,433,716 
 
 1893 
 
 11,587,629 
 
 1899 
 
 24,683,173 
 
 1894 
 
 11,879,679 
 
 1900 
 
 27,553,161
 
 IRON ORES 
 
 275 
 
 PRODUCTION OF IRON ORE IN THE MORE IMPORTANT STATES FROM 
 1901 TO 1903 
 
 
 1901 
 
 LONG TONS 
 
 1902 
 
 LONG TONS 
 
 1903 
 
 LONG TONS 
 
 
 11 109 537 
 
 15 137 650 
 
 15 371 396 
 
 
 9 654 067 
 
 11 135 215 
 
 10 600 330 
 
 
 2,801,732 
 
 3,574,474 
 
 3,684,960 
 
 
 789 494 
 
 874 542 
 
 85-> 704 
 
 Virginia and West Virginia . . 
 
 925,394 
 738 868 
 
 987,958 
 783 996 
 
 801,161 
 675,053 
 
 
 1,040,684 
 
 822,932 
 
 644,599 
 
 New York 
 
 420 218 
 
 555 321 
 
 540 460 
 
 
 401 989 
 
 441 879 
 
 484 796 
 
 
 215,599 l 
 
 364,890 2 
 
 443,452 
 
 Other states 
 
 789,897 
 
 875,278 
 
 920,397 
 
 Total 
 
 28,887,479 
 
 35,554,135 
 
 35,019,308 
 
 PRODUCTION OF LAKE SUPERIOR IRON ORES BY RANGES 
 
 RANGE 
 
 1901 
 LONG TONS 
 
 1902 
 
 LONG TONS 
 
 1903 
 
 LONG TONS 
 
 
 3 041 869 
 
 3 683 792 8 
 
 3 422 341 
 
 
 3 597 089 
 
 3 734 712 
 
 3 686 214 
 
 
 3 697 408 
 
 4 421 250 8 
 
 4 093 320 
 
 Mesabi 
 
 9,303,541 
 
 13,080,118 
 
 13,452,812 8 
 
 
 1 805 996 
 
 2 057 532 3 
 
 1 918 584 
 
 
 
 
 
 PRODUCTION OF MOST IMPORTANT IRON-ORE PRODUCING COUNTRIES 
 
 COUNTRY 
 
 YEAR 
 
 QUANTITY 
 LONG TONS 
 
 PERCENTAGE 
 WORLD'S 
 PRODUCTION 
 
 United States 
 
 1903 
 
 35 019 308 
 
 3471 
 
 Germany and Luxemburg . 
 Great Britain 
 
 1903 . 
 1903 
 
 21,230,639 
 13 715 645 
 
 21.04 
 1359 
 
 
 1903 
 
 8 478 600 
 
 840 
 
 Russia and Finland. . . . 
 France 
 
 1902 
 1902 
 
 5,648,227 
 5 003 782 
 
 5.60 
 496 
 
 
 1903 
 
 3 677 841 
 
 3 65 
 
 Austria-Hungary .... 
 
 1902 
 
 3,329,128 
 
 3.30 
 
 Includes North and South Carolina. 
 
 3 Maxima. 
 
 2 Includes North Carolina.
 
 276 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The exports of iron ore from the United States in 1903 
 amounted to 80,611 long tons, valued at $255,728. 
 
 REFERENCES ON IRON ORES 
 
 GENERAL. 1. Birkenbine, Chapters on Iron Ores in Mineral Resources of 
 United States, published annually by U. S. Geol. Survey ; 1 a. Mining 
 Census, 1902, Mines and Quarries. 2. Kimball, Amer. Geol., XXI : 
 155, 1898. (Concentration by weathering.) 3. Penrose, Jour. 
 Geol., 1 : 356, 1893. (Chemical relations of iron and manganese.) 
 3 a. Pumpelly, Tenth Census, XV. 4. Swank, Eng. and Min. Jour., 
 LXXIII : 347, 1902. (U. S. iron and steel works.) 5. Winchell, 
 Amer. Geol., X : 277, 1892. (Theories of origin.) 
 
 STATE REPORTS. 6. Chauvenet, Amer. Inst. Min. Engrs., Trans. XVIII : 
 266, 1890. (Colo.) 7. Nason, Mo. Geol. Surv., II, 1892. (Mo.) 
 8. Nitze, N. Ca. Geol. Surv., Bull. I, 1893. (N. Ca.) 9. Orton, 
 Ohio Geol. Surv., V: 371, 1884. (Ohio.) 10. Putnam, 10th Census, 
 XV : 469. (U.S.) 11. Shaler, Ky. Geol. Surv., New Series, III : 163, 
 1877. 12. Smock, N. Y. State Museum, Bull. 7, 1889. (N. Y.) 
 13. Van Hise, U. S. Geol. Surv., 21st Ann. Rept., Ill: 305, 1901. 
 (Lake Superior region.) 14. Winchell, Minn. Geol. Surv., Bull. 6, 
 1891. (Minn.). 
 
 SPECIAL PAPERS. Magnetite. 15. D'Invilliers, Second Pa. Geol. Surv., 
 D3, II, pt. 1 : 237, 1883. (Berks Co.) 16. Prime, Ibid. 1 : 190, 
 1883. (Lehigh Co.) 17. D'Invilliers, Amer. Inst. Min. Engrs., 
 Trans. XIV: 873, 1886. (Cornwall.) 18. Hulst, Eng. and Min. 
 Jour., LXXVIII : 350,1904. (Titaniferous ores.) 18 a. Keith, U.S. 
 Geol. Surv., Bull. 213 : 243, 1903. (N. Ca.) 19. Kemp, Amer. 
 Inst. Min. Engrs., Trans. XXVII: 146, 1898. (Mineville, N.Y.) 
 20. Kemp, U.S. Geol. Surv., 19th Ann. Rept., Ill: 377, 1899. 
 (Adirondack titaniferous ores.) 21. Kemp, S. of M. Quart., XX : 
 323, 1899. (Titaniferous magnetites.) 22. Nason, Amer. Inst. Min. 
 Engrs., Trans. XXIV : 505, 1895. (N. J.) 23. Spencer, Min. Mag., 
 X : 377, 1904. (N.J.) 24. Wolff, N. J. Geol. Surv., Ann. Rept. for 
 1893 : 359, 1894. (N.J.) 
 
 Hematite. 25. Bayley, U. S. Geol. Surv., Mon. XLVI, 1904. (Menomi- 
 nee range.) 26. Boutwell, U. S. Geol. Surv., Bull. 225: 221, 1904. 
 (Uinta Mts., Utah.) 27. Clements, Smythe, Bayley, and Van Hise, 
 U. S. Geol. Surv., 19th Ann. Rept., Ill: 1, 1899. (Crystal Falls 
 district.) 28. Clements, U. S. Geol. Surv., Mon. XLV, 1903. (Ver- 
 milion range.) 29. Dewees, Second Pa. Geol. Surv., Rept. F, 1878. 
 (Pa.) 30. Eckel, Eng. and Min. Jour., LXXIX : 897, 1905. 31. Leith,
 
 IKON ORES 277 
 
 U. S. Geol. Surv., Mon. XLIII, 1903. (Mesabi range.) 32. Leith, 
 U. S. Geol. Surv., Bull. 225 : 229, 1904. (S. Utah.) 33. McCreath, 
 Second Pa. Geol. Surv., MM : 229, 1879. (Many analyses.) 34. Pechin, 
 Amer. Inst. Min. Engrs., Trans. XIX : 1016, 1891. (Va.) 35. Porter, 
 Amer. Inst. Min. Engrs., Trans. XV: 170, 1887. (Tenn., Ala., Ga.) 
 35 a. Russell, U.S. Geol. Surv., Bull. 52: 22, 1889. (Clinton ore.) 
 36. Smyth, Amer. Jour. Sci., XLIII : 487, 1892 (Clinton ore) ; and 
 N. Y. State Geologist, 22d Ann. Kept., 1902 : 116, 1904. 37. Van Hise, 
 U. S. Geol. Surv., 21st Ann. Kept., Ill : 305, 1901. (Lake Superior 
 region.) 37 a. Van Hise, Bay ley and Smyth, U. S. Geol. Surv., Mon. 
 XXVIII, 1897. (Marquette.) 38. Van Hise and Irving, U. S. Geol. 
 Surv., Mon. XIX, 1892. (Penokee-Gogebic range.) 39. Weidman, 
 Wis. Geol. and Nat. Hist. Surv., Bull. 13, 1904. (Baraboo district, 
 Wis.) 40. Woodbridge, Series of articles on Mesabi range, Eng. and 
 Min. Jour., 1905. 
 
 Limonite. 41. Calvin, la. Geol. Surv., IV : 97,1895. (la.) 42. Cat- 
 lett, Amer. Inst. Min. Engrs., Trans. XXIX : 308, 1900. (Va.) 
 43. Diller, U. S. Geol. Surv., Bull. 213 : 219, 1903. (Redding quad- 
 rangle, Calif.) 44. Eckel, Eng. and Min. Jour., LXXVIII : 432, 
 1904. (E. N. Y. and W. New Eng.) 45. Garrison, Eng. and Min. 
 Jour., LXXIII : 258, 1904. (Chemical characteristics.) 46. Hayes, 
 Amer. Inst. Min. Engrs., Trans. XXX : 403, 1901. (Ga.) 47. Hayes 
 and Eckel, U. S. Geol. Surv., Bull. 213 : 233, 1903. (Cartersville, Ga.) 
 48. Hopkins, Geol. Soc. Amer., Bull. XI : 475, 1 900. (Pa.) 48 a. Mc- 
 Calley, Ala. Geol. Surv., Report on Valley Region, II, 1897. (Ala.) 
 48 b. Moxham, Amer. Inst. Min. Eng., Trans. XXI : 133. (Great 
 Gossan Lead.) 49. Pechin, Eng. and Min. Jour., LIV: 150, 1892. 
 (Va. Oriskany ores.) 50. Penrose, Geol. Soc. Amer., Bull. Ill : 44, 
 1892 (Ark. and Tex. Tertiary ores); also Ark. Geol. Surv., Rep. 
 1892, vol. 1, 1892. 51. Phillips, Bug. and Min. Jour., LXV : 489, 
 1898. (Ala.) 52. Walker, Tex. Geol. Surv., 2d Ann. Rept., 291, 
 1891. (Cherokee Co., Texas.) 
 
 Siderite. 53. Moore, Ky. Geol. Surv., 2d Ser., I, pt. 3 : 63, 1876. (Ky.) 
 54. Orton, Ohio Geol. Surv., V : 378, 1884. (Ohio.) 55. Second Pa. 
 Geol. Surv., K: 386, and MM: 159, 1879. (Pa.) 56. Raymond, 
 Amer. Inst. Min. Engrs., Trans. IV : 339, 1876. (N. Y.) 57. Smock, 
 N. Y. State Museum, Bull. 7 : 62, 1889. (N.Y.)
 
 CHAPTER XV 
 
 COPPER 
 
 Ores of Copper. Copper-bearing minerals are not only 
 numerous, but widely although irregularly distributed. 
 More than this, copper is found associated with nearly 
 every variety of ore or ore deposit. Nevertheless but few 
 minerals serve as ores of copper, and the same may be said 
 regarding the number of important producing districts in the 
 United States. 
 
 The ores of copper together with their theoretic composi- 
 tion are as follows : 
 
 ORE 
 
 COMPOSITION 
 
 Cu 
 
 S 
 
 Fe 
 
 
 Cu 
 
 100 
 
 
 
 Chalcocite 
 
 Cu S 
 
 79.8 
 
 20.2 
 
 
 
 CuFeS 
 
 345 
 
 350 
 
 305 
 
 (Copper pyrite) 
 
 CuoFeS 
 
 555 
 
 281 
 
 164 
 
 Covellite 
 
 CuS 
 
 6648 
 
 33.52 
 
 
 Tetrahedrite .... 
 
 4 Cu 2 S Sb S 3 
 
 52.1 
 
 23.10 
 
 1 39 
 
 Enargite 
 
 Cu 3 AsS 4 
 
 48.40 
 
 32.50 
 
 
 Melaconite (Black oxide) 
 
 CuO 
 Cu O 
 
 79.86 
 
 8880 
 
 
 
 Azurite 
 
 3 CuO, 2 CO 2 +H 2 
 
 55.00 
 
 
 
 (Blue carbonate) 
 Malachite 
 
 2 CuO CO 2 H 2 O 
 
 57.40 
 
 
 
 (Green carbonate) 
 Chrysocolla 
 
 CuO, SiO 2 , 2 H 2 O 
 
 36.10 
 
 
 
 
 
 
 
 
 278
 
 COPPER 279 
 
 Very few ores approach the theoretic percentages given 
 above. Thus in Michigan, where native copper is the ore 
 mineral, this, as now mined, rarely averages above 1 per 
 cent metallic copper. At Butte, Montana, the copper-bear- 
 ing minerals are chalcocite, enargite, bornite, and chalco- 
 pyrite, but much of the ore does not usually contain more 
 than 5 or 6 per cent metallic copper, and in rarer instances 
 12 per cent. The same holds true in many other regions. 
 At the present time chalcopyrite is probably the most widely 
 distributed of all the copper ores, and the one most often 
 worked, but it is not the prominent ore in the largest pro- 
 ducing districts. 
 
 Copper ores are found in many formations, ranging from 
 the pre-Cambrian to the Tertiary, but grouped according to 
 their mode of origin they fall mostly into one of the four 
 following groups (2) : 
 
 1. Magmatic segregations. No workable deposits of this 
 type are known in the United States. 
 
 2. Contact metamorphic deposits, in crystalline, usually 
 garnetiferous limestone, along igneous rock contacts. The 
 copper is thought to have been introduced by vapors from 
 the igneous rock. 
 
 3. Deposits formed by ascending, circulating, probably 
 hot waters, the ores being deposited in fissures, pores, spaces 
 of brecciation, or sometimes by replacement of the rock. 
 
 4. Pod or lens-shaped deposits in crystalline schists, which 
 may represent concentration of material from a disseminated 
 condition in the surrounding rocks. 
 
 While the third and fourth groups include all the largest 
 deposits of the world, still these do not in all cases owe their 
 economic importance to the mode of formation, but rather to
 
 280 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 secondary changes which have taken place in them, resulting 
 in a leaching of the copper in the upper part of mass, as 
 copper sulphate, and its transference to lower levels, where 
 it is redeposited through the influence of copper sulphide, 
 iron compounds, or limestone. 
 
 Impurities in Copper Ores. The impurities which copper 
 ores may contain are iron, silver, antimony, arsenic, tellurium, 
 silica, sulphur, and phosphorus, and in the metallurgical treat- 
 ment of the ore it is desirable to rid the metal of these as 
 fully as possible. Both iron and silver may affect the elec- 
 trical conductivity of copper, and antimony and arsenic do 
 so to a smaller extent. 
 
 Tellurium is not uncommon in some districts, and renders 
 the metal red-short even in small amounts. Silver, even 
 if present in as small amounts as .5 per cent, lowers the 
 electrical conductivity, and above 3 per cent affects the 
 toughness and malleability of the copper. Sulphur up to 
 .25 per cent lowers the malleability and .5 per cent renders 
 the metal cold-short, while .4 or more per cent phosphorus 
 makes it red-short. 
 
 Many low-grade ores can be concentrated by crushing and 
 mechanical concentration, as in the Lake Superior district of 
 Michigan and at Butte, Montana. Sulphide ores may also 
 be given a preliminary roasting to get rid of the volatile 
 sulphur, arsenic, etc. The ore is then usually put through 
 a smelting process, followed sometimes by electrolytic treat- 
 ment for refining the metal. 
 
 Superficial Alteration of Copper Ores (see 25, ore deposits). 
 This may produce results of great economic importance, 
 and excellent examples of it are seen in some of the Arizona
 
 COPPER 281 
 
 deposits, where the upper portions of the copper deposits are 
 brown or black ferruginous porous masses brightly colored 
 with oxidized copper minerals such as cuprite, malachite, 
 azurite, and chrysocolla, while below this at a variable depth 
 they pass into sulphides. 
 
 In weathering, the copper minerals, such as chalcopyrite 
 or other sulphides, are usually oxidized first to sulphates, 
 and subsequently changed to oxides, carbonates, or silicates 
 and occasionally even to chlorides and bromides. A con- 
 centration of the ore deposit may take place partly by segre- 
 gation and partly by leaching, and pockets of the ore form, 
 which are surrounded by oxidized iron minerals forming 
 part of the gangue. 
 
 While the oxidation will not increase the total copper 
 contents of the ore body, still it may change it into a more 
 concentrated form, for the carbonates and other oxidized 
 copper minerals contain more copper than the original sul- 
 phide. The ore in the gossan may therefore run from 8 to 30 
 per cent or more, while below it may show only 5 per cent of 
 copper (see 25, ore deposits). These altered ores cannot how- 
 ever be more cheaply treated. If leaching follows oxidation, 
 the gossan may be freed of its ore, as at Butte, Montana, 
 where the upper part of the ore-bearing fissures is poor 
 siliceous gangue. Secondary enrichment may also occur 
 below the water level, giving chalcocite, chalcopyrite, and 
 bornite of later origin. 1 
 
 Distribution of Copper Ores in the United States. About 
 90 per cent of the copper produced in the United States is 
 obtained from three states, viz., Montana, Michigan, and 
 Arizona, named in the order of their output, the rest coming 
 
 1 Both chalcopyrite and bornite are more often regarded as primary 
 sulphides.
 
 282 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 from the Appalachians and Cordilleran area ; the ores of the 
 latter are often worked chiefly for their gold contents, with 
 copper as a secondary product. 
 
 Montana. The mining camp of Butte (29-31), which is 
 not only the greatest producer of copper in the world, but 
 in which one mine, the Anaconda, yields one seventh of the 
 entire world's supply, lies in the central part of the Rocky 
 
 FIG. 52. Map showing distribution of copper ores in United States. Adapted 
 from Ransome, Min. Mag., X: 1. 
 
 Mountain region. The ore-bearing veins occur in an older 
 hornblendic granite, known as the Butte granite, found chiefly 
 in the eastern part of the district, and which is cut by the 
 acid Bluebird granite or aplite, that forms dikes and small 
 masses in this region. Both of these granites are intersected 
 by dikes of quartz porphyry of doubtful genetic relation to 
 the ore bodies, although the latter are usually low-grade 
 when bounded by either the porphyry or the aplite. The 
 last stage of igneous activity consisted of the extrusion of
 
 COPPER 
 
 Pair- ALLUVIUM AND WASH PLEISTOCENE 
 
 t;; ;J Nrl - INTRUSIVE RHVOL'ITE NEOCENE 
 
 Oft- APLITE 
 
 POST CARBONIFEROUS 
 
 GRANITE 
 
 Fia. 53. Map of Butte, Mont., district showing distribution of veins and geology. 
 After Weed, U. S. Geol Surv., Atlas Folio.
 
 284 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 rhyolite flows and ash beds, and dikes of the same rock also 
 cut the silver veins of the region. 
 
 The Butte district contains both silver and copper veins. 
 The latter are found in an area about a mile long and one 
 
 half mile wide, in the south- 
 eastern part of the district, 
 while the silver veins sur- 
 rounding it are of much less 
 importance. 
 
 The granites are traversed 
 by several systems of joints 
 and shear planes, and the ore 
 has not only been deposited 
 in them, but has replaced 
 the wall rock as well. The 
 veins are of varying age, the 
 larger and richer ones hav- 
 ing been broken, reopened, 
 and even displaced by fault- 
 ing, and a careful study of 
 the district has shown four 
 separate periods of fracture, 
 in three of which ores have 
 been formed. 
 
 In the earliest, the vein 
 filling, which was the result 
 of replacement in sheeted granite, is quartz and pyrite with 
 some copper. Later fracturing produced large masses of 
 crushed granite, clay, etc., with boulders of ore, and this 
 was sometimes added to by the deposition of enargite by 
 later ascending solutions. The richest masses or bonanzas 
 
 QUARTZ PORPHYRY 
 
 a. OXIDIZED ZONE 
 6. CHALCOCITE 
 C. ENARGITE 
 
 d. PYRITE 
 
 e. QUARTZ 
 /. BORNITE 
 
 a. CHALCOCITE 
 
 I 1 FAULT 
 
 FIG. M. Section at Butte, Mont., show- 
 ing mode of occurrence of ore. 
 After Winchell, Eng. and Min. 
 Jour.,LXXVIII:-7.
 
 PLATE XVIII
 
 COPPER 285 
 
 of glance found in some of the mines are of secondary 
 origin. 
 
 While the veins exhibit a curious uniformity of direction, 
 most of them striking nearly east and west, and few of them 
 departing more than 15 to 20 from the vertical, still they 
 show considerable variation in width, ranging from a few 
 feet to 50, or even 150 where the altered country rock is 
 impregnated with glance. Unfortunately, the complexity of 
 the veins and uncertainty of boundaries has given rise to 
 much costly litigation in the district. 
 
 The common vein minerals are quartz, pyrite, and chalco- 
 cite. Bornite and enargite are locally important, while 
 chalcopyrite and covellite are known. Present in sub- 
 ordinate quantities are tetrahedrite, tennantite, and argen- 
 tite. The chalcocite is always of secondary character. 
 
 The average composition of first-class ore in Butte in 
 1902 was: Cu, 11.4 per cent; Fe, 16.6 per cent; Zn, .3 per 
 cent; S, 22.6 per cent; As and Sb, 1.4 per cent; A1 2 O 3 , 7.9 
 per cent; insoluble, 44.7 per cent; SiO 2 , 38.2 per cent; Ag, 
 oz. 5.2; Au, oz. .04. Second-class ore averages: Cu, 5.2 
 per cent ; Fe, 16 per cent ; S, 19.8 per cent ; insoluble, 
 56 per cent; Ag, 3 oz. 
 
 Gold is quite universally distributed through the ores, 
 though in very small amounts, forming 3 per cent of the 
 values in the copper bullion. Small amounts of arsenic, anti- 
 mony, bismuth, tellurium, selenium, and nickel have been 
 found, and manganese is widespread in the silver veins, 
 though wanting in copper-bearing ones. Zinc is not limited 
 in distribution, but is more abundant in the silver veins. 
 
 The deposition of the ores is considered by Weed to be 
 due to aqueous alkaline solutions, which have probably
 
 286 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 leached the metals from the granite at considerable depths. 
 These solutions, which came up in the fissures, were hot, 
 but not necessarily under pressure. Where the fissures 
 were open they were filled with ore, and where narrow, 
 replacement of the walls occurred, so that the vein matter 
 shades off into the country rock. Since their formation 
 faulting has occurred, usually parallel to the vein. The 
 entrance of meteoric waters into the vein has carried much 
 ore downward, resulting in a richer zone below even the 
 zone of oxidation, and showing bornite, chalcocite, and 
 covellite as a result of this; some of these have been 
 derived from the breaking up of the pyrite. It has been 
 found that these bonanza bodies of secondary origin pass 
 downward into lower-grade ores. Most of the ores are 
 put through a process of mechanical concentration before 
 being sent to the smelter. The vertical limits of the ore 
 have not yet been determined, but certain silver mines 
 have reached a depth of 1450 to 1500 feet, while most of 
 the copper mines have gone to 2000 or 2500 feet. 
 
 The history of this mining camp is full of interest. Butte in 1864 
 was a gold camp, but difficulties in working the gravels directed atten- 
 tion to the mineral-vein outcrops, and unsuccessful attempts were made 
 to work their copper and silver contents, so that it was not until 1875, 
 following a period of quiescence, that the discovery of rich silver ore 
 in the Travona lode revived the mining industry of Butte. In 1877 
 several silver mines were opened, followed by others ; but this did not 
 last many years, for with the drop in the price of silver many mines 
 closed, although one, the Bluebird, had produced 2,000,000 ounces of 
 silver from 1885 to 1892. 
 
 The copper mines were worked to only a limited extent at first, 
 and the industry did not assume permanence until 1879-1880, when 
 niatte smelting was introduced. In 1881 the Anaconda mine, which
 
 COPPER 287 
 
 was first worked for silver, began to show rich bodies of copper ore, 
 and since then the output of copper has steadily increased, there being 
 a number of large smelting plants distributed between Butte, Ana- 
 conda, and Great Falls. 
 
 Up to the end of 1896 the commercial value of the copper pro- 
 duced was about $330,000,000. This greatly exceeds the total output 
 of Leadville, and nearly equals the famous Comstock lode. W. H. 
 Weed has estimated that up to January 1, 1897, the district had 
 yielded 500,000 ounces of gold, 100,000,000 ounces of silver, and 
 1,600,000,000 pounds of copper. In 1887 Butte passed the Lake Superior 
 District in the production of copper, and has kept ahead of it ever since, 
 having in 1903 produced 38.9 per cent of the United States produc- 
 tion. 
 
 GEOLOGICAL CROSS-SECTION OF THE COPPER MINING REGION 
 FIG. 55. Section across Keweenaw Point. After Rickard. 
 
 Michigan (2,24-26). This region, which was discovered 
 in 1830 by Douglas Houghton, a young geologist, has 
 become one of the most famous, and for some years one 
 of the leading, copper-producing districts of the world. 
 
 The rocks of the region, known as the Keweenaw series, 
 consist of steeply northwesterly dipping, interbedded lava 
 flows, sandstones, and conglomerates. These form a belt 
 from 2 to 6 miles wide, which extends from Houghton to 
 the end of the Keweenaw peninsula, and rises as a ridge 
 from 400 to 800 feet above the lake, being flanked on 
 either side by Potsdam sandstone (Fig. 55). 
 
 The ore, which is native copper, and is occasionally asso- 
 ciated with native silver, occurs (1) as a cement in the
 
 288 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 conglomerate of porphyry pebbles or replacing the latter ; 
 (2) as a filling in the amygdules of the lava beds ; (3) as 
 masses of irregular and often large size, in veins with 
 calcitic and zeolitic gangue. 
 
 The veins, which cut both the igneous and sedimentary 
 rocks, have yielded much copper in former years, and the 
 large masses obtained from them have made the region 
 famous; but at the present time about 75 per cent of the 
 production comes from the Calumet conglomerate, while 
 
 FIG. 56. Section showing occurrence of amygdaloidal copper, Quincy mine, 
 Mich. After Rickard, Eng. andMin. Jour., LXXVIII: 626, 1904. 
 
 the balance comes from two other copper-bearing conglom- 
 erates known as the Albany and the Allouez, and from 
 the ash-beds and amygdaloids, whose gas cavities are filled 
 with a mixture of native copper, calcite, and zeolites. 
 
 A curious and hitherto unexplained feature is the irregu- 
 lar distribution of the copper in the different beds. Thus 
 the Calumet conglomerate carries practically no ore outside 
 of the Calumet and Hecla ore shoot which is three miles long, 
 12-15 feet thick, and has been mined to a depth of 5000 feet. 
 
 Various theories have been brought forward to account 
 for the origin of the copper ores in this region.
 
 COPPER 289 
 
 That it is not a true contact deposit is shown by the fact 
 that the amygdules in the diabase, the fissure veins, and the 
 crevices in the broken pebbles are filled with copper, show- 
 ing a subsequent deposition. The diabase was looked upon 
 by Pumpelly (25 &) as a possible source of the ore, and since 
 its extensive alteration was no doubt accompanied by the 
 oxidation of protoxides, this might account for the reduc- 
 tion of copper mineral to the native or metallic condition, 
 it being known that ferrous salts may precipitate metallic 
 copper (1). More recently Lane (25 a) has suggested that 
 originally buried water has also been an important factor in 
 concentration, but agrees that the final precipitation was by 
 water working downward. For the water in the upper part 
 of the mines is fresh, below saline, and copper is also in the 
 iron ores, and has been thought to occur mainly under the 
 higher portions of the point. 
 
 Although these deposits have been worked in prehistoric 
 times, as evidenced by copper implements and ornaments 
 found in the mines, the famous Calumet and Hecla Mine 
 was not opened up until 1846. In 1847 Michigan pro- 
 duced 213 long tons of the total United States production 
 of 300 tons of copper. Since 1863 the annual output has 
 exceeded 1000 tons and has gradually and steadily increased, 
 reaching 85,893 long tons in 1903, having a market value of 
 120,269,000. 
 
 The ores from this district, which are known as Lake ores, 
 are all of low grade, some running as low as .55 per cent 
 native copper. Owing, however, to the brittle character of 
 the gangue and the malleability of the ore, as well as their 
 difference in specific gravity, it is possible to separate the 
 two quite thoroughly by crushing in stamps and concentrat-
 
 290 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 ing by jigs, tables, etc. This concentrated material is then 
 refined by smelting. 
 
 Arizona (8-16). This territory ranks third as a producer 
 of copper ores in the United States, and differs from most 
 other copper-producing localities in supplying chiefly ores 
 of oxidized character ; in fact, from 1880 to 1895 Arizona was 
 the only copper area in the world whose ores were exclusively 
 oxidized. 
 
 The territory contains four important districts, all lying 
 within the mountain region, and which in the order of their 
 importance are, (1) Bisbee or Warren, (3) Jerome or Black 
 Range, (3) Clifton, Morenci, or Copper Mountain, and (4) 
 Globe. In all except the second the modes of the ore occur- 
 rences possess certain similarities. 
 
 Bisbee or Warren District. This district (11,15), which 
 contains the famous Copper Queen Mine, lies on the eastern 
 slope of the Mule Pass Mountains, but a short distance from 
 the Mexican boundary. The section at that locality involves 
 strata from pre-Cambrian to Cretaceous age, with an im- 
 portant unconformity between the Carboniferous and Cre- 
 taceous (Fig. 57). Prior to the deposition of the latter the 
 rocks had been broken by numerous faults, one of these, the 
 Dividend fault, being specially prominent in forming one 
 boundary of the ore-bearing area. This was followed by 
 intrusions of a granitic magma forming dikes, sills, or 
 irregular stocks, which have metamorphosed the Carbon- 
 iferous limestones, with the production of characteristic 
 contact minerals. 
 
 The ore bodies, which are generally developed in the zone 
 of metamorphic silicates surrounding the porphyry, as well as 
 sometimes outside of it, form large, irregularly distributed,
 
 COPPER 
 
 291 
 
 but rudely tabular masses, which are generally parallel to 
 the limestone bedding. As now found they consist of oxi- 
 dized ores, such as malachite, azurite, and cuprite, above, 
 which pass at variable depths into unaltered sulphides ; but 
 between the two, or at least never far from the effects of 
 
 GENERALIZED COLUMNAR SECTION OF THE ROCKS OF THE BISBEE QUADRANGLE. 
 
 FIG. 57. Geological section at Bisbee, Ariz. After Ransome. U. S. Geol. Surv., 
 Prof. Pap. 21. 
 
 oxidation, masses of massive or sooty chalcocite are fre- 
 quently found. 
 
 The ore-bearing solutions are believed to have been stimu- 
 lated by the porphyry and to have risen from an unknown 
 source, but although they may have followed some of the
 
 292 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 fault fissures, the ore, which originally consisted of pyrite, 
 chalcopyrite, and occasionally sphalerite, owes its deposition 
 to metasomatic replacement in the limestone. As originally 
 formed, the deposits contained too little copper to make 
 
 them of commer- 
 cial value, but they 
 have been subse- 
 quently enriched 
 by concentration 
 due to weather- 
 ing in the upper 
 
 part ' and second - 
 
 ary deposition of 
 FIG. 58. Generalized section of ore bodies at Bisbee, chalcocite in the 
 
 underlying zone. 
 
 Indeed it is said that nearly all the bodies of workable 
 sulphides owe their value to its presence. 
 
 The gossan of some of the ore bodies forms prominent 
 ferruginous ledges, and while these rarely show surface in- 
 dications of copper, still experience has shown that they are 
 connected with underlying ore bodies; however, many of 
 the latter have no outcrops. 
 
 Although always important, this region assumed great 
 prominence in 1903, due to the opening and extensive de- 
 velopment of new ore bodies of great extent. 
 
 Jerome District. This was the leading copper-producing 
 district of Arizona for 1897 to 1900 inclusive, but then 
 dropped to second place. The mode of occurrence of the 
 ore differs markedly from that noted in other areas. It is 
 bornite and chalcopyrite, which is associated with a sheared 
 dike and fills fissures and impregnates the slate rock.
 
 PLATE XIX 
 
 FIG. 1. Smelter of Arizona Copper Co., Clifton, Ariz. After Church, Min. Mag. 
 X: 2, 1904. 
 
 FIG. 2. View of Bingham Cauon, Utah. After Keith, U. S. Geol. Surv., Prof. 
 Paper 38, 1905.
 
 COPPER 293 
 
 Clifton District. In this district (12, 13), which ranks 
 third among the Arizona copper districts, the conditions 
 are in part similar to the Bisbee district in so far as the 
 geologic section and the intrusion of porphyry and granite 
 into the Palaeozoic sediments is concerned. They have 
 likewise been broken by extensive fracturing and faulting, 
 the faults sometimes having a throw of 1000 to 1500 feet, 
 and there was also an extensive flow of Tertiary eruptives. 
 The ore bodies differ from the Bisbee ones, however, in 
 point of origin, being true contact deposits, the porphyry 
 by contact influence having produced great masses of garnet 
 
 FIG. 59. Section of Morenci district. P, porphyry; S, unaltered sediments; 
 F, fissure veins ; M, metamorphosed limestone and shale ; 0, contact meta- 
 morphic ores ; R, disseminated chalcocite. After Lindgren, Eng. and Min. 
 Jour., LXXVIII: 987, 1904. 
 
 and epidote in the Carboniferous limestones ; and wherever 
 alteration has not masked the phenomena, the metallic 
 minerals, magnetite, pyrite, chalcopyrite, and sphalerite, are 
 found accompanying the contact silicates, and often inter- 
 grown with them in such a manner as to leave no doubt 
 concerning the contact origin of the ores and the porphyry 
 as their source. The concentration and commercial value 
 of the ores is due, however, to later processes intimately 
 connected with weathering. This has produced malachite 
 and azurite in the gossan, but some of the copper has been 
 carried to lower levels and precipitated as chalcocite. The 
 sphalerite has been removed in solution as zinc sulphate, and 
 the magnetite and garnet have yielded silica and limonite.
 
 294 ECOKOMIC GEOLOGY OF THE UNITED STATES 
 
 The ore deposits in the limestone are irregular or tabular, 
 due to the accumulation of the minerals along bedding 
 planes, but in addition, fissure veins, cutting through many 
 of the rocks, and of later age than the porphyry, are found. 
 
 Grlobe District (14). While the most important deposits 
 here occur in limestone, near the contact with granite and 
 trachyte, still others are found as fissure veins in sand- 
 stone (Old Dominion Mine), or in slate and gneiss, or 
 even veinlets in gneiss ; the ores are largely oxidized. 
 The output of this district, which has been the least actively 
 worked of any, though small for several years, increased 
 greatly in 1901. 
 
 Appalachian Region (42, 43). The existence of copper 
 in the Appalachian belt has been known for a number of 
 years, but the copper-mining industry has not been active. 
 The early attempts to work the deposits were chiefly to 
 obtain both gold and copper, and resulted in failure, due 
 chiefly to the low market values of copper ; hence for many 
 years the deposits, with few exceptions, have been but 
 little worked, and it is only recently that a demand for 
 the metal and cheaper metallurgical treatment have revived 
 copper mining. 
 
 The deposits in many cases occur in metamorphic rocks 
 scattered over a wide belt, but five important types are 
 recognizable (42) : 
 
 1. True fissure veins, filled with quartz and copper, the 
 vein crossing or conforming to the banding of the schists, 
 and replacement of the wall rock being rare. The ores 
 are bornite, with a little chalcopyrite and iron pyrite. The 
 deposits at Virgilina, Virginia, belong in this group. 
 
 2. True fissure veins with auriferous quartz, chalcopyrite,
 
 COPPER 295 
 
 and pyrite formed chiefly by replacement. The fissures 
 are usually found along sheeting planes, and the deposits 
 at Gold Hill, North Carolina, are taken as a type of this 
 group. 
 
 3. Pyrrhotite veins of the Ducktown type (36-38), filling 
 true fissures, and consisting chiefly of pyrrhotite and pyrite 
 with a little quartz. The ore has been formed by the 
 replacement of a zone of sheeted rock, which was com- 
 posed chiefly of metamorphic minerals, such as garnet, 
 actinolite, epidote, pyroxene, etc., these latter being the 
 products of alteration of a calcareous shale. The Duck- 
 town ore body represents a type forming a belt extending 
 all the way from Vermont to Alabama. They all show a 
 gossan which can be mined for iron ore, while under this 
 there is a zone of black copper, the result of local enrich- 
 ment, which passes into the sulphide ore below. The 
 copper is richest in those portions where the pyrrhotite 
 predominates. The Ducktown ore, which has been worked 
 for a number of years, averages 3.5 per cent copper as it 
 comes from the mine. Some of the chambers are from 50 
 to 150 feet across, and from 25 to 150 feet high without 
 timbering. 
 
 The great gossan lead of Virginia and the copper de- 
 posits of Ore Knob, North Carolina, also belong to this 
 type. 
 
 4. The Catoctin type, representing segregations of native 
 copper, copper oxides, and carbonates along shear zones in 
 altered igneous rocks of Algonkian age, the ores extend- 
 ing below ground water level. They are found at a num- 
 ber of localities in the Appalachian and Piedmont plateau 
 districts, usually in the Catoctin schist. The ore shows
 
 296 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 on the outcrop, but does not extend usually more than 50 
 to 60 feet below the surface. It is supposed to have been 
 leached out of the vein walls. Occurrences of this type 
 occur in Green County, Virginia. 
 
 5. Deposits of native copper along the contact of diabase 
 and sandstone. These have been found in New Jersey (32, 33), 
 but are unimportant, although the mines have been worked 
 from time to time. Similar occurrences have been reported 
 from Pennsylvania (34, 35) and Connecticut. 
 
 Utah. This state ranks fourth among the copper-produc- 
 ing regions of the United States. The most important dis- 
 trict is that of Bingham Canon (44), in the Oquirrh range, 
 southwest of Salt Lake City, and is unique in that it includes 
 the oldest mining claim in the state. It moreover differs 
 from the other important copper mining localities in the 
 country, in having a considerable quantity of gold, silver, 
 and lead associated with the copper. 
 
 The rocks of this district include: (1) a great thickness 
 of sedimentaries of Carboniferous age and divisible into a 
 lower member consisting of massive quartzite with several 
 interbedded limestones which carry most of the ore bodies 
 in the camp, and an upper member of quartzite with 
 black calcareous shales, sandstones, and impure limestones; 
 (2) igneous rocks, which have pierced the entire series of 
 sedimentaries, forming dikes, sills, or laccoliths, and consist- 
 ing either of a type between diorite porphyrite and mon- 
 zonite, which is closely associated with the ore bodies, or an 
 andesite, having no relation to the ores. 
 
 Folding, fracturing, and faulting have greatly complicated 
 the structural relations of this region. 
 
 The ores form lenses in the limestone, which lie roughly
 
 COPPER 297 
 
 parallel to its bedding, or occupy fractures or fissure zones. 
 Copper, lead, silver, and gold may occur in either, but the 
 copper rather favors the lenses, and the lead and silver the 
 fissures. 
 
 The mining operations have been based in turn on the 
 oxidized gold ores, carbonate ores of lead and copper, sul- 
 phides of lead, and finally sulphides of copper, which now 
 constitute the mainstay of the district. These copper sul- 
 phides are cupriferous pyrite, chalcopyrite, black sulphides 
 (probably tetrahedrite), and chalcocite with a little galena, 
 zinc, and siliceous gangue. The pyrite, which is widespread 
 in the district, forms immense replacement bodies in the 
 limestone, but is of secondary importance in the fissure zones. 
 The Bingham ores are of low value, and bonanzas are rare ; 
 indeed, the copper ores can often only be profitably worked 
 because of their gold, lead, and silver contents. 
 
 California. California (17, 18, 2) in 1903 was fifth in the 
 list of copper-producing states, and owes its position to the 
 output from Shasta County in the northern part of the state. 
 This region lies at the northern end of the Sacramento Valley, 
 and contains a series of sedimentary rocks, ranging from 
 Devonian to Miocene and pierced by igneous intrusions. 
 Folding, faulting, and shearing are common. The ore 
 is found either: (1) as sulphide deposits in contact zones, 
 between diabase dikes and Carboniferous limestones; or (2) as 
 bodies of sulphides, in shear zones, the latter having been 
 mineralized with the development of irregular ore bodies of 
 variable size. The ores are rare generally in the metamor- 
 phosed igneous rocks. Superficial alteration has produced 
 a gossan w r hich may show a thickness of as much as 100 feet 
 at some localities (Iron Mountain).
 
 298 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The important districts are the Iron Mountain and Bully 
 Hill. In both, the ores are chalcopyrite and pyrite, but 
 that from the latter district also contains some bornite and 
 chalcocite. An analysis of the Iron Mountain ore gave, Cu, 
 7.45 per cent; S, 45.60 per cent; Fe, 36.97 per cent; Zn, 
 
 3.41 per cent ; SiO 2 , 5.62 per cent ; 
 
 A1 2 O 3 , 1.57 per cent; Moisture, 
 0.88 per cent. This is probably 
 higher than the average in cop- 
 per. 
 
 Copper deposits are also known 
 in other parts of California (17). 
 
 Other Occurrences. Colorado 
 has few copper mines proper, but 
 many of the ores mined in the 
 state carry copper, and it is util- 
 ized by lead smelters as a carrier 
 in the extraction of other metals. 
 Copper is mined in New Mexico 
 and Idaho, the Seven Devils Dis- 
 trict of the latter state being well 
 known (23). The Grand Encampment district of southern 
 Wyoming (50) has also supplied more or less ore, and a small 
 amount is mined in Missouri (28). Copper has been found 
 at several localities in Alaska (4-7), but no shipments were 
 made prior to 1903. 
 
 Uses of Copper. Since prehistoric times copper alloyed 
 with tin has been used in various parts of the world for the 
 manufacture of bronze. Thus it was used for this purpose 
 in Homeric times, and it is found in the lake dwellings of 
 
 OXIDIZED ORES 
 
 Eleossw. EDeNRicHED SOLPHIOES 
 
 FIG. 60. Section of ore body at 
 Bully ffill, Calif. After Diller.
 
 COPPER 299 
 
 Switzerland. The bronze found in Troy contains a very little 
 tin, and since this metal is not found in the excavations in 
 the West, it seems probable that the bronze was made in 
 Asia, perhaps in China or India, by some secret process and 
 imported to the western countries. 
 
 By an alloy of copper and tin, although both metals 
 are soft, a comparatively hard metal is produced. The 
 properties of this alloy, bronze, vary greatly according 
 to the proportions of the two metallic constituents, and 
 these vary with the use for which the alloy is intended. 
 United States ordnance is 90 per cent copper and 10 per 
 cent tin, while ordinary bell metal is about 80 per cent 
 copper, though the percentage varies with the tone re- 
 quired. Statuary bronze is generally an alloy of copper, 
 tin, and zinc ; and, in these various bronzes, the color 
 varies from copper-red to tin-white, passing through an 
 orange-yellow. 
 
 An alloy of copper and zinc produces brass, which is found 
 of so much value for small articles used in building and for 
 ornamental purposes in machinery. Copper is also used in 
 roofing and plumbing. 
 
 A large supply of this metal is made into copper wire, 
 and the most important present use of copper is in electricity, 
 for which its high conductivity especially fits it for the 
 transmission of electric currents. 
 
 Production of Copper. The production of copper in the 
 United States has increased steadily and rapidly in the last 
 fifty years, placing the United States in the lead of the 
 world's copper producers. This increase can be seen from 
 the table given below :
 
 300 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 PRODUCTION OF COPPER IN UNITED STATES FROM 1845 TO 1903 
 
 YEAR 
 
 PRODUCTION 
 LONG TONS 
 
 YEAR 
 
 PRODUCTION 
 LONG TONS 
 
 1845 
 
 100 
 
 1885 
 
 74,052 
 
 1850 
 
 650 
 
 1890 
 
 115,996 
 
 1855 
 
 3,000 
 
 1895 
 
 169,917 
 
 1860 
 
 7,200 
 
 1900 
 
 270,588 
 
 1865 
 
 8,500 
 
 1901 
 
 268,782 
 
 1870 
 
 12,600 
 
 1902 
 
 294,423 
 
 1875 
 
 18,000 
 
 1903 
 
 311,627 
 
 1880 
 
 27,000 
 
 
 
 PRODUCTION OF COPPER IN THE UNITED STATES BY STATES 
 (In pounds) 
 
 SOURCE 
 
 1901 
 
 1902 
 
 1903 
 
 Arizona 
 
 130,778,511 
 33 667 456 
 
 119,944,944 
 25 038 724 
 
 147,648,271 
 17 776 756 
 
 Colorado 1 
 Lake Superior 
 Montana 
 
 9,801,783 
 156,289,481 
 229,870,415 
 
 8,422,030 
 170,609,228 
 288,903,820 
 
 4,158,368 
 192,400,577 
 272,555,854 
 
 New Mexico 
 Utah 
 
 9,629,884 
 20,116,979 
 
 6,614,961 
 23,939,901 
 
 7,300,832 
 38,302,602 
 
 Eastern Atlantic States . . 
 All others 
 
 6,860,039 
 4,526,341 
 
 13,599,047 
 1,935,989 
 
 13,855,612 
 3,546,645 
 
 
 
 
 
 Of the several producing states Montana has for some 
 years been the first, with Michigan second and Arizona 
 third. The marked decrease of Montana in 1903 was due 
 to litigation and labor troubles. 
 
 1 Including copper smelters purchasing copper ore and mattes in the open 
 market, sources not known.
 
 COPPER 301 
 
 WORLD'S PRODUCTION OF COPPER IN LONG TONS 
 COUNTRY 1903 
 
 Chile 30,930 
 
 Germany 21,205 
 
 Japan 31,360 
 
 Mexico 50,480 
 
 Spain and Portugal 49,740 
 
 United States 311,627 
 
 All others 89,739 
 
 The total value of the imports of copper (including ore, 
 matte, and manufactured copper) in 1903 was 120,441,977, 
 while the total value of the exports covering the same class 
 of materials was 144,365,155. 
 
 REFERENCES ON COPPER 
 
 GENERAL. 1. Biddle, Jour. GeoL, IX: 430, 1901. (Origin.) 2. Weed, 
 Min. Mag., X:185, 1904. (United States.) 3. Winchell, Geol. 
 Soc. Amer., Bull. XIV: 269, 1903. (Origin.). Alaska: 4. Brooks, 
 Eng. and Min. Jour., LXXIV : 13. (Tanana and Copper River 
 regions.) 5. Mendenhall and Schrader, U. S. Geol. Surv., Bull. 
 213 : 141, 1903. (Mt. Wrangell region.) 6. Rohn, U. S. Geol. Surv., 
 21st Ann. Rept., II : 393, 1900. (Chitina River and Skolar Mts.) 
 
 7. Schrader, U. S. Geol. Surv., 20th Ann. Rept., VII: 341, 1900. 
 (Prince William Sound and Copper River district.) Arizona : 
 
 8. Blandy, Eng. and Min. Jour., LXIV : 97, 1897. (Ariz.) 9. Church, 
 Amer. Inst. Min. Engrs., Trans. XXXIII: 3, 190-J. (Tombstone 
 district.) 10. Douglas, Min. Indus., VI: 227, 1898. 11. Douglas, 
 Amer. Inst. Min. Engrs., Trans. XXIX : 511, 1900. (Copper Queen 
 Mine). 12. Lindgren, U. S. Geol. Surv., Bull. 213 : 133, 1903. (Clif- 
 ton district.) 13. Lindgren, Amer. Inst. Min. Engrs., Trans. XXXV, 
 1905. (Clifton district.) 14. Ransome, U. S. Geol. Surv., Prof. 
 Paper 12, 1903. (Globe district.) 15. Ransome, U. S. Geol. Surv., 
 Prof . Paper 21, 1904. (Bisbee district.) 16. Wendt, Amer. Inst. Min. 
 Engrs., Trans. XV : 25, 1887. California : 17. Aubury, Calif. State 
 Mining Bureau, Bull. 23, 1902. 18. Diller, Eng. and Min. Jour., 
 LXXIII:857, 1902. (N. Calif .) Colorado : 19. Emmons, Tenth 
 Census, XIII: 68, 1885. (Gilpin Co.) 20. Spencer, U. S. Geol. 
 Surv., Bull. 213:163, 1903. (Pearl, Colo.) 21. Emmons, U. S. 
 Geol. Surv., Bull. 260:221, 1905. (Red Beds, Colo, plateau.)
 
 302 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Georgia: 22. Weed, U. S. Geol. Surv., Bull. 225:180, 1904. 
 Idaho: 23. Lindgren, Min. and Sci. Pr., LXXVI1I:125, 1899. 
 (Seven Devils district.) Michigan : 24. Irving, U. S. Geol. Surv., 
 Mon. V, 1883, also 3d Ann. Kept. : 89, 1883. 25. Lane, Amer. 
 Geol., XXII: 251, 1898. (Magmatic differentiation in copper 
 rocks.) 25 a. Lane, Mich. Miner, Jan.-Feb., 1904. 25 b. Pumpelly, 
 Mich. Geol. Surv., I, pt. 2, 1873. 26. Rickard, Eng. and Min. Jour., 
 LXX VIII: 585, 625, 665, 745, 785, 865, 905, 1025, 1904. Missouri: 
 27. Nicholson, Amer. Inst. Min. Engrs., X : 444, 1882. (St. Genevieve 
 district.) 28. Bain and Ulrich, U. S. Geol. Surv., Bull. 260 : 233, 1905. 
 (General.) Montana: 29. Weed, U. S. Geol. Surv., Bull. 213:170, 
 
 1903. (Butte.) 30. Winchell, Eng. and Min. Jour., LXXVIII: 7, 
 
 1904. 31. Winchell, Geol. Soc. Amer., Bull. XIV: 269, 1903. New 
 Jersey : 32. Kiimmel, N. J. Geol. Surv., Ann. Kept., 1899 : 171, 1900. 
 33. Weed, U. S. Geol. Surv., Bull. 225 : 187, 1904. (Griggstown.) 
 Pennsylvania : 34. Bailey, Eng. and Min. Jour., XXXV : 88, 1883. 
 (Adams County.) 35. Lyman, Jour. Franklin Inst., CXLVI:416, 
 1898. (Bucks and Montgomery counties.) Tennessee : 36. Hen- 
 rich, Amer. Inst. Min. Engrs., Trans. XXV : 173, 1896. (Ducktown.) 
 37. Kemp, Amer. Inst. Min. Engrs., Trans. XXXI : 244, 1902. 
 (Ducktown.) 38. Weed, Amer. Inst. Min. Engrs., Trans. XXX: 
 449, 1901. (Southern Appalachians.) Texas: 39. Schmitz, Amer. 
 Inst. Min. Engrs., Trans. XXVI : 97, 1897. (Permian ores.) 
 United States : 40. Douglas, Amer. Inst. Min. Engrs., Trans. 
 XIX: 678, 1891. 41. Stevens, Copper Handbook, published an- 
 nually at Houghton, Michigan, by the author, $5. 42. Weed, U. S. 
 Geol. Surv., Bull. 213 : 181, 1903 (Appalachians) ; and Bull. 260 : 217, 
 
 1905. (E. U. S.) 43. Weed, U. S. Geol. Surv., Bull. 260 : 211, 1905. 
 (U. S. localities and industry.) Utah : 44. Boutwell, U. S. Geol. 
 Surv., Bull. 213 : 105, 1903. (Bingham.) Also U. S. Geol. Surv., Prof. 
 Paper 38, 1905. Vermont : 45. Weed, U. S. Geol. Surv., Bull. 225 : 
 190, 1904. 46. Smyth and Smith, Eng. and Min. Jour., April 28, 
 1904. Virginia : 47. Watson, Geol. Soc. Amer., Bull. XIII: 353, 
 1902. ( Virgilin a district.) Wisconsin: 48. Grant, Wisconsin Geol. 
 and Nat. Hist. Surv., Bull. No. 6, 1900. (Douglas Co.) Wyoming : 
 49. Kennedy, Eng. and Min. Jour., LXVI: 640, 1898. 50. Spencer, 
 U. S. Geol. Surv., Bull. 213 : 158, 1903. (Encampment region.)
 
 CHAPTER XVI 
 LEAD AND ZINC 
 
 THESE two ores can hardly be treated separately for the 
 reason that they occur so often associated with each other ; 
 the combination of lead and silver, of importance in the 
 Rocky Mountain region, is treated under a separate head. 
 
 Ores of Lead. The ores of lead, together with their com- 
 position and the percentage of lead which they contain, are : 
 Galena, PbS, 86.4 ; 
 Cerussite, PbCO 3 , 77.5; 
 Anglesite, PbSO 4 , 68.3; 
 Pyromorphite, Pb 3 P 2 O 8 + PbCl 2 , 76.36. 
 Of these, galena is the commonest, while the other two are 
 usually found in those localities where superficial oxidation 
 of the ore deposit has taken place. The lead obtained from 
 argentiferous ore is commonly spoken of as desilverized or 
 hard lead, while that from non-argentiferous ones, such as 
 those of the Mississippi Valley areas, is known as soft lead. 
 
 Ores of Zinc. The ores of zinc, together with the per- 
 centage of zinc they contain, are : 
 Sphalerite, ZnS, 67 ; 
 Smithsonite, ZnCO 3 , 51.96 ; 
 Calamine, H 2 Zn 2 SiO 6 , 54.2; 
 Zincite, ZnO, 80.3; 
 Willemite, Zn 2 SiO 4 , 58.5; 
 
 Franklinite (FeZnMn)O(FeMn) 2 O 3 , composition vari- 
 able but containing about 51.8 Fe and 7.5 Mn.
 
 304 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Of these ores, sphalerite (also known as blende, jack, or 
 black-jack) is by far the most important, except in northern 
 New Jersey, where it is practically lacking and franklinite 
 and willemite abound. With few exceptions, zinc is con- 
 stantly associated with lead, and at times, as in portions of 
 the Cordilleran region, carries silver or even gold. 
 
 Calcite, dolomite, and pyrite are common gangue minerals 
 of non-argentiferous lead, and zinc ores, and others may 
 occur at certain localities. In the argentiferous ores, quartz 
 is probably the commonest gangue mineral, but there may 
 be other less important ones. 
 
 Iron, lead, and manganese are not uncommon impurities 
 in zinc ores, and those of Missouri contain small amounts of 
 cadmium, but this is not injurious, as it is more volatile than 
 the zinc and easily driven off by heat. 
 
 Argentiferous lead ores sometimes contain antimony, 
 arsenic, and iron as impurities. Those of the Appala- 
 chians, which are practically non-argentiferous, are free from 
 most of these. 
 
 Neither lead or zinc ores are restricted to any one forma- 
 tion, but the majority of economically valuable deposits of 
 these metals, without silver, gold, or copper, are found in the 
 Paleozoic formations, although a few are known in pre- 
 Cambrian rocks. They exist as disseminations, chamber 
 deposits, as filling in brecciated zones, in gash veins and 
 replacements. While the metallic contents of the ore as 
 mined is often low, still, owing to the great difference in 
 gravity between ore and gangue (excepting pyrite), it is 
 often possible to separate them by mechanical concentration ; 
 and for the zinc ores magnetic separation has been success- 
 fully tried.
 
 LEAD AND ZINC 
 
 305 
 
 Superficial Alteration of Lead and Zinc Ores. Galena is 
 often altered near the surface to anglesite or cerussite. The 
 former, however, is unstable in the presence of carbonated 
 waters and changes readily to carbonate. Phosphates are 
 developed in rare instances. 
 
 Sphalerite, the common ore of zinc, is often changed super- 
 ficially to smithsonite, hydrozincite, or calamine. Such oxi- 
 dized ores are of greater value than unoxidized ones, because 
 
 FIG. 61. Map showing distribution of lead and zinc ores in United States. 
 Adapted from Ransome, Min. Mag., X: 1. 
 
 although carrying a lower percentage of zinc, they occur in 
 a more concentrated form and yield more easily to metal- 
 lurgical treatment. 
 
 Distribution of Lead and Zinc Ores in the United States. 
 
 The occurrence of lead or zinc with gold, silver, and copper 
 is confined chiefly to the Cordilleran region, and shows a 
 most varied mode of occurrence; but commercially valuable 
 deposits of lead alone, or lead and zinc, are confined to the
 
 306 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Mississippi Valley, while those of zinc alone or with little 
 lead are restricted to the Appalachian region as seen 
 below. 
 
 Lead Alone. Appalachian Belt (11, 25, 29). Lead (some- 
 times argentiferous) occurs at a number of localities from 
 Maine to Georgia, filling small veins in metamorphic rocks, 
 and the deposits have at various times aroused temporary 
 interest. There is no likelihood of their ever becoming im- 
 portant producers, although exciting rumors regarding them 
 are occasionally circulated. 
 
 Southeastern Missouri (12, 18, 19). This area forms a 
 subdistrict of the Ozark lead and zinc region, to be 
 
 mentioned later. 
 The galena is 
 found in Lower 
 Silurian lime- 
 stones, the larger 
 lead deposits oc- 
 curring in mas- 
 sive strata near 
 
 RS 
 
 FIG. 62. Generalized section of Southeastern Missouri the base, called 
 lead region. After Bain. ^ Joseph lime . 
 
 stone, while others with a little zinc are in the cherty Potosi 
 limestone near the summit ; the sandstone layers are barren. 
 The ore forms great impregnations, but cavern or vein de- 
 posits so common in other parts of Missouri are wanting 
 in this region; while many small faults occur, the ore sel- 
 dom favors them. The origin of these ores is treated under 
 lead and zinc. The average ore runs from 6 to 8 per cent 
 galena; when roughly handpicked, 10 to 12; and subse-
 
 LEAD AND ZINO 307 
 
 quent jigging of the crushed ore brings the galena contents 
 up to 60 or 70 per cent. 
 
 The Missouri lead mines were worked at a very early date 
 for making bullets, and their product is said to have been 
 used during the Revolution. 
 
 Desilverized Lead. The important localities supplying 
 this type of lead are described under lead-silver ores, but 
 brief reference may be made to them here. Idaho is the 
 most important producer, more than 96 per cent coming 
 from the Cceur d'Alene district. In Utah much is ob- 
 tained from the Park City district of Summit County, 
 the Bingham Canon and Cottonwood districts of Salt 
 Lake County, and the Tintic district of Juab County. 
 Colorado's main supply is yielded by the Leadville mines 
 in Lake County and the Aspen mines of Pitkin County, 
 while smaller amounts are obtained from Creede, Lake 
 City, Ouray, and Rico. (See Lead-Silver references, also 
 map, Fig. 73.) (28.) 
 
 Comparatively little lead is produced in the western states, 
 except in the three mentioned above. 
 
 As pointed out by Bain, the important lead ores of this 
 region are closely associated with both igneous and sedi- 
 mentary rocks. At Leadville, Aspen, and Park City the 
 sediments are dolomites and limestones, and at Cceur d'Alene 
 they are shales and quartzites. While the ores seem to favor 
 igneous associations, still the larger bodies are found where 
 both classes of rocks occur. 
 
 Zinc Ores. The zinc-producing regions of the United 
 States are the eastern and southern states, the Mississippi 
 Valley, and the Rocky Mountain region.
 
 308 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The ore from the different districts varies in grade, associa- 
 tions and mode of occurrence. 
 
 In tonnage terms, the main zinc-producing districts are 
 the Joplin, Missouri, Sussex County, New Jersey, and 
 Colorado. The Joplin ores are the main source of supply 
 of the Kansas, Missouri, and Illinois smelters, but Colorado 
 and even British Columbia ore is shipped to Kansas. 
 Most of the New Jersey ore is used for zinc oxide, but 
 smaller amounts are exported or used for spelter. 
 
 Eastern and Southern States. The localities where zinc 
 alone occurs are Sussex County, New Jersey ; Saucon Valley, 
 Pennsylvania ; and the Virginia-Tennessee belt. Of these 
 the first is the most important, and the third yields a little 
 lead. 
 
 Sussex County, New Jersey (20-22). The output of these 
 mines is second in importance to those of the Mississippi 
 Valley region. The district includes two general mining 
 areas situated close together, the one called Mine Hill, at 
 Franklin, and the other called Sterling Hill, at Ogdens- 
 burg, two miles farther south, but not now worked. 
 
 The ore-bearing minerals, which represent a unique type 
 of occurrence, consist of franklinite, zincite, willemite, and 
 calamine, the typical ore being a granular mixture of frank- 
 linite and calcite, with zincite and willemite scattered 
 through it. Manganese minerals are also present, thus giv- 
 ing a combination of three common elements, viz., man- 
 ganese, zinc, and iron. 
 
 The average mineralogical composition of the Franklin 
 Furnace ore (Ingalls) is franklinite, 51.92 ; willemite, 
 31.58 ; calcite, 12.67 ; zincite, .52 ; other silicates, 3.31 ;
 
 LEAD AND ZINC 309 
 
 while the average chemical composition is : Fe 2 O 3 , 32.06 ; 
 MnO, 11.06 ; ZnO, 29.35; CaCO 3 , 12.67; silica and in- 
 soluble matter, 14.57. 
 
 The ore body at both localities is interbedded with a 
 white crystalline limestone of probably pre-Cambrian age, 
 which in turn rests on gneiss. The Ogdensburg ore deposit 
 forms a great hook, giving two veins apparently, and the 
 ore body seems to be an impregnated streak of limestone ; 
 while at Mine Hill the northerly pitching ore body is also 
 
 FIG. 63. Model of Franklin zinc ore body. After Nason, Aiuer. Inst. Min. 
 Engrs., Trans. XXIV: 127. 
 
 a synclinal fold, whose southern end in addition appears 
 to be doubled over into an anticline. In both cases the 
 wall rock is heavily impregnated at the bends of the fold 
 with franklinite and other minerals, while the ore bodies 
 are pierced by intrusive rocks. The origin of these de- 
 posits is of unusual interest, for they not only contain in 
 abundance a number of zinc minerals rare or unknown 
 elsewhere, but many other mineral species as well. No 
 sulphides of either zinc or iron have been noted, to suggest 
 a derivation from that source, and faults which might serve 
 as ore channels are likewise lacking, consequently their 
 origin is difficult to explain.
 
 310 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Kemp (20) considers that the ore was probably deposited 
 from solutions stimulated by intrusions of granite, and sub- 
 sequently metamorphosed, but Wolff (21) suggests that they 
 are contemporaneous in form and structure with the in- 
 closing limestones, and hence older than the granites. The 
 extent to which they have been metamorphosed has served 
 to hide their original character, and theories regarding their 
 possible origin have been largely speculative. 
 
 FIG. 64. Section of Bertha zinc mines, Wythe Co., Va., showing irregular 
 surface of limestone covered by residual clay bearing ore. After Case, Amer. 
 Inst. Min. Engrs., Trans. XXII: 520. 
 
 These ore bodies are of some historic interest, having been prospected 
 as early as 1640 and mined in 1774. The Mine Hill deposits were worked 
 for iron ore as early as the beginning of the last century, the zinc mining 
 having begun about 1840. The ores are now treated by magnetic sepa- 
 rators, which remove the franklinite and garnet from the willemite and 
 zincite, while the calcite is taken out by jigging. The zinc ores are used 
 for metallic zinc and zinc white, and the manganese for Bessemer steel. 
 
 Virginia-Tennessee Belt (32-35, 26, 27). Zinc and some 
 lead occur in a belt extending from southwest Virginia 
 into Tennessee. The ores are intimately associated with 
 Cambro-Ordovician limestone, and show two types, viz. : 
 (1) secondary or weathered ores, including calamine, smith-
 
 LEAD AND ZINC 311 
 
 sonite, and cerussite, which are concentrated in the residual 
 clays next to the irregular weathered surface of the lime- 
 stone (PL. XVII, Fig. 2); and (2) primary ores, including 
 sphalerite, galena, and some pyrite, belonging to the dis- 
 seminated replacement breccia type, and which have been 
 localized by ground waters along the crushed and faulted 
 axes of the folds. The gangue minerals are chiefly calcite, 
 dolomite, and some barite. Fluorite is known, and quartz 
 may occur in the form of chert. One deposit only, in Albe- 
 marle County, is found in schist, and is closely associated 
 with igneous rocks. 
 
 Pennsylvania (25 a). The Saucon Valley deposits promised 
 at one time to become prominent producers, but have not, 
 owing more to geological conditions than actual scarcity of ore. 
 
 Lead and Zinc Ores of the Mississippi Valley Region. 
 This includes two important areas, viz., the Upper Missis- 
 sippi Valley and the Ozark Region. 
 
 Upper Mississippi Valley Area (36, 8, 9). This area em- 
 braces southwestern Wisconsin, eastern Iowa, and north- 
 western Illinois, but the first-named state contains the 
 most productive territory. The section in the Wisconsin 
 area, which may be taken as typical, involves the following 
 formations, beginning at the top : 
 
 Niagara limestone Silurian. 
 
 Cincinnati (Maquoketa) shales 
 
 Galena limestone 250 ft. 
 
 Trenton limestone . . .* . 40-100 ft. 
 St. Peter's sandstone .... 150 ft. 
 Lower magnesian limestone, 100-250 ft. 
 
 Ordovician. 
 
 Potsdam sandstone . 700-800 " ' Cambrian ' 
 
 ft.J 
 ft./
 
 312 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 A bituminous shaly layer, known as the oil rock, occurs 
 at the base of the Galena, and below it, or at the top of 
 the Trenton, is a fine-grained limestone called the glass rock. 
 While the series as a whole shows a very gentle southwest 
 dip, there are a few low folds. 
 
 The ore-bearing minerals, consisting of galena, smith- 
 sonite, and sphalerite, associated with marcasite and some 
 
 FIG. 65. Section showing occurrence of lead and zinc ore in Wisconsin, show- 
 ing fissure ore in flats and pitches, and disseminated ore in oil rock. After 
 Chamberlin. 
 
 calcite, occur as disseminations, as honeycomb masses in 
 brecciated or porous limestone, and in crevices. The last 
 type, which forms the most important source of the ore, 
 consists of a vertical fissure, which at its lower end splits 
 into two horizontal branches called flats, while these in 
 turn pass into a steeply dipping fissure termed pitches 
 (Figs. 42 and 65). There are at times several flats. Galena 
 commonly predominates in the crevices, while sphalerite 
 occurs in great abundance lower down. The main crevices 
 extend approximately east and west, but there are other
 
 LEAD AND ZINC 313 
 
 less important intersecting fissures. The Galena limestone 
 is the most important ore-bearing formation, but ore is 
 also known to occur in the lower-lying limestones and 
 sandstones, although no deposits have been worked in 
 them. In the crevices the order of deposition is mar- 
 casite, sphalerite, and galena. The ores, are frequently 
 oxidized, yielding smithsonite and some calamine. 
 
 A careful study of the origin of the ore bodies indicates 
 that the metallic minerals have been gathered by circulat- 
 ing meteoric waters from the Galena limestone ; these waters 
 entered the limestone probably from the northeast, where 
 the overlying shales had been eroded, and moved to the 
 southwest. The ore was precipitated in crevices as sul- 
 phides, either because of a reducing action exerted by bitu- 
 minous matter present in the rocks or hydrogen sulphide. 
 
 Surface waters descending crevices have produced a sec- 
 ondary concentration, which has resulted in a separation 
 of the zinc and galena, accompanied by a transferal of 
 much of the former to lower levels. 
 
 Lead was discovered in the Upper Mississippi area as early as 1692, 
 and the first mining was done in Dubuque in 1788. The early work 
 was i-estricted to lead mining entirely, the zinc ores being disregarded. 
 Owing to uncertainty regarding the size of the deposits, the mining for 
 many years has been done in a most primitive manner, but more re- 
 cently prospecting at lower levels and the discovery of new ore bodies 
 has stimulated the erection of better plants. Mechanical concentration 
 methods have also been introduced, and while the galena can be sepa- 
 rated quite thoroughly from the sphalerite and marcasite, the last two 
 are parted with difficulty. On account of the presence of marcasite 
 in most of the mines, the zinc ores of this district command a lower 
 price than those from other areas. For this same reason much of the 
 ore cannot be used for spelter, but is employed for zinc oxide and sul- 
 phuric acid manufacture.
 
 314 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Ozark Region (12,13,15,17). The position of the region 
 is shown on the map, Fig. 66. The southern part of the 
 area is underlain by Carboniferous sandstone and shales, 
 
 while the northern 
 part, forming the 
 Ozark plateau, and 
 containing the lead 
 and zinc deposits, 
 is underlain by 
 slightly disturbed 
 sedimentaries. In 
 the eastern part of 
 the plateau, or Salem 
 Upland, they are 
 Cambro-Silurian dol- 
 omites and magne- 
 sian limestone, while 
 
 FIG. 66. Map of Ozark region. After Branner, 
 Eng. and Min. Jour., LXXI1I: 475. 
 
 those of the western portion, or Springfield Upland, are 
 Lower Carboniferous limestones. 
 
 Within this region the following four districts are 
 recognized : 
 
 1. Southeastern Missouri, yielding lead from dissem- 
 inated ores. This area has been mentioned under Lead 
 Alone. 
 
 2. Southwestern Missouri, or the Missouri-Kansas dis- 
 trict, with Joplin as the most important mining town. It 
 yields chiefly zinc, with some lead. The ore occurs in 
 limestones of Subcarboniferous age, filling fissures, as a 
 cement of brecciated patches, or more rarely parallel to 
 the bedding. The ore bodies are sometimes hundreds of 
 feet in diameter. In some cases the ore extends to the
 
 LEAD AND ZINC 315 
 
 surface, and is then usually surrounded by more or less 
 residual clay. 
 
 3. Central Missouri district, containing small deposits 
 of both lead and zinc. In this area the ore as far as 
 exploited occurs 
 
 rather in vertical 
 crevices or chim- 
 neys than in brec- 
 cias. 
 
 4. The nor them 
 Arkansas district, 
 but partly devel- 
 oped, and with . un j=3 __ __ M H IIS S3 
 
 many rich ores, oc- 
 
 i i-i 1 FIQ. 67. Generalized section showing occurrence of 
 lead and zinc ore in southwest Missouri. After 
 deposits (dissem- Bain - 
 
 inations), veins (in faults or filling breccias), or as altera- 
 tions. 
 
 The common ores are sphalerite and galena, with a gangue 
 of secondary chert, dolomite, calcite, and barite. Residual 
 clays occur in some mines, and bitumen is not uncommonly 
 found with the ores. 
 
 These deposits afford an interesting example of the para- 
 genesis of minerals, the succession seeming to be (Win- 
 slow, Trans. Am. Inst. Min. Engrs., p. 651, 1893) dolomite, 
 blende, galena, barite, calcite, and pyrite. 
 
 The ores of this region are mechanically concentrated 
 after mining, and the composition of an average sample of 
 3800 carloads of blende shipped from the Joplin district 
 in the first part of 1904 is given by Ingalls as : Zn, 58.26 ; 
 Cd, .304; Pb, .70; Fe, 2.23; Mn, .01; Cu, .049; CaCO 3 ,
 
 316 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 1.88; MgCO 3 , .85; SiO 2 , 3.95; BaSO 4 , .82; S, 30.72; total, 
 99.773. 
 
 Origin of the Ores. Most of the theories of the origin 
 of these ores agree in considering that their concentration 
 has been caused by circulating meteoric waters which have 
 collected the ore particles from the limestones, although 
 in one instance at least they seem, to be associated with 
 
 Fid. 68. A typical hoisting outfit in the southwestern Missouri zinc region. 
 Photo, by U. F. Bain. 
 
 igneous intrusions (19). Analyses of the limestones show 
 amounts of from .001 to .015 per cent of lead and zinc in the 
 Cambro-Silurian magnesian limestones and Archaean rocks 
 to the southeast of the region, and from .002 to .003 per 
 cent in the Lower Carboniferous limestones. These aver- 
 ages calculated give 87 pounds of galena per acre in a 
 one-foot layer, and 261 pounds of blende in the same 
 volume of rock. W. P. Jenney, who studied the deposits 
 in some detail, has emphasized the importance of ascend-
 
 LEAD AND ZINC 317 
 
 ing waters, while Winslow has argued for their concen- 
 tration by descending currents. 
 
 The more recent studies of H. F. Bain indicate that both 
 ascending and descending waters were active, and that the 
 chemical reactions involved were characteristic of dilute 
 solutions; rich ores, therefore, indicate great aqueous 
 activity. 
 
 The more important circulations have occurred in the 
 Cambro-Silurian limestones and those of the Mississippi 
 or Lower Carboniferous series, but the concentration pro- 
 cess has been often repeated in many different horizons 
 and at different depths. - 
 
 The chemical changes which took place in the primary 
 concentration of the ores were the oxidation of sulphides 
 to sulphates, the transportation of these in solution, and 
 their reprecipitation as sulphides in favorable localities. 
 The localization of the ore bodies has been due to the pres- 
 ence of fissures which permitted the mixing of the ore-bear- 
 ing solutions, but the circulation of the latter has been 
 limited in many instances by impervious beds of shale, and 
 organic matter has served as a- reducing agent. All of the 
 ores are found to be closely associated with lines of sub- 
 terranean seepage, and since the open character of the brec- 
 cias favored circulation, much ore is found in them. Where 
 folding has occurred, the water has also sought the troughs 
 of synclines as in the Lake Superior district. 
 
 In the section presented in the Ozark region, the Devono- 
 Carboniferous shales and the undifferentiated Carboniferous 
 shales afforded impermeable barriers to circulation. The 
 former, where not faulted, held down the ascending solu- 
 tions; but where absent or fissured, the solutions from the
 
 318 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 underlying Cambro-Silurian formation were able to pass up- 
 ward into the Mississippian and impregnate them. 
 
 The Cambro-Silurian ores were first concentrated by deep 
 circulation, and formed the disseminated ores. Later, when 
 erosion cut away the Devono-Carboniferous capping, further 
 concentration took place by descending solutions, giving rise 
 to the ore bodies in crevices, breccias, and synclines. 
 
 Two concentrations have occurred in the Mississippian 
 limestones. 
 
 The ore bodies are of two types, viz. : (1) those containing 
 sulphides and clean untarnished minerals, the result of pri- 
 mary concentration; and (2) those due to surface concen- 
 tration, and containing oxidized ones with red clay. The 
 ores pass into sulphides below the water level. 
 
 Where ascending solutions alone acted, the ore bodies are 
 less rich but more reliable, however secondary enrichment of 
 the deposits has been marked. 
 
 Rocky Mountain States (28). Although much ore is 
 mined in this region, its resources of this metal are still 
 largely undeveloped, and up to 1903 most of the ore mined 
 was either shipped to Kansas smelters or exported. The 
 recent construction of a zinc-smelting plant at Pueblo, 
 Colorado, and the enlargement of the oxide plant at 
 Canyon, Colorado, has largely stimulated the production 
 of both that state and Utah. 
 
 The zinc-producing localities of Colorado are chiefly the 
 same as those yielding lead, Leadville being the largest pro- 
 ducer. According to Ingalls the zinc shipments average 
 about 25 per cent Zn, 10 Pb, 2.2 Fe, 4 SiO 2 , 39 S, and 10 
 oz. Ag. Much zinc ore is also supplied by the mines at
 
 LEAD AND ZINC 319 
 
 Creede (Ingalls), where it is concentrated to a product 
 assaying 55-59 per cent Zn, 3.75-6 Pb, and 1.1-2.1 Fe, 
 which is shipped to Kansas. The blende carries 2-3 oz. 
 Ag per T. Blende concentrates are also produced at Mon- 
 tezuma and Rico, Colorado. The Colorado ores are usually 
 of lower grade than the Joplin ones, and their complex 
 nature makes treatment difficult; indeed until recently zinc 
 has been a source of loss to the miners and smelters, those 
 ores high in zinc being either neglected or thrown out. 
 
 In addition to Colorado, New Mexico produces considerable 
 ore, the deposits near Hanover yielding blende and smith- 
 sonite (28) from Carboniferous limestone near igneous con- 
 tacts. It was shipped to Wisconsin for treatment. Utah, 
 Idaho, and Montana will no doubt also become important 
 sources of supply in the future. 
 
 Uses of Lead and Zinc. Both of these are important base 
 metals, although in value of production they rank below gold, 
 silver, copper, and iron, neither do they come into competi- 
 tion with these, for they lack the high tenacity of iron and 
 steel, the conductivity of copper, and the value resulting from 
 scarcity possessed by gold and silver. They are of value, 
 however, on account of their high malleability and the 
 application of their compounds for pigments. 
 
 Uses of Lead. Lead finds numerous uses in the arts, the 
 most important being for white lead. Litharge, the oxide 
 of lead, is used not only for paint, but also somewhat in the 
 manufacture of glass, although red lead is more frequently 
 employed instead. 
 
 A further use of lead is for making pipe for water supply, 
 sheet lead for acid chambers, and shot.
 
 320 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Among the alloys formed by lead are type metal (lead, anti- 
 mony, and bismuth, with copper or iron), white metal, organ 
 pipe composition, and fusible alloys used in electric lighting. 
 
 In addition to these, the acetate, carbonate, and other com- 
 pounds are used in medicine. In smelting, lead is used to 
 collect the gold and silver, and the bulk of the lead of com- 
 merce is obtained as a by-product in the smelting of the 
 precious metals. 
 
 Uses of Zinc. Metallic zinc is used for a variety of 
 purposes, partly owing to its slight alteration in air, and 
 secondly, because it can be rolled into thin sheets. In this 
 condition it is used extensively for roofing and also for plumb- 
 ing, and as a coating to iron this metal is extensively called 
 for in galvanizing. It is also used for cyaniding gold. 
 
 One of the most important applications is for making 
 brass, which is ordinarily composed of from 66 to 83 parts 
 of copper and 27 to 34 parts of zinc. The composition 
 varies, entirely depending on the use to which it is to be put, 
 and, with the variation in proportion, the color becomes more 
 golden, or whiter, according as the percentage of copper 
 is increased or decreased. With an increase in the amount 
 of zinc, the alloy becomes more fusible, harder, and 
 more brittle. Brass was made long before zinc, as a metal, 
 was discovered, and Aristotle says that the people by the 
 Euxine Sea made their copper a beautiful whitish color by 
 mixing it with a white earth found there. Strabo also tells 
 us that the Phrygians made brass in this way. 
 
 White metal is an alloy of zinc and copper in which zinc 
 predominates, and which is often employed for making 
 buttons. Imitation gold is also made by alloying zinc 
 with a predominance of copper, varying from 77 to 85 per
 
 LEAD AND ZINC 
 
 321 
 
 cent of the mass, and this is in common use as " gold foil " 
 for gilding. Zinc is also made use of in the construction of 
 electric batteries. 
 
 German silver has 60 parts copper, 20 zinc, and 20 nickel. 
 Its use is for mathematical and scientific instruments. 
 
 Production of Lead and Zinc. The production of lead in 
 the United States from -1825 to 1900 was as follows : 
 
 YEAR 
 
 SHORT TONS 
 
 YEAR 
 
 SHORT TONS 
 
 18^5 
 
 1 500 
 
 1875 
 
 59,640 
 
 1835 
 
 13 000 
 
 1885 
 
 129 412 
 
 1845 
 
 30000 
 
 1895 . . 
 
 170000 
 
 1855 . . . 
 
 15800 
 
 1900 
 
 270 824 
 
 1865 
 
 14,700 
 
 
 
 
 
 
 
 About 70 per cent of the lead produced in the United 
 States is derived from five districts, viz. : Southeastern Mis- 
 souri; Joplin, Missouri; Leadville, Colorado: Park City, 
 Utah ; and Cceur d'Alene, Idaho. 
 
 LEAD CONTENT OF ORES SMELTED IN THE UNITED STATES 
 FROM 1901 TO 1903 
 
 
 1901 
 
 1902 
 
 1903 
 
 
 Short tons 
 
 73,265 
 
 Short tons 
 
 51,833 
 
 Short tons 
 
 45,554 
 
 Idaho 
 
 79,654 
 
 84,742 
 
 99,590 
 
 Utah 
 
 49,870 
 
 53914 
 
 51,129 
 
 
 5,791 
 
 4,438 
 
 3,303 
 
 New Mexico 
 
 1,124 
 
 741 
 
 613 
 
 
 1 873 
 
 1269 
 
 2237 
 
 
 4,045 
 
 599 
 
 1,493 
 
 California 
 
 381 
 
 175 
 
 55 
 
 Washington 
 
 
 ( 1,457 
 
 538 
 
 Oregon, Alaska, South Dakota, ! 
 Texas J 
 
 1,029 
 
 \ 
 [ 2,184 
 
 1,765 
 
 Missouri, Kansas, Wisconsin, 
 Illinois, Iowa, Virginia, 
 Kentucky 
 
 67.172 
 
 79,445 
 
 86,597 
 
 Total 
 
 284,204 
 
 280,797 
 
 292,874
 
 322 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The production of spelter in the United States from 1873 
 to 1900 was : 
 
 YEAR 
 
 SHORT TONS 
 
 YEAR 
 
 SHORT TONS 
 
 1873 
 
 7,343 
 
 1890 
 
 63,683 
 
 1880 
 
 23,239 
 
 1895 
 
 89 686 
 
 1885 
 
 40688 
 
 1900 
 
 123 886 
 
 
 
 
 
 PRODUCTION OF SPELTER FROM 1901 TO 1903 BY STATES 
 
 
 EASTERN 
 
 ILLINOIS 
 
 
 
 
 
 
 AND 
 
 AND 
 
 KANSAS 
 
 MISSOURI 
 
 COLORADO 
 
 TOTAL 
 
 
 SOUTHERN 
 STATES 
 
 INDIANA 
 
 
 
 
 
 
 Short tons 
 
 Short tons 
 
 Short tons 
 
 Short tons 
 
 Short tons 
 
 Short tons 
 
 1901 
 
 8,603 
 
 44,896 
 
 74,240 
 
 13,083 
 
 
 140,822 i 
 
 1902 
 
 12,180 
 
 47,096 
 
 86,564 
 
 11,087 
 
 
 156,927 2 
 
 1903 
 
 12,301 
 
 47,659 
 
 88,388 
 
 9,994 
 
 877 
 
 159,219* 
 
 World's Production of Lead. This in 1902 amounted to 
 926,895 metric tons. Of this quantity the United States 
 produced approximately 26 per cent; Spain, 19 per cent; 
 Germany, 15 per cent; and Mexico, 11 per cent. Of these 
 countries Spain and Mexico afforded the greatest surplus 
 production, and both Germany and the United Kingdom 
 required more lead than they mined. 
 
 The figures of world's production together with imports 
 and exports in metric tons for 1902 are given below : 
 
 1 Including 2716 tons dross spelter. 
 
 2 Including 2675 tons dross spelter. 
 8 Including 3302 tons dross spelter.
 
 LEAD AND ZINC 
 
 323 
 
 
 PRODUC- 
 TION 
 
 IMPORTS 
 
 TOTAL 
 
 EXPORTS 
 
 CONSUMP- 
 TION 
 
 Austria-Hungary . . 
 Belgium 
 
 13,543 
 
 19,500 
 
 18817 
 
 8,706 
 53,000 
 72730 
 
 22,249 
 72,500 
 91 547 
 
 53 
 50,000 
 6454 
 
 22,196 
 22,500 
 85,093 
 
 Germany .... 
 
 140,331 
 
 39,006 
 
 179,337 
 
 23,100 
 
 156,237 
 
 Italy 
 
 26494 
 
 7 563 
 
 34057 
 
 5650 
 
 28,407 
 
 Prussia 
 
 250 
 
 23,000 
 
 23,250 
 
 
 23,250 
 
 
 177 560 
 
 
 177 560 
 
 172 480 
 
 5,080 
 
 United Kingdom . . 
 United States ... 
 
 27,100 
 342,160 
 
 235,522 
 65,235 
 
 262,622 
 407,395 
 
 24,408 
 129,637 
 
 238,214 
 
 277,758 
 
 World's Production of Zinc. The production of zinc ore 
 and spelter in metric tons for 1902 is given below : 
 
 COUNTRY 
 
 SPELTER 
 
 ORE 
 
 COUNTRY 
 
 SPELTER 
 
 ORB 
 
 Germany . . . 
 
 174,927 
 
 702,504 
 
 Austria . . . 
 
 7,960 
 
 31,927 
 
 United States . 
 
 143,552 
 
 500,000 
 
 Spain . . . 
 
 5,569 
 
 127,618 
 
 Belgium . . . 
 
 124,780 
 
 3,852 
 
 Italy .... 
 
 485 
 
 149,965 
 
 United Kingdom 
 
 40,244 
 
 25,462 
 
 Sweden . . . 
 
 
 48,783 
 
 France .... 
 
 36,282 
 
 57,982 
 
 Algeria . . . 
 
 
 33,139 
 
 Holland . . . 
 
 20,760 
 
 
 Greece . . . 
 
 
 18,020 
 
 Russia .... 
 
 8,280 
 
 
 Tunis . . . 
 
 
 18,400 
 
 The above table indicates that the mining districts and 
 smelting centers are not identical. Belgium and Holland 
 have a smelting industry greatly in excess of the local min- 
 ing interests, but in the United States they are in approxi- 
 mate equilibrium. 
 
 REFERENCES ON LEAD AND ZINC 
 
 Arkansas : 1. Adams, U. S. Geol. Surv., Bull. 213 : 187, 1903. (N. Ark.) 
 2. Adams, U. S. Geol. Surv., Prof. Paper No. 24, 1904. 3. Branner, 
 Ark. Geol. Surv., Kept, for 1892, V. (N. Ark.) Colorado : 4. Em- 
 mons, U. S. Geol. Surv., Mon. XII, 1886. (Leadville.) 5. Ran- 
 some, U. S. Geol. Surv., 22d Ann. Kept, II : 229, 1901. (Rico Mts.)
 
 324 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 6. Spurr, U. S. Geol. Surv., Mon. XXXI, 1898. (Aspen.) Idaho : 
 
 7. Lindgren, U. S. Geol. Surv., 20th Ann. Kept., Ill: 190, 1900. 
 (Wood River district.) Illinois : 8. Bain, U. S. Geol. Surv., Bull. 
 225: 202, 1904, and Bull. 246, 1904. Iowa: 9. Leonard, la. Geol. 
 Surv., VI: 10, 1897. Kentucky : 10. Ulrich and Smith, U. S. Geol. 
 Surv., Prof. Paper No. 36, 1905. Massachusetts: 11. Hubbard, 
 Amer. Jour. Sci., IX: 166, 1825. Missouri : 12. Bain, U. S. Geol. 
 Surv., 22d Ann. Kept., II : 23, 1901. (Ozark region.) 13. Bain, 
 U. S. Geol. Surv., Bull. 267, 1905. (Mo.) 14. Ball and Smith, Mo. 
 Bureau Geol. and Mines, Bull. Vol. I, 2d Series, 1903. (Central 
 Mo.) 15. Branner, Eng. and Min. Jour., LXXIII : 475, 1902. 
 (Ozark region.) 16. Jenney, Amer. Inst. Min. Engrs., Trans. XXII : 
 171, 1894. (Mo.) 17. Winslow, Mo. Geol. Surv., Vols. VI and VII, 
 1894. 18. Winslow, U. S. Geol. Surv., Bull. 132, 1896. (S. E. 
 Mo.) 19. Wheeler, Eng. and Min. Jour., LXXVII: 517, 1904. 
 (Relation of lead ore to igneous rock.) New Jersey: 20. Kemp, 
 Trans. N. Y. Acad. Sci., XIII: 76, 1894. 21. Wolff, U. S. Geol. 
 Surv., Bull. 213 : 214, 1903. 22. Nason, Amer. Inst. Min. Engrs., 
 Trans. XXIV: 121, 1894. A U. S. Geol. Surv. report by Spencer 
 is also in preparation. New Mexico: 23. Blake, Amer. Inst. 
 Min. Engrs., Trans. XXIV: 187, 1894. (S. W. New Mexico.) 
 24. Keyes, Min. Mag., XII: 109, 1905. (Magdalena Mts.) New 
 York : 25. Ihlseng, Eng. and Min. Jour., LXXV : 630, 1903. (El- 
 lenville.) Pennsylvania: 25 a. Clerc, U. S. Geol. Surv., Min. Res. 
 1882, 361. Tennessee: 26. Keith, U. S. Geol. Surv., Bull. 225: 208, 
 1904. 27. See also Morristown, Maynardville, and Cleveland folios, 
 U. S. Geol. Surv. United States: 28. Bain, U. S. Geol. Surv., Bull. 
 260 : 251, 1905. 29. Whitney, Metallic Wealth of U. S., 1854. (Ap- 
 palachians.) Utah : 30. Emmons, Amer. Inst. Min. Engrs., Trans. 
 XXXI : 658, 1902. (Delamar and Hornsilver Mines.) 31. Tower 
 and Smith, U. S. Geol. Surv., 19th Ann. Rept., Ill: 601, 1899. 
 (Tintic.) Virginia : 32. Boyd, Resources of Southwest Virginia, 
 1881. 33. Case, Amer. Inst. Min. Engrs., Trans. XXII : 511, 1894. 
 34. Payne, Eng. and Min. Jour., LXXVIII : 544, 1904. 35. Watson, 
 Va. Geol. Surv., Bull. 1, 1905. ( Va.-Tenn.) Wisconsin : 36. Grant, 
 Wis. Geol. and Nat. Hist. Surv., Bull. 9, 1903.
 
 CHAPTER XVII 
 
 GOLD AND SILVER 
 
 GOLD and silver are obtained from a variety of ores, in 
 some of which the gold predominates, in others silver, while 
 in still a third class these two metals may be mixed with the 
 baser metals, lead, copper, and zinc. Few gold ores are 
 absolutely free from silver, and vice versa, so that a separate 
 treatment of the two is more or less difficult ; however some 
 lead-silver ores, although they may carry some gold, are 
 sufficiently prominent to be discussed as a separate type, and 
 are described as such on a later page. 
 
 Ores of Gold. Gold occurs in nature chiefly as native 
 gold, mechanically mixed with pyrite, or as a telluride such 
 as calaverite (Au, 39.5 per cent ; Ag, 3.1 per cent ; Te, 57.4 
 per cent). 1 
 
 Ores of Silver. The minerals which may serve as ores 
 of silver, together with the percentage of silver they con- 
 tain, are : 
 
 ORES 
 
 
 Ag 
 
 S 
 
 
 Ag 
 (Ag 2 S) 
 3 Ag 2 S, Sb 2 S 3 
 3 Ag 2 S, As,S 3 
 5Ag 2 S, Sb 2 S 3 
 AgCl 
 AgBr 
 Ag(ClBr) 
 9 Ag 2 S, SbjSg 
 
 100.00 
 87.1 
 59.9 
 65.5 
 68.5 
 75.3 
 57.4 
 64.5 
 75.6 
 
 12.9 
 17.8 
 19.4 
 16.3 
 
 approx. 
 
 Argentite silver glance 
 
 
 
 Stephanite, brittle silver, black silver . 
 
 
 Embolite 
 
 Polybasite 
 
 
 1 Other tellurides are sylvanite, kalgoorlite, and krennerite.
 
 326 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Mode of Occurrence. Most of the gold and silver mined 
 in the United States is obtained from fissure veins, or closely 
 related deposits of irregular shape (79), in which the gold 
 and silver ores have been deposited from solution, either in 
 fissures, or other cavities, or by replacement. Considerable 
 gold and a little silver is obtained from gravel deposits. 
 Some true contact deposits are known. Gold has been found 
 to occur in rare instances as an original constituent of igneous 
 rocks (1, 8, 11) and also metamorphic ones (12), but there are no 
 known deposits of commercial value belonging to this type. 
 
 The gold and silver-bearing fissure veins include two 
 prominent types (79), viz. : (1) the quartz veins, and (2) the 
 propylitic type, in which the metasomatic alteration of the 
 wall rock is often propylitic, that is, accompanied by the for- 
 mation of chlorite and epidote, but near the veins of sericite 
 and kaolin. In the quartz-vein type silver is present usu- 
 ally in but small quantities, while in the propylitic type the 
 silver often is an important constituent. 
 
 While the mode of occurrence of gold and silver is quite 
 variable, the character of the wall rock is equally so, gold 
 and silver ores being found in either sedimentary or igneous 
 rocks, and along the contact between the two, showing that 
 the kind of rock exerts little influence, except perhaps where 
 replacement has been active. On the other hand the influ- 
 ence of locality is much stronger, for it has been found that 
 many gold and silver-bearing deposits are closely associated 
 with masses of igneous rock, the most common of these being 
 diorite, monzonite, quartz-monzonite, granodiorite, while true 
 granites are rare as associates. A second large class of vein 
 systems shows a close association with lavas of recent age, 
 and the telluride ores rather favor these (6).
 
 GOLD AND SILVER 327 
 
 Weathering and Secondary Enrichment. The superficial 
 alteration of gold ores differs somewhat from that of deposits 
 containing ores of the other metals. In quartz veins with 
 auriferous pyrite, the change of the latter to limonite leaves 
 a rusty quartz with nuggets or threads of free gold, and 
 leaching may remove most of the iron. Some of the gold 
 may also be leached out by the ferric sulphate, formed by 
 the oxidation of the pyrite, and carried to lower levels, where 
 it is reprecipitated. Whether the reprecipitation of the gold 
 is due to pyrite or carbonaceous matter, is, in some cases at 
 least, an unsettled question (4, and Ref. on ore deposits). 
 
 The silver sulphides are changed to sulphates or chlorides, 
 part of which at least are leached out of the gossan and 
 carried to lower levels, where they are reprecipitated by iron 
 or even copper sulphides. 
 
 Classification. The gold and silver ores are some- 
 times grouped (80) according to their associations, as below ; 
 this also has the advantage of bringing out more clearly 
 their metallurgical character. 
 
 1. Placers or gravel deposits. These serve chiefly as a 
 source of native gold, but may and often do contain a little 
 silver, much of which is never separated from the ore in 
 which it occurs. These gravels are derived chiefly from 
 quartz veins of Mesozoic age in the Pacific coast region, 
 and to a less extent from pre-Cambrian veins of the Ap- 
 palachian region and Black Hills of South Dakota. Some 
 are also derived from veins in Tertiary lavas, but these 
 usually contain the metals in such a finely divided con- 
 dition, or in such combination, that they do riot readily 
 accumulate in stream channels.
 
 328 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 2. Quartzose or dry ores, in which the gold and some silver 
 are found in a quartz gangue, and are either free or mixed 
 with sulphides, commonly pyrite. They are of varying age. 
 Those of California, Oregon, and Alaska are Mesozoic and 
 associated chiefly with quartz inonzonite, granodiorite, and 
 diorite. Another great class of post-Miocene age, found 
 chiefly in Colorado, Nevada, and Montana, is associated with 
 Tertiary lavas and characterized by bonanzas. The most 
 productive ones carry fluorite and normally also tellurides. 
 In some, gold may predominate ; in others, silver. A third 
 class, of pre-Cambrian age, is found in the Atlantic States, 
 Wyoming and South Dakota, the last mentioned including 
 the famous Homestake Mine. These are classified as dry 
 ores, because they are not as a rule smelting ones ; they con- 
 tain limited quantities of copper and lead, but may have 
 some pyrite. 
 
 3. Gold and silver bearing copper ores. These are widely 
 distributed throughout the United States, and exhibit great 
 differences in form and age, neither do all the occurrences 
 yield much gold or silver. The output is obtained chiefly 
 from Colorado, Utah, and Montana. Those of the last two 
 states, which supply most of the production, are found as 
 replacement veins in granites or early Tertiary igneous rocks. 
 The large copper deposits of Arizona produce but little gold 
 or silver, with the exception of those at Jerome. This class 
 of ores yields about one third of all the silver mined in 
 the United States. 
 
 4. Gold and silver bearing lead ores. This class includes 
 a variety of deposits, containing much lead, and also silver, 
 with gold usually in subordinate amounts. They occur 
 chiefly in Colorado, Utah, and Idaho, and furnish about one
 
 GOLD AND SILVER 329 
 
 half of the silver obtained in the United States. They are 
 discussed separately under the head of Silver-Lead ores. 
 
 A subtype of this class is represented by the veins of 
 argentiferous galena and tetrahedrite of the Wood River 
 district, Idaho. These are veins in slates near the contact 
 of intrusive granite and are of late Mesozoic age. Arizona, 
 California, Washington, and New Mexico produce small 
 amounts of argentiferous lead ores. 
 
 Geological Distribution. Gold and silver ores have been 
 formed at a number of different periods in the geological 
 history of the continent, notably in the pre-Cambrian, Cam- 
 brian, Cretaceous, and Tertiary ages, but Silurian, Devonian, 
 and Carboniferous gold deposits are not definitely known to 
 exist in North America, although some of the Appalachian 
 veins may be of this age (79). Silver ores show much the 
 same geological distribution. 
 
 Extraction. Since gold and silver ores vary so in their 
 mineralogical associations and richness, the metallurgical 
 processes involved in their extraction are varied and often 
 complex. 
 
 Those ores whose precious metal contents can be readily 
 extracted after crushing, by amalgamation with quicksilver, 
 are termed free-milling ores. This includes the ores which 
 carry native gold or silver, and often represent the oxidized 
 portions of ore bodies. Others, containing the gold as tel- 
 luride or containing sulphides of the metals, are known as 
 refractory ores and require more complex treatment. These, 
 after mining, are sent direct to the smelter if sufficiently 
 rich, but if not they are often crushed and mechanically 
 concentrated. The smelting process is also used for mixed
 
 330 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 ores, the latter being often smelted primarily for their lead 
 or copper contents, from which the gold or silver is then 
 separated. While in some cases there are smelters at the 
 mines, still there is a growing tendency towards the central- 
 ization of the industry, and large smelters are now located 
 at Denver, Salt Lake City, etc., which draw their ore supply 
 from many mining districts. 
 
 Low-grade ores may first be roasted, and the gold then 
 extracted by leaching with cyanide or chlorine solutions. 
 The introduction of the cyanide and chlorination processes, 
 which are applied chiefly to gold ores, has permitted the 
 working of many deposits formerly looked upon as worth- 
 less, and in some regions even the mine dumps are now 
 being worked over for their gold contents. It is estimated 
 that in 1902 $8,000,000 worth of gold ores were cyanided. 
 The chief fields are in the Cripple Creek region of Colo- 
 rado ; the De Lamar district, Idaho ; Marysville, Montana ; 
 Bodie, California ; and in Arizona. 
 
 The most important gold-milling centers of the United 
 States are the Mother Lode district of California, the Black 
 Hills, South Dakota, and Douglas Island, Alaska. 
 
 The value of ore and bullion is determined from a sample 
 assay, and the smelter, in paying the miner for his ore, 
 allows for gold in excess of $1 per ton of ore at the coin- 
 ing rate of $20.67 per ounce, and for silver at New York 
 market price, deducting 5 per cent in each case for smelter 
 losses. Lead and copper are paid for in the same manner, 
 as are also iron and manganese, if there is a sufficient quan- 
 tity present. No allowance is, however, made for zinc, 
 and, in fact, a deduction is made if it exceeds a certain 
 per cent.
 
 GOLD AND SILVER 
 
 331 
 
 Distribution of Gold and Silver Ores. Gold ores are 
 widely distributed in the Cordilleran region and Appa- 
 lachian province, while the silver ores are found chiefly 
 between the Great Plains and Pacific coast ranges, exclu- 
 sive of the Colorado plateau region. This occurrence in 
 two widely separated areas is brought out in an interest- 
 ing manner in Fig. 69. 
 
 
 FIG. 69. Map showing distribution of gold and silver ores in United States. 
 Adapted from Ransome, Min. Mag., X'. 1. 
 
 More than a third of the United States production of 
 gold comes from the southern half of the Rocky Moun- 
 tains, Colorado being the main producer. In this area, 
 however, the ores vary widely in their mineralogical asso- 
 ciations, the gold occurring mostly in combination with 
 silver, lead, copper, and zinc ores, but also at times free, 
 or, in the most productive district, as a telluride. 
 
 The Pacific belt, excluding Alaska, supplies about one 
 fourth the total amount of gold produced, the famous 
 Mother Lode region, mentioned later, being the most im-
 
 332 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 portant producer. Alaska yields about 10 per cent, and 
 the Basin Range province about 14 per cent, collected 
 from widely separated deposits in Utah, Nevada, Arizona, 
 and New Mexico, and in which the gold is associated with 
 copper, silver, or lead. 
 
 Probably two thirds of the silver obtained in the United 
 States comes from the Rocky Mountain region, Colorado 
 alone yielding about one third, while Montana supplies 
 about one third of the total amount produced, and about 
 three fourths of this is obtained as a by-product in copper 
 smelting. The Basin Range province furnishes about 28 
 per cent, two thirds of this coming from Utah, especially 
 from the Park City mines near Salt Lake City (83). 
 
 The gold and silver occurrences of the United States 
 and Alaska can be grouped under five areas, as follows : 
 
 1. Cordilleran region. 
 
 2. Black Hills, South Dakota region. 
 
 3. Michigan region. 
 
 4. The eastern crystalline belt. 
 
 5. Alaska. 
 
 Of these, the first, second, and fifth are the most impor- 
 tant, while the third is insignificant. 
 
 CORDILLERAN REGION 
 
 This area contains a number of important deposits of gold 
 and silver ores, occurring chiefly in quartz veins, and to a 
 lesser extent in gravels. There are also some representa- 
 tives of the propylitic type. 
 
 Pacific Coast Cretaceous Gold-quartz Ores. Extending 
 along the Pacific coast from Lower California up to the
 
 PLATE XX 
 
 FIG. 1. Kennedy mine on the Mother Lode near Jackson, Calif. 
 
 FIG. 2. Auriferous quartz veins in Maryland mine, Nevada City, Calif. 
 Lindgren, U. S. Geol. Surv., llth Ann. Kept., III. 
 
 After
 
 GOLD AND SILVER 333 
 
 British Columbia boundary there is a gold belt of great 
 importance, which throughout its extent is characterized 
 by quartzose ores and gold-bearing sulphides. The de- 
 posits belonging to this are especially important in Cali- 
 fornia, but farther north, in Oregon and Idaho, the veins 
 in many cases have been covered up by the lava flows 
 of the Cascade Range, and those known in that region 
 differ somewhat from the California deposits in containing 
 many mixed silver-gold ores and also veins carrying aurif- 
 erous sulphides without free gold. The ores of this belt 
 are all of undoubted Mesozoic age, and are accompanied 
 by many extensive placer deposits, which have been derived 
 by the weathering down of the upper parts of the quartz 
 veins, the portions now remaining in the ground repre- 
 senting probably but the stump of originally extensive 
 fissure veins (79). 
 
 Among the deposits of this belt two groups stand out 
 in some prominence, namely, those of the so-called Mother 
 Lode district and of Nevada County. 
 
 Mother Lode Belt (25, 27). This includes a great series of 
 quartz veins, beginning in Mariposa County and extending 
 northward for a distance of 112 miles. The veins of this 
 system break through black, steeply dipping slates and 
 altered volcanic rocks of Carboniferous and Jurassic age, and 
 since they are often found at a considerable distance from 
 the granitic rocks of the Sierra Nevada, they have apparently 
 no genetic relation with them. The veins, which occur either 
 in the slate itself or at its contact with diabase dikes, show a 
 remarkable extent and uniformity, due to the fact that in 
 the tilted layers of the slates there lay planes of weakness 
 for the mineral-bearing solution to follow. The ore is native
 
 334 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 gold or auriferous pyrite in a gangue of quartz, and the 
 average value may be said to vary from $3 or $4 up to $50 
 or $60 per ton. The veins often split and some of the mines 
 have reached a depth of several thousand feet. 
 
 FIG. 70. Map and section of portion of Mother Lode district, Calif. Pffv, river 
 gravels, usually auriferous ; Ng, auriferous river gravels. Sedimentary 
 rocks: Jm, mariposa formation (clay, slate, sandstone, and conglomerate); 
 Cc, calaveras formation (slaty mica schists). Igneous rocks: Nl, latite; 
 Nat, andesite tuffs, breccia, and conglomerate; nidi, meta-diorite ; Sp, ser- 
 pentine; ma, meta-andesite ; ams, amphibole schist. From U. S. Geol. 
 Surv., Atlas Folio, Mother Lode sheet. 
 
 Nevada County (26). In Nevada County the mines of 
 Grass Valley and Nevada City are likewise quartz veins, but 
 they occur along the contact between a granodiorite and 
 diabase porphyry, as well as cutting across the igneous rock 
 (Fig. 71). Two systems of fault fissures occur, and in 
 these the ore is found either in native form or associated
 
 GOLD AND SILVER 
 
 335 
 
 with metallic sulphides. The width of the vein averages 
 from 2 to 3 feet, and the lode ore generally occurs in well- 
 defined bodies or pay shutes. The vein filling was deposited 
 by hot solution, and while the wall rocks contain the rare 
 metals in a disseminated condition, Lindgren (26) believes 
 that the ores have been leached out of the rocks at a con- 
 siderable depth. The mines at Nevada City and Grass 
 Valley have been large producers of gold and some silver. 
 Placer mines have furnished a small portion of the product, 
 but at the present day these latter are of little importance. 
 
 \ GRANODIORITE 
 
 ' O.MERRIFIELC 
 
 /EIN 6. URAL VEIN C. SLATE VEIN 
 
 FIG. 71. Section illustrating relations of auriferous quartz veins at Nevada City, 
 Calif. After Lindgren, U. S. Geol. Surv., YIth Ann. Sept., II. 
 
 In Oregon, the quartz veins are worked in Baker County, 
 which is the most important gold-producing region of the 
 state (72, 73). Gold ores with sulphides in quartz gangue 
 are worked in the Monte Cristo district of Washington (88). 
 
 Central Belt of Gold-Silver Ores. To the east of the Creta- 
 ceous gold-quartz belt there lies a second one, in the central 
 and eastern part of the Cordilleran region, containing many 
 gold and silver deposits of late Cretaceous or early Ter- 
 tiary age, although they occur in older rocks, such as Car- 
 boniferous.
 
 336 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Mercur, Utah. The gold-silver mines of the Mercur (85) 
 district in Utah form perhaps the most important occurrence 
 in this central zone. Here the Carboniferous limestones, 
 shales, and sandstones, representing about 12,000 feet of 
 sediments, are folded into a low anticline. Near the center 
 of the section is the great blue limestone, carrying an upper 
 and a lower shale bed. Quartz porphyry has intruded the 
 limestone, and at two places especially, spread out laterally 
 in the form of sheets, on whose under side the ore is found, 
 the silver ores under the lower sheet, the gold ores under the 
 
 GREAT BLUE LIMESTCM 
 
 LOWER INTERCALATED SERIES 
 OWER LIMESTONE 
 
 Fio. 72. Section of Mercur, Utah. After Spurr, U. S. Geol. Surv., 16th Ann. 
 Rept., II. 
 
 upper one, about 100 feet above the first. The silver ore is 
 cerargyrite and argentiferous stibnite in a silicified belt of the 
 limestone. The gold is native and occurs in a belt of re- 
 sidual contact clay, near northeast fissures cutting the lime- 
 stone, being oxidized in places and accompanied by sulphides 
 in others. The ore runs 1-19 ounces of silver per ton, and 
 2-3 ounces of gold, with a gangue of quartz, barite, limonite, 
 and arsenical sulphides. The silver minerals are thought to 
 have been deposited by heated solutions which came up along 
 the igneous sheet some time after its intrusion, and the deposi- 
 tion of the gold ore is believed to have taken place some time
 
 GOLD AND SILVER 337 
 
 after the silver was deposited. Some doubt exists as to the 
 exact source of the ascending waters, but in all probability 
 they were derived from some deep-seated cooling laccolith. 
 The ores are especially suited to the cyanide treatment. 
 
 Other Occurrences. The northward continuation of this 
 belt of gold-bearing veins in Idaho and Montana presents 
 somewhat different types of deposits, for there the veins are 
 causally connected with great batholiths of Mesozoic gran- 
 ite ; and while the veins resemble those of the Pacific Coast 
 in the quartz filling and free gold contents, they differ from 
 the latter in containing more silver, and often large quanti- 
 ties of sulphides with little free gold. In fact in their geo- 
 logic relations they are intermediate between the quartz vein 
 and propylitic type. Of special prominence are those of 
 Marysville, Montana, and Idaho Basin, Florence, etc., in 
 Idaho. This difference is more marked in the Montana 
 occurrences, in which the gold becomes subordinate and is 
 obtained as a by-product in silver mining. 
 
 Eastern Belt of Tertiary Gold-Silver Veins. Of greater 
 importance than the preceding class are the veins of Tertiary, 
 mostly post-Miocene, age, which, according to Lindgren, are 
 characteristic of regions of intense volcanic activity, and cut 
 across andesite flows, or more rarely rhyolite and basalt. 
 The veins may be entirely within the volcanic rocks, or the 
 fissures may continue downward into the underlying rocks, 
 which have been covered by the extrusive masses. Most 
 of these Tertiary deposits belong to the propylitic class, 
 showing characteristic alterations of the wall rock. The 
 ores are commonly quartzose, and though either gold or 
 silver may predominate, the quantities of the two metals are
 
 338 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 apt to be equal. Bonanzas are of common occurrence, and 
 on this account the mines may be very rich but short-lived ; 
 still, the workable ore in many, extends to great depths, 
 but is less rich than nearer the surface. Extensive and 
 rich placers are rarely found in the Tertiary belt of veins, 
 for the reason that the fine distribution of the gold is 
 not favorable to its concentration and retention in stream 
 
 FIG. 73. Map of Colorado showing location of mining regions. After Richard, 
 Amer. Inst. Min. Eng., Trans., 19(M. 
 
 channels. Deposits of this type are worked in a number 
 of states, including Colorado, Nevada, Arizona, New Mexico, 
 and Idaho. Colorado leads in the production of gold 
 ores, for in no state are the Tertiary deposits of the pro- 
 pylitic type developed on such a scale. 
 
 Cripple Creek (39, 45, 47). This district, which is the 
 most important in this belt, is a producer of ores containing
 
 GOLD AND SILVER 
 
 339 
 
 gold almost exclusively, and may therefore be mentioned 
 in some detail. The region lies about ten miles west of 
 Pikes Peak proper, but in the foothills of this mountain 
 mass. 
 
 The most common rock of the region is the red Archaean 
 granite of Pikes Peak, in which, however, are inclusions of 
 still older schists. In Tertiary 
 times, the region was one of 
 great volcanic activity, which 
 began with the expulsion of the 
 breccias of phonolitic and pos- 
 sibly in part andesitic types, 
 and was followed by a series of 
 phonolitic rocks, which grade 
 into each other. Finally, there 
 were intrusions of basaltic dikes 
 of several types. 
 
 The ore is chiefly calaverite, 
 and to a less extent sylvanite, 
 and probably some other gold- 
 silver-lead tellurides. The tel- 
 lurides are often associated 
 with auriferous and highly 
 argentiferous tetrahedrite, molybdenite, and even stibnite. 
 Pyrite, though widely disseminated in both country rock 
 and fissures, rarely carries enough gold to serve as an ore. 
 Native gold exists only as an oxidation product of the tel- 
 luride. The common gangue minerals are quartz, fluorite, 
 and dolomite ; secondary orthoclase is sometimes prom- 
 inent in the granites, while other minerals occur in small 
 amounts. 
 
 ORE ALONG SHEETED ZONE'- 
 
 FIG. 74. Section of vein at Cripple 
 Creek, Colo. After Rickard.
 
 340 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Two types of ore bodies exist : 1. Fissure veins, some- 
 times simple, but more often compound, and formed in the 
 more or less closely spaced fractures of a sheeted zone. 
 These may occur in any kind of rock, but favor the brec- 
 cias. Their dip is generally steep, and the lode may vary 
 from 1 foot to 50 or 60 feet in width. A subtype of this 
 are composite veins in sheeted basalt dikes. 
 
 2. Irregular deposits, often of large size, formed by the 
 replacement of granite, and usually occurring close to or 
 within 1000 feet of its contact with the breccias. The 
 ore is of somewhat lower grade than that found in the 
 fissures. 
 
 The two types are not always distinct, and in both the 
 ore has been deposited in relatively small spaces, with but 
 small quantities of gangue minerals, so that the fissures are 
 never completely filled. The ores which show oxidation 
 to a depth of from 200 to 400 feet often occur in shutes, 
 but no evidence of secondary enrichment has been found 
 by recent investigators. The principal productive zone does 
 not seem to extend more than 1000 feet from the surface, 
 and while ore may be looked for below this, the quantity 
 of it will probably be less. 
 
 The Cripple Creek ores as a rule run low in silver and 
 from 1 to 10 ounces of gold per ton, with an average value 
 of $30 to $40 per ton. Most of the ores are treated by the 
 chlorination or cyanide process, especially the former, and 
 about one sixth of the output is shipped directly to the 
 smelters at Denver and Pueblo. 
 
 The rapid rise of this district is well shown by the fol- 
 lowing figures of production. A maximum was reached in 
 1900, since which the output has gradually declined.
 
 PLATE XXI 
 
 FIG. 1. View of Independence Mine and Battle Mountain, Cripple Creek, Colo. 
 A. J. Harlan, photo. 
 
 FIG. 2. General view of region around Tonopah, Nev. ./. E. Spurr, photo.
 
 GOLD AND SILVER 341 
 
 PRODUCTION IN CRIPPLE CREEK DISTRICT IN 1893-1903 
 
 YEAR 
 
 VALUE 
 
 YEAR 
 
 VALUE 
 
 1893 
 
 12010367 
 
 1899 
 
 f 15 658 254 
 
 1894 
 
 2,908,702 
 
 1900 ...... 
 
 18,073,539 
 
 1895 
 
 6 879 137 
 
 1901 
 
 17 261 579 
 
 1896 
 
 7,512,911 
 
 1902 
 
 16,912,783 
 
 1897 
 
 10,139,708 
 
 1903 
 
 12,967,338 
 
 1898 
 
 13,507,244 
 
 Total .... 
 
 $123,831,562 
 
 
 
 
 
 San Juan Region. As an example of a more mixed 
 type of ore of this class may be mentioned the San Juan 
 region of southwestern Colorado, which includes the counties 
 of San Juan, Dolores, La Plata, Hinsdale, and Ouray, and is 
 one of the most important gold and silver producing regions 
 of the state, being noted for its persistent vertical veins, 
 carrying gold, silver, and lead ores in varying proportions. 
 Those in the vicinity of Rico are mentioned under Silver- 
 Lead. Other important mining camps are Silverton, Creede, 
 Telluride, and Ouray. 
 
 The rocks of the San Juan district consist of a series of 
 older sedimentaries, ranging from Algonkian to Cretaceous, 
 buried under a complex of Tertiary volcanics, of both acid 
 and basic types. In the Silverton quadrangle (43), for ex- 
 ample, this volcanic series is several thousand feet thick and 
 consists of tuffs, agglomerates, and lava flows. The more 
 or less distinctly horizontal surface volcanics have been pen- 
 etrated by later stocks of igneous rock, ranging from gabbro 
 nearly to granite in composition, and by many small dikes 
 of different types. 
 
 The ore deposits form lodes, stocks, or masses (locally 
 called chimneys), and replacement deposits. The lode
 
 342 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 fissures, which form the most important class, have been 
 formed at several different periods and show varying strikes, 
 but are often of great length, two or three miles being not 
 uncommon, while some of the fractures probably extend 
 continuously for as much as six miles. The ore-bearing 
 
 minerals are pyrite 
 and sulphides of cop- 
 per, silver, lead, or 
 zinc, in a gangue of 
 quartz, barite, calcite, 
 dolomite, rhodochro- 
 site, etc. They have 
 probably been depos- 
 ited from aqueous 
 solutions either in 
 spaces or pores of 
 the rock, or by re- 
 placement. The ores 
 are mostly low grade, 
 and require careful 
 milling to yield profit- 
 able returns, but some 
 are sufficiently rich to be shipped directly to the smelter. 
 
 Another remarkable development of veins is found around 
 Telluride (42) (Fig. 75), one of which, the Smuggler vein, 
 has been traced four miles, and cuts the Tertiary volcanics. 
 The ores are gold and silver in a gangue of quartz, with 
 some rhodochrosite, siderite, calcite, and barite. The ore 
 bodies around Ouray (36) differ from those around Silver- 
 ton and Telluride in being found in the sedimentaries of 
 the region, and form either fissure veins or replacements 
 
 FIG. 75. Geologic map of Telluride district, 
 Colorado, showing outcrop of more important 
 veins. After Winslow, Amer. Inst. Min, 
 Eng., Trans. XXIX: 290.
 
 GOLD AND SILVER 
 
 343 
 
 in quartzite or limestone connected with vertical fissures. 
 Owing to the different degrees of replaceability shown by 
 the wall rocks, the ore bodies present a most varied form. 
 Tonopah, Nevada. Some fine examples of replacement 
 deposits are also known in Nevada, an excellent one being 
 that found in the recently discovered mining district of 
 Tonopah, Nevada (63), which, although opened up only in 
 1900, has during the first three years produced over 13,000,000 
 worth of gold. The district, which lies in the arid desert 
 
 * 
 
 FIG. 76. Ideal cross section of rocks at Tonopah, Nev. After Spurr, U.S. 
 Geol. Surv., Bull. 225: 108. 
 
 region of Nevada, contains a series of Tertiary lavas and tuffs, 
 the former including andesites, dacites, rhyolites, and basalt 
 (Fig. 76). The earlier lavas and tuffs have been broken by 
 a complex series of faults which have not, however, affected 
 the older dacites and closely associated rhyolite necks. Four 
 periods of vein formation have been discovered closely fol- 
 lowing periods of eruption, and of these only the oldest, 
 namely, those found in the earlier andesite, are available 
 sources of ore. The veins, which have been formed by 
 replacement in sheeted zones and show more or less de-
 
 344 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 velopment of ore shoots, contain quartz with orthoclase, 
 and inclose as metallic minerals stephanite and probably 
 polybasite. The values are about two sevenths gold and 
 five sevenths silver. Subsequent to their formation they 
 have been pierced and covered by later volcanic rocks, 
 and these, together with the complex faulting, has pro- 
 duced most puzzling structural conditions. The Tonopah 
 ore deposits are analogous genetically to the Comstock 
 lode deposits of Nevada (61). 
 
 FIG. 77. Section of Comstock lode. D, diorite; Q, quartz; V, vein matter in 
 earlier diabase (Db) ; H, earlier hornblende andesite; A, augite andesite. 
 After Seeker. 
 
 Comstock Lode, Nevada. This lode, which is of historic 
 interest, occurs near Virginia City, in southwestern Ne- 
 vada, and is a great fissure vein, about four miles long, sev- 
 eral hundred feet broad, and branching above, following 
 approximately the contact between eruptive rocks, and dip- 
 ping at an angle of 35 to 45 degrees. There is abundant 
 evidence of faulting, which in the middle portion of the vein 
 has amounted to 3000 feet. The lode is of Tertiary age, 
 and contains silver and gold minerals in a quartzose gangue.
 
 GOLD AND SILVER 345 
 
 One of the peculiar features of the deposit is the extreme 
 irregularity of the ore, which occurs in great "bonanzas," 
 some of which carried several thousand dollars to the ton. 
 The faulting is considered to have been quite recent, and 
 the high temperatures encountered in the lower levels of 
 the mine indicates that there is probably a partially cooled 
 mass of igneous rock at no great depth. 
 
 In former years the enormous output of this mine caused Nevada to 
 be one of the foremost silver producers. It was discovered as early as 
 1858, and increased until 1877, after which it declined. Many serious 
 obstacles were met with in the development of the mine, such that it 
 has never become a source of much profit in spite of its enormous output. 
 In 1863, at a depth of 3000 feet, the mine was flooded by water of a tem- 
 perature of 170 F., due to a break in the clay wall ; and to drain it 
 $2,900,000 were spent in the construction of the Sutro tunnel, which was 
 nearly four miles long, but by the time it was finished the workings were 
 below its depth. A second difficulty was the encountering of high tem- 
 peratures in lower workings, these in the drainage tunnel mentioned being 
 110 to 114 F. The mine is credited with a total production of $368,- 
 000,000. In recent years its output has been slowly increasing again. 
 
 Other occurrences of the propylitic type are found in Gil- 
 pin, Boulder, and Clear Creek (48) counties, Colorado. 
 
 In Arizona the Commonwealth Mine of Cochise County 
 is probably referable to this group, as is also the Congress 
 Mine (19,20). 
 
 Fissure veins associated with Tertiary eruptives are 
 found in Owyhee County, Idaho, in the Monte Cristo dis- 
 trict of Washington (88), and the Bohemia district of 
 Oregon (70). The auriferous copper veins of Butte, Mon- 
 tana, also belong in this group, but since they are more 
 important as producers of copper, they are described under 
 that head.
 
 346 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Auriferous Gravels (23,29,30). These form an important 
 source of supply of gold, together with a little silver, and, 
 although widely distributed, become prominent chiefly in 
 those areas in which auriferous quartz veins are abundant. 
 So, while they are found in many parts of the Cordilleran 
 region, in the Black Hills, and in the Atlantic States, their 
 greatest development is in the Pacific coast belt from Cali- 
 fornia up to Alaska. 
 
 These auriferous gravels represent the more resistant 
 products of weathering, such as quartz and native gold, 
 which have been washed down from the hills on whose 
 slopes the gold-bearing quartz veins outcrop, and were too 
 coarse or heavy to be carried any distance, unless the grade 
 was steep. They have consequently settled down in the 
 stream channels, the gold, on account of its higher gravity, 
 collecting usually in the lower part of the gravel deposit. 
 
 Although the gold-bearing gravels have been derived 
 from veins of varying age, the deposition of the gravel 
 has rarely occurred in pre-Tertiary times, and some, indeed, 
 are of very recent origin. 
 
 The gold occurs in the gravels in the form of nuggets, 
 flakes, or dustlike grains, the last being usually hard to 
 catch. The nuggets represent the largest pieces, and the 
 finding of some very large ones has been recorded from 
 time to time in different parts of the world. Two large 
 nuggets are recorded from Victoria : one, the " Welcome 
 Stranger," weighing 2280 ounces ; and the other, the " Wel- 
 come Nugget," weighing 2166 ounces. Since the auriferous 
 gravels of the Pacific coast belt are the most important, 
 they will be specially referred to. 
 
 These have been derived from the wearing down of the
 
 GOLD AND SILVER 
 
 347 
 
 Sierras, and are found in those valleys leading off the 
 drainage from the mountains. Many were formed during 
 the Tertiary period, when the Sierras were subjected to a 
 long- continued denudation, while violent volcanic outbursts 
 at the close of the Tertiary have often covered the gravels 
 and protected them from subsequent erosion. These lava 
 cappings are at times 150 to 200 feet thick, as in Table 
 Mountain, Tuolumne County. 
 
 Many of the gravel deposits are on lines of former drain- 
 age, while others lie in channels still occupied by streams. 
 Some show but one streak 
 of gold, while in others 
 there may be several, some 
 of which are on rock 
 benches of the valley bot- 
 tom (Fig. 78). 
 
 During the early days 
 
 of gold mining 111 Calif Or- FIG. 78. Generalized section of old placer, 
 
 with technical terms, a, volcanic cap; 
 
 nia the gravels at lower b, upper lead; c, bench gravel; d, chan- 
 , n nel gravel. After R. E. Browne. 
 
 levels and in the valley 
 
 bottoms were worked, but as these became exhausted, those 
 
 farther up the slopes or hills were sought. 
 
 In the earlier operations the gravels were washed en- 
 tirely by hand, either with a pan or rocker, and this plan 
 is even now followed by small miners and prospectors; 
 but mining on a larger scale is carried on by one of three 
 methods, viz. drift mining, hydraulic mining, and dredging. 
 
 Drift mining is employed in the case of gravel deposits 
 covered by a lava cap, a tunnel being run in to the paying 
 portion of the bed and the auriferous gravel carried out 
 and washed.
 
 348 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 In hydraulic mining, a stream is directed against the 
 bank of gravel and the whole washed down into a rock 
 ditch lined with tree sections, or into a wooden trough 
 with cross pieces or riffles on the bottom. The gold, being 
 heavy, settles quickly and is caught in the troughs or 
 ditches, while the other materials are carried off and dis- 
 charged into some neighboring stream. Mercury is some- 
 times put behind the riffles to aid in catching the gold. 
 
 The water which is used to wash down the gravel de- 
 posits is often brought a long distance, sometimes many 
 miles, and at great expense, bridging valleys, passing 
 through tunnels, and even crossing divides, this being 
 done to obtain a large enough supply as well as a sufficient 
 head of water. 
 
 Owing to the great amount of debris which was swept 
 down into the lowlands, a protest was raised by the farm- 
 ers dwelling there, who claimed that their farms were 
 being ruined; and it soon became a question which should 
 survive, the farmer or the miner, for in places the gravels 
 and sand from the washings choked up streams and accu- 
 mulated to a depth of 70 or 80 feet. The question was 
 settled in 1884 in favor of the farmer by an injunction, 
 issued by the United States Circuit Court, which caused 
 many of the hydraulic mines to suspend operations; and 
 at a later date this was extended by state legislation, 
 adverse to the hydraulic mining industry. Owing to this 
 setback, hydraulic mining fell to a comparatively unim- 
 portant place in the gold-producing industry of California, 
 while at the same time quartz mining increased. 
 
 The passage of the Caminetti law now permits hydraulic 
 mining, but requires that a dam shall be constructed across
 
 PLATE XXII 
 
 FiG. 1. Hydraulic mining of auriferous gravel. The sluice box in the foreground 
 is for catching the gold. 
 
 Fro. 2. An Alaskan placer depos
 
 GOLD AND SILVER 349 
 
 the stream to catch the tailings. This resulted in a revival 
 of the industry. 
 
 Dredging consists in taking the gravel from the river 
 with some form of dredge. The method, which was first 
 practised in New Zealand, has been introduced with great 
 success into California, especially on the Feather River, 
 near Oroville, and its use has spread to other parts of the 
 Cordilleran region. The gravel when taken from the river 
 is discharged on to a screen, which separates the coarse 
 stones, and the finer particles pass over amalgamated plates, 
 tables with riffles, and then over felt. 
 
 Formerly much placer gold was obtained by hydraulic 
 mining, but the annual supply from this source is slowly 
 decreasing, as is that from drift mining, while the returns of 
 dredger gold have been continually increasing since 1900, 
 being 1200,000 in that year and $1,500,000 in 1903. This is 
 due to the fact that large areas in Yuba, Sutler, Nevada, Butte, 
 and Sacramento counties have been found adapted to dredg- 
 ing processes, while the improvement and enlargement of the 
 dredging machines has greatly decreased the cost of mining. 
 
 Placer gold is also worked in Idaho, Montana, Oregon, New 
 Mexico, and Colorado, all of the deposits except those of the 
 last two states having been derived mostly from Mesozoic veins. 
 
 Gold also occurs in beach sand of certain portions of the 
 Pacific coast of Washington (86), and placer mining has been 
 carried on since 1894 ; but the supply of gold, which is ob- 
 tained from Pleistocene sands and gravels, is small. 
 
 In arid regions where the gold-bearing sands are largely 
 the product of disintegration, and water for washing out the 
 metal is wanting, a system known as dry-blowing is some- 
 times resorted to.
 
 350 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 BLACK HILLS REGION 
 
 The gold-bearing ores are found chiefly in the northern 
 Black Hills, and include (1) auriferous schists in pre- 
 Cambrian rocks; (2) Cambrian conglomerates; (3) re- 
 fractory siliceous ores; (4) high-grade siliceous ores; and 
 (5) placers. Of these the first and third are the most 
 important. 
 
 The surface placers, being the most easily discovered, were 
 developed first, followed by the conglomerates at the base of 
 
 J CEMENT MINES 
 
 FIG. 79. Section of Homestake belt at Lead, S. Dak., showing relation of ancient 
 and modern placers to Homestake lode. From Min. Mag. XI: 467. 
 
 the Cambrian. These are found near Lead, occupying depres- 
 sions in the old schist surface, and the material is thought 
 to have been derived from the reef formed by the Homestake 
 ledge in the Cambrian sea. These deposits are of interest 
 as being probably the oldest gold placers known in the 
 United States. The fact, however, that the matrix of the 
 gold-bearing portion of the conglomerate is pyrite rather 
 than quartz, and the occurrence of the gold along fractures 
 stained by iron, has led some to believe that the gold has 
 been precipitated chemically by the action of iron sulphide 
 and is not a detrital product.
 
 ROBERT W. WEBB 
 GEOLOGY DEPT., U.C.LA
 
 PLATE XXIII
 
 GOLD AND SILVER 
 
 351 
 
 Homestake Belt. The gold ores of the Hornestake belt 
 (76, 77), which are the most important in the Black Hills, oc- 
 cur in a broad zone of impregnated schists, containing many 
 quartz lenses, alternating with dikes of fine-grained rhyolite, 
 which also formed sheets in the Cambrian sediments over- 
 lying the schists, and now remain as a resistant cap on many 
 of the surrounding ridges. The ore, which is all low grade, 
 averaging $5 to $6 per ton, is usually a mixture of quartz, 
 
 CONGLOMERATE 
 
 Pio. 80. Typical section of siliceous gold ores, Black Hills, S. Dak. After 
 Irving, U. S. Geol. Surv., Prof. Pap. 26. 
 
 pyrite, and occasionally other minerals having no definite 
 connection with it, occupying a zone in the Algonkian rocks 
 which shows greater hardness, irregularity of structure, and 
 mineralization than the surrounding schists. The boundaries 
 are poorly defined, and superficial examination may fail to 
 distinguish between ore and barren rock. In the upper levels 
 the ore seems to be with the dikes, but diverges from them 
 in depth, and there is apparently no genetic relation between 
 the two. In the earlier days the ore encountered was oxidized 
 and free-milling, but the appearance of sulphides with depth
 
 352 ECONOMIC GEOLOGY OP THE UNITED STATES 
 
 has necessitated the introduction of the cyanide method of 
 extraction. In spite of the low grade of its ores the Home- 
 stake mine, due to proper management, stands out as one 
 of the richest mines of the world, its monthly production 
 amounting to about $ 300,000 (Curie). The ore was origi- 
 nally worked as an open cut (PL XXIII), but later by 
 underground methods. 
 
 Siliceous Cambrian Ores. A second important type is 
 the refractory siliceous Cambrian ore found in the region 
 between Yellow Creek and Squaw Creek, and yielding about 
 two thirds as much gold as the Homestake. The deposits, 
 which occur as replacements in a siliceous dolomite, are found 
 at two horizons, one immediately overlying the basal Cam- 
 brian quartzite, and the other near the top of the Cambrian 
 series. The ore forms flat banded masses known as shoots, 
 and varying in width from a few inches to 300 feet. It is 
 overlain by shale or eruptive rock, and associated with a 
 series of vertical fractures, made prominent by a slight silici- 
 fication of the wall rock. These fractures, which are termed 
 verticals, are supposed to have conducted the ore-bearing 
 solutions. 
 
 The ore is a hard, brittle rock, composed of secondary 
 silica, with pyrite and fluorite, and at times barite, wolfram- 
 ite, stibnite, and jarosite. Its contents range from $3 or $4 
 per ton to in rare cases $100 per ton, with an average of 
 $17. Other, but less important, siliceous ores occur in the 
 Carboniferous rocks. 
 
 Michigan Region (55). A small amount of gold has been 
 found in a quartzose zone in schists, near Marquette, Mich- 
 igan, but the area is of little importance. 
 
 Eastern Crystalline Belt (82) . Gold, with some silver, has
 
 GOLD AND SILVBB 353 
 
 been found in the rocks of this belt from Vermont to Alabama, 
 but the deposits are of little importance except in North 
 Carolina (68), South Carolina (74), Georgia (49, 50), and Ala- 
 bama (3). In this belt the ore occurs as auriferous pyrite, 
 in quartz veins, as impregnations in metamorphic rocks, or 
 in placers derived from either of the foregoing groups. The 
 last-named type is practically exhausted. Of the other types, 
 there are many occurrences, in all of which the ore exists in 
 variable quantities, but is of very low grade, so that to be 
 profitable the deposits must be worked on a large scale by 
 proper methods. In many localities the free gold of the 
 oxidized portion of the ore body has been worked out and 
 the mine abandoned. 
 
 The deposits are in many instances associated with in- 
 trusives, some of which are metamorphosed, still they bear 
 no genetic relation to them, being frequently of later origin. 
 They are usually classed as pre-Cambrian, but some may be 
 of later age. 
 
 Alaska (14). Although gold has been known to occur 
 in Alaska since the early part of the century, and was 
 even worked in 1860, its production is not definitely stated 
 until 1880, when it was added to the list of gold-producing 
 regions, with an output of $6000, which since that time has 
 increased many times over, but not steadily, until in 1903 it 
 amounted to $8,614,700. 
 
 The first gold was discovered on the islands of the Alex- 
 ander Archipelago and along the adjoining coast, but sub- 
 sequently prospectors found their way into the interior, the 
 first strikes there being made in British Columbia near the 
 head of the Stikine River. These were followed by di- 
 coveries in the Yukon Valley, especially along some of the
 
 354 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 tributaries known as Birch Creek, Mission Creek, and 
 Forty Mile Creek. In 1896 still richer discoveries were 
 made along the Klondike River, and within one year the 
 yield of this region had exceeded the purchase price of 
 Alaska. Other discoveries have since followed rapidly. 
 The gold deposits of Alaska are of two types, viz. quartz 
 
 FIG. 81. Map showing mineral deposits of Alaska as far as known. After 
 Brooks, U. S. Geol. Surv., Bull. 259. 
 
 veins and placers. The former are prominent along the 
 coast, and the most important producer is the Treadwell 
 group of mines on Douglas Island, southeast of Juneau (14). 
 The geology of this region bears in many ways a strong 
 resemblance to the California gold belt, and is probably of 
 similar age. The section involves a series of steeply dipping 
 slates and greenstone and diorite dikes (Fig. 83). The ore
 
 GOLD AND SILVER 
 
 355 
 
 bodies are dikes of albite-diorite, permeated with metallic 
 sulphides and carrying small amounts of gold (14), with a 
 hanging wall of greenstone and a foot wall of black slate. 
 The veinlets, which are thought to have been formed by 
 shearing stresses incident to epeirogenic movements, occur 
 in two sets of fractures at right angles to each other. 
 Spencer believes that the mineralization has been caused 
 by hot ascending solutions of possibly magmatic origin. 
 
 FIG. 82. Sketch map of Douglas Island, Alaska. After Spencer, U. S. Geol. 
 Surv.,Bull.259:71. 
 
 Secondary concentration is not in evidence, and it is 
 thought that the depth to which the ores can be worked 
 will depend more on the increased cost of mining at great 
 depths rather than on exhaustion of the ore. At present 
 an almost continuous ore body has been developed for 
 3500 feet. 
 
 The placer deposits have been found in many parts of 
 Alaska, but the two regions which have yielded the largest 
 amount are the Yukon region (16) and the Seward Penin- 
 sula (14, 15), the latter being now the first.
 
 356 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Gold was discovered in the Forty Mile district of the 
 Yukon in 1886, and caused a stampede for this region; but 
 the deposits of the Klondike did not become known until 
 1896, and their discovery was followed by a rush of gold 
 seekers that eclipsed all previous ones. Indeed, it is said 
 that by 1898 over 40,000 people were camped out in the 
 vicinity of the present site of Dawson. 
 
 The Klondike region proper is situated on the eastern 
 side of the Yukon River, and the richer deposits found 
 have been on the Canadian side of the boundary. The 
 
 SCALE 1,050 FEET=1 INCH 
 
 ED M\ 
 
 FIG. 83. Cross section through Alaska Tread well mine on northern side of 
 Douglas Island. After Spencer, U. S. Geol. Surv., Bull. 259 
 
 gold has collected either at the bottom of the gravel in the 
 smaller streams tributary to the Yukon, or else in gravels 
 on the valley sides, this latter occurrence being known as 
 bench gravel. The metal is supposed to have been derived 
 from the quartz veins found in the Birch Creek, Forty Mile, 
 and Rampart series of metamorphic rocks lying to the east. 
 Up to the end of 1902 the total production of the Klondike 
 is stated to have been $80,000,000. The annual output has, 
 however, decreased, and mining in that region has settled 
 down to a more permanent basis. Gravels running under 
 $9 per cubic yard cannot be worked at a profit, because the 
 difficulties and expenses of running in such a region are
 
 GOLD AND SILVER 357 
 
 great, and form an interesting comparison with conditions 
 in California, where gravel carrying 25 cents per yard is 
 considered good, while that running as low as 5 cents per 
 yard can be worked (18). 
 
 Since the discovery of the rich gold gravels on the Yukon, 
 auriferous gravels have been developed in many other parts 
 of Alaska, where they are being more or less actively worked 
 (Fig. 81), but of these various finds those in the Seward 
 Peninsula, which is now the largest producer, have been 
 the most important. 
 
 The first of the localities discovered in the last-mentioned 
 region was Cape Nome (15), which for a time proved to be a 
 second Klondike. The gold was discovered here on Anvil 
 Creek, and the following year in the beach sands where 
 Nome now stands. These discoveries caused another north- 
 ward stampede, which resulted in the rapid exhaustion of 
 the beach sands ; but other deposits were found farther 
 inland near Nome, as well as the other localities on the 
 Seward Peninsula. Some quartz veins are also worked. 
 Ophir Creek is now the largest producer on the Seward 
 Peninsula. Up to the end of 1902 the Seward Peninsula 
 had produced $20,000,000 in gold, and in 1903 the produc- 
 tion of the Nome region is given as $4,437,449. 
 
 Uses of Gold. Gold is chiefly used for coinage, orna- 
 ments, and ornamental utensils. It is also employed to 
 a considerable extent in dentistry and in an alloy for the 
 better class of gilding. 
 
 Its value for use in the arts depends on its brightness, 
 freedom from tarnish, and its ductility and malleability, 
 which permit it to be easily worked. As pure 24-carat
 
 358 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 gold is too soft for use, it is alloyed with a small amount 
 of some other metal, such as copper, to gain hardness. 
 
 Uses of Silver. This metal was formerly of much im- 
 portance for coinage, but is much less so now. It is, 
 however, widely employed in the arts for making jewelry 
 and utensils such as tableware. Its salts are of more 
 or less value in medicine and in photography. Its bright- 
 ness and white color are valuable properties when the metal 
 is used, but, unlike gold, it tarnishes somewhat readily when 
 exposed to sulphurous gases. There are a number of alloys 
 of silver, those with gold and copper, respectively, being 
 of importance. 
 
 Production of Gold and Silver : 
 
 PRODUCTION OF GOLD AND SILVER IN THE UNITED STATES FROM 
 1845 TO 1903 
 
 YKAR 
 
 TOTAL 
 
 GOLD 
 
 SILVER 
 (Coining Value) 
 
 1845 
 
 $1,058,327 
 
 $1,008,327 
 
 $50,000 
 
 1855 
 
 55 050 000 
 
 55 000 000 
 
 50000 
 
 1865 
 
 64,475,000 
 
 53,225,000 
 
 11,250,000 
 
 1875 . . 
 
 65 100 000 
 
 33,400 000 
 
 31 700 000 
 
 1885 
 
 83,400,000 
 
 31,800,000 
 
 51,600,000 
 
 1895 
 
 118,661 000 
 
 46 610 000 
 
 72,051,000 
 
 1900 
 
 153 704 495 
 
 79 171 000 
 
 74 533 495 
 
 1901 
 
 150 054 500 
 
 78 666 700 
 
 71,387,800 
 
 1902 
 
 151 757 575 
 
 80 000 000 
 
 71 757 575 
 
 1903 
 
 143,797,760 
 
 73,591,700 
 
 70,206,060 
 
 The production by states for 1903 is given below, and 
 shows well the overwhelming importance of the Cordil- 
 leran region:
 
 GOLD AND SILVER 
 
 359 
 
 PRODUCTION AND VALUE OF GOLD AND SILVER IN THE UNITED 
 STATES IN 1903, BY STATES 
 
 
 GOLD 
 
 SILVER 
 
 TOTAL 
 
 
 
 
 (Silver at 
 
 
 
 
 
 r * i 
 
 Commercial 
 
 
 Quantity 
 
 Value 
 
 Quantity 
 
 Value 
 
 Value) 
 
 
 Fine oz. 
 
 Dollars 
 
 Fine oz. 
 
 Dollars 
 
 Dollars 
 
 Alabama . . 
 
 213 
 
 4,400 
 
 
 
 4,400 
 
 Alaska . . . 
 
 416,738 
 
 8,614,700 
 
 143,600 
 
 77,544 
 
 8,692,244 
 
 Arizona . . . 
 
 210,799 
 
 4,357,600 
 
 3,387,100 
 
 1,879,034 
 
 6,186,634 
 
 California . . 
 
 779,057 
 
 16,104,500 
 
 931,500 
 
 503,010 
 
 16,607,510 
 
 Colorado . . 
 
 1,090,376 
 
 22,540,100 
 
 12,990,200 
 
 7,014,708 
 
 29,554,808 
 
 Georgia . . . 
 
 3,000 
 
 62,000 
 
 400 
 
 216 
 
 62,216 
 
 Idaho . . . 
 
 75,969 
 
 1,570,400 
 
 6,507,400 
 
 3,513,996 
 
 5,084,396 
 
 Kansas . . . 
 
 468 
 
 9,700 
 
 97,400 
 
 52,596 
 
 62,296 
 
 Maryland . . 
 
 24 
 
 500 
 
 
 
 500 
 
 Michigan . . 
 
 
 
 50,000 
 
 27,000 
 
 27,000 
 
 Montana . . 
 
 213,425 
 
 4,411,900 
 
 12,642,300 
 
 6,826,842 
 
 11,238,742 
 
 Nevada . . . 
 
 163,892 
 
 3,388,000 
 
 5,050,500 
 
 2,727,270 
 
 6,115,270 
 
 New Mexico . 
 
 11,833 
 
 244,600 
 
 180,700 
 
 97,578 
 
 342,178 
 
 North Carolina 
 
 3,411 
 
 70,500 
 
 11,000 
 
 5,940 
 
 76,440 
 
 Oregon . . . 
 
 62,411 
 
 1,290,200 
 
 118,000 
 
 63,720 
 
 1,353,920 
 
 South Carolina 
 
 4,872 
 
 100,700 
 
 300 
 
 162 
 
 100,862 
 
 South Dakota . 
 
 330,243 
 
 6,826,700 
 
 221,200 
 
 119,448 
 
 6,946,148 
 
 Tennessee . . 
 
 38 
 
 800 
 
 13,000 
 
 7,020 
 
 7,820 
 
 Texas . . . 
 
 
 
 454,400 
 
 245,376 
 
 245,376 
 
 Utah .... 
 
 178,863 
 
 3,697,400 
 
 11,196,800 
 
 6,046,272 
 
 9,243,672 
 
 Virginia . . 
 
 654 
 
 13,500 
 
 9,500 
 
 15,130 
 
 18,630 
 
 Washington . 
 
 13,539 
 
 297,900 
 
 294,500 
 
 159,030 
 
 438,930 
 
 Wyoming . . 
 
 175 
 
 3,600 
 
 200 
 
 108 
 
 3,708 
 
 Total . . 
 
 3,560,000 
 
 73,591,700 
 
 54,300,000 
 
 29,322,000 
 
 102,913,700 
 
 Mr. Lindgren (80) has recently given a most interesting 
 and valuable classification of the figures of gold and silver 
 production, grouped according to the kind of ores from 
 which they have been derived. These are given below, 
 and indicate that the Tertiary quartz veins yield the 
 largest amount of gold, and the lead ores the greatest 
 quantity of silver.
 
 360 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 PRODUCTION OF GOLD AND SILVER IN 1904 ACCORDING TO 
 KINDS OF ORE 
 
 
 GOLD 
 FINE OUNCES 
 
 SILVER 
 FINE OUNCES 
 
 Placers 
 
 619 700 
 
 64 000 
 
 Quartzose gold and silver ores 
 Pre-Cambrian quartz veins 
 Mesozoic quartz veins 
 
 264,000 
 1 045 000 
 
 79,000 
 860 000 
 
 
 1 727 000 
 
 11 000 000 
 
 Copper ores 
 
 206 000 
 
 18 600 000 
 
 
 22 500 
 
 23 000 000 
 
 
 
 
 
 4,086,200 
 
 53,603,000 
 
 WORLD'S PRODUCTION OF GOLD AND SILVER IN 1903 
 
 
 GOLD 
 
 SILVER 
 
 TOTAL 
 
 North and Central America . 
 Australia 
 
 $104,979;000 
 89 210,100 
 
 $70,235,500 
 5 228,700 
 
 $175,214,500 
 94,438,800 
 
 Africa 
 
 67 998 100 
 
 185 300 
 
 68 183 400 
 
 
 27,117,800 
 
 8 182 100 
 
 35 299,900 
 
 
 25 434 000 
 
 359 100 
 
 25 793 100 
 
 South America 
 
 10 788 200 
 
 7 848 900 
 
 18,637,100 
 
 
 
 
 
 Total 
 
 $325,527,200 
 
 $92,039,600 
 
 $417,566,800 
 
 REFERENCES ON GOLD AND SILVER 
 
 GENERAL. 1. Blake, Amer. Inst. Min. Engrs., Trans. XXVI : 290, 1897. 
 (Gold in igneous rocks.) 2. Cumenge and Robellaz, L'Or dans la 
 nature (Paris, 1898). 3. Curie, The Gold Mines of the World 
 (London, 1902). 4. Don, Amer. Inst. Min. Engrs., Trans. XXVII : 
 564, 1898. (Genesis of certain auriferous lodes.) 5. Emmons, 
 Amer. Inst. Min. Engrs., Trans. XVI : 804, 1888. (Structural rela- 
 tions of ores.) 6. Kemp, Min. Indus., VI : 295, 1898. (Telluride 
 ores.) 7. Liversidge, Amer. Jour. Sci., XLIII : 245, 1892. 8. Mer- 
 rill, Amer. Jour. Sci., 1 : 309, 1896. (Gold in granite.) 9. Pearce, 
 Ores of Gold, etc., Colo. Sci. Soc. Proc., Ill: 237. 10. Rickard, 
 Min. and Sci. Pr., LXXVII: 81 and 105, 1898. (Minerals ac-
 
 GOLD AND SILVER 861 
 
 companying gold.) 11. Spurr, Eng. and Min. Jour., LXXVI : 
 500, 1903. (Gold in diorite.) 12. Spurr, Eng. and Min. Jour., 
 LXXVII : 198, 1904. (Native gold original in metamorphic gneis- 
 ses.) Alabama : 13. Brewer, Ala. Geol. Surv., Bull. 5, 1896; Phil- 
 lips, Ala. Geol. Surv., Bull. 3, 1892. Alaska : 14. Brooks and 
 others, U. S. Geol. Surv., Bull. 259, 1905. (Mineral resources.) 
 15. Schrader and Brooks, Amer. Inst. Min. Engrs., Trans. XXX: 
 236, 1901. (Cape Nome.) 16. Spurr, U. S. Geol. Surv., 18th Ann. 
 Kept., Ill : 101, 1898. (Yukon district.) 17. See also various papers 
 on Alaska in U. S. Geol. Surv., Bull. 213, 1903, and Bull. 225, 1904. 
 18. Penrose, Eng. and Min. Jour., LXXVI: 807, 852, 1903. 
 Arizona : 19. Blandy, Amer. Inst. Min. Engrs., Trans. XI : 286, 1883. 
 (Prescott district.) 20. Comstock, Amer. Inst. Min. Engrs., Trans. 
 XXX: 1038, 1901. (Geology and vein phenomena.) 21. Pratt, 
 Eng. and Min. Jour., LXXIII : 795, 1902. Literature on Arizona 
 gold ores, especially of recent character, is scarce. 22. See reports 
 of Director of Mint. California: 23. Browne, Calif. State Min. 
 Bur., 10th Ann. Kept.: 435. (River gravels.) 24. Diller, U. S. 
 Geol. Surv., Bull. 260 : 45, 1905. (Indian Valley region.) 25. Fair- 
 banks, Calif. State Min. Bur., X: 23, 1890, and XIII: 665, 1896. 
 (Mother Lode district.) 26. Lindgren, U. S. Geol. Surv., 17th Ann. 
 Kept., II : 1, 1896. (Nevada City and Grass Valley.) 27. Liiidgren, 
 Geol. Soc. Amer., Bull. VI: 221, 1895. (Gold quartz veins.) 
 28. Lindgren, U. S. Geol. Surv., 14th Ann. Kept., II: 243, 1894. 
 (Ophir.) 29. Lindgren, U. S. Geol. Surv., Bull. 213: 64, 1903. 
 (Neocene river gravels.) 30. Turner, Amer. Geol., XV : 371, 1895. 
 (Auriferous gravels.) 31. See also various annual reports of Calif. 
 State Mineralogist. Colorado : 32. Comstock, Amer. Inst. Min. 
 Engrs., Trans. XV: 218, 1886, and XI: 165, 1882. (Geology and 
 vein structure, southwestern Colo.) 33. Emmons, Eng. and Min. 
 Jour., XXXV : 332, 1883. (Summit district.) 34. Emmons, U. S. 
 Geol. Surv., 17th Ann. Kept., II : 405, 1896. (Custer Co.) 35. Farish, 
 Colo. Sci. Soc., Proc. IV : 151, 1892. (Rico.) 36. Irving, U. S. 
 Geol. Surv., Bull. 260 : 50, 1905. (Ouray.) 37. Irving, U. S. Geol. 
 Surv., Bull. 260 : 78, 1905. (Lake City.) 38. Kedzie, Amer. Inst. Min. 
 Engrs., Trans. XVI: 570,1888. (RedMt.) 39. Lindgren and Ran- 
 some, U. S. Geol. Surv., Bull. 246, 1905. (Cripple Creek.) 40. Pen- 
 rose and Cross, U. S. Geol. Surv., 16th Ann. Rept., II : 111, 1895. 
 (Cripple Creek.) 41. Porter, Amer. Inst. Min. Engrs., Trans. XXVI : 
 449, 1897. (Telluride.) 42. Purington, U. S. Geol. Surv., 18th Ann. 
 Rept., Ill : 751, 1898. (Telluride.) 43. Ransome, U. S. Geol. Surv., 
 Bull. 182, 1901. (Silverton.) 44. Rickard, Min. Indus., II: 325, 
 1894, and IV : 315, 1896. 45. Rickard, Amer. Inst. Min. Engrs.,
 
 362 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Trans. XXX : 367, 1901. (Cripple Creek.) 46. Schwartz, Amer. Inst. 
 Min. Engrs., Trans. XVIII : 139, 1890. (Cripple Creek.) 47. Skewes, 
 Amer. Inst. Min. Engrs., Trans. XXVI : 553, 1897. (Cripple Creek.) 
 48. Spurr, U. S. Geol. Surv., Bull. 260 : 99, 1905. (Georgetown.) 
 Georgia : 49. Eckel, U. S. Geol. Surv., Bull. 213 : 57, 1903. (Dahlonega 
 district.) 50. Yeates, McCallie, and King, Ga. Geol. Surv., Bull. 4 a, 
 
 1896. Idaho: 51. Lindgren, U.S. Geol. Surv., 20th Ann. Kept., 
 Ill : 75, 1900. (Silver City, De Lamar Co.) 52. Lindgren, U. S. 
 Geol. Surv., 18th Ann. Kept., Ill : 625, 1898. (Idaho Basin and 
 Boise Ridge.) Kansas : 53. Lindgren, Eng. and Min. Jour., LXXIV : 
 111, 1902. (Tests for gold and silver in shales.) Maryland : 
 54. Weed, U. S. Geol. Surv., Bull. 260 : 128, 1905. (Great Falls.) 
 
 Michigan : 55. Wadsworth, Ann. Kept., 1892, Mich. State Geologist. 
 
 Minnesota : 56. Winchell and Grant, Minn. Geol. and Nat. Hist. 
 Surv., XXIII : 36, 1895. (Rainy Lake district.) Montana : 57. Lind- 
 gren, U. S. Geol. Surv., Bull. 213 : 66, 1903. (Bitter Root and Clear- 
 water Mts.) 58. Weed, U. S. Geol. Surv., Bull. 213: 88, 1903. 
 (Marysville.) 59. Weed and Barrell, U. S. Geol. Surv., 22d Ann. 
 Rept., II : 399, 1902. (Elkhorn district.) 60. Weed and Pirsson, 
 U. S. Geol. Surv., 18th Ann. Rept., Ill : 589, 1898. (Judith Mts.) 
 
 Nevada: 61. Becker, U. S. Geol. Surv., Mon. Ill, 1882. (Corn- 
 stock Lode.) 62. Lord, U. S. Geol. Surv., Mon. IV, 1883. (Comstock 
 mining.) 63. Spurr, U. S. Geol. Surv., Prof. Pap. 42, and Bull. 
 260 : 140, 1905. (Tonopah.) 64. Spurr, U. S. Geol. Surv., Bull. 225 : 
 118, 1904, and Bull. 260 : 132, 1905. (Gold fields.) 65. Spurr, U. S. 
 Geol. Surv., Bull. 225: 111, 1904. (Silver Peak quadrangle.) 66. See 
 also annual reports of Director of Mint. New England : 67. Smith, 
 U. S. Geol. Surv., Bull. 225 : 81, 1904. (Me. and Vt.) North 
 Carolina : 68. Nitze and Hanna, N. Ca. Geol. Surv., Bulls. 3 and 10. 
 
 Oklahoma: 69. Bain, U. S. Geol. Surv., Bull. 225: 120, 1904. 
 (Wichita Mts.) Oregon : 70. Diller, U. S. Geol. Surv., 20th Ann. 
 Rept., Ill: 7, 1900. (Bohemia district.) 71. Kimball, Eng. and 
 Min. Jour., LXXIII: 889, 1902. (Bohemia district.) 72. Lindgren, 
 U. S. Geol. Surv., 22d Ann. Rept., II: 551, 1901. (Blue Mts.) 
 73. See also bulletin on Oregon Mineral Resources issued by Uni- 
 versity of Oregon. South Carolina : 74. Thies and Mezger, Amer. 
 Inst. Min. Engrs., Trans. XIX : 595, 1891. (Haile Mine.) See also 
 No. 82. South Dakota: 75. Carpenter, Amer. Inst. Min. Engrs., 
 Trans. XVII : 570, 1889. 76. Irving, U. S. Geol. Surv., Bull. 225 : 
 123, 1904, and U. S. Geol. Surv., Prof. Paper 26, 1904. (N. Black 
 Hills.) 77. O'Harra, S. Dak. Geol. Surv., Bull. 3, 1902. (Black 
 Hills.) 78. Smith, Amer. Inst. Min. Engrs., Trans. XXVI: 485, 
 
 1897. (Cambrian ores.) United States: 79. Lindgren, Amer. Inst.
 
 GOLD AND SILVER 363 
 
 Min. Engrs, Trans. XXXIII: 790, 1903. (N. Amer. production 
 and geology.) 80. Lindgren, U. S. Geol. Surv., Bull. 260 : 32, 1905. 
 81. Nitze and Wilkens, Amer. Inst. Min. Engrs., Trans. XXV: 661, 
 1896. (Appalachians.) 82. Pratt, Eng. and Min. Jour., LXXIV : 
 241, 1902. (S. Appalachians.) 83. Ransome, Min. Mag., X: 7, 
 
 1904. See also annual reports on Precious Metals, issued by Director 
 of Mint, the Mineral Resources issued by U. S. Geol. Survey, the 
 Mineral Industry, and Census Report on Mines and Quarries, 1902. 
 Utah : 84. Spurr, U. S. Geol. Surv., 16th Ann. Kept., II : 343, 1895. 
 (Mercur.) See also annual reports of Director of Mint, all of which 
 contain much general information, partly of statistical character; 
 also references under Silver-Lead. 85. Warren, Eng. and Min. Jour. 
 LXVIII : 455, 1899. (Daly-West Mine.) Vermont : See New Eng- 
 land. Washington: 86. Arnold, -U. S. Geol. Surv., Bull. 260: 154, 
 
 1905. (Beach placers.) 87. Smith, Eng. and Min. Jour., LXXIII : 
 379, 1902. (Mt. Baker district.) 88. Spurr, U. S. Geol. Surv., 22d 
 Ann. Kept., II : 777, 1901. (Monte Cristo.)
 
 CHAPTER XVIII 
 SILVER-LEAD ORES 
 
 THE Silver-Lead Ores form a large class, which are widely 
 distributed in the Cordilleran region, and not only supply 
 most of the lead mined in the United States, but in ad- 
 dition may also and often do carry variable quantities of 
 silver, gold, and copper. 
 
 The deposits as a whole present a variety of forms. The 
 associated rocks are often faulted, and the ore bodies are 
 commonly oxidized above so that the altered portions re- 
 quire different metallurgical treatment from the sulphide 
 ores found below. Secondary enrichment has in some cases 
 raised the grade of the ore. Deposits of this class are 
 prominent in Colorado, Idaho, and Utah, but are also known 
 in New Mexico, Montana, Wyoming, Nevada, Arizona, Cali- 
 fornia, and South Dakota. Idaho is the largest producer of 
 silver-lead ores, but they average only one third silver, 
 while those of Colorado average three quarters silver, and 
 those of Utah about two thirds silver. A few of the more 
 prominent occurrences are mentioned. 
 
 Leadville District, Colorado (1, 7). This region lies in the 
 Mosquito range at the headwaters of the Arkansas River in 
 south central Colorado, while the town of Leadville is situ- 
 ated in an old lake basin on the west side of the range. 
 The latter is composed of crystalline rocks, Paleozoic sedi-
 
 SILVER-LEAD ORES 365 
 
 ments, and igneous intrusions, the last in part conforming 
 to the bedding planes of the sedimentary rocks. The 
 Paleozoic section alone is over 5000 feet and involves the 
 following members: 
 
 Upper Carboniferous limestone . . 1000 to 1500 feet. 
 
 Weber shales and sandstone . . . 2000 feet. 
 
 Oldest or white porphyry .... 
 
 Carboniferous blue limestone (chief 
 
 ore-bearing stratum) 200 feet. 
 
 Gray porphyry 
 
 g . jQuartzite ...... 40 feet. 
 
 n { White limestone .... 160 feet. 
 
 Cambrian quartzite 150 to 200 feet. 
 
 The rocks on the western side of the Mosquito range are 
 folded and faulted, this having taken place during late Cre- 
 taceous times, when the Rocky Mountains were uplifted, and 
 subsequent to the intrusion of the igneous rocks. It is con- 
 sidered that the latter stimulated the ascension of the ore- 
 bearing solutions, the ore being commonly deposited on the 
 under side of the porphyry sheets and in contact with the 
 blue Carboniferous limestones. Later developments have 
 shown its presence along some of the other contacts. The 
 unaltered ore is argentiferous galena with some native gold, 
 but within the zone of oxidation the galena is changed to 
 carbonate and sulphate, with silver chloride and at times 
 containing considerable limonite. The gangue is calcite, 
 barite, and chert. 
 
 The older mines are mostly east of the city on Fryer, Car- 
 bonate, and Iron Hill, but in recent years the continuation of 
 the deposits has been found under the city.
 
 366 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 \ 
 
 The origin of the ores has been discussed by several geolo- 
 gists, among them Emraons and Blow (1, 7). The former 
 believes that the ores were originally deposited as sulphides 
 from aqueous solutions ascending from 
 . some deep source, and by a process in- 
 I volving metasomatic interchange, the 
 I ore-bearing solutions following the con- 
 K| tact because it happened to form a 
 i> good channel. 
 
 ^ For many years the oxidized ores of 
 ^ the Leadville district have been an 
 
 important source of material for the 
 
 1 smelters; but latterly the silver ores 
 k have shown signs of exhaustion, and 
 
 ill^ their place has been taken to some 
 extent by the discovery of gold ore to 
 
 1 the east of the town, as well as of zinc 
 sulphides at greater depths and the 
 S shipment of larger quantities of iron 
 
 and manganese ores than formerly. 
 
 Even in former years Leadville was a mining 
 camp of great importance, having indeed given 
 % Colorado its first serious start as a mining state. 
 | From an area of about a square mile the output 
 | of silver was for a number of years greater than 
 that of any foreign country except Mexico, 
 
 2 and during the same period the production of 
 lead was nearly equal to that of England and 
 greater than that of any European country 
 
 excepting Spain and Germany. Although regarded originally as a 
 silver camp, it really ceased being such nearly ten years ago, and is now 
 an important producer of at least eight metals, of which five or six are
 
 SILVER-LEAD ORES 367 
 
 sometimes all obtained from the same group of properties. It will thus 
 be seen that the successful marketing of one may affect all the others. 
 Leadville began as a gold camp in 1860, when a placer deposit of gold 
 was found in a gulch near there and several million dollars' worth of 
 metal were extracted, resulting in the establishment of a flourishing 
 town called Oro, which, however, soon lost its importance when the gold 
 began to be exhausted. Not until 1875 was the carbonate of lead, which 
 has since been so important, actually recognized. 
 
 That Leadville is no longer entirely a lead-silver camp is evident 
 from the fact that, in 1901, of the 850,000 long tons of ore mined, 35,000 
 tons were zinc ores, 70,000 tons manganese iron ores, and the remainder 
 lead and copper smelting ores. 
 
 Aspen, Colorado (15). Here again the ores are oxidized 
 and occur in highly folded and faulted Carboniferous lime- 
 stone, although the section involves rocks ranging in age from 
 Archaean to Mesozoic. Two quartz porphyries, one at the 
 base of the Devonian, the other in the Carboniferous, are 
 present, but bear no special relation to the ore. 
 
 At the close of the Cretaceous the rocks were folded into 
 a great anticline, with a syncline on its eastern limit, which 
 passed into a great fault along Castle Creek west of the 
 mines. Contemporaneous with the folding there were also 
 produced two faults parallel to the bedding of the Carbonif- 
 erous dolomite, while at the same time much cross faulting 
 occurred. The ore is found chiefly at the intersection of 
 these two sets of fault planes, and Spurr considers that the 
 ore-bearing solutions followed the bed faults. 1 
 
 On account of the intimate association of the dolomite, 
 quartz, and barite with the ore their origin is considered as 
 similar. 
 
 1 Weed has suggested that this accumulation of ore at the intersection of 
 fault planes is the result of secondary enrichment, rather than of primary 
 concentration.
 
 368 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The ores are peculiarly free from other metals except 
 lead, and the rich polybasite (Ag 9 SbS 6 ) ores of Smuggler 
 
 Mountain do not contain 
 even this. 
 
 The mining camp of 
 Aspen started in 1879, 
 but its development for 
 a time was much re- 
 tarded by lawsuits. The 
 richer ore bodies were 
 not discovered until 
 1884, and then by un- 
 derground exploration, 
 for owing to the heavy 
 mantle of glacial gravels 
 their outcrops were hid- 
 den. Since also the 
 ore carries no iron or 
 manganese, as do the 
 Leadville ores, its out- 
 crop may be incon- 
 spicuous. 
 
 The railroads did not 
 reach the camp until 1887, 
 so that during the first few 
 
 J GLACIAL DRIFT 
 
 } WEBER FORMATION 
 
 loRE 
 
 J LEADVILLE DOLOMITE 
 
 l PARTING QUARTZITE 
 l YULE FORMATION 
 l SAWATCH FORMATION" 
 | GRANITE 
 
 *M QUARTZ PORPHYRY 
 
 FIG. 85. Section of ore body at Aspen, Colo. 
 After Spurr, U.S. Geol. Surv., Mon. XXXI. 
 
 years of its history the ore had to be carried out on burros. 
 
 In both Aspen and Smuggler mountains long tunnels have been run 
 for drainage and hauling purposes. The Cowenhoven tunnel, which is 
 the largest of these, is over 8300 feet long, and taps a number of mines. 
 Aspen was one of the first mining camps in the West to install electric 
 machinery for hoisting, haulage, etc., and the current was cheaply sup- 
 plied by the neighboring water power. One shaft 1000 feet deep is 
 operated electrically.
 
 PLATE XXIV 
 
 FIG. 1. General view of Rico, Colo., and Enterprise group of mines. 
 
 FIG. 2. Ontario mine, Park City, Utah.
 
 SILVER-LEAD ORES 
 
 369 
 
 At the present day the larger ore bodies are worked out, but the camp 
 is still an active producer. From 1881 to 1895 it produced $63,653,989 
 worth of silver. 
 
 Other Occurrences. Argentiferous lead ores also occur in 
 the Ten Mile district (8), in Chaffee County, and along the 
 Eagle River (11). They 
 are also known in Red 
 Mountain (10 a), and in 
 Rico Mountain, Dolores 
 County (4, 12, 13). In the 
 last-mentioned region the 
 mountains, which are 
 the remains of the struc- 
 tural dome arising above 
 the Dolores plateau lying 
 in the San Juan region, 
 contain a series of sedi- 
 mentary beds ranging 
 from Algonkian to Juras- 
 sic in agre, which have 
 
 FIG. 86. Diagrammatic section across a 
 northeasterly lode at Rico, Colo., showing 
 " blanket " of ore. After Ransome, U. S. 
 Geol. Surv., Z2d Ann. Rept., II. 
 
 been uplifted partly by 
 
 the intrusion of igneous 
 
 rocks, as stocks, sills, and dikes, and partly by upthrows due 
 
 to faulting. 
 
 The ore occurs as lodes, replacements in limestone, stocks, 
 and blankets, the last consisting usually of deposits lying 
 parallel to the planes of bedding or to the sheets of igneous 
 rock, and known locally as "contacts," although not such 
 in the true sense. 
 
 The four types of deposit mentioned may pass into each 
 other. Most of the ore in the district has, however, 
 
 2B
 
 370 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 come from the blankets, and the bulk of this has been 
 found in the Carboniferous, especially in the Hermosa 
 formation, a striking feature of the deposits being their 
 limited vertical range. 
 
 The ores are primarily galena, often highty argentifer- 
 ous and associated with rich silver-bearing minerals. In 
 
 many deposits the more or 
 less complete oxidation of 
 the silver ores has resulted 
 in powdery masses, often 
 very rich in silver. Below 
 the zone of oxidation, the 
 veins have not been success- 
 fully worked. 
 
 The bulk of the ores can 
 be roughly divided into py- 
 ritic ores, usually low grade, 
 and silver-bearing galena 
 ores, sometimes containing 
 rich silver minerals. Quartz 
 is the commonest gangue 
 mineral, but the beautiful 
 pink rhodochrosite is also 
 conspicuous. 
 
 The ore deposition is be- 
 lieved to be closely associated with the igneous intrusions 
 of the district, especially with the later ones. 
 
 Most of the ore produced in the Rico district has been 
 shipped crude or smelted in Rico without mechanical 
 concentration. 
 Park City, Utah (2), which is located on the eastern 
 
 FIG. 87. Vein filling a fault fissure, 
 Enterprise mine, Rico, Colo. After 
 Richard, Amer. Inst. Min. Eng., 
 Trans. XXVI: 927.
 
 SILVER-LEAD ORES 371 
 
 slope of the Wasatch range, about 25 miles southeast of 
 Salt Lake City, has made Summit County famous as one 
 of the important mining centers of this country, as there 
 are here large bodies of rich silver-lead ores carrying minor 
 values of gold and copper. The success of this camp, 
 therefore, depends more or less on the condition of the 
 silver and copper industry. 
 
 The geological section involves a series of limestones, 
 sandstones, and shales, chiefly of Carboniferous age, and 
 having an aggregate thickness of over 6000 feet, with a 
 general dip of 30 to 40 degrees northwest, and traversed 
 by many fissures, faults, and intrusions, the last being of 
 either dioritic or porphyritic types. The ores, which in 
 the oxidized zone are cerussite, anglesite, azurite, mala- 
 chite, etc., and in the sulphide zone are galena, tetrahe- 
 drite, and pyrite, occur either as lodes or fissures, or as 
 bedded deposits in limestones. The latter, which supply 
 most of the ore, form replacements in certain strata of 
 both the upper Carboniferous and Permocarboniferous, and 
 lie between siliceous members as walls. Both types of ore 
 deposit are frequently associated with porphyry. 
 
 The fissures carry either silver or lead with or without 
 zinc, and copper or gold with some silver. The replace- 
 ment ores of the limestones hold silver and lead chiefly. 
 The contact ores contain copper and gold with or without 
 silver, and form irregular bodies in metamorphic limestone 
 adjacent to the igneous rock. The ordinary crude ore 
 carries 50 to 55 ounces silver, 20 per cent lead, .04 to .05 
 ounce gold, 1.5 per cent copper, 10 to 18 per cent zinc. 
 Silver is obtained in the proportion of 3 ounces silver to 
 each per cent iron, 1 ounce silver to each per cent lead,
 
 372 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 and .5 ounce silver to each per cent zinc. Bonanzas are 
 known. The low-grade ores are treated at the concen- 
 trating mill, while the rich ores are shipped to the smelter. 
 
 Tintic District, Utah (16). This district lies in the Tintic 
 Mountains, about 65 miles southwest of Salt Lake City. 
 The ores are argentiferous galena, with a little copper, the 
 average per ton of 240,000 tons being silver, 52.44 oz.; lead, 
 270 Ibs.; copper, 11.2 Ibs.; gold, .135 oz. 
 
 The section of nearly 14,000 feet of folded Paleozoic 
 sediments includes chiefly limestones, which after uplift 
 and erosion were covered by Tertiary lavas and tuffs. 
 The ores occur in zones in the limestones, as fissures in 
 the igneous rocks, and along the contact. The minerals 
 in the ore bodies are quartz, barite, pyrite, galena, sphal- 
 erite, enargite, silver and gold minerals and their oxida- 
 tion products. 
 
 The Tintic is one of the oldest camps in the state, the ore 
 having been discovered in 1869, and it was at first shipped 
 as far as Baltimore and Wales. Since then mills have been 
 erected at the mines. The chief towns are Eureka, Mam- 
 moth, Robinson, Silver City, and Diamond. 
 
 The same type of ore occurs in Big and Little Cottonwood 
 canons and Bingham Canon, the latter having been worked 
 longer than those of the Tintic district. The camps lie 
 southeast and southwest of Salt Lake City, and the ores 
 are oxidized lead-silver ores, parallel to the bedding of 
 Carboniferous limestones and the underlying quartzite. 
 Galena and pyrite occur in the lower workings below 
 water level. 
 
 Oceur d'Alene, Idaho (14), lying in the northern part of 
 the state, is one of the most prominent producers in the
 
 SILVER-LEAD ORES 
 
 373 
 
 United States, having, in the fifteen years preceding 1902, 
 produced about $60,000,000 worth of lead and silver. 
 
 The formations of the region consist of slates, sandstones, 
 and quartzites, which have been bent into east and west folds, 
 the accompanying metamor- 
 phism having been sufficient 
 to produce new minerals. 
 Igneous intrusions are, how- 
 ever, rare. The ore bodies, 
 which are typical veins, con- 
 taining argentiferous galena, 
 associated with much siderite, 
 occupy fault planes, and are 
 oxidized above. The chief 
 minerals are quartz, siderite, 
 galena, and sphalerite. The 
 workable deposits carry from 5 to 25 per cent lead, the 
 average of the district being 10 per cent and 7 ounces 
 per ton silver. 
 
 Montana and Nevada, etc. Montana contains several 
 lead-silver ore localities. Those of Neihart (17) occur as 
 veins in gneiss and igneous rocks, the ores being galena, 
 silver sulphides, and some blende. The veins are best de-. 
 fined in the gneiss, and are mostly replacement deposits, 
 which have been subsequently fractured and secondarily 
 enriched. Lead-silver ores also occur at Glendale and in 
 Jefferson County. Some are also known in South Dakota 
 and New Mexico (3). 
 
 The Eureka district (10) of eastern Nevada, discovered in 
 1868, is chiefly of historic importance. The ores are oxidized 
 lead-silver ores, carrying some gold. They occur in Cambrian 
 
 FIG. 88. Section of lead-silver vein, 
 Coeur d'Alene, Ido. (1) Country 
 rock. (2) Sheared rock. (3) Galena 
 and siderite. (4) Fissure with fine- 
 grained galena. (5) Barren , silicified 
 country rock. After Finlay, Amer. 
 Inst. Min. Engrs., Trans. XXXIII : 
 249.
 
 374 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 limestone which is much faulted and crushed, and is part of 
 a Paleozoic section 30,000 feet thick. 
 
 The ore is associated with a great fault, and is oxidized to 
 a depth of 1000 feet. There are two mining districts, Pros- 
 pect Hill and Ruby Hill. Near the mines are great por- 
 phyry masses which are supposed to have afforded the ores. 
 Up to 1882 the output was not far from 160,000,000 of pre- 
 cious metals and 225,000 tons of lead. 
 
 REFERENCES ON LEAD-SILVER ORES 
 
 1. Blow, Amer. Inst. Min. Engrs., Trans. XVIII : 145, 1889. 2. Boutwell, 
 U. S. Geol. Surv., Bull. 213 : 31, 1903 ; 225 : 141, 1904 ; 260 : 150, 1905. 
 (Park City, Utah.) 3. Clark, Amer. Inst. Min. Engrs., Trans. XXIV : 
 138. (Lake Valley, New Mex.) 4. Cross and Spencer, U. S. Geol. 
 Surv., 21st Ann. Kept., II: 15, 1900. (Rico Mts., Colo.) 5. Curtis, 
 U. S. Geol. Surv., Mon. VII, 1884. (Eureka, Nev.) 6. Eldridge, 
 U. S. Geol. Surv., 16th Ann. Kept., II : 217, 1895. 7. Emmons, U. S. 
 Geol. Surv., Mon. XII, 1886. (Leadville, Colo. A new report is in 
 preparation.) 8. Emmons, U. S. Geol. Surv., Ten Mile Atlas Folio. 
 (Ten Mile district, Colo.) 9. Parish, Colo. Sci. Soc., Proc. IV : 151. 
 (Rico.) 10. Hague, U. S. Geol. Surv., Mon. XX, 1892. (Eureka, 
 Nev.) 10 a. Kedzie, Amer. Inst. Min. Engrs., Trans. XVI: 570, 1888. 
 (Red Mt.) 11. Olcott, Eng. and Min. Jour. XLIII : 418, 436, 1887, 
 and LIII : 545, 1892. (Eagle Co., Colo.) 12. Rickard, Amer. Inst. 
 Min. Engrs., Trans. XXVI : 906, 1896. (Enterprise mine, Rico, Colo.) 
 
 13. Ransome, U. S. Geol. Surv., 22d Ann. Rept., II: 229, 1901. 
 
 14. Ransome, U. S. Geol. Surv., Bull. 260: 274, 1905. (Coaur 
 d'Alene.) 15. Spurr, U. S. Geol. Surv., Mon. XXXI, 1898. (Aspen, 
 Colo.) 16. Tower and Smith, U. S. Geol. Surv., 19th Ann. Rept., 
 Ill : 601, 1899. (Tintic district, Utah.) 17. Weed, U. S. Geol. Surv., 
 20th Ann. Rept., Ill : 271, 1900.
 
 CHAPTER XIX 
 ALUMINUM 
 
 Ores. This is one of the few metals whose ores do not 
 present a metallic appearance. Many different minerals con- 
 tain aluminum, but it can be profitably extracted from only 
 a few. Common clay, for example, presents an inexhaustible 
 supply, but the chemical combination of the aluminum in it 
 is such that its extraction up to the present time has not been 
 found practicable. 
 
 The ores of aluminum, together with the percentage of 
 the metal which they contain, are : corundum, A1 2 O 3 
 (53.3 per cent); cryolite, A1F 3 , 3 NaF (12.8 per cent); 
 bauxite, A1 2 O 3 , 2 H 2 O (39.13 per cent); gillsite, A1 2 O 3 , 
 3 H 2 O (34.6 per cent). Of these, corundum is too valuable 
 as an abrasive, and is not found in sufficient quantity to 
 permit its use as an ore of aluminum. Until the discovery 
 of bauxite, cryolite was the chief source of the metal, all of 
 it being obtained from Greenland (8). 
 
 Bauxite derives its name from Baux in southern France, 
 where it was first discovered, but in recent years large de- 
 posits have been found in the United States. It is usually 
 pisolitic in structure, and may sometimes resemble clay in 
 appearance. The common impurities are silica, iron oxide, 
 and titanic acid ; and the variation in the amount of these 
 ingredients can be seen from the following analyses of both 
 domestic and foreign occurrences : 
 376
 
 376 ECONOMIC GEOLOGY OP THE UNITED STATES 
 ANALYSES OF BAUXITE 
 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 Alumina (A1 2 8 ) . . . 
 Ferric oxide (Fe 2 O 8 ) . . 
 Silica (SiOa) 
 Lime carbonate (CaCO 8 ) . . 
 Titanic acid (TiOa) . . . 
 Water (H 2 O) 
 
 57.60 
 25.30 
 2.80 
 .40 
 3.10 
 10.80 
 
 61.89 
 1.96 
 6.01 
 
 27.82 
 
 63.16 
 23.55 
 4.15 
 
 8.34 
 
 59.22 
 3.16 
 3.30 
 
 3.62 
 28.80 
 1 90 
 
 61.00 
 2.20 
 2.10 
 
 31.58 
 3 12 
 
 62.05 
 1.66 
 2.00 
 
 30.31 
 350 
 
 Alkalies (Na 2 O, K 2 O) . . . 
 
 
 
 .79 
 
 
 
 
 1. Baux, France. 2. Glenravel, Ireland. 3. Wochein, Germany. 
 4. Georgia. 5. Rock Run, Alabama. 6. Arkansas. 
 
 Distribution of Bauxite in the United States. Bauxite in 
 commercial quantity is known to occur in but three districts 
 in the United States. These are the Georgia- Alabama dis- 
 trict, the Arkansas district, and a small area in southwestern 
 New Mexico. The New Mexico deposits are of little com- 
 mercial importance on account of their inaccessibility. 
 
 G-eorgia- Alabama (4, 6, 7). The bauxite deposits of these 
 two states form a belt about 60 miles long extending from 
 Jacksonville, Alabama, to Cartersville, Georgia. The ore, 
 which is either pisolitic or claylike in its character, forms 
 pockets or lenses of variable diameter and depth, in the re- 
 sidual clay derived from the Knox dolomite. A pronounced 
 feature is their occurrence close to 900 feet above sea level, 
 few being found above 950 feet or below 850 (4). 
 
 The bauxite is believed by Hayes (4) to be a hot spring 
 deposit. It is underlain by the Knox dolomite and this in 
 turn by the Connasauga shales which are several thousand 
 feet in thickness, and contain from 15 to 20 per cent of alu- 
 mina, and also pyrite. The region is one of marked faulting.
 
 PLATE XXV 
 
 FIG. 1. View of Bauxite bauk, Rock Run, Ala. H. Hies, photo. 
 
 FIG. 2. Furnace for roasting mercury ore, Terlingua, Tex. W. H. Turner, photo.
 
 ALUMINUM 
 
 377 
 
 Alteration of the pyrite by percolating meteoric waters has 
 yielded sulphuric acid, which attacked the alumina of the 
 shale, with the formation of alum and also ferrous sulphate. 
 Both of these have been carried toward the surface by spring 
 waters, but since they had to pass through the higher lying 
 
 FIG. 89. Geologic map of Alabama-Georgia bauxite region. After Hayes, 
 U. S. Geol. Surv., 16th Ann. Kept., Ill: 552. 
 
 limestones, the lime carbonate acted on the dissolved alum 
 according to the following equation : J 
 
 A1 2 (SO 4 ) 3 + 3 CaCO 3 = A1 2 O 3 + 3 CaSO 4 + 3 CO 2 . 
 The alumina thus formed was a light, gelatinous precipi- 
 tate, which was carried upward into spring basins on the 
 surface, where it finally settled. The pisolitic structure is 
 thought to have been caused by the balling together of the 
 gelatinous mass by currents. 
 
 1 For clearness, the water combined with the alumina is left out.
 
 378 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The Georgia- Alabama deposits, which represent a unique 
 type of occurrence, were discovered in 1887, and have been 
 worked steadily since that time. There have been some mis- 
 givings regarding the exhaustibility of the domestic supply, 
 but the discovery and development of the next described 
 district have allayed these fears. 
 
 Arkansas (2, 3). The occurrence of bauxite in Arkansas 
 has been known since 1891, but owing to a more accessible 
 eastern supply, there was little development in that region 
 until 1900. The deposits, which are much more extensive 
 than the Georgia- Alabama ones, are confined to a small area 
 
 FIG. 90. Section of Bauxite deposit, (a) Residual mantle ; (6) Red sandy clay 
 soil; (c) Pisolitic ore; (d) Bauxite with clay; (e) Clay with bauxite; 
 (/) Talus; (g) Mottled clay; (h) Drainage ditch. After Hayes. 
 
 in Pulaski and Saline counties, north and southwest of Little 
 Rock. They have an average thickness of 10 to 15 feet and 
 show two distinct types. In the southwesterly or Bryant 
 district the lower beds show a granitic structure and rest 
 directly on a mass of kaolin derived from the elseolite- 
 syenite, and it is probable that the bauxite has also been 
 derived directly from this rock. The upper beds are piso- 
 litic and similar in character to the Georgia- Alabama ones. 
 In the Fourche Mountain area only the pisolitic form is 
 found. The granitic type is the purest and corresponds in 
 composition to the formula of gibbsite rather than bauxite, 
 while the white bauxitic kaolins run high in silica.
 
 ALUMINUM 379 
 
 The origin of the Arkansas bauxites is somewhat obscure, 
 but Hayes (3) considers that subsequent to the intrusion of 
 the syenite into the palaeozoics of that region, the former 
 was exposed by erosion of the latter. This was followed by 
 a submergence of the surface below a body of salt or highly 
 alkaline waters, which in some way penetrated the still 
 partially hot syenite, and dissolved its minerals. On re- 
 turning to the surface they attacked the syenite there, 
 removing silica and alkalies and depositing alumina in its 
 place. Much of the alumina was also deposited from these 
 waters as a gelatinous precipitate on the ocean bottom, over 
 the syenite surface. Some was also deposited with the 
 Tertiary sediments then forming. 
 
 New Mexico (1). The bauxite deposits which occur near 
 Silver City appear to have been derived from a basic volcanic 
 rock, by decomposition and alteration in place. 
 
 Uses of Aluminum. The chief use of this metal is for 
 making wire for the transmission of electric currents, but a 
 large quantity of it is also used in the manufacture of articles 
 for domestic or culinary use, instruments, boats, and other 
 articles where lightness is wanted. It is also employed in 
 the manufacture of special alloys, among which may be men- 
 tioned magnalium, an alloy of aluminum and magnesium; 
 and wolframinium, a tungsten-aluminum alloy. One alloy 
 of this type known as partinmm is said to have a ten- 
 sile strength of over 49,000 pounds per square inch; Mc- 
 Adamite, an alloy of aluminum, zinc, and copper, is said 
 to possess a tensile strength exceeding 44,000 pounds per 
 square inch ; aluminum silver is an alloy of copper, nickel, 
 zinc, and aluminum; aluminum zinc includes a series of
 
 380 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 alloys containing various proportions of these two metals. 
 Of growing importance is the use of aluminum for litho- 
 graphic work as a substitute for stone or zinc. Another 
 extending application is that of powdered aluminum for 
 the production of intense heat by combustion, and in this 
 connection it is used for welding tramway rails, or for the 
 reduction of rare metals from their oxides. Aluminum has 
 also been tried for the manufacture of grindstones and whet- 
 stones, for which purpose it is said to be peculiarly suited 
 owing to the property it has for forming under whetting 
 action a very fine mass which adheres strongly to steel. A 
 small amount of aluminum added to steel prevents air holes 
 and cracks in casting. 
 
 Uses of Bauxite. Aside from being used for the manu- 
 facture of aluminum and alum, bauxite is of some value 
 for the manufacture of refractory products, its heat-resisting 
 qualities being very great. 
 
 Production of Bauxite. The production of bauxite in the 
 United States has been as follows : 
 
 PRODUCTION OF BAUXITE IN THE UNITED STATES FROM 1889 TO 1903 
 
 YBAB 
 
 GEORGIA 
 LONG TONS 
 
 ALABAMA 
 LUNG TONS 
 
 ARKANSAS 
 LONG TONS 
 
 TOTAL 
 
 VALUE 
 
 1889. . . . 
 1890. . . . 
 1895. . . . 
 1899. . . . 
 
 1900. . . . 
 1902. . . . 
 1903. . . . 
 
 728 
 1844 
 3756 
 15,736 
 
 13,313 
 14,499 
 
 5045 
 
 3445 
 4645 
 25,713 
 
 728 
 1844 
 17,069 
 35,280 
 
 23,184 
 27,322 
 48,087 
 
 $2366 
 6012 
 44,000 
 125,598 
 
 89,676 
 120,366 
 171,306 
 
 19,739 
 22,677 
 22,374
 
 ALUMINUM 
 
 381 
 
 The following table shows the annual consumption of 
 bauxite and its value in the United States : 
 
 PRODUCTION, IMPORTS, EXPORTS, AND CONSUMPTION OF BAUXITE IN 
 THE UNITED STATES 
 
 
 
 
 
 
 
 PRODUCTION 
 
 IMPORTS 
 
 EXPORTS 
 
 CONSUMPTION 
 
 YEAR 
 
 Quan- 
 
 
 Quan- 
 
 
 Quan- 
 
 
 Quan- 
 
 
 
 tity 
 Long 
 
 Value 
 
 tity 
 Long 
 
 Value 
 
 tity 
 Long 
 
 Value 
 
 tity 
 Long 
 
 Value 
 
 
 Tons 
 
 
 Tons 
 
 
 Tons 
 
 
 Tons 
 
 
 1901 
 
 18,905 
 
 $79,914 
 
 18,313 
 
 167,107 
 
 1,000 
 
 $3,000 
 
 36,218 
 
 $144,021 
 
 1902 
 
 27,322 
 
 120,366 
 
 15,790 
 
 54,410 
 
 nil 
 
 
 
 43,112 
 
 175,875 
 
 1903 
 
 48,087 
 
 171,306 
 
 14,684 
 
 49,684 
 
 nil 
 
 
 
 62,976 
 
 220,990 
 
 WORLD'S PRODUCTION OF BAUXITE 
 
 COUNTRY 
 
 1900 
 
 1901 
 
 1902 
 
 QUANTITY 
 METRIC 
 TONS 
 
 VALUE 
 
 QUANTITY 
 METRIC 
 TONS 
 
 VALUB 
 
 QUANTITY 
 METRIC 
 TONS 
 
 VALUE 
 
 United 
 States . 
 France . . 
 United 
 Kingdom 
 
 Total . 
 
 23,556 
 58,530 
 
 5,873 
 
 $89,676 
 92,596 
 
 6,750 
 
 19,207 
 76,620 
 
 10,357 
 
 $79,914 
 124,168 
 
 14,515 
 
 29,785 
 96,900 
 
 9,192 
 
 $128,206 
 174,685 
 
 13,395 
 
 87,959 
 
 $189,022 
 
 106,184 
 
 $218,597 
 
 135,877 
 
 $316,286 
 
 Prior to 1890 nearly all the bauxite consumed in the 
 United States was imported from France. The French 
 ore has a high iron oxide content, and very little is now 
 imported, except during periods of low ocean freights. 
 Most of it is purchased by Germany.
 
 382 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Most of the bauxite used in the United States is for 
 the manufacture of aluminum, but from one fourth to one 
 half of the total is employed in the manufacture of chemi- 
 cal salts of aluminum, and artificial corundum, known as 
 alundum. The Georgia-Alabama bauxites, on account of 
 their freedom from iron, are of special value for the manu- 
 facture of alum. In Europe much is used as a refractory 
 material for lining furnaces. 
 
 The production of aluminum in the United States since 
 1883 has been as follows : 
 
 PRODUCTION OF ALUMINUM IN THE UNITED STATES 
 
 YEAR 
 
 QUANTITY 
 POUNDS 
 
 YEAR 
 
 QUANTITY 
 POUNDS 
 
 1883 .... 
 
 83 
 
 1900 
 
 7 150 000 
 
 1885 
 
 283 
 
 1901 
 
 7 150 000 
 
 1890 .... 
 
 61281 
 
 1902 
 
 7 300 000 
 
 1895 
 
 920 000 
 
 1903 
 
 7 500 000 
 
 
 
 
 
 The domestic output comes from four large plants. 
 WORLD'S PRODUCTION OF ALUMINUM 
 
 
 IS 
 
 01 
 
 1] 
 
 )02 
 
 COUUTBY 
 
 QUANTITY 
 METRIC 
 TONS 
 
 VALUE 
 
 QUANTITY 
 METRIC 
 TONS 
 
 VALUE 
 
 United States . . . 
 
 3,244 
 1 200 
 
 $2,238,000 
 560 000 
 
 3,311 
 1 355 
 
 $2,284,900 
 638 830 
 
 United Kingdom . . 
 Switzerland .... 
 
 560 
 2,500 
 
 1,225,000 
 
 600 
 2,500 
 
 1,201,425 
 
 Total .... 
 
 7,504 
 
 
 7,766 
 
 
 
 
 

 
 MANGANESE 383 
 
 REFERENCES ON ALUMINUM AND BAUXITE 
 
 Blake, Arner. Inst, Min. Engrs., Trans. XXIV : 571, 1895. (N. Mex.) 
 2. Branner, Jour. Geol., V : 263, 1897. (Ark.) 3. Hayes, U. S. 
 Geol. Surv., 21st Ann. Kept., Ill : 435, 1901. (Ark.) 4. Hayes, 
 U. S. Geol. Surv., 16th Ann. Kept., Ill: 547, 1895. (Ga.-Ala.) 
 ,5. Laur, Amer. Inst. Min. Engrs., Trans. XXIV : 234, 1895. (The 
 bauxites.) 6. Watson, Amer. Geol., XXVIII: 25, 1901. (Ga.) 
 7. Watson, Ga. Geol. Surv., Bull. 11, 1904. (Ga.) 8. For cryolite, 
 see Min. Indus., VI : 251, 1897. 
 
 MANGANESE 
 
 Ores. While many different minerals contain this metal, 
 practically the only ones of commercial value are the oxides 
 and carbonates, and in this country only the former. The 
 silicates are not used as a source of manganese, owing to their 
 high silica percentage. 
 
 The important ores of manganese are the following : pyro- 
 lusite, the black oxide (MnO 2 ; 63.2 per cent Mn) ; psilome- 
 lane (chiefly MnO 2 , H 2 O ; K and Ba variable), one of the 
 most abundant manganese ores ; braunite (Mn 2 O 3 ; 69.68 per 
 cent Mn) ; and wad, a low-grade, earthy brown or black ore, 
 with the percentage of manganese varying from 15 to 40 per 
 cent. Wad is often of too low grade, due to impurities, 
 to be used as an ore of manganese ; but it is sometimes em- 
 ployed for paint. Rhodochrosite (MnCO 3 ), though found as 
 a common gangue mineral in some western mines, does not 
 serve as a source of manganese. 
 
 The several ores of manganese are often intimately as- 
 sociated, the pyrolusite generally assuming a crystalline and 
 the psilomelane a massive character. Manganese oxides are 
 also often intermixed with more or less oxide of iron, and 
 considerable amounts of the metal are obtained from man-
 
 384 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 ganiferous zinc, silver, or iron ores. Since much manga- 
 nese is used in iron reduction, the last association is of 
 importance. 
 
 To be of commercial value a manganese ore should have 
 at least 40 per cent metallic manganese, and should be low 
 in phosphorus and silica. High-grade ores run from 50 to 
 60 per cent manganese. 
 
 The price of manganese ores in 1903 was $8.97 per long 
 ton; of manganiferous iron ore, $2.69 (18-32 per cent Mn) 
 and $2.40 (1-10 per cent Mn) ; of manganiferous silver ores, 
 $3.63. 
 
 Origin. Manganese oxide deposits are usually of second- 
 ary origin, having been formed by weathering processes, 
 which caused the decay of the parent rock containing man- 
 ganiferous silicates, and the change of these latter to oxides. 
 By circulating ground water they have often been concen- 
 trated in residual clays. Although iron also may have been 
 present in the parent rock, and the two are sometimes de- 
 posited together, still they have in many instances been 
 separated from each other, due to the fact that conditions 
 favorable for precipitation are not the same for both (4), 
 or because the soluble compounds of manganese formed by 
 weathering are sometimes more stable than corresponding 
 iron compounds, and hence may be carried farther by cir- 
 culating waters before they are deposited. 
 
 Distribution of Manganese Ores in the United States. 
 
 Although manganese ores are widely distributed in the 
 United States, only a few localities are of commercial im- 
 portance. This is partly owing to the uncertainty of the 
 extent of the ore deposits and partly to the high percentage
 
 MANGANESE 
 
 385 
 
 of phosphorus which many of the ores contain, together with 
 their remoteness from lines of transportation. 
 
 Eastern Area. Manganese deposits are found in the At- 
 lantic States from Vermont to Alabama, and two states in 
 this belt, Georgia 
 and Virginia, lead 
 in the domestic 
 production. The 
 common mode of 
 occurrence in this 
 district is as nod- 
 ules or lumps in 
 residual clay, simi- 
 lar to the limonites 
 of the same area. 
 In Virginia, at 
 Crimora, Augusta 
 County (2), the ore 
 
 forms pockets 5 to 6 feet thick and 20 to 30 feet long in a 
 bed of clay 276 feet thick. 
 
 In northern Georgia (1, 3, 7) the ore results from the 
 decay of limestone and shales, Cave Spring and Carters- 
 ville being important localities. The deposits are found 
 in the areas underlain by both the crystalline and Paleozoic 
 rocks, but only those associated with the latter have proven 
 to be of commercial importance. In this region the rocks 
 consist of Cambro-Silurian limestones and quartzites, which 
 have been much folded and faulted, and have then weath- 
 ered down to a residual clay, which is often not less than 
 100 feet thick. The ore occurs as pockets, lenticular masses, 
 stringers, grains, or lumps, irregularly scattered through the 
 
 2c 
 
 FIG. 91. Map showing Georgia manganese areas. 
 After Watson, Amer. Inst. Min. Engrs., Trans. 
 XXXIV: 209.
 
 386 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 clay and rarely forming distinct beds. None of the de- 
 posits are large, though some 30 feet in length have been 
 worked. More or less limonite, barite, ocher, and bauxite 
 may be associated with the ore, and, indeed, complete gra- 
 dations from manganese to iron ore are found, as shown 
 by the following analyses : 
 
 Mn 
 
 60.61 
 
 54.94 
 
 41.98 
 
 15.26 
 
 2.30 
 
 Fe 
 
 1.45 
 
 3.62 
 
 16.22 
 
 39.25 
 
 52 02 
 
 p 
 
 052 
 
 .034 
 
 007 
 
 193 
 
 04 
 
 
 
 
 
 
 
 The better-grade ores are usually low in silica, iron, and 
 phosphorus. In the Cartersville district, which is the more 
 
 FIG. 92. Section in Georgia manganese area, showing geologic relations of 
 manganese, limonite, and ocher. After Watson, Amer. Inst. Min. Engrs., 
 Trans. XXXIV: 219. 
 
 important, the ore is found in residual clays derived from 
 the Beaver limestone and Weisner quartzite, while in the 
 Cave Spring area it occurs only in the clays overlying the 
 Knox dolomite. 
 
 Penrose (5) thought that the manganese was derived from 
 the underlying Cambro-Silurian sediments, while Watson 
 on the contrary believes that the crystalline rocks to the 
 east and south have furnished the ore, as none is found in 
 the parent rock from which the clays were derived. The 
 manganese was probably taken into solution as a sulphate 
 and concentrated by circulating waters of meteoric origin 
 in the residual clays where now found.
 
 MANGANESE 
 
 387 
 
 The Georgia (7) deposits have been worked for a num- 
 ber of years, and the manganese was formerly marketed 
 chiefly in England ; but the output is now sold entirely in 
 the United States. The ore, which has to be purified by 
 washing and crushing, is used in part for paint and in 
 part for steel manufacture. 
 
 Arkansas. Manganese ore is found in the region around 
 Batesville (5, 6), associated with horizontally stratified lime- 
 stones and shales, ranging from Ordovician to Carbonifer- 
 ous age (Fig. 93). The Cason shale, of Silurian age, 
 occurring near the middle of the section (Fig. 93 ), carries 
 
 FIG. 93. Section in Batesville, Ark., manganese region, illustrating geological 
 structure and relation of different formations to marketable and non-market- 
 able ore. After Van Ingen, Sch. of M. Quart., XXII: 324. 
 
 manganese nodules high in phosphorus, which are not 
 marketable, and others are found in the pits of residual 
 clay derived from it. Farther down the slopes marketable 
 ore (Fig. 93 c), which has been derived by leaching of the 
 first-mentioned ore, is found occurring in residual pockets 
 in the lower lying limestones, while the residual clays 
 (Fig. 93 a), formed at a higher level than the Cason shale, 
 are barren of manganese. 
 
 Other United States Occurrences. California has a num- 
 ber of manganese deposits, of which some are reported to 
 be of high quality (8) ; they have been used largely in
 
 388 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 chlorination works for the reduction of gold ores. Man- 
 ganese occurs in Triassic sandstones near Thompson, Utah, 
 and the locality became a producer in 1901 (8). Much 
 manganiferous iron ore and manganiferous silver ore is 
 annually obtained from the Leadville district of Colorado, 
 the former being used by steel works in making spiegel- 
 eisen and the latter as a flux in smelters. Lake Superior 
 iron ores at times carry manganese, but it usually does 
 not exceed 1 per cent. 
 
 Uses of Manganese. One of the principal uses of man- 
 ganese is in the manufacture of alloys. Of these, spiegel- 
 eisen, an alloy of iron and manganese with under 20 per 
 cent manganese, and ferromanganese, a similar alloy with 
 over 20 per cent manganese, are important. Other alloys 
 are manganese bronze, manganese and copper with or 
 without iron; silver bronze, an alloy of manganese, alu- 
 minum, zinc, copper, and silver; and manganese-titanium 
 alloys. 
 
 Manganese is also used as an oxidizing agent in the 
 manufacture of chlorine, bromine, and disinfectants ; as a 
 coloring agent in calico printing and dyeing, in the making 
 of glass, pottery, brick, as well as in paints. It is also 
 employed as a decolorizer in green glass. 
 
 Production of Manganese. Although much used in mak- 
 ing glass and steel, of which latter material the United 
 States is the largest manufacturer in the world, neverthe- 
 less the domestic production is small. This consequently 
 necessitates the importation of large quantities, which are 
 obtained chiefly from Brazil.
 
 MANGANESE 
 
 PRODUCTION AND VALUE OF MANGANESE ORES IN THE UNITED 
 STATES (IN LONG TONS) 
 
 YEAR 
 
 PRODUCTION 
 
 VALUE 
 
 1880 
 
 5761 
 
 f 86 415 
 
 1885 
 
 23,258 
 
 190,281 
 
 1890 
 
 25684 
 
 219 050 
 
 1895 
 
 9,547 
 
 71,769 
 
 1900 
 
 11 771 
 
 100 289 
 
 1901 
 
 11,995 
 
 116,722 
 
 1902 
 
 7477 
 
 60911 
 
 1903 
 
 2,825 
 
 25,335 
 
 
 
 
 PRODUCTION AND VALUE OF MANGANESE ORES IN THE UNITED 
 STATES BY STATES (IN LONG TONS) 
 
 STATE 
 
 1901 
 
 1902 
 
 1903 
 
 PRODUC- 
 TION 
 
 VALUE 
 
 PRODUC- 
 TION 
 
 VALUE 
 
 PRODUC- 
 TION 
 
 VALUE 
 
 Arkansas . . . 
 Georgia .... 
 Utah 
 Virginia .... 
 All others . . . 
 Total . . . 
 
 91 
 4,074 
 2,500 
 4,275 
 1,055 
 
 $657 
 24,674 
 31,250 
 52,853 
 7,288 
 
 82 
 3,500 
 
 3,041 
 
 824 
 
 $422 
 20,830 
 
 29,444 
 10,215 
 
 500 
 483 
 1,801 
 41 
 
 $2,930 
 2,415 
 19,611 
 379 
 
 11,995 
 
 $116,722 
 
 7,477 
 
 $60,911 
 
 2,825 
 
 $25,335 
 
 PRODUCTION AND VALUE OF DIFFERENT KINDS OF MANGANESE ORES 
 IN THE UNITED STATES (IN LONG TONS) 
 
 
 1901 
 
 1902 
 
 1903 
 
 KIND OF ORE 
 
 PRODUC- 
 TION 
 
 VALUE 
 
 PRODUC- 
 TION 
 
 VALUE 
 
 PRODUC- 
 TION 
 
 VALUE 
 
 Manganese ores . 
 
 11,995 
 
 $116,722 
 
 7,477 
 
 $60,911 
 
 2,825 
 
 $25,335 
 
 Manganiferous 
 
 
 
 
 
 
 
 iron ores . . . 
 
 574,489 
 
 1,475,084 
 
 901,214 
 
 2,001,626 
 
 584,493 
 
 1,571,750 
 
 Manganiferous 
 
 
 
 
 
 
 
 silver ores . . 
 
 228,187 
 
 865,959 
 
 194,132 
 
 908,098 
 
 179,205 
 
 649,727 
 
 Manganiferous 
 
 
 
 
 
 
 
 zinc residuum l 
 
 52,311 
 
 52,311 
 
 65,246 
 
 65,246 
 
 73,264 
 
 73,264 
 
 Total . . . 
 
 866,982 
 
 $2,510,076 
 
 1,168,069 
 
 $3,035,881 
 
 839,787 
 
 $2,320,076 
 
 1 As this is a by-product in the treatment of zinc ores, the value given 
 to it is nominal.
 
 390 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The imports of manganese ore in 1903 amounted to 
 146,056 long tons, valued at $1,278,108, and came chiefly 
 from Brazil, but the British East Indies, Cuba, Germany, 
 and Russia also supplied some. 
 
 REFERENCES ON MANGANESE 
 
 1. Brewer, Ala. Ind. and Sci. Soc. Proc., VI : 72. (Ga.) 2. Hall, Amer. 
 Inst. Min. Engrs., Trans. XX : 46, 1892. (Crimora, Va.) 3. Hayes, 
 Amer. Inst. Min. Engrs., Trans. XXX : 403, 1901. (Ga.) 4. Pen- 
 rose, Jour. Geol., 1 : 275, 1893. (Chemical relations of iron and 
 manganese in sedimentary rocks.) 5. Penrose, Ark. Geol. Surv., 
 Kept, for 1890, Vol. I, 1891. (Uses, ores, and deposits.) 6. Van 
 Ingen, Sch. of M. Quart., XXII : 318, 1901. (Batesville, Ark.) 
 7. Watson, Amer. Inst. Min. Engrs., Trans. XXXIV: 207, 1904. 
 (Ga.) 8. Birkenbine, Mineral Census, 1902, Mines and Quarries. 
 
 MERCURY 
 
 Ores. While mercury is sometimes found native in the 
 form of quicksilver, the most common ore is cinnabar (HgS), 
 which contains 86.2 per cent mercury. Native amalgam 
 of mercury and silver is known, and calomel, the chloride, 
 as well as other compounds, are sometimes found. 
 
 Mode of Occurrence. Mercury ores are not confined to 
 any particular formation, but are found in rocks ranging 
 from the Ordovician to Recent Age in different parts of 
 the world. Nor are they peculiar to any special type of 
 rock, although igneous rocks are often found in the vicinity 
 of them. They occur as veins, disseminations, or as masses 
 of irregular form. Silica, either crystalline or opaline, and 
 calcite are common gangue minerals, while pyrite or mar- 
 casite are rarely wanting, and bitumen is widespread. 
 
 Distribution in the United States. California has always 
 been the most important, and, in fact, at times, the only
 
 MERCURY 
 
 391 
 
 producing state. Deposits are, however, also known in 
 Texas, Oregon, Utah, Nevada, and New Mexico. 
 
 California (1,2,7). The California ores occur chiefly 
 in metamorphosed Cretaceous or Jurassic rocks, with some 
 in the Miocene and even 
 Quaternary. The depos- 
 its, which are termed 
 " chambered veins " by 
 Becker, are fissured zones. 
 Eruptive rocks seem in 
 many cases to be involved 
 in the ore formation, and 
 at New Almaden a rhyo- 
 lite dike runs parallel with 
 the ore body. The ore 
 here occurs along the con- 
 tact between serpentine 
 and shale, filling in part 
 the interstices of a brec- 
 cia. These mines, which are the largest in the state, have 
 been worked to a depth of over 2500 feet. 
 
 Other occurrences are in Colusa County, where the cin- 
 nabar is found in altered serpentine, and in Napa County, 
 where it occurs along the contact of sandstone and slate. 
 The minerals associated with these are bitumen, free sul- 
 phur, stibnite, mispickel, gold and silver, chalcopyrite, py- 
 rite, millerite, quartz, calcite, barite, and borax. At New 
 Idria the ore is the same, but the wall rock is metamor- 
 phic sandstones and shales. A third important mine is 
 the Sulphur Bank, which is of very recent date. The 
 vein is a fissure filled with brecciated fragments, and cuts 
 
 FIG. 94. Map of California mercury local- 
 ities.
 
 392 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 through sandstone, shale, and augite andesite, the cinnabar 
 cementing the breccia together, but at times also impreg- 
 nating the walls. Hot waters which circulate through the 
 vein still deposit gelatinous silica. 
 
 At Steamboat Springs the waters carry gold, sulphide 
 of arsenic, antimony, and mercury, sulphides or sulphates 
 of silver, lead, copper, zinc, iron oxide, and possibly other 
 metals. They also contain sodium carbonate, sodium chlo- 
 ride, sulphur, and borax. 
 
 Cinnabar is known in Lane and Douglas counties, Oregon. 
 
 Texas (3, 4, 5). The Terlingua district of Brewster 
 
 County, Texas, has caused much interest in recent years. 
 
 The ore bodies thus far known lie in a belt 15 miles east 
 
 and west by 4 miles 
 wide, with Fresno 
 Canon on the west- 
 ern boundary, but 
 the remoteness from 
 the railroad (90 
 miles) and the lack 
 of water form seri- 
 ous obstacles to the 
 rapid development 
 of this district. The 
 rocks are Cretaceous 
 limestone, which 
 have been broken by 
 several large northwest-southeast faults, with minor parallel 
 ones between. Overlying these are younger sediments and 
 volcanics. Only one of the ore bodies is close to an intru- 
 sive contact. 
 
 FIG. 95. Map showing Texas mercury region. 
 After Hill, Eng. and Min. Jour., LXXIV: 305.
 
 MEBCURY 393 
 
 Cinnabar is the commonest ore, but other mercury min- 
 erals are present, including quicksilver, which is usually 
 intimately associated with calcite. Hematite and limonite 
 are very common accessories, 
 but pyrite is rare. The ore is 
 most frequently found in fis- 
 sure veins with calcite gangue, 
 these fissures forming two 
 series at right angles to each 
 
 Other, of which the northeast- FIG. 96. Section of cinnabar vein in 
 
 limestone, Terlingua, Tex. After 
 
 SOUthwest ones are productive. Phillips, Univ. Tex. Min. Surv., 
 
 Still 4 * 32 
 
 The ore also occurs in brec- 
 
 ciated strips, or as lateral extension veins. The workings 
 are all shallow. Recently an extension of this area has been 
 found in the Chisos Mountains near Terlingua. 
 
 Origin. The origin of mercury ores has been studied 
 chiefly by Becker (1) and later by Schrauf (6). The for- 
 mer points out that silica (either crystalline or amorphous) 
 and calcite are common gangue minerals, but pyrite or 
 marcasite are almost equally abundant, as is also bitumen. 
 In addition to these, the ores show an irregular association 
 with other metallic minerals, such as antimony, silver, lead, 
 copper, arsenic, zinc, or even gold. Becker believes that 
 the cinnabar has been precipitated from ascending waters 
 by bituminous matter, having come up in solution as a 
 double sulphide with alkaline sulphides. He further sug- 
 gests that the deposits represent impregnations and are 
 not replacements. 
 
 Uses of Mercury. The most important use of quick- 
 silver is in the extraction of gold and silver by the process
 
 394 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 of amalgamation (see Gold and Silver). Its power of form- 
 ing amalgams with other metals makes it of value in the 
 arts for the preparation of a substance used for silver- 
 ing mirrors and for other purposes. Because it is liquid 
 at ordinary temperatures it can be employed in the manufac- 
 ture of thermometers ; and this fact, added to its weight, 
 renders it of special value in the construction of mercurial 
 barometers. In medicine mercury is used in various forms, 
 chiefly as calomel, while cinnabar and other compounds of 
 mercury are valuable in the manufacture of pigments. For 
 this purpose it was used by the American Indians and by 
 the other early races of people. 
 
 Extraction. The mercury is usually obtained from the 
 ore by the simple process of sublimation, the cinnabar 
 being heated in furnaces, and the fumes of sulphur and 
 metallic mercury allowed to pass off. The latter are 
 caught in condensing chambers, while the former escape 
 into the air. 
 
 Production of Mercury. California was for many years 
 practically the only domestic source of mercury, but in 
 1898 Texas became a producer, and will no doubt con- 
 tinue so. The output of mercury is quoted in flasks of 
 76 pounds net. That of California since 1850 has been 
 as follows : 
 
 PRODUCTION OF MERCURY IN CALIFORNIA FROM 1850 TO 1900 
 (Flasks of 76 pounds) 
 
 1850 7,723 
 
 1860 10,000 
 
 1870 30,077 
 
 1880 59,926 
 
 1890 22,926 
 
 1900 26,317
 
 MERCURY 
 
 395 
 
 PRODUCTION OF MERCURY IN CALIFORNIA AND TEXAS FROM 
 1901 TO 1903 
 
 
 1901 
 
 1902 
 
 1903 
 
 
 QUANTITY 
 FLASKS 
 
 VALUB 
 
 QUANTITY 
 FLASKS 
 
 VALUE 
 
 QUANTITY 
 
 FLASKS 
 
 VALU* 
 
 Texas . . 
 
 2,932 
 
 $132,438 
 
 5,319 
 
 $239,350 
 
 5,029 
 
 $211,218 
 
 California 
 
 26,720 
 
 1,285,014 
 
 28,974 
 
 1,228,498 
 
 30,526 
 
 1,330,916 
 
 The imports of mercury in 1903 were valued at $1065, 
 and the exports at $446,845. 
 
 The world's production for 1902 was as follows: 
 
 COUNTRY 
 
 QUANTITY 
 METRIC TONS 
 
 VALTTM 
 
 United States 
 
 1 190 
 
 $1 467 848 
 
 
 511 
 
 568,929 
 
 Italy 
 
 260 
 
 310,080 
 
 
 1425 
 
 1,941,387 
 
 
 
 
 REFERENCES ON MERCURY 
 
 1. Becker, Geology of Quicksilver Deposits of Pacific Slope, U. S. Geol. 
 Surv., Mon. XIII, 1888. 2. Becker, U. S. Geol. Surv., Min. Res., 
 1892: 139, 1893. (Origin.) 3. Blake, W. P., Amer. Inst. Min. 
 Engrs., Trans. XXV : 68, 1896. (Cinnabar in Texas.) 4. Hill, Eng. 
 and Min. Jour., LXXIV : 305, 1902. (Tex.) 5. Phillips, Univ. Tex. 
 Min. Surv., Bull. 4, 1902. (Terlingua district, Texas.) 6. Schrauf, 
 Zeitsch. prak. Geologic, II : 10, 1894. (Origin.) 7. Watts, W. L., 
 Cal. State Min. Bur., XI : 239, 1893. (Lake County, California.)
 
 CHAPTER XX 
 ANTIMONY 
 
 Ores. Stibnite (Sb 2 S 3 ) is the most important ore of 
 antimony, and the metal is rarely obtained from any other 
 mineral, although native antimony has been sparingly 
 found. The oxide senarmontite (Sb 2 O 3 ) seldom occurs in 
 any quantity. A small amount of antimony is present in 
 some silver-lead ores. The stibnite, together with a gangue 
 of quartz, and sometimes calcite, usually forms veins cutting 
 igneous, sedimentary, or metamorphic rocks. 
 
 Distribution of Antimony in United States. Antimony 
 has been found at a number of localities in the Cordilleran 
 region, but the great distance of the deposits from the rail- 
 road, together with the fact that the smelting plants are 
 located in the East, make them of little commercial value, 
 and no domestic production has been reported since 1901. 
 Moreover, the large output of antimony ores and metal 
 abroad, combined with low ocean freights and the absence 
 of any import tax on crude antimony, are of themselves 
 discouraging to domestic competition. 
 
 The large amount of antimony now manufactured in 
 the United States is obtained : (1) as a by-product from 
 the smelting of foreign and domestic lead-silver ores con- 
 taining small quantities of antimony ; (2) antimony regu- 
 lus, or metal from foreign countries ; (3) foreign ore. 
 306
 
 ANTIMONY 
 
 397 
 
 Uses. Antimony metal is used chiefly in the manufac- 
 ture of alloys of lead, tin, zinc, etc. Type metal, which is 
 an alloy of lead, antimony, and bismuth, has the property 
 of expanding at the moment of solidification. Britannia 
 metal is tin with 10 to 16 per cent antimony and 3 per 
 cent copper. Babbitt, or antifriction, metal consists of 
 antimony and tin, with small amounts of lead, copper, bis- 
 muth, zinc, and nickel. Tartar emetic, a potassium-anti- 
 mony tartrate, is used in medicine and as a mordant for 
 dyeing, while antimony persulphide is employed for vulcan- 
 izing and coloring rubber. 
 
 Production of Antimony. The production of metallic 
 antimony from domestio and foreign ores since 1890 was 
 as follows : 
 
 PRODUCTION OF ANTIMONY FROM DOMESTIC AND FOREIGN ORES 
 
 YEAR 
 
 QUANTITY 
 SHORT TONS 
 
 VALUE 
 
 YEAR 
 
 QUANTITY 
 SHORT TONS 
 
 VALUE 
 
 1890 
 
 938 
 
 $175,508 
 
 1901 
 
 2639 
 
 8539,902 
 
 1895 
 
 2013 
 
 304,169 
 
 1902 
 
 3561 
 
 634,506 
 
 1900 
 
 4226 
 
 837,896 
 
 1903 
 
 3128 
 
 548,433 
 
 The production in 1903 was about three fifths of the 
 entire consumption. The hard lead (antimonial lead) 
 produced in the United States in 1903, as a by-product 
 from impure lead-silver ores, was 21,237,440 pounds, con- 
 taining 24 per cent antimony. 
 
 REFERENCES ON ANTIMONY 
 
 1. Blake, U. S. Geol. Surv., Min. Res., 1883-4 : 641, 1885. 2. Comstock, 
 Ark. Geol. Surv., Ann. Kept, for 1888, I: 136. (Ark.) 3. Min. 
 Indus., 2: 13,1894. (General.)
 
 398 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 ARSENIC 
 
 Although arsenic-bearing minerals are widely distributed 
 in many countries, the commercially valuable occurrences 
 are few. 
 
 Arsenopyrite (FeAsS), called also mispickel and arsenical 
 pyrites, is the main source of the metal. Realgar (As 2 S 2 ) 
 and orpiment (As 2 S 8 ) may also serve as ores. 
 
 Arsenopyrite is mined in Washington, where the mineral 
 is used for making arsenious oxide, and more recently de- 
 posits have been opened up in Floyd and Montgomery 
 counties, Virginia. At the former locality the ore, which 
 is chiefly arsenopyrite, averages about 14 per cent arsenic, 
 .7 ounce gold, and 3 ounces silver per ton (2). 
 
 Arsenopyrite is used chiefly for the manufacture of arse- 
 nious oxide. It is employed in medicine, as a pigment, and 
 as an alloy with lead for making shot. Arsenious oxide is 
 used for making paris green, in glassware for destroying 
 the iron coloration, in certain enamels, and as a fixing and 
 conveying substance for aniline dyes. 
 
 The domestic production of arsenious oxide in 1903 
 amounted to 611 short tons valued at $36,691, and was all 
 made at Everett, Wash. This, however, supplied only one 
 quarter of the domestic demand, and large quantities were 
 imported from Canada, Germany, and Spain. The imports 
 of arsenic and its compounds in 1903 amounted to 8,357,661 
 pounds, valued at $294,602. 
 
 REFERENCES ON ARSENIC 
 
 1. Min. Indus., n : 25, 1894. 2. Strnthers, U. S. Geol. Surv., Min. Res., 
 1903 : 321, 1904. (General.) 3. Merrill, Non-Metallic Minerals, 
 30, 1904.
 
 CHROMIC IKON OEE 399 
 
 BISMUTH 
 
 Ores. The principal ores of this metal, together with 
 the percentage of metallic bismuth which they contain, are : 
 Bismuthinite (Bi 2 S 3 , 81.2) ; biwnite (Bi 2 O 3 , 96.6) ; and bis- 
 mutite (Bi 2 O 3 , CO 2 , H 2 O, 80.6). Although all of these 
 contain a high percentage of metallic bismuth, the content 
 of the ore as mined does not usually exceed ten or fifteen 
 per cent. Bismuth ores are commonly associated with those 
 of gold and silver, and the metal is obtained as a by-product 
 in the smelting of these. 
 
 Distribution. There are many scattered occurrences of 
 bismuth ores throughout the Rocky Mountain states, but 
 Colorado is the most important, and in 1904 Leadville was 
 the only producing region. 
 
 Uses and Production. Bismuth is chiefly valuable on 
 account of the easily fusible alloys which it forms with lead, 
 tin, and cadmium ; the melting point of some of these lies 
 between 64 C. and 94.5 C. They are therefore employed 
 in safety fuses for electrical apparatus, safety plugs for 
 boilers, dental amalgams, etc. The production of bismuth 
 in 1904 was 5184 pounds, valued at $314. The imports of 
 metallic bismuth in 1904 amounted to 185,905 pounds, 
 valued at $339,058. 
 
 CHROMIC IRON ORE 
 
 Ores. Chromite (FeO, Cr 2 O 3 ) is the chief source of the 
 compounds of the metal chromium which are used in the arts. 
 This ore occurs sometimes in alluvial deposits, but more 
 commonly in basic magnesian rocks, notably serpentine.
 
 400 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 Origin of Chromite. It has been pointed out by Pratt (4) 
 that chromite occurs most commonly around the border of 
 basic magnesian rocks of igneous origin. This is believed 
 to indicate that the chromium existed in the original molten 
 rock, and that, as this basic magma cooled, the chromite, 
 being one of the earliest minerals to crystallize, separated 
 out along the border of the mass because this portion was 
 the first to cool. As the cooling proceeded, convection cur- 
 rents within the molten mass would bring additional supplies 
 to the border. 
 
 Analyses (5). The following table gives the composition 
 of several of the types of chromic iron ores : 
 
 
 
 COLERAINE, 
 
 
 
 
 
 
 FRANCE 
 
 CAN. 
 
 Concentrated 
 
 ASIA 
 MINOR 
 
 STYRIA 
 
 CALIF. 
 
 RUSSIA 
 
 
 
 Product 
 
 
 
 
 
 Cr 2 3 
 
 37.00 
 
 53.64 
 
 53.00 
 
 53.00 
 
 42.20 
 
 59.00 
 
 SiO 2 
 
 2.53 
 
 2.31 
 
 2.15 
 
 2.50 
 
 5.48 
 
 2.20 
 
 A1 2 3 
 
 13.15 
 
 14.02 
 
 7.62 
 
 8.00 
 
 13.60 
 
 10.00 
 
 MgO 
 
 12.53 
 
 15.75 
 
 12.31 
 
 11.58 
 
 14.88 
 
 11.62 
 
 FeO 
 
 34.79 
 
 11.47 
 
 24.92 
 
 24.92 
 
 23.84 
 
 18.18 
 
 CaO 
 
 
 2.81 
 
 
 
 
 
 The price of chromic iron ore is based on its percentage of chromic 
 oxide, the standard ore containing 50 per cent. Every unit above this 
 is valued at from 75 cents to $1 per ton ; but when the percentage is 
 below 50 per cent, the value decreases at an even greater rate. How- 
 ever, ores carrying only 45 per cent of chromic oxide are easily market- 
 able. Low silica is desirable. 
 
 Distribution in the United States. In the United States 
 chromite was for a time obtained from Chester and Delaware 
 counties, Pennsylvania, and Baltimore County, Maryland,
 
 CHKOMIC IRON ORE 401 
 
 and the exhaustion of these deposits was followed by the 
 opening of others in San Luis Obispo County, California. 
 Subsequently the importation of Turkish and Russian chro- 
 mite commenced, followed by additional supplies from 
 Canada and Newfoundland. This foreign chrome iron ore, 
 especially the Turkish, can be placed on the American 
 market so cheaply that there has been little development of 
 our own deposits. The importation of chromic iron ore 
 from New Caledonia is also increasing. 
 
 Chromite occurs in a number of places in California besides the one 
 referred to above ; and also in North Carolina, in a belt of peridotite rock 
 extending from Ashe County to Clay County. In this area, however, the 
 chromite has been found in quantity at only a few localities (3). 
 
 Uses. Metallic chromium has no direct use; but raw 
 chromite and chromium salts have a variety of applications. 
 Owing to its great heat-resisting qualities, chromite is 
 employed in the manufacture of refractory bricks. Such 
 bricks are sometimes used for lining basic open-hearth fur- 
 naces, and as a hearth lining for water-jacket furnaces in 
 copper smelting. They stand rapid changes of temperature 
 well, and are not attacked by molten metals. 
 
 In the presence of carbon, chromium makes steel extremely 
 hard and resistant to shocks ; therefore chrome steel is 
 suited to a variety of uses, as in the manufacture of plates, 
 hard-edged tools, etc. An alloy of iron and chromium is 
 used in armor plates, alloys of ferro-chromium and ferro- 
 nickel being added to the molten steel before casting. Most 
 of the chromite mined is used for pigments because of the 
 red, yellow, and green color of its compounds, chromate and 
 bichromate of potash. In these forms the substance is em-
 
 402 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 ployed in dyeing, calico printing, and the making of pig- 
 ments useful in painting, printing wall papers, and coloring 
 pottery. Alkaline bichromates are employed for tanning 
 skins, and some chromium salts have a medicinal value. 
 
 Production of Chromite. The amount of chromite pro- 
 duced in the United States is small, and in 1903 California 
 was the only source of supply. The production for several 
 years was as follows : 
 
 PRODUCTION OF CHROMITE m THE UNITED STATES FROM 1900 TO 1903 
 
 YEAR 
 
 QUANTITY 
 LONG TONS 
 
 VALUE 
 
 1900 
 
 140 
 
 $1400 
 
 1901 
 
 368 
 
 5790 
 
 1902 
 
 315 
 
 4567 
 
 1903 
 
 150 
 
 2250 
 
 
 
 
 The value of the imports for the last three years was : 
 
 YEAR 
 
 CHBOMATE AND 
 BICHROMATE 
 OF POTASH 
 
 CHROMIC 
 ACID 
 
 CHROME 
 ORB 
 
 TOTAL 
 
 1901 
 
 129,224 
 
 $10,861 
 
 $363,108 
 
 $403,193 
 
 1902 
 
 
 11,115 
 
 582,597 
 
 593,712 
 
 1903 
 
 3 174 
 
 
 292 025 
 
 324 199 
 
 
 
 
 
 
 REFERENCES ON CHROMIC IRON ORE 
 
 1. Glenn, Amer. Inst. of Min. Engrs., Trans. XXXI : 374, 1902. 2. May- 
 nard, ibid., XXVII : 283, 1898. (Newfoundland.) 3. Pratt, U. S. 
 Geol. Surv., Mineral Resources, 1901 : 941, 1902. (General.) 
 4. Pratt, N. Ca. Geol. Surv., 1 : 269, 1905. (Origin.) 5. Anon., 
 Min. Indus., VI : 147, 1898. (Analyses.)
 
 NICKEL AND COBALT 403 
 
 MOLYBDENUM 
 
 Ores and Occurrences. Molybdenite (MoS 2 ) and, less com- 
 monly, wulfenite (PbMoO 4 ), are the chief sources of this 
 metal. 
 
 Molybdenite forms irregular masses or disseminations in 
 crystalline rocks, and many occurrences are known in the 
 West, for example, in California, Washington, Montana, Utah, 
 Arizona, New Mexico, and in the East, in Maine. An ore to 
 be marketable must contain over 45 per cent of molybdenum 
 and be free from copper, the average price of a 50 to 55 per 
 cent ore being about $400 per ton. 
 
 Uses. Its chief use is in the manufacture of chemicals, 
 especially ammonium molybdate, and for coloring porcelain 
 green. A nick el -molybdenum alloy is also made. The use 
 of molybdenum for hardening steel is increasing, it being 
 used chiefly for tool steel. 
 
 Production of Molybdenum. The production of molyb- 
 denite in 1903 was 6200 tons crude ore, but very little of 
 this was concentrated and marketed. 
 
 REFERENCES ON MOLYBDENUM 
 
 1. Crooks, Bull. Geol. Soc. Amer., XV: 283, 1904. (N.Y.) 2. Pratt, 
 U. S. Geol. Surv., Min. Res., 1903 : 307, 1904. (General.) 3. Smith, 
 U. S. Geol. Surv., Bull. 260 : 197, 1905. (E. Me.) 
 
 NICKEL AND COBALT 
 
 Ores. These two metals can best be treated together, for 
 nearly all the ores containing one are apt to carry some of the 
 other, and furthermore, in smelting, the two metals go into 
 the same matte, and are separated later in the refining process.
 
 404 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The ores of nickel and cobalt, together with their composi- 
 tion and the percentage of nickel or cobalt they contain, are : 
 
 ORE 
 
 COMPOSITION 
 
 Ni 
 
 Co 
 
 Pyrrhotite (nickeliferous) 
 Millerite 
 
 Fe n S 12 
 
 NiS 
 
 0-6 
 646 
 
 
 
 Pentlandite 
 
 (FeNi)S 
 
 22 
 
 
 Genthite 
 
 2 NiO 2 MgO 3 SiO 6 H O 
 
 2246 
 
 
 
 NiAs 
 
 43 9 
 
 
 
 (CoND S 
 
 30 53 
 
 21 34 
 
 
 
 
 
 The nickeliferous pyrrhotite is the most widely distributed 
 of the nickel ores, and may carry small amounts of cobalt. 
 It is also called magnetic pyrites. The percentage of nickel 
 ranges from a trace to 6 per cent, but an increase above this 
 brings it into pentlandite. The millerite is sometimes found 
 associated with pyrrhotite ores. Of the genthite, the variety 
 known as garnierite forms the ores, and carries from 21 to 45 
 per cent nickel oxide. 
 
 Distribution. Very little direct mining for nickel and 
 cobalt is done in the United States, but at Mine la Motte, 
 Missouri, considerable quantities have been obtained annually 
 as a by-product in lead mining. (See under Lead.) 
 
 Eastern Occurrences of Nickel. The Gap Nickel Mine, 
 Lancaster County, Pennsylvania, is the most important 
 eastern occurrence. It was actively worked from 1863 to 
 1880, being during that period the only nickel ore mined 
 on this continent. In 1902 the mine was again operated. 
 The ore is pyrrhotite associated with amphibolite, an altered 
 intrusive, the whole inclosed by mica-schist. The pyrrhotite 
 is believed to have originated by magmatic segregation (4).
 
 NICKEL AND COBALT 405 
 
 Nickel minerals have also been found in the basic magnesian 
 rocks of North Carolina. 
 
 Western Occurrences. Deposits of nickel and cobalt ores are 
 known in Idaho and Oregon, but they have not yet assumed 
 importance. Nickel ore is found in Ferry County, Wash- 
 ington, and other deposits are reported from Sheridan and 
 Piney Creek, Wyoming, as well as at several localities in 
 Nevada, Idaho, Arizona, and South Dakota ; but none of the 
 occurrences are worked, and the main source of supply on 
 this continent comes from Sudbury, Ontario (1, 2). 
 
 There, the ore, which occurs in enormous masses, is a nickeliferous 
 pyrrhotite, and the output forms probably one half of the world's produc- 
 tion. The ore occurs on the contact of quartzite and diorite, or forms, 
 more often, scattered irregular masses in the latter. Its origin has been 
 a matter of some dispute, some having regarded it as a product of mag- 
 matic segregation, while others believe the ore to have been deposited in 
 the crushed diorite. A partial analysis shows : Cu, 8.05 ; Ni, 2.97 ; Fe, 
 26.21 ; SiOa, 26.05 ; S, 19.08. 
 
 The second important source of the world's nickel ore is the mines of 
 New Caledonia, in the Pacific Ocean, off the east coast of Australia. The 
 ore is garnierite. 
 
 Uses of Nickel. The most important and increasing use of 
 nickel is for the manufacture of nickel and nickel-chromium 
 steel. This, on account of its great hardness, strength, and 
 elasticity, is used for making armor plate, gun shields, turrets, 
 ammunition hoists, etc. Krupp steel, which may be taken 
 as a type, has approximately 3.5 per cent nickel, 1.5 per cent 
 chromium, and .25 per cent carbon. Owing to its abrasive 
 resistance, nickel-steel is now much used for rails. Other 
 important uses are for large forgings, marine engines, wire 
 cables, and electrical apparatus. A steel with 25 to 30 per 
 cent nickel shows high resistance to corrosion by salt, fresh
 
 406 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 or acid waters, or by superheated steam. German silver is 
 an alloy of zinc, copper, and nickel. 
 
 Uses of Cobalt. Cobalt steel, while having a high elastic 
 limit and breaking strength, cannot compete with nickel steel 
 on account of its high cost, and the main use for cobalt is as 
 a pigment. 
 
 Production. The production of nickel from domestic ores 
 and cobalt oxide in the United States from 1892 to 1901 was : 
 
 PRODUCTION OF NICKEL AND COBALT FROM DOMESTIC ORES 
 
 YEAR 
 
 NICKEL 
 
 COBALT OXIDE 
 
 Quantity 
 Pounds 
 
 Value 
 
 Quantity 
 Pounds 
 
 1892 
 
 92,252 
 10,302 
 9,715 
 6,700 
 
 5,748 
 114,200 
 
 $50,739 
 3,091 
 3.8B6 
 3,551 
 2,701 
 45,900 
 
 7,869 
 14,458 
 6,471 
 13,360 
 3,730 
 120,000 
 
 1895 
 
 1900 
 
 1901 
 
 1902 
 
 1903 
 
 
 The amount of nickel produced in Canada in 1903 was 
 12,505,510 pounds. The imports of cobalt oxide in 1903 were 
 73,350 pounds, valued at $ 145,264, while the total value of 
 the nickel imported in the same year was $1,849,620. The 
 exports of nickel oxide and matte in 1901 were $1,483,889. 
 
 THE WORLD'S PRODUCTION OF NICKEL 
 
 
 QUANTITY 
 
 VALUE 
 
 Canada, 1903 
 
 12 505 510 pounds 
 
 $5,002,204 
 
 France 1902 .... 
 
 1 600 met tons 
 
 1 080 800 
 
 Germany, 1902 
 
 1,605 met. tons 
 
 1,122,271 
 
 

 
 PLATINUM GROUP OF METALS 407 
 
 REFERENCES ON NICKEL AND COBALT 
 
 1. Barlow, Can. Geol. Surv., Ann. Kept., XIV, pt. H, 1904. (Ontario.) 
 2. Dickson, Amer. Inst. Min. Engrs., Trans. XXXIV: 3, 1904. 
 (Ontario.) 3. Hodges, Amer. Inst. Min. Engrs., Trans. XIII : 657, 
 1885. (Nev.) 4. Kemp, Amer. Inst. Mm. Engrs., Trans. XXIV : 
 620, 1895. (Pa.) 5. Neill, Amer. Inst. Min. Engrs., Trans. XIH : 
 634, 1885. (Mo.) 
 
 PLATINUM GROUP OF METALS 
 
 Platinum. The ores of platinum are native platinum 
 (100 per cent Pt), and sperrylite, PtAS 2 (56.5 per cent 
 Pt). The former is commonly found in placer deposits, but 
 it has also been noted in basic igneous rocks rich in olivine, 
 such as peridotite, or in serpentine derived from it. The 
 sperrylite never occurs in large quantities, but has been 
 found in association with nickel and copper ores. Iridos- 
 mine and osmiridiuni are also known to carry platinum. 
 
 The nuggets found in placers are commonly regarded as 
 being pure native platinum, but this, according to Kemp (4), 
 is only true in part, most of those assayed yielding between 
 70 and 85 per cent, and the richest recorded being 86.5 per 
 cent. The balance is made up largely of iron, the highest 
 percentage of this noted being 19.5 per cent in a Ural 
 specimen. Iridium, rhodium, and palladium are always 
 present. Until the platinum falls below 60 per cent the 
 iridium rarely reaches 5 per cent, rhodium 4 per cent, while 
 palladium is less than 2 per cent. Other elements that have 
 been detected in the nuggets are osmium, ruthenium, cop- 
 per, and even gold, while chromite is a common associated 
 mineral (4). 
 
 Distribution in the United States. The domestic supply 
 of platinum, never large, has been obtained in recent years
 
 408 
 
 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 as a secondary product from gold-placer deposits in Trinity 
 and Shasta counties, California, and while its occurrence has 
 been reported in many other gold placers of the Northwest 
 and Alaska, still none of them have proven sufficiently rich 
 to work. Iridosmine and a natural alloy of iron and nickel 
 called josephinite are found associated with the gold. 
 
 In addition to the above sources, platinum is also found in 
 the copper ores of the Rambler mine, Wyoming, and has 
 been saved from the slimes obtained in treating the copper 
 ore and matte at this locality. The covellite in the ore 
 assays .06 to 1.4 ounces per ton of platinum. 
 
 Uses. Platinum was first used as an adulterant of gold, 
 and in Russia it was used for coinage from 1828 to 1845. 
 At the present time it is employed for crucibles and other 
 chemical apparatus which are to be subjected to high temper- 
 atures or strong acids. It is also of value in dentistry, for 
 electric lamps and electric apparatus, for jewelry, and in 
 photography. The price of it has risen steadily in recent 
 years, so that it is as valuable as gold. 
 
 Production. The production in the United States from 
 1880 to 1903 was as follows : 
 
 PRODUCTION OF PLATINUM IN THE UNITED STATES 
 
 YEAR 
 
 QUANTITY 
 
 OUNCES 
 
 VALUE 
 
 YEAR 
 
 QUANTITY 
 OUNCES 
 
 VALUE 
 
 1880 
 
 100 
 
 $400 
 
 1900 
 
 400 
 
 $2,500 
 
 1885 
 
 250 
 
 187 
 
 1901 
 
 1,408 
 
 27,526 
 
 1890 
 
 600 
 
 2,500 
 
 1902 
 
 94 
 
 1,874 
 
 1895 
 
 150 
 
 900 
 
 1903 
 
 
 
 6,080
 
 PLATINUM GROUP OF METALS 409 
 
 Since the close of 1899 platinum has risen steadily in price, 
 reaching a maximum of $20 per ounce in 1902. 
 
 The imports of platinum, both crude and manufactured, 
 amounted to $1,987,980 in 1902, and $2,055,933 in 1903. 
 The domestic production is entirely inadequate to supply 
 the demand, and the greater portion of the supply of the 
 United States, and in fact the world, is obtained from the 
 platinum placers of the Urals (5). 
 
 REFERENCES ON PLATINUM 
 
 1. Day, U. S. Geol. Surv., 19th Ann. Kept., VI : 265, 1898. 2. Day, Amer. 
 Inst. Min. Engrs., Trans. XXX : 702, 1901. (N. Amer.) 3. Donald, 
 Eng. and Min. Jour., LV : 81, 1893. (Can.) 4. Kemp, Min. Indus., 
 X : 540, 1902 ; and U. S. Geol. Surv., Bull. 193, 1902. (General.) 
 5. Purington, Eng. and Min. Jour., LXXVII : 720, 1904. (Russia.) 
 
 Palladium. This metal is found associated with platinum 
 and also native and alloyed with gold (Brazil). It is of 
 silver-white color, ductile and malleable, and is unaffected 
 by the air. Its great rarity and consequent high value has 
 restricted its use, but a small amount is used for some mathe- 
 matical and surgical instruments, for compensating balance 
 wheels and hair springs for watches, and for finely graduated 
 scales. 
 
 In the United States it has been reported from the platinum 
 deposits of the Pacific Coast and from the Rambler mine in 
 Wyoming. 
 
 Osmium. This, the heaviest and most infusible metal 
 known, occurs alloyed with platinum and also with iridium 
 in iridosmine. In the United States small quantities have 
 been found in the platinum placers of California. 
 
 Iridosmine is employed for pointing pens and fine tools,
 
 410 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 while osmic acid is used for staining anatomical prepara- 
 tions in microscopic work. 
 
 Iridium. Iridium is found chiefly in Russia and Cali- 
 fornia, alloyed with platinum or osmium. It is a lustrous, 
 steel-white metal of great hardness, and is, next to osmium, 
 the most refractory metal known. 
 
 An alloy of iridium and platinum has been used for 
 standard weights and measures, and iridium is also used 
 in photography. 
 
 TIN 
 
 Ores. Cassiterite (SnO 2 ), with 78.6 per cent metallic tin, 
 is the principal ore of this metal, but owing to the pres- 
 ence of impurities the ore rarely shows this composition. 
 Its hardness (6-7), imperfect cleavage, nonmagnetic charac- 
 ter, high specific gravity (6.8-7.1), and brittleness help to 
 distinguish it from other minerals that are liable to occur 
 with it. The mineral stannite* or tin pyrites, a complex 
 sulphide of copper, iron, and tin, rarely serves as an ore. 
 Stream tin is the name applied to cassiterite found in 
 placers. 
 
 Mode of Occurrence. Cassiterite of primary character is 
 usually found in veins of pegmatite, or, more commonly, 
 greisen (quartz and muscovite or lepidolite), around the 
 edges of granite areas. This, together with the associa- 
 tion of fluorite, tourmaline, and topaz with the ore, indicate 
 quite clearly that it may be the result of fumarolic action. 
 This type of occurrence is, however, of little commercial 
 value, and over 80 per cent of the world's supply comes 
 from placers whose materials have been derived from tin- 
 bearing veins.
 
 TIN 
 
 411 
 
 Distribution in the United States. Although tin has 
 been found at a number of localities in the United States, 
 only a very few of these can be looked upon as commercial 
 sources. 
 
 The Black Hills (1,2,6) of South Dakota and Wyoming 
 is perhaps the best known tin-producing region of the 
 United States, 
 and although 
 much money has 
 been sunk in 
 its development 
 and many ex- 
 citing rumors 
 have been pub- 
 lished regarding 
 it, the output 
 has been ex- 
 ceedingly small. 
 Here the tin oc- 
 curs either in 
 pegmatite dikes 
 or quartz veins and in placers. The Harney Peak deposits 
 of the northern Black Hills have produced but little, but 
 the Nigger Hill region of Wyoming, in the northwestern 
 part of the hills, seems to be more promising. 
 
 More recently the tin deposits of North and South Caro- 
 lina (4, 6) have been attracting considerable attention. These 
 lie in a belt extending from Cherokee County, South Caro- 
 lina, to Lincoln County, North Carolina. The cassiterite 
 occurs as an original constituent of pegmatite dikes, but 
 is somewhat irregularly distributed in them. Some of the 
 
 FIG. 97. Sketch map showing location of Carolina tin 
 belt. After Graton, U. S. Geol. Sura., Bull. 260.
 
 412 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 mines now being worked at Gaffney, South Carolina, and 
 Kings Mountain, North Carolina, are promising. An inter- 
 esting feature is that the dikes are of undoubted igneous 
 origin. 
 
 Tin has been reported from a number of localities in 
 Alaska (3), but the production is still very small, that 
 during 1903 and 1904 having amounted to not more than 
 100 tons. 
 
 The most important occurrences are on the Seward pen- 
 insula, where it occurs in placers, quartz-porphyry dikes, 
 granites, or in sedimentaries near their contact with the 
 igneous rock. In the dikes the accompanying minerals are 
 tourmaline, topaz, fluorite, zinnwaldite, wolframite, quartz, 
 epidote, pyrite, galena, etc. 
 
 The amount of tin ore produced in the United States 
 is entirely too small to supply the demand, and the main 
 source of supply for this country, and indeed for the world, 
 is the Malay peninsula, while other regions of commercial 
 importance are Australia, Bolivia, and Great Britain. 
 
 Uses of Tin. Tin is used chiefly for the manufacture of 
 bronze and tin plate, and to a smaller extent in plumbing 
 as well as less important purposes. Britannia metal is com- 
 posed of from 82 to 90 parts of tin alloyed with antimony, 
 copper, and sometimes zinc. 
 
 Production of Tin. The world's production for a number 
 of years has been behind the demand, a fact which has not 
 only kept up the price of this metal, but also stimulated 
 prospecting and mining. 
 
 The world's production for 1904 as given by the Engineer- 
 ing and Mining Journal was :
 
 TITANIUM 413 
 
 COUNTRY TONS 
 
 Straits Settlements 65,696 
 
 Banka and Billiton 16,394 
 
 Bolivia 10,304 
 
 Australia and Tasmania 5,692 
 
 England 4,796 
 
 Germany and Austria 112 
 
 Miscellaneous 140 
 
 Total 103,134 
 
 The price of tin on the New York market in 1904 averaged 
 about 28 cents per pound. The United States in 1904 con- 
 sumed about 43,120 tons of tin. 
 
 REFERENCES ON TIN 
 
 1. Blake, Amer. Inst. Min. Engrs., Trans. XIII: 691. (Black Hills.) 
 2. Blake, U. S. Geol. Surv., Min. Res., 1883-84 : 592, 1885. (Ores 
 and deposits). 3. Collier, U. S. Geol. Surv., Bull. 225, 1904. 
 (Alaska and general.) 4. Graton, U. S. Geol. Surv., Bull. 260 : 188, 
 1905. (N. Ca. and S. Ca.) 5. Hess and Graton, U. S. Geol. Surv., 
 Bull. 260 : 161, 1905. (Occurrence and distribution). 6. Struthers 
 and Pratt, U. S. Geol. Surv., Min. Res., 1903 : 335, 1904. (U. S.) 
 7. Weed, U. S. Geol. Surv., Bull. 178, 1901. (Texas.) Also 
 Bull. 213 : 99, 1903. 8. Winslow, Eng. and Min. Jour., XL : 320, 
 1885. (Va.) 
 
 TITANIUM 
 
 Ores. Among the minerals carrying titanium the most 
 abundant is ilmenite (FeO, TiO 2 ), which occurs in many 
 deposits of magnetite. Rutile (TiO 2 , 60 per cent Ti when 
 pure), though less abundant, is not uncommon. Titanium is 
 also found in a number of other minerals, many of which 
 
 Occurrence. For many years Norway has been the chief 
 producer of this metal ; but in 1900 large deposits of rutile 
 were discovered in Virginia, from which, up to the end of 
 1901, about 40,000 pounds had been extracted.
 
 414 ECONOMIC GEOLOGY OF THE UNITED STATES 
 
 The Virginia ore (2), which is found in Nelson County, 
 occurs in the form of small granules, disseminated through 
 a ground mass of feldspar or as a segregation in quartz, in a 
 rock of probable igneous origin. Until the discovery of the 
 Virginia deposits, the domestic demand, which has been 
 small, was supplied from deposits in Chester County, 
 Pennsylvania. 
 
 Uses. Titanium is used for producing yellow underglaze 
 colors on pottery, and also in the manufacture of artificial 
 teeth, to give them an ivory tint. Another use is in the 
 alloy ferro-titanium. Its commercial values as a steel-hard- 
 ening metal are not yet thoroughly proven, but from .5 to 3 
 per cent titanium appear to materially increase the transverse 
 and tensile strength of steel. By the use of the electric fur- 
 nace, ferro-titanium can be produced directly from the ores, 
 which would open a use for our American titaniferous 
 magnetites. 
 
 REFERENCES ON TITANIUM 
 
 1. Merrill, Non-metallic Minerals: 109, 1904. (General.) 2. Merrill, 
 Eng. and Min. Jour., LXXIII : 351, 1902. (Va.) 3. Pratt, U. S. 
 Geol. Surv., Min. Res., 1903 : 309, 1904. 
 
 TUNGSTEN 
 
 Ores. The ores of tungsten are wolframite ([FeMn] WO 4 ), 
 hubnerite (MnWO 4 ), and scheelite (CaWO 4 ). Of these 
 wolframite is the most abundant, and scheelite, the most 
 easily reducible ore of tungsten, the least abundant. Schee- 
 lite is found in but few localities in the world, and in the 
 United States occurs in commercial quantity at only one 
 locality. Although the ores of tungsten are rare, the 
 quantity available exceeds the demand.
 
 TUNGSTEN 415 
 
 Occurrence. Most of the known American deposits of 
 tungsten ores are found in the western states, especially 
 Arizona (1, 2, 6), Nevada, and Colorado. That found near 
 Dragoon, Arizona (6), consists of hiibnerite with subordinate 
 scheelite, and concentrates easily to a product yielding WO 3 , 
 70.22; SiO 2 , .30; Fe, 1.90; Mn, 19.82; CaO, 4.87; MgO, 
 3.40. Rich ores are found in White Pine County, Nevada, 
 at some distance from the railroad. In Colorado wolframite 
 and hiibnerite occur in several counties, and have been mined 
 to some extent. Eastern occurrences are rare, but scheelite 
 is found at Longhill, Connecticut (8), where it occurs along 
 the contact of limestone with diorite and hornblende gneiss. 
 Tungsten is also found associated with the Cambrian sili- 
 ceous gold ores of the Black Hills region, South Dakota (4), 
 but this source has not become of great importance. 
 
 Uses. Tungsten has been used for some years to fix the 
 color in wash goods and make them fireproof. It has also 
 been employed for manufacturing stained paper. But the 
 most important present use is for the alloy ferro-tungsten, 
 or in the manufacture of tungsten-steel. Alloys of tung- 
 sten, aluminum, and copper are also made. The fluores- 
 cent properties of tungstate of lime make it useful in the 
 Rontgen ray apparatus. Tungsten is also employed for 
 coloring glass. 
 
 Production. In 1903 the production was 2451 short 
 tons, yielding 292 short tons concentrates valued at 143,639, 
 or $149 per ton. This production came from Colorado, 
 Arizona, and Connecticut. 
 
 In 1903 ferro-tungsten-chrome alloys were imported to 
 the value of 118,136.
 
 416 ECONOMIC GEOLOGY OF THE UNITED STATES 
 REFERENCES ON TUNGSTEN 
 
 1. Blake, Eng. and Min. Jour., LXV : 608, 1898. (Ariz.) 2. Blake, Min. 
 Indus., VII : 720, 1899. (Ariz.) 3. Blake, Amer. Inst. Min. Engrs., 
 Trans., XXVIII : 543, 1899. 4. Irving, Amer. Inst. Min. Engrs., 
 Trans., XXXI : 683, 1902. (S. Dak.) 5. Pratt, U. S. Geol. Surv., 
 Min. Res., 1903: 304, 1904. (General.) 6. Rickard, Eng. and 
 Min. Jour., LXXVIII : 263, 1904. (Ariz.) 7. Thomas, Min. and 
 Met., XXIV : 301. (Ores and uses.) 8. Hobbs, U. S. Geol. Surv., 
 22d Ann. Rept., II : 13, 1902. (Conn.) 
 
 URANIUM AND VANADIUM 
 
 Ores. The minerals serving as the ores of uranium metals 
 are uraninite (UO 3 , UO 2 , PbO, N, etc.), gummite (doubt- 
 ful composition), and gamotite. The last-mentioned also 
 carries vanadium, as does also vanadinite [(PbCl)Pb 4 (VO 4 ) 3 ]. 
 The chief sources of uraninite are the mines near Central 
 City and in Montrose County, Colorado. Gamotite occurs 
 in Montrose County, Colorado, and also in Utah, while 
 vanadinite has been found in some quantity in the gold 
 and silver mining districts of Arizona and New Mexico. 
 
 Uses. Uranium and vanadium increase the strength and 
 toughness of steel, and are used to a small extent in the 
 manufacture of ferro-alloys. Uranium oxides are used for 
 coloring porcelain and glass, and vanadium oxide as a 
 dyeing material. Vanadium compounds are employed in 
 making vanadium bronze. 
 
 Production. The output of the ores of these minerals 
 in 1901 came chiefly from Colorado, and amounted to 375 
 short tons. In 1903, as a result of much prospecting and 
 developmental work, there was a production of 432 short 
 tons of crude ore. Thirty tons of concentrates were sold
 
 URANIUM AND VANADIUM 417 
 
 at a value of $5625. Most of the uranium and vanadium 
 ores mined in the United States are exported, but a large 
 quantity of uranium and vanadium salts are imported, the 
 value of these in 1903 amounting to $13,498. 
 
 REFERENCES ON URANIUM AND VANADIUM 
 
 1. Boutwell, U. S. Geol. Surv., Bull. 260 : 200, 1905. (Utah.) 2. Pratt, 
 U. S. Geol. Surv., Min. Res., 1901. 3. Merrill, Non-Metallic Min- 
 erals : 299 and 320, 1904. (General.)
 
 APPENDIX I 
 
 STATISTICS OF MINERAL PRODUCTION 
 
 UNLESS otherwise stated, the statistics are in all cases those for 
 1905, the figures being taken from the annual report on Mineral 
 Resources issued by the United States Geological Survey. These 
 figures, when first published by the Geological Survey, are not 
 always to be regarded as final, because, when repeated in the 
 report of the following year, they are not infrequently changed, 
 probably because of corrected returns. A similar set of statistics 
 is issued annually by the Engineering and Mining Journal. 
 
 COAL 
 
 STATE 
 
 QUANTITY 
 SHORT TONS 
 
 VALUE 
 
 FIELD 
 
 SHORT TONS 
 
 Pennsylvania 
 
 Anthracite . 
 Bituminous 
 Illinois . . . 
 West Virginia 
 Ohio .... 
 
 77,659,850 
 118,413,637 
 38,434,363 
 37,791,580 
 25,552,950 
 
 $141,879,000 
 113,390,507 
 40,577,592 
 32,341,790 
 26,486,740 
 
 Anthracite (Pa., Colo., 
 N. Mex.) 
 Triassic 
 Appalachian 
 Northern 
 Eastern Interior 
 
 77,734,673 
 1,557 
 212,830,030 
 1,473,211 
 65,255,541 
 
 Indiana . . 
 Alabama 
 Colorado . 
 Kentucky . 
 Iowa . . 
 Kansas . . 
 Tennessee . 
 Wyoming . 
 
 11,895,252 
 11,866,099 
 8,826,429 
 8,432,523 
 6,798,609 
 6,423,979 
 5,963,396 
 5,602,021 
 
 12,492,255 
 14,387,721 
 10,810,978 
 8,385,232 
 10,586,381 
 9,350,542 
 6,797,550 
 7,336,951 
 
 Western 
 Rocky Mountain, etc. 
 Pacific coast 
 Alaska 
 
 23,265,750 
 19,303,188 
 3,051,617 
 3,774 
 
 Total United States production in 1905, 392,919,341 short tons; value, 
 $476,756,963. Exports in 1905 : 2,229,983 long tons anthracite ; value, $11,104,654 ; 
 6,959,265 long tons bituminous; value, $17,867,964. 
 
 PRODUCTION OF LEADING COAL-PRODUCING COUNTRIES 
 
 COUNTRY 
 
 United States (1905) . 
 Great Britain (1905) . 
 Germany (1905) 
 
 
 
 
 
 
 SHORT TONS 
 392,919,341 
 264,464,408 
 191 576 074 
 
 Austria-Hungary (1904) 
 France (1904) 
 Belgium (1905) . 
 Russia and Finland (1904) . 
 Japan (1903) .... 
 
 
 
 
 
 45,209,933 
 37,663,349 
 24,078,862 
 21,294,639 
 11,120,934 
 
 419
 
 420 
 
 APPENDIX I 
 
 PETROLEUM SERIES 
 
 PETROLEUM 
 
 NATURAL GAS 
 
 STATE 
 
 BARRELS 
 
 VALUE 
 
 STATE 
 
 VALUE 
 
 
 33,427,473 
 28,136,189 
 16,346,660 
 
 12,013,495 
 11,578,110 
 10,9H4,247 
 10,437,195 
 8,910,416 
 1,217,337 
 134,717,580 
 
 $8,201,846 
 7,552,262 
 17,054,877 
 
 6,546,398 
 16,132,631 
 9,404,909 
 14,653,278 
 1,601,325 
 943,211 
 884,157,399 
 
 Pennsylvania 
 West Virginia 
 Ohio . . . 
 Indiana . . 
 Kansas . . 
 New York . 
 Kentucky and 
 Tennessee . . . 
 Indian Territory 
 and Oklahoma . 
 Total, United States 
 
 $19,197,336 
 10,075,804 
 5,721,462 
 3,094,134 
 2,2(51,836 
 623,251 
 
 237,590 
 
 130,137 
 
 $41,562,855 
 
 Texas 
 Ohio 
 
 Kansas, Oklahoma, 
 Indian Territory . . 
 West Virginia . . . 
 Indiana 
 Pennsylvania . . . 
 
 Kentucky 
 Total, United States 
 
 PRODUCTION OF ASPHALTUM AND BITU- 
 MINOUS ROCK IN THE UNITED STATES 
 
 PRODUCTION OF ASPHALTUM 
 BY STATES 
 
 VARIETY 
 
 SHORT 
 TONS 
 
 VALUE 
 
 STATE 
 
 SHORT 
 TONS 
 
 VALUE 
 
 Bituminous sandstone . 
 Bituminous limestone . 
 Mastic 
 Hard and refined gum . 
 Liquid or maltha . . . 
 Wurtzilite 
 
 39,273 
 6,029 
 2,200 
 3,036 
 3,139 
 500 
 10,916 
 5 
 50,169 
 
 $94,972 
 42,000 
 22,000 
 41,438 
 34,292 
 44,000 
 47,040 
 1,500 
 430,911 
 
 California . . . 
 Kentucky . . . 
 Indian Territory 
 Arkansas . . . 
 Utah 
 
 91,076 
 8,834 
 2,936 
 1,000 
 11,421 
 
 $568,403 
 66,420 
 27,790 
 3,000 
 92,540 
 
 
 Gilsonite 
 
 Oil asphaltum .... 
 Total 
 
 115,267 
 
 $758,153 
 
 WORLD'S PRODUCTION OF 
 PETROLEUM 
 
 WORLD'S PRODUCTION OF ASPHAL- 
 TUM IN 1904 
 
 COUNTRY 
 
 BARRELS (42 gal.) 
 
 COUNTRY 
 
 SHORT 
 TONS 
 
 VALUE 
 
 United States .... 
 Russia 
 Sumatra, Java, Borneo 
 Galicia 
 
 134,717,580 
 54,960,270 
 7,768,0001 
 5,765,317 
 4,420,987 
 4,137,098 
 1,341,157 
 634.095 
 560,<)63 
 37,720 
 25,0001 
 30,0001 
 
 United States 2 . . 
 Trinidad 
 
 64,167 
 152,392 
 101,121 
 250,222 
 123,347 
 4,146 
 4,029 
 14,910 
 
 $420,701 
 727,552 
 212,058 
 289,415 
 307,985 
 7,259 
 59,386 
 262,809 
 
 
 
 Roumania 
 India 
 
 Italy 
 
 Spam 
 Austria-Hungary . . 
 Venezuela .... 
 
 Canada 
 
 Germany 
 Peru 
 
 Italy 
 
 All others 
 Total 
 
 214,398,187 
 
 
 Exports in 1905, 1,220,513,587 gal 
 Ions; value, $79,640,929. 
 
 Refined oil imports, 13,725,720 gal 
 Ions; value, $672,127. 
 
 1 Estimated. 
 
 Imports of crude asphaltum, 100,596 
 shert tons, valued at $479,296. 
 
 2 Exclusive of oil asphaltum.
 
 APPENDIX I 
 
 421 
 
 BUILDING STONES 
 
 CLAY PRODUCTS 
 
 PRODUCTION OF BUILDING STONES IN 
 THE UNITED STATES 
 
 PRODUCTION OF CLAY PRODUCTS IN 
 THE UNITED STATES 
 
 KIND 
 
 VALUE 
 
 STATE 
 
 VALUE 
 
 Granite 
 
 $17,563,139 
 3,074,554 
 7,129,071 
 5,496,207 
 10,006,774 
 26,025,210 
 
 Ohio 
 
 $28,303,039 
 19,124,553 
 16,699,525 
 14,486,347 
 12,361,786 
 6,499,573 
 $149,697,188 
 
 Trap 
 
 Pennsylvania .... 
 New Jersey 
 
 Marble 
 
 Slate 
 
 New York 
 
 Sandstone 
 
 Illinois 
 
 Limestone 
 
 Indiana 
 
 Total 
 
 869,294,955 
 
 Total, United States . . 
 
 
 CEMENTS 
 
 PRODUCTION OF PORTLAND CEMENT 
 IN THE UNITED STATES 
 
 PRODUCTION OF NATURAL CEMENT 
 IN THE UNITED STATES 
 
 STATE 
 
 QUANTITY 
 BARRELS 
 
 VALUE 
 
 STATE 
 
 QUANTITY 
 
 BARRELS 
 
 VALUE 
 
 Pennsylvania . 
 Missouri . . . 
 New Jersey . . 
 Indiana . . . 
 Michigan . . . 
 New York. . . 
 Illinois .... 
 Ohio .... 
 
 13,813,487 
 3,879,542 
 3,654,777 
 3,127,042 
 2,773,283 
 2,111,411 
 1,545,500 
 1,312,977 
 1,225,429 
 35,246,812 
 
 $11,195,940 
 4,164,974 
 2,775,678 
 3,134,219 
 2,921,507 
 2,044,253 
 1,741,150 
 1,390,481 
 1,671,816 
 $33,245,867 
 
 New York . . 
 Pennsylvania 
 Indiana . 
 Illinois . 
 Kansas . 
 Kentucky 
 Wisconsin 
 Minnesota 
 Georgia . 
 Total, U.S. . . 
 
 1,926,837 
 748,057 
 527,600 
 368,645 
 230,686 
 207,500 
 139,128 
 115,314 
 89,167 
 4,473,049 
 
 $1,332,809 
 306,552 
 211,040 
 116,549 
 110,750 
 83,000 
 63,737 
 57,643 
 51,040 
 $2,413,052 
 
 California . . . 
 Total, U.S. . . 
 
 Imports of hydraulic cement in 1905, 846,577 barrels. Exports of hydraulic 
 cement in 1905, 897,686 barrels; value, $1,387,906. Production of slag cement in 
 United States, 382,447 barrels ; value, $272,614. 
 
 SALT 
 
 PRODUCTION OF SALT IN THE UNITED 
 STATES 
 
 WORLD'S PRODUCTION OF SALT IN 
 1904 
 
 STATE 
 
 BARRELS 
 
 VALUE 
 
 COUNTBY 
 
 SHORT 
 TONS 
 
 VALUE 
 
 Michigan . 
 New York . . . 
 Ohio 
 
 9,492,173 
 8,359,121 
 2,526,558 
 
 $1,851,332 
 2,167,931 
 565,946 
 
 United States . 
 United Kingdom 
 France ana Al- 
 
 3,084,200 
 2,118,629 
 
 $6,021,222 
 2,900,375 
 
 Kansas .... 
 
 2,098,585 
 
 576,139 
 
 geria .... 
 
 1,292,557 
 
 3,660,052 
 
 Louisiana . . . 
 
 1,055,186 
 
 303,507 
 
 German Empire 
 
 1,875,733 
 
 4,693,122 
 
 California . . . 
 
 664,099 
 
 188,330 
 
 Japan (1903) . . 
 
 724,750 
 
 4,692,539 
 
 Texas .... 
 
 444,832 
 
 142,993 
 
 Italy 
 
 511,827 
 
 713,595 
 
 West Virginia . 
 Utah .... 
 
 202,151 
 177,342 
 
 74,063 
 135,465 
 
 Austro-Hungary 
 Russia .... 
 
 595,335 
 not avail 
 
 16,024,783 
 able 
 
 Total, U.S. . . 
 
 25,966,122 
 
 $6,095,922 
 
 Spain .... 
 India .... 
 
 599,292 
 1,236,702 
 
 738,348 
 
 
 
 
 Canada .... 
 
 68,777 
 
 318,628 
 
 Exports in 1905, 50,886,454 pounds ; value, $190,376. 
 Imports in 1905, 308,572,025 pounds; value, $496,734.
 
 422 
 
 APPENDIX I 
 
 BORAX 
 
 Production in California, 46,334 short tons crude borax, valued 
 at $1,019,154. 
 
 Imports of borax, borates, and boric acid, 863,460 pounds, 
 valued at $32,800. 
 
 WORLD'S PRODUCTION OF BORAX IN 1904 
 
 COUNTRY 
 
 METKIO TONS 
 
 Coi'XTKY 
 
 MKTRIC TONS 
 
 United States . . . 
 Bolivia 
 
 42,034 
 1 1% 
 
 Germany 
 Italy .' 
 
 135 
 2624 
 
 Chile (1903) .... 
 
 16879 
 
 Peru 
 
 2,675 
 
 India 
 
 '212 
 
 
 
 GYPSUM 
 
 PRODUCTION OF GYPSUM IN THE 
 UNITED STATES 
 
 WORLD'S PRODUCTION OF GYPSUM 
 IN 1904 
 
 STATES 
 
 SHORT 
 TONS 
 
 VALUE 
 
 COUNTRY 
 
 SHOBT 
 TONS 
 
 VALUE 
 
 Michigan ... 
 Iowa 
 New York . . 
 Oklahoma, Texas 
 Ohio, Virginia . 
 Kansas ... 
 California, Nevada, 
 
 299,585 
 179,016 
 153,367 
 148,947 
 134,276 
 47,276 
 
 29,155 
 26,880 
 
 24,700 
 
 $143,597 
 114,354 
 151,272 
 148,947 
 134,474 
 32,940 
 
 39,947 
 26,930 
 
 29,500 
 
 France . . . 
 United States 
 Canada . . . 
 Great Britain 
 German Empire 
 Algeria . . . 
 Cyprus . . . 
 
 1,749,875 
 940,917 
 298,211 
 262,086 
 25,095 
 386 
 12,449 
 
 $2,916,483 
 2,784,325 
 316,436 
 354,138 
 17,307 
 169 
 31,721 
 
 Wyoming .... 
 Utah, Montana, South 
 Dakota, New Mex- 
 ico 
 
 Total 
 
 1,043,202 
 
 $821,967 
 
 Imports of ground and unground gyps 
 FERTILIZERS 
 
 am, and plaster of Paris, $446,152. 
 ABRASIVES 
 
 PRODUCTION OF PHOSPHATE IN THE 
 UNITED STATES 
 
 PRODUCTION OF ABRASIVES IN THE 
 UNITED STATES 
 
 STATE 
 
 LONG 
 TONS 
 
 VALUE 
 
 KINDS 
 
 VALUE 
 
 Florida 
 
 1,194,106 
 270,225 
 482,859 
 
 $4,251,845 
 878,169 
 1,633,389 
 
 Oilstones and scythestones 
 Grindstones and pulpstones 
 Buhrstones and millstones 
 
 $244,346 
 777,606 
 37,974 
 5,540 
 64,637 
 88,118 
 148,095 
 61,464 
 $1,427,780 
 701,400 
 654,821 
 $2,784,001 
 
 South Carolina . . 
 Tennessee .... 
 
 Total 
 
 1,947,190 
 
 $6,763,403 
 
 Infusorial earth and tripoli 
 Crystalline quartz . . . 
 Garnet 
 
 Imports of phosphates and other fertili- 
 zers in 1905, $832,216. 
 
 Corundum and emery . . 
 Total 
 
 Artificial abrasives . . . 
 
 Grand total 

 
 APPENDIX I 423 
 
 PRODUCTION OF MINOR NON-METALLIC MINERALS IN UNITED STATES 
 
 KIND 
 
 QUANTITY 
 
 VALUE 
 
 IMPORTS VALUE 
 
 
 3 109 sh t 
 
 $42 975 
 
 $846479 
 
 Barite .... 
 
 
 
 102,262 
 
 Missouri. . . . . . 
 
 26 761 sh t 
 
 84095 
 
 
 North Carolina 
 Tennessee and Kentucky . . . 
 Virginia 
 
 5,519 sh. t. 
 9,487 sh. t. 
 6,468 sh. t. 
 
 21,545 
 15,325 
 27,838 
 
 
 Feldspar .... .... 
 
 48,235 
 35 419 sh t 
 
 148,803 
 226 157 
 
 
 
 
 
 
 
 1 156 sh t 
 
 8 200 
 
 
 Illinois 
 
 33 275 sh t 
 
 220 206 
 
 
 Kentucky 
 
 22 694 sh t 
 
 132 362 
 
 
 Tennessee 
 
 260 sh. t. 
 
 1,720 
 
 
 Fuller's earth 
 Glass sand 
 Graphite . . . 
 
 57,385 
 25,178 sh. t. 
 1,030,334 sh. t. 
 
 362,488 
 214,497 
 1,083,730 
 
 74,006 (1904) 
 
 Crystalline 
 
 6,036,567 Ib. 
 21 953 sh t 
 
 [ 318,211 
 
 
 Artificial 
 World's production (1904) . . 
 Magnesite 
 
 4,591,550 Ib. 
 105,923 sh. t. 
 3,933 sh. t. 
 
 313,980 
 3,042,199 
 15,221 
 
 63,264 
 
 Ocher 
 
 13,402 sh. t. 
 689 sh t 
 
 126,351 
 17 004 
 
 92,553 
 21 451 
 
 Metallic paint . . 
 
 16 489 sh t 
 
 176 722 
 
 
 
 10 494 sh t 
 
 120 430 
 
 
 Slate . . . . . 
 
 5 181 sh t 
 
 44 108 
 
 
 
 47 590 081 eal 
 
 6 811 611 
 
 926 357 1 
 
 Monazite . 
 
 1 352 418 2 Ibs 
 
 163 908 
 
 
 
 
 326 350 
 
 34 998 513 
 
 Sulphur 
 Pyrite 
 Quartz 
 Talc and soapstone .... 
 New Jersey and Pennsylvania 
 North Carolina and Virginia 
 Massachusetts and Vermont 
 California, Georgia, Maryland 
 and Washington .... 
 New York 
 
 181,677 L t. 
 253,000 1. t. 
 51,145 sh. t. 
 
 5,796 sh. t. 
 21,700 sh. t. 
 10,188 sh. t. 
 
 2,450 sh. t. 
 56,500 sh. t. 
 
 3,706,560 
 938,492 
 104,109 
 
 38,241 
 499,780 
 75,405 
 
 23,636 
 445,000 
 
 1,567,485 
 1,774,379 
 
 48,225 (talc) 
 
 
 96,634 
 
 1,082,062 
 
 
 1 Includes artificial. 2 Includes a small quantity of zircon and coluinbite.
 
 424 
 
 APPENDIX I 
 
 METALLIC MINERALS 
 IRON ORES 
 
 PRODUCTION OF IRON ORES IN 
 THE UNITED STATES 
 
 PRODUCTION OF MOST IMPORTANT IRON 
 ORE PRODUCING COUNTRIES 
 
 STATE 
 
 LONG TONS 
 
 COUNTRY 
 
 QUANTITY 
 
 LONG TONS 
 
 PER CENT 
 WORLD'S 
 PRODUCTION 
 
 Minnesota .... 
 Michigan 
 
 21,735,182 
 10,885,902 
 3,782,831 
 1.139,937 
 859,283 
 808,717 
 
 752,045 
 734,770 
 526,271 
 133,471 
 1 167 724 
 
 United States . . 
 Germany and 
 Luxemburg . . 
 Great Britain . . 
 Spain 
 
 35,019,308 
 
 21,230,650 
 13,715,645 
 8,304,153 
 6,219,541 
 
 5,648,227 
 3,677,841 
 
 3,269,175 
 
 34.41 
 
 20.86 
 13.48 
 8.16 
 6.11 
 
 5.55 
 3.61 
 
 3.21 
 
 
 New York . . . 
 Wisconsin . . . 
 Pennsylvania . . 
 Virginia and 
 West Virginia . 
 Tennessee . . . 
 New Jersey . . . 
 Colorado 
 
 France 
 
 Russia and 
 Finland i . . . 
 Sweden .... 
 Austria and 
 Hungary 2 . . . 
 
 Total . . . 
 
 42,526,133 
 $75,165,604 
 
 Total 8 
 
 101,185,000 
 
 100.00 
 
 Value of the above . 
 
 Imports in 1905, 845,651 long tons; value, $2,062,161. 
 Exports in 1905, 208,017 long tons ; value, $530,457. 
 
 COPPER ORES 
 
 PRODUCTION OF COFFER IN UNITED 
 
 STATES 
 
 WORLD'S COFFER PRODUCTION IN 
 1905 
 
 STATE OR TERRITORY 
 
 POUNDS 
 
 COUNTRY 
 
 LONG 
 TONS 
 
 Montana 
 
 314,750,582 
 235,908,150 
 230,287,992 
 58,153,393 
 16,697,489 
 15,134,960 
 9,404,830* 
 5,334,192 
 16,2:36,255 
 
 United States 
 
 402,637 
 70,185 
 44,810 
 35,910 
 29,165 
 22,160 
 96,385 
 701 ,252 
 
 Arizona 
 Michigan . 
 
 Mexico . . . 
 
 Spain and Portugal .... 
 Japan 
 Chile 
 Germany 
 All others 
 Total 
 
 Utah . 
 
 California 
 Tenn. and Southern States 
 Colorado 
 New Mexico 
 
 All others 
 
 Total . . . 
 
 901,907,843 
 
 
 Imports of copper ore and matte, $5,765,238. 
 Exports of copper ore and metal, $86,408,731. 
 
 1 1902. 2 Includes Bosnia-Herzegovina. 
 
 4 Including copper smelters. 
 
 8 Approximate.
 
 APPENDIX I 
 
 425 
 
 LEAD AND ZINC 
 PRODUCTION or LEAD AND SPELTEB IN THE UNITED STATES 
 
 SHORT TONS 
 
 Lead 307,000 
 
 Spelter 
 
 LEAD CONTENT OF AMERICAN 
 ORES SMELTED IN 1905 
 
 PRODUCTION OF SPELTER BY 
 STATES 
 
 STATE OK TERRITORY 
 
 SllORT 
 
 TONS 
 
 STATES 
 
 SHORT 
 TONS 
 
 Colorado 
 Idaho 
 
 56,638 
 99,027 
 44,99(5 
 2,207 
 1,232 
 2,206 
 2,091 
 116 
 66 
 
 101 
 104,058 
 
 Eastern and Southern . . . 
 Illinois 
 Kansas 
 
 24,513 
 46,606 
 114,287 
 11,844 
 6,599 
 
 Utah 
 
 
 Missouri 
 Colorado 
 Total 
 
 New Mexico 
 Nevada 
 Arizona 
 
 203,849 
 
 California 
 
 WORLD'S PRODUCTION OF 
 SPELTER 
 
 Oregon, Alaska, South 
 Dakota, and Texas . . 
 Missouri, Kansas, Wisconsin, 
 Illinois, Iowa, Virginia, 
 and Kentucky .... 
 Total 
 
 COUNTRY 
 
 SHOUT 
 TONS 
 
 312,728 
 
 18,709. 
 ,611. 
 in 1905, 
 
 Belgium 
 
 160,345 
 74,127 
 15,176 
 56,140 
 55,524 
 143,243 
 10,315 
 8,422 
 203,849 
 727,141 
 
 Imports of lead in 1905, $1,1 
 Imports of zinc in 1905, $61 
 Exports of domestic zinc 
 $1,690,700. 
 
 Rhine district 
 
 Holland 
 
 Great Britain 
 
 France and Spain 
 
 Silesia 
 
 Austria and Italy 
 Poland 
 United States 
 
 Total 
 
 ALUMINUM 
 
 United States production in 1905, 11,347,000 pounds. 1 
 Imports in 1903 of crude and manufactured aluminum, 
 $143,471. 
 
 WORLD'S PRODUCTION OF ALUMINUM IN 1904 
 
 COUNTRY 
 
 QUANTITY 
 METRIC TONS 
 
 VALUB 
 
 United States 
 
 3,402 
 
 $2,325,000 
 
 Switzerland . . . 
 
 2500 
 
 1 413 125 
 
 France 
 United Kingdom 
 
 1,700 
 650 
 
 849,025 
 328,250 
 
 
 8,252 
 
 $4,915,400 
 
 Consumption.
 
 426 
 
 APPENDIX I 
 GOLD AND SILVER 
 
 PRODUCTION OF GOLD AND SILVER IN 1904, BY STATES AND 
 TERRITORIES 
 
 STATE AND TEBBITOBY 
 
 GOLD 
 
 SILVER 
 
 QUANTITY 
 FINE Oz. 
 
 VALUE 
 
 QUANTITY 
 FINE oz. 
 
 COMMERCIAL 
 VALUE 
 
 
 1,417 
 443,177 
 168,274 
 901,484 
 1,183,518 
 4,668 
 82,739 
 116 
 
 206,419 
 244,823 
 18,476 
 5,994 
 68,321 
 5,892 
 356,264 
 208 
 9 
 202,675 
 184 
 15,214 
 837 
 
 $29,300 
 9,160,458 
 3,478,532 
 18,633,676 
 24,463,322 
 96,900 
 1,710,365 
 2,400 
 
 4,267,062 
 5,060,494 
 381,930 
 123,900 
 1.412,186 
 121,800 
 7,363,977 
 4,300 
 186 
 4,189,292 
 3,800 
 314,463 
 17,305 
 
 200 
 193,695 
 2,314,940 
 1,480,589 
 13,947,635 
 1,500 
 7,666,382 
 
 122,807 
 12,817,285 
 4,268,123 
 214,553 
 14,800 
 132,077 
 500 
 161,611 
 59,200 
 385,576 
 12,049,446 
 6,700 
 157,598 
 4,647 
 
 $116 
 110,405 
 1,325,303 
 843,936 
 7,985,028 
 870 
 4,389,004 
 
 70,000 
 7,334,146 
 2,432,830 
 124,103 
 8,584 
 75,284 
 290 
 92,522 
 34,336 
 213,935 
 6,898,308 
 3,886 
 89,831 
 2,661 
 
 Alaska 
 
 Arizona 
 California 
 
 Colorado 
 
 Georgia . ... 
 
 Idaho 
 
 Michigan ... . . 
 
 Montana 
 
 Nevada 
 
 North Carolina 
 
 South Carolina 
 
 South Dakota 
 Tennessee 
 
 Texas 
 Utah 
 
 Virginia 
 
 Washington . ... 
 
 Wyoming 
 
 Total ... ... 
 
 3,910,729 
 
 $80,835,648 
 
 55,999,864 
 
 
 BAUXITE 
 
 PRODUCTION OF BAUXITE IN 
 UNITED STATES 
 
 WORLD'S PRODUCTION OF BAUXITE 
 IN 1904 
 
 STATE 
 
 LONG TONS 
 
 COUNTRY 
 
 LONG TONS 
 
 VALUE 
 
 Georgia ) 
 
 15,173 
 
 United States . . 
 
 47,661 
 
 $235,704 
 
 Alabama j 
 Arkansas 
 
 32,956 
 
 France .... 
 United Kingdom . 
 
 74,449 
 8,700 
 
 8,340 
 
 Total 
 
 48 129 
 
 Total 
 
 130810 
 
 375,273 
 
 Value oi above .... 
 
 $240,292 
 
 
 
 
 Imports of bauxite, 11,726 long tons ; value, $46,517. 
 Exports of bauxite, none since 1901.
 
 APPENDIX I 
 
 427 
 
 MANGANESE 
 
 PRODUCTION OF MANGANESE IN 
 THE UNITED STATES 
 
 PRODUCTION OF MANGANESE ORES BY 
 KINDS IN THE UNITED STATES 
 
 STATE 
 
 QUANTITY 
 LONG 
 TONS 
 
 VALUE 
 
 KIND 
 
 LONG 
 TONS 
 
 VALUE 
 
 Virginia . . . 
 Georgia . . . 
 Tennessee . . . 
 California . . . 
 Total . . ' , . 
 
 3,947 
 150 
 20 
 1 
 
 $35,209 
 900 
 100 
 5 
 
 Manganese ores . . . 
 Manganiferous iron ores 
 Manganiferous silver 
 
 4,118 
 709,256 
 
 81,738 
 90,289 
 
 .136,214 
 1,554,9(59 
 
 270,299 
 20.289 
 
 4,118 
 
 $36,214 
 
 Manganiferous zinc 
 
 Total 
 
 945,401 
 
 $1,951,771 
 
 
 Imports of manganese ores in 1905, 257,033 long tons ; valued at $1,952,407. 
 
 MERCURY 
 PRODUCTION OF MERCURY IN THE UNITED STATES 
 
 STATE 
 
 QUANTITY 
 FLASKS, 76J LB. 
 
 VALUE 
 
 California ... 
 
 24635 
 
 $886081 
 
 Texas 
 
 4 723 
 
 173362 
 
 
 43 
 
 1 677 
 
 Utah 
 
 1,050 
 
 42,000 
 
 Total 
 
 30451 
 
 $1 103 120 
 
 
 
 
 Imports of mercury in 1905, 2690 Ib. ; value, $1710. Exports of mercury in 
 1905, 13,534 flasks ; value, $489,756. 
 
 WORLD'S PRODUCTION OP MERCURY IN 1904 
 
 COUNTEY 
 
 QUANTITY 
 METBIO TONS 
 
 VALUE 
 
 United States 
 
 1 188 
 
 $1 503 795 
 
 Austria .... . 
 
 536 
 
 602 236 
 
 Italy .... 
 
 355 
 
 396 335 
 
 Russia . . . 
 
 393 
 
 441 597 
 
 Spain 
 
 1,020 
 
 1,146,132 
 
 Total 
 
 3 492 
 
 $4 090 097 
 
 

 
 428 APPENDIX I 
 
 PRODUCTION OF MINOR METALS IN THE UNITED STATES 
 
 KIND 
 
 QUANTITY 
 
 VALUE 
 
 IMPORTS 
 VALUE 
 
 
 3,240 sh. t. 
 1,507,386 Ib. 
 2,288 Ib. 
 25 Ib. 
 
 90 sh. t. 
 
 318 oz. 
 Practically 
 803 
 4 
 
 $705,787 
 35,210 
 4,187 
 375 
 
 19,410 
 
 5,320 
 none 
 268,676 
 375 
 
 $53,0261 
 256,5402 
 318,007 
 
 2,173,263 
 26,316,023 
 
 Arsenic (white) 
 
 
 
 Molybdenum ] 
 Nickel 
 
 Titanium | 
 
 Cobalt J 
 
 Tin 
 
 
 
 
 1 Crude antimony and ore. 
 
 2 Arsenic and compounds.
 
 APPENDIX II 
 
 THIS contains a list of the more important papers which have 
 been issued since the appearance of the first edition. Except in 
 the case of a few important mineral products, such as Coal and 
 Gold, the references under each kind of material are arranged 
 alphabetically by authors. 
 
 COAL 
 
 GENERAL. Reports on Fuel-testing Operations at St. Louis ; U. S. Geol. 
 Surv., Prof. Paper 48, and Bulls. 261 and 290. Campbell, Amer. Inst. 
 Min. Engrs., Bimonthly Bull., March, 1906. (Classification.) Campbell, 
 Econ. Geol., I, No. 1, 1905. (Origin.) Smith, Econ. Geol., June, 
 1906. (Criticism of Campbell's theory.) Ford, Nat. Ass'n. Coll. Mgrs., 
 June 30, 1906. (Origin.) Parr, Jour. Amer. Chem. Soc., Oct., 1906. 
 (Classification.) 
 
 AREAL. Alaska: Collier, U. S. Geol. Surv., Bull. 278. (Cape Lisburne.) 
 Martin, Ibid., Bull. 284. (Bering Kiver.) Stone, Ibid., Bull. 277. 
 (Kachernak Bay.) California : Arnold, U. S. Geol. Surv., Bull. 285. 
 (Mount Diablo Range. ) Colorado : Schrader, U. S. Geol. Surv., Bull. 
 285. (Durango-Gallup field.) Fenneman and Gale, U. S. Geol. Surv., 
 Bull. 285. (Yampa field.) Illinois : Parr, Illinois Geol. Surv., Bull 
 3, 1900. Kentucky : Ashley and Glenn, U. S. Geol. Surv., Prof. Paper 
 49. (Cumberland Gap field.) Crandall, Ky. Geol. Surv., Bull. 4, 1905. 
 (Big Sandy Valley. ) Montana : Rowe, Univ. of Mont., Bull. 4. New 
 Mexico : Schrader, U. S. Geol. Surv., Bull. 285. (Durango-Gallup field.) 
 Lee, U. S. Geol. Surv., Bull. 285. (Engle field.) North Dakota: 
 Wilder, Econ. Geol., July-Aug., 1906. (Lignites. ) Pennsylvania : 
 Ashley, U.S. Geol. Surv., Bull. 285. (Clearfield field.) Utah: Taff, 
 Ibid. (Weber River field.) Taff, Ibid. (Book Cliffs field.) Richard- 
 son, Ibid. (Sanpete Co.) Virginia: Randolph, Cassier's Mag., 
 Feb., 1905. (Anthracite.) Wyoming : Trumbull, Bull. 7, Wyo. Sch. 
 of M. 
 
 PEAT 
 
 Hindshaw, U. S. Geol. Surv., Min. Res., 1904. (General U. S.) McCourt 
 and Parmelee, N. J. Geol. Surv., 1905: 223. (N. J. and general.) 
 Wilder and Savage, la. Geol. Surv., 1905. (Iowa.) 
 429
 
 430 APPENDIX II 
 
 PETROLEUM 
 
 Arnold, U. S. Geol. Surv., Bull. 285. (California.) Ashburner, Amer. Inst. 
 Min. Engrs., XVI: 906. (New York.) Bishop, N. Y. State Museum, 
 22d Ann. Kept. N. Y. State Geologist : r. 63. (New York.) Blatchley, 
 111. Geol. Surv., Bull. 2. (S. E. Illinois.) Clapp, U. S. Geol. Surv., 
 Bull. 285. (Greene Co., Pa.) Coste, Amer. Inst. Min. Engrs., XXXV : 
 288. (Volcanic origin.) Fenneman, U. S. Geol. Surv., Bull. 282. 
 (Texas-Louisiana field.) Gould, Eng. and Min. Jour., Aug. 11, 1906. 
 (Kansas-Oklahoma.) Kichardson, Jour. Frank. Inst., July, 1906. 
 (North America.) Veatch, U. S. Geol. Surv., Bull. 285. (Uinta Co., 
 Wyo.) 
 
 NATURAL GAS 
 
 Adams, Haworth, Crane, U. S. Geol. Surv., Bull. 238. (Kansas.) Newland, 
 N. Y. State Mus., Bull. 93 : 943. (New York.) 
 
 ASPHALT 
 
 Taff and Smith, U. S. Geol. Surv., Bull. 285. (Utah ozokerite.) Eldridge, 
 Econ. Geol., 1 : 437. (Asphalt vein formation.) 
 
 BUILDING STONES 
 
 Dale, U. S. Geol. Surv., Bull. 285. (Maine slate.) Dale and others, U. S. 
 Geol. Surv., Bull. 275. (United States slate.) McCourt, N. Y. State 
 Mus., Bull. 100. (Fire tests, N. Y. stones.) Watson, Laney, and Merrill, 
 N. Ca. Geol. Surv., Bull. 2. (North Carolina general.) 
 
 CLAYS 
 
 Kies, Clays, their Occurrence, Properties, and Uses, New York, 1906. 
 (Wiley and Sons.) Ashley, U. S. Geol. Surv., Bull. 285. (Clearfield 
 Co., Pa.) Crider, Ibid. (W. Kentucky.) Fuller, Ibid. (Cape Cod.) 
 Phalen, Ibid. (N. W. Kentucky.) Siebenthal, Ibid. (Bentonite in 
 Wyo.) Grimsley and Grout, W. Va. Geol. Surv., III. (West Virginia.) 
 Logan and Hand, Bull. Miss. Agric. and Mech. Coll., II, No. 3. (Mis- 
 sissippi.) Ries, Amer. Inst. Min. Engrs., Bimonthly Bull., Sept., 
 1906. (Texas.) Ries, Va. Geol. Surv., Bull. II. (Virginia.) 
 
 LIME AND CALCAREOUS CEMENTS 
 
 Eckel, Cements, Limes, and Plasters, New York, 1906. (Wiley and Sons.) 
 Meade, Portland Cement, Easton, 1906. (Chemical Publishing Co.) 
 Bastin, U. S. Geol. Surv., Bull. 285. (Knox Co., Me.) Bain and Eckel, 
 la. Geol. Surv., XV : 33. (Iowa.) Eckel, U. S. Geol. Surv., Bull. 285. 
 (Tenn.-Va. district.) Grimsley, W. Va. Geol. Surv., III. (West Vir- 
 ginia.) Kummel, N. J. Geol. Surv., 1905: 173. (Sussex and Warren 
 counties limestones.) Landes, U. S. Geol. Surv., Bull. 285. (Washing- 
 ton.) Orton and Peppel, Ohio Geol. Surv., 4th ser., Bull. 4. (Ohio.)
 
 APPENDIX II 431 
 
 SALT 
 
 Bownocker, Ohio Geol. Surv., 4th ser., Bull. 8. (Ohio.) Lane, Jour. Geol., 
 XIV: 221. (Chemical evolution of ocean.) 
 
 GYPSUM 
 
 Siebenthal, U. S. Geol. Surv., Bull. 285. (Laramie dist., Wyo., and Un- 
 compahgre region, Colo.) 
 
 FERTILIZERS 
 
 Jumeau, Annales de Chimie, June 15, 1906. (United States.) Prather, 
 Jour. Geol., Sept. -Oct., 1905. (N. J. glauconite.) 
 
 ABRASIVES 
 
 For general on diatomaceous earth see : Bull. Imp. Inst., Ill, No. 1 : 88 and 
 Can. Geol. Surv., Ann. Kept., XV, Pt. S. Magnus, N. Y. State Mus., 
 57th Kept., I : 158. (New York.) Newland, Eng. and Min. Jour., 
 Jan. 6, 1906. (New York garnet.) Pratt, N. Ca. Geol. Surv., I. 
 (Corundum, North Carolina.) Pratt, U. S. Geol. Surv., Bull. 269. 
 (Corundum, United States.) Desau, Min. World, Dec. 31, 1904. 
 (Borts and carbons.) 
 
 MINOR MINERALS 
 
 ASBESTOS : Cirkel, Can. Dept. Int., Mines Branch, 1905. (Occurrence and 
 uses.) Pratt, Min. World, July 8, 1905. (Arizona.) BAKITE : Dick- 
 son, Sch. of M. Quart., XXIII : 366. (Conc'n in limestone.) Lakes, 
 Min. Rep., Aug. 16, 1906. (Idaho.) FELDSPAR: Hopkins, Min. Indus., 
 VII: 262. (General.) Also A. A. A. S., XL VII : 293. (S. E. Penn- 
 sylvania.) Kies, U. S. Geol. Surv., Min. Res., 1901 : 937. (General.) 
 FLUORSPAR : Fohs, Eng. and Min. Jour., Jan. 6, 1906. (U. S. industry.) 
 GLASS SAND: Burchard, U. S. Geol. Surv., Bull. 285. (General and 
 Missouri.) Stose, ibid. (E. West Virginia.) GRAPHITE : Newland, 
 Eng. and Min. Jour., Jan. 13, 1906. (New York.) MAGNESITE : Hess. 
 U. S. Geol. Surv., Bull. 285. (Calif ornia.) MICA : Cirkel, Can. Dept. 
 Int., Mines Branch, 1905. (Occurrence, etc.) Colles, Mica, and 
 the Mica Industry. New York, 1906. (General.) MOLDING SAND: 
 Field, Iron Tr. Rev., Mar. 15, 1906. Kummel and Hamilton, N. J. 
 Geol. Surv., 1904: 187. (New Jersey.) Palmer, Amer. Mach., Oct. 5, 
 1905. (Core sands.) Ries, Foundry, July, 1906. (Laboratory exami- 
 nation methods.) Visonneau, Bull, de la Soc. d'Enc. pour 1'Ind. Nat., 
 Rev. de Met., July 1, 1906. (General.) PRECIOUS STONES : Crookes, 
 Min. Jour., Sept. 9, 16, 23, and 30, 1905. (Diamonds.) Kunz, Calif. 
 St. Min. Bur., Bull. 37. (Calif.) See also same author in U. S. Geol. 
 Surv., Min. Res., 1904 and 1905. SULPHUR AND PYRITE : Nason, Eng.
 
 432 APPENDIX II 
 
 and Min. Jour., July 28, 1906. (Origin Appalachian pyrites.) Thomas, 
 Min. World, Aug. 25, 1906. (Texas sulphur. ) TALC : Peck, N. J. 
 Geol. Surv., 1904: 163. (N. J.-Pa.) WATBE : Gautier, Econ. Geol., 
 July- Aug., 1906. (Genesis of thermal waters.) Numerous water- 
 supply bulletins issued by U. S. Geol. Surv. SOILS : Hilgard, Soils, 
 New York, 1906. (Macmillan Co.) Merrill, Rocks, Eock-weathering, 
 and Soils, New York, 1906. (Macmillan Co.) 
 
 ORE DEPOSITS 
 
 Bain, Econ. Geol., I. No. 4. (Classification.) Beck, Trans. Geol. Soc. S. 
 Afr., VIII : 147. (Ore veins and pegmatites.) Demaret, Annal. des M. 
 de Belg., XI: 542. (Genesis.) Kemp, Econ. Geol., I, No. 3. (Forma- 
 tion of ore deposits.) Kemp, Min. and Sci. Pr., March 31, 1906. 
 (Garnet zones.) Kemp, Econ. Geol., I, No. 1. (Sec'y enrichment cop- 
 per ores.) Lane, Jour. Can. Mg. Inst., IX. (Magmatic segregation.) 
 Lindgren, Econ. Geol., Oct. to Nov., 1905. (Ore deposition and deep 
 mining.) Miller, Elements of Mining Geology and Metallurgy, Denver, 
 1906. Parks, Inst. Mg. and Met., Apr. 13, 1905. (Border segregation.) 
 Park, A Text-book of Mining Geology, Philadelphia, 1906. Read, 
 Amer. Inst. Min. Engrs., Bimonthly Bull., Mar. 1906. (Sec'y enrich.) 
 Smyth, Amer. Jour. Sci., XIX: 277, 1905. (Pyrite replacing quartz.) 
 Spurr, Geology Applied to Mining, New York, 1904. Stokes, Econ. 
 Geol., July-Aug., 1906. (Sec'y enrich.) Sullivan, Ibid., Oct. -Nov., 
 1905. (Ore deposition.) Weed, Eng. and Min. Jour., Feb. 23, 1905. 
 (Absorption.) Day and Eichards, U. S. Geol. Surv., Bull. 285. (In- 
 vestigation of black sands.) 
 
 IRON ORES 
 
 Bowron, Amer. Inst. Min. Eng., Trans. XXXVI : 587. (Clinton ore, Ala.) 
 Eckel, U. S. Geol. Surv., Bull. 285. (Clinton ore, Ala.) Eckel, Ibid. 
 (Oriskany and Clinton ore, Va.) Holden, Ibid. (Virginia limonites.) 
 Kindle, Ibid. (Bath Co., Kentucky.) Leith, Econ. Geol., I, No. 4 
 (Iron ore reserves.) Leith, U. S. Geol. Surv., Bull. 285. (W. United 
 States.) 
 
 COPPER ORES 
 
 Kemp, Econ. Geol., I. (Sec'y enrich.) Beeler,Wyo. Geol. Surv., Sept. 
 1, 1905. (Grand Encampment dist.) Fishburn, Eng. and Min. Jour., 
 Sept. 22, 1906. (Inyo Co., Calif.) Grant, U. S. Geol. Surv., Bull. 284. 
 (Alaska.) Lane, Lake Sup. Min. Inst., 1906. (L. Sup. dist.) Law- 
 son, Bull. Dept. Geol. Univ. Calif., IV: 287. (Robinson dist., Nev.) 
 Lindgren, U. S. Geol. Surv. , Prof. Paper 43. (Clifton-Morenci. ) Phalen, 
 U. S. Geol. Surv., Bull. 285. (Luray, Va.) Root, Min. World, Sept. 
 29, 1906. (Ely, Nev.) Weed, U. S. Geol. Surv., Bull. 285. (U. S. 
 copper deposits.) Weed and Watson, Econ. Geol., I: 309. (Virginia.)
 
 APPENDIX II 433 
 
 LEAD AND ZINC ORES 
 
 Bain, U. S. Geol. Surv., Bull. 246. (N. W. Illinois.) Bain, Min. Mag., 
 July, 1905. (Soft lead resources, U.S.) Buckley and Buehler, Mo. 
 Geol. Surv., 2d ser., IV. (Granby area, Mo.) Bain, U. S. Geol. 
 Surv., Bull. 285. (Nevada zinc.) Brinsmade, Mines and Min., Sept., 
 1906. (Kelly, N. Mex.) Grant, Wis. Geol. and Nat. Hist. Surv., Bull. 
 14. (Wisconsin.) Miller, Ky. Geol. Surv., Bull. 2. (C. Kentucky.) 
 Siebenthal, Econ. Geol., 1 : 119. (Joplin district, Mo.) Ulrich and 
 Smith, U. S. Geol. Surv., Prof. Paper 36. (W. Kentucky.) Watson, 
 Amer. Inst. Min. Engrs., XXXV : 681. (Va.-Tenn. area.) 
 
 GOLD AND SILVER 
 
 GENERAL. Lovewell, Trans. Kan. Acad. Sci., XX, Pt. 1 : 205. (Genesis 
 placer and vein gold.) Smyth, Eng. and Min. Jour., June 29, 1905. 
 (Placers, origin, and class'n.) De Launay, Rev. gen. d. Sci., June 15 
 and 30, 1906. (Gold occurrence and production in world.) 
 
 AKEAL. Alaska: Papers by various authors in U. S. Geol. Surv., Bulls. 
 277, 284, 247, 280, 251, and 287. Arizona : Kellogg, Econ. Geol., July- 
 Aug., 1906. (Cochise Co.) Crosby, Amer. Inst. Min. Engrs., Trans. 
 XXXVI: 626. (Washington Camp.) California: Bateson, Amer. 
 Inst. Min. Engrs., Bimonthly Bull., Jan., 1906. (Mojave dist.) Diller, 
 U. S. Geol. Surv., Bull. 260: 45. (Indian Valley region.) Ball, U. S. 
 Geol. Surv., Bull. 285. (S. W. Nev. and E. Calif.) Colorado : Spurr 
 and Garrey, Ibid. (Idaho Springs.) Wolff, Min. World, Dec. 16, 1905. 
 (Boulder Co.) Gale, U. S. Geol. Surv., Bull. 285. (Hahn's Peak.) 
 Idaho: Collier, Ibid. (St. Joe River basin.) Montana: Douglass, 
 Mines and Min., Feb. 1905. (Alder Gulch. ) Nevada : Ball, U. S. 
 Geol. Surv., Bull. 285. (S. W. Nev. and E. Calif.) Hastings, Amer. 
 Inst. Min. Engrs., Trans. XXXVI. (Silver Peak.) Hastings and 
 Berkey, Amer. Inst. Min. Engrs., Bimonthly Bull., March, 1906. (Gold- 
 field.) Pack, Sen. of M. Quart., April and July, 1906. (Pioche.) 
 Reid, Bull. Dept. Geol. Univers. Calif., IV: 177. (Comstock Lode.) 
 Rice, Eng. and Min. Jour., Sept. 22, 1906. (Bullfrog district.) Spurr, 
 U. S. Geol. Surv., Prof. Paper 55. (Silver Peak.) Spurr, Amer. Inst. 
 Min. Engrs., Trans. XXXVI : 372. (W. Nevada ores.) New Mexico : 
 Lindgren and Graton, U. S. Geol. Surv., Bull. 285. 
 
 MERCURY 
 
 Phillips, Econ. Geol., I, No. 2. (Texas.) Stovall, Min. World, Aug. 25, 
 1906. (Oregon.) Turner, Econ. Geol., I, No. 3. (Texas.) 
 
 NICKEL, COBALT 
 
 Coleman, Ont. Bur. Mines, XIV, Ann. Rept., Pt. III. (Sudbury nickel 
 field.) Miller, Ibid., Pt. II. (Cobalt-nickel deposits, Temiskaming. ) 
 2r
 
 434 APPENDIX II 
 
 TIN 
 
 Hess, U. S. Geol. Surv., Bull. 284. (Alaska.) Eichardson, Ibid., Bull. 285. 
 (Texas.) 
 
 TUNGSTEN 
 
 Joseph, Eng. and Min. Jour., March 3, 1906. (Washington.) Van Wag 
 enen, Colo. Sen. of M. Bull., Jan., 1906. (Colorado and general.)
 
 INDEX 
 
 Abrasives, 168. 
 artificial, 165. 
 production of, 165. 
 references on, 166. 
 
 See Buhrstones, Whetstones, Pumice, Co- 
 rundum, Garnet, Quartz, Infusorial 
 Earth. 
 
 Actinolite, as gangue mineral, 295. 
 Adobe clay, defined, 99. 
 uEolian soils, 214. 
 
 Alabama, bauxite, 876 ; clinton ore, 266 ; fuller's 
 earth, 175 ; graphite, 179 ; kaolin, 101 ; 
 limonite, 271 ; phosphate, 158 ; Port- 
 land cement materials, 119 ; stoneware 
 clay, 108 ; Warrior coal, analysis, 7. 
 Alabaster, 143. 
 
 Alaska, coal, 82 ; coal mining, 83 ; copper, 298 ; 
 gold, 353 ; lignite, analysis from, 6 ; 
 magmatically segregated ores, 225; 
 petroleum, 54 ; tin, 412 ; yield of gold 
 ores, 832. 
 Albertite, properties, 59. 
 
 distribution, 59. 
 Algeria, onyx marbles, 83. 
 Algonkian, copper in, 295 ; Iron in, 260. 
 Alkali soils, 215. 
 Alkalies, effect on clay, 96. 
 Alluvial soils, 214. 
 Almandite, uses as gem, 194. 
 Alumina, effect on clay, 95. 
 in iron ores, 252. 
 in soils, 214. 
 Aluminum, 375. 
 
 for lithographic work, 182. 
 ores of, 375. 
 production of, 882. 
 references on, 888. 
 uses of, 879. 
 Alundum, 165. 
 Amethyst, as gem, 195. 
 Amorphous phosphates, see Phosphates. 
 Amygdaloids, copper-bearing, 288. 
 Analyses of, anthracite coal, 8; asphaltites, 
 60 ; bauxite, 376 ; bituminous coal, 8 ; 
 bituminous rocks, 61 ; cement rock, 
 natural, 112 ; chromite, 400 ; clays, 98 ; 
 coal, elementary, 14 ; copper ores, 
 Butte, 285; fuller's earth, 175; glass 
 sand, 177 ; greensand, 156 ; gypsum, 
 148; hematites, 364, 268; kaolin, 
 
 crude, 101 ; kaolin, washed, 101 ; lig- 
 nite, elementary, 14 ; limestones, 109 ; 
 limonites, 272; lithographic stone, 
 181 ; magnetites, uon-titaniferous, 
 257; magnetites, titaniferous, 258; 
 maltha, 60 ; mine waters, 227 ; min- 
 eral waters, 206; monazite, 191; 
 natural gas, 48 ; peat, elementary, 
 14 ; petroleum, 41 ; phosphates, 154 ; 
 Portland cement materials, 115 ; Port- 
 land cements, 116; proximate, of 
 United States coals, 6; rock salt, 
 181; solid matter in brine, 181; 
 waters, sea and ocean, 124. 
 Analysis of, barite, 170; bat guano, 155 ; bitu- 
 minous coal ash, 9 ; brick clay, 98 ; 
 calcareous clay, 98 ; copper ore, 298 ; 
 fire clay, 98 ; graphite, 178 ; gypsum, 
 calcined, 144 ; kaolin, 98 ; kaollnite, 
 98 ; lignite ash, 9 ; molding sand, 189 ; 
 nickel ore, Canada, 405 ; oil shale, 57 ; 
 peat ash, 9; pyrite, 199; shale, 98; 
 stoneware clay, 98 ; tungsten concen- 
 trates, 415; zinc ore, 315; zinc ore, 
 Creede, Colo., 819 ; zinc ore, Lead- 
 ville, 818; zinc ore, New Jersey, 
 
 Anglesite, 308, 305, 871. 
 Anhydrite, defined, 189. 
 Anthracite, 5, 22. 
 
 effect of igneous intrusions on, 15. 
 
 price per ton, 84. 
 
 properties of, 5. 
 
 Anthraxolite, occurrence and properties, 59. 
 Antimony, 896. 
 
 distribution in United States, 896. 
 
 gangue minerals, 396. 
 
 mode of occurrence, 896. 
 
 production, 897. 
 
 references on, 897. 
 
 sources, 896. 
 
 uses, 397. 
 
 with mercury, 893. 
 Apatite, as a fertilizer, 14T. 
 
 sources, 147. 
 Apex, 289. 
 Appalachian coal field, 20. 
 
 anthracite area, 22. 
 
 bituminous area, 21. 
 
 character of bituminous coals, 22. 
 Appalachian petroleum, distillates from, 42. 
 
 435
 
 436 
 
 INDEX 
 
 Appalachian region, copper ores of, 294. 
 depth of oxidation in ore bodies, 244. 
 petroleum in, 48. 
 Apsdin, Joseph, discoverer of Portland cement, 
 
 118. 
 
 Aquamarine, 194. 
 Archaean, Iron ores in, 261. 
 Argentite, 286, 826. 
 
 Argillaceous limestone,for Portland cement,114. 
 Arizona, asbestos, 168 ; fluorspar, 173 ; garnet, 
 195; molybdenum, 403; rubies (so 
 called), 193 ; tungsten, 415 ; turquoise, 
 194; vanadium, 416; weathering of 
 ores, 281. 
 
 Arkansas, bauxite In, 378; bituminous coal, 
 analysis of, 7 ; coal fields, 29 ; fuller's 
 earth, 175 ; lignite, 30 ; llmonite, 271 ; 
 manganese, 887; novaculite, 160; 
 phosphate, 158 ; Portland cement ma- 
 terials, 119; semi-bituminous coal, 
 analysis of, 7 ; whetstone, 160 ; zinc 
 ores, 815. 
 
 Arkose, defined, 85. 
 Arsenic, 898. 
 
 distribution.Virginia, 898 ; Washington, 398. 
 in iron ores, 252. 
 references on, 898. 
 sources of, 898. 
 uses, 898. 
 with mercury, 893. 
 Arsenopyrite, 898. 
 Artesian water, 209. 
 
 depth below surface, 209. 
 distinction from ground water, 210. 
 distribution, Atlantic coast, 210; Great 
 
 Plains, 211 ; Mississippi Valley, 211. 
 geologic horizon of, 209. 
 in metamorphlc rocks, 210. 
 Asbestos, asbestos minerals, 167. 
 
 amphibole, mode of occurrence, 167. 
 
 as mineral pigment, 188. 
 
 chrysotile veins, origin, 168. 
 
 distribution, 167 ; Canada, 168 ; Georgia, 167 ; 
 
 North Carolina, 167 ; Virginia, 167. 
 production, 169. 
 references on, 169. 
 serpentine, mode of occurrence, 167. 
 uses, 169. 
 
 Ashburner, on origin of petroleum, 44. 
 Ash, coal, analyses of, 9. 
 Ash in coal, 9. 
 Ash soils, 214. 
 
 Ash, volcanic, see Volcanic Ash. 
 Asia Minor, turquoise in, 194. 
 Aspen, Colo., lead-silver, 807, 367. 
 Asphaltites, defined, 57. 
 properties, 58. 
 uses of, 61. 
 
 Asphaltum, references on, 67. 
 Astral oil, 56. 
 
 Atlantic Ocean, analysis of water, 124. 
 Azurite, 278, 281, 291, 293, 871. 
 
 Babbitt metal, 897. 
 
 Bain, on Missouri lead-zinc ores, 817. 
 
 Ball clay, defined, 99. 
 
 distribution of, 108. 
 Barite, as mineral pigment, 187. 
 
 distribution, 170; Connecticut, 170; Mis- 
 souri, 170; North Carolina, 170; 
 Pennsylvania, 170 ; Tennessee, 170; 
 Virginia, 170. 
 mode of occurrence, 170. 
 production, 170. 
 references on, 171. 
 uses, 170. 
 
 Barre, Vermont granite, 77. 
 Bauxite, analyses of, 876. 
 
 distribution, Alabama, 376 ; Arkansas, 375 ; 
 
 Georgia, 376 ; New Mexico, 879. 
 production of, 880. 
 properties, 375. 
 
 Bavaria, lithographic stone, 182. 
 
 Beaufort, 8. C., phosphate deposits, 150. 
 
 Beaumont, Texas, petroleum, 51. 
 
 Becker, on mercury origin, 393. 
 
 Bedding planes, effect on quarrying, 74. 
 
 Belgium, buhrstones from, 161. 
 
 Benzine, in petroleum, 42. 
 
 Berea sandstone, 86. 
 
 Bessemer ores, defined, 252. 
 
 Bingham Canyon, Utah, copper, 296, 807. 
 
 Bisbee, Ariz., copper, 290. 
 
 Bismite, 899. 
 
 Bismuth, distribution, Colorado, 399. 
 
 production, 899. 
 
 Bismuthinite, 899. 
 
 Bismutite, 399. 
 
 Bitumen, with mercury, 390, 893. 
 
 with zinc, 315. 
 Bituminous coal, price per ton, 34. 
 
 properties of, 4. 
 
 See Coal. 
 Bituminous rocks, analyses, 61. 
 
 California, described, 60. 
 
 defined, 57. 
 
 distribution, geographic, 57. 
 geologic, 57. 
 
 Indian Territory, mentioned, 60. 
 
 Kentucky, mentioned, 60. 
 
 origin, 57. 
 
 Black copper, at base of gossan, 244. 
 Black Hills, S. Dak., tin, 411. 
 
 tungsten, 415. 
 
 Black Sea, analysis of water, 124. 
 Black silver, 825. 
 Blende, as contact ore, 235. 
 
 See Sphalerite. 
 Blnestone, defined, 85. 
 
 See Building stones.
 
 INDEX 
 
 437 
 
 Bonanzas, 237, 286, 888, 845. 
 Bone coal, 24. 
 Boracite, 134. 
 Borax, 184. 
 
 marshes, California, 185. 
 
 minerals containing, 184. 
 
 near Daggett, 185. 
 
 production, 136. 
 
 references on, 185. 
 
 uses, 185. 
 Bornite, 278, 279, 286, 292. 
 
 as contact ore, 235. 
 
 secondary, 286. 
 Bort, 192. 
 
 Boulder, Colo., petroleum at, 53. 
 Boulder, Mont., auriferous hot spring, 228. 
 Bradford district, Pa., natural gas in, 54. 
 Brass, 299, 820. 
 Braunite, 383. 
 Brazil, emerald, 198 ; magnetite sand, 258 ; 
 
 monazite, 190; topaz, 194. 
 Breaker, coal, 24. 
 Brick clay, analysis of, 98. 
 
 defined, 99. 
 
 distribution of, 104. 
 Brines, natural, 127. 
 Britannia metal, 897. 
 Brittle silver, 325. 
 Bromyrite, 325. 
 Bronze, 299. 
 
 Brooks, on Lake Superior ores, 262. 
 Brownstone, defined, 85. 
 Buhrstones, characters, 161. 
 
 distribution, 161. 
 
 German, 161. 
 Building stones, 69. 
 
 absorption of, 78. 
 
 color, 70. 
 
 crushing strength, 72. 
 
 cut off, 74. 
 
 density, 70. 
 
 distribution, gee under Granite, Sandstone, 
 Limestone, Marble, Slat*. 
 
 fading, cause of, 70. 
 
 hardness, 71. 
 
 lift, 74. 
 
 permanent swelling, 78. 
 
 porosity of, 78. 
 
 production of, 89. 
 
 properties of, 69. 
 
 quarry water in, 78. 
 
 references on, 90. 
 
 resistance to frost, 73. 
 to heat, 78. 
 
 rift, 74. 
 
 sap of, 78. 
 
 specific gravity, 71. 
 
 strength, 71. 
 
 texture, 70. 
 
 Bully Hill, Calif., copper, 298. 
 Butte, Mont., copper ores, 282. 
 
 metasomatism at, 284. 
 
 Calamine, 303, 305, 810, 81. 
 Calaverite, 339. 
 
 Calcareous clay, analysis of, 98. 
 Calcite, see Gangue minerals. 
 California, asbestos mentioned, 168; coal, 31, 
 82 ; copper, 297 ; fire clay, 108 ; infu- 
 sorial earth, mentioned, 162; Kern 
 Kiver oil field, 58; lignite, analysis, 
 1 ; lithium, 183 ; magnesite, 184 ; mag- 
 netite, 256 ; manganese, 887 ; marble, 
 82 ; mercury, 891 ; molybdenum, 403 ; 
 natural gas, 56 ; petroleum, 52 ; petro- 
 leum, characters, 58 ; platinum, 408 ; 
 Portland cement materials, 119 ; salt, 
 180; stoneware clay, 108; topaz, 194. 
 Californite, as gem, 195. 
 Calomel, 390, 391. 
 Calumet conglomerate, 288. 
 Cambrian, glass sand, 177. 
 gold ores, 329. 
 ocher, 187. 
 silver ores, 829. 
 tungsten, 415. 
 Cambro-Silurian limonite, 271. 
 
 pyrite, 199. 
 
 Cannel coal, properties of, 5. 
 Cape Nome, Alaska, 357. 
 Carbonado, 192. 
 
 Carboniferous, Appalachian section, 21 ; tee 
 Coal, Anthracite, distribution ; cop- 
 per, 290, 293, 296; gold ores, 886; 
 gypsum, 140; hematite, 268; lime- 
 stones for Portland cement, 119; 
 petroleum, 53; salt, 129; shales for 
 Portland cement, 119 ; siderite, 273 ; 
 silver ores, 336 ; silver-lead, 865, 867, 
 870; zinc ores, 314, 819. 
 Carbonite, 25. 
 Carborundum, 165. 
 Carters ville, Ga., manganese, 386. 
 Cassiterite, 410. 
 Cat's eye (oriental), 194. 
 Cavities, depth of occurrence, 229. 
 fault, 28. 
 
 formation of, 281. 
 in earth's crust, 229. 
 shrinkage, 281. 
 solution. 231. 
 Cement, calcareous, 109. 
 hydraulic, defined, 111. 
 natural, analyses, 118. 
 
 difference from Portland, 118. 
 properties of, 112. 
 Portland, analyses of, 116. 
 properties, 118. 
 raw materials, 114. 
 pozzuolano, defined, 111. 
 
 composition, 111. 
 production, 120. 
 references, 121. 
 Roman, 112.
 
 438 
 
 INDEX 
 
 Cement continued. 
 Kosendale, defined, 112. 
 uses of, 119. 
 
 Cement materials, natural rock, Appalachian 
 region, 117 ; Illinois, 118 ; Kentucky, 
 118; Maryland, 117 ; New Tork, 117 ; 
 Ohio, 117; Pennsylvania, 117; Wis- 
 consin, 118. 
 
 Portland, Alabama, 119; Arkansas, 119; 
 California, 119 ; Colorado, 119 ; Indi- 
 ana, 119; Kansas, 119; Michigan, 
 119; New Jersey, 118; New Tork, 
 118 ; North Dakota, 119 ; Ohio, 119 ; 
 Pennsylvania, 118; South Dakota, 
 119 ; Texas, 119 ; Utah, 119. 
 geologic age, 118. 
 Cement plaster, 144^ 
 Cement rock, natural, analyses, 112. 
 Cerargyrite, 825, 336. 
 Cerium, in monazite, 191. 
 Cerussite, 303, 305, 311, 871. 
 Ceylon, graphite from, 179. 
 
 topaz in, 194. 
 Chalcocite, 278, 281, 285, 286, 291, 292, 297, 
 
 298. 
 
 Chalcocite, secondary, 286. 
 Chalcopyrite, 278, 279, 281, 292, 293, 294. 
 as a contact ore, 235. 
 in pyrite deposits, 199. 
 Chalk, 80. 
 
 Champion Springs, N.Y., 205. 
 Chara, as aid in marl formation, 119. 
 Chester, Mass., emery deposits, 164. 
 China clay, defined, 99. 
 Chlorastrolite, as gem, 195. 
 Chlorine, in soils, 214. 
 Chlorite, 826. 
 
 Chrome yellow, as mineral pigment, 188. 
 Chromic iron, 399. 
 Chromite, 399. 
 analyses, 400. 
 as mineral pigment, 188. 
 associated rocks, 399. 
 association with peridotite, 226. 
 distribution in United States, 400; Cali- 
 fornia, 401; North Carolina, 401; 
 Pennsylvania, 401. 
 origin of, 400. 
 production of, 402. 
 references on, 402. 
 uses of, 401. 
 with platinum, 408. 
 Chrysocolla, 278, 281. 
 Chrysoprase, as gem, 195. 
 Chrysotlle, 167. 
 Chrysotile reins, origin, 168. 
 Cinnabar, 890, 393. 
 Cinnabar, as mineral pigment, 188. 
 Classification of, clays, 98. 
 
 ore deposits, 246. 
 Clay, adobe, defined, 99. 
 
 air shrinkage, 96. 
 
 alkalies in, 96. 
 
 alumina in, 95. 
 
 analyses of, 98. 
 
 ball, distribution of, 103. 
 
 classification of, 98. 
 
 defined, 92. 
 
 distribution, by kinds, 100, 
 
 fire, distribution of, 104. 
 
 fire shrinkage, 97. 
 
 flood-plain, 94. 
 
 fusibility of, 97. 
 
 geologic distribution, 100. 
 
 glacial, 94. 
 
 glass pots, sources, 104. 
 
 iron oxide in, 95. 
 
 kaolin, defined, 99, 100. 
 
 lake, 94, 104. 
 
 lime in, 96. 
 
 magnesia in, 96. 
 
 marine, 94. 
 
 miscellaneous, referred to, 104. 
 
 origin, 92, 98. 
 
 paper, sources, 104. 
 
 physical properties, 96. 
 
 plasticity of, 96. 
 
 pottery, 99, 103. 
 
 products, production of, 105. 
 
 properties of, 95. 
 
 references on, 106. 
 
 residual, 104. 
 
 sedimentary, 98. 
 
 silica in, 95. 
 
 specific gravity, 97. 
 
 stoneware, distribution of, 103. 
 
 sulphur trioxide in, 96. 
 
 tensile strength, 96. 
 
 titanic acid in, 96. 
 
 uses of, 105. 
 
 varieties, 99. 
 
 water in, 96. 
 
 Clay soils, properties, 215. 
 Clausthal, Prussia, banded veins at, 287. 
 Clifton, Ariz., copper, 293. 
 Clinton limestone, gas in, 55. 
 Clinton ore, 266. 
 
 analyses, 268. 
 
 Birmingham, Ala., 266. 
 
 character, 266. 
 
 distribution, 266. 
 
 origin, 267. 
 Coal, 8. 
 
 age of, 19. 
 
 anthracite, defined, 5. 
 
 bituminous, defined, 4. 
 
 bone, 24. 
 
 onnnel, defined, 5. 
 
 Carboniferous, distribution, 19. 
 
 cretaceous, distribution, 19. 
 
 distribution, Alabama, 20; Alaska, 82; 
 Appalachian field, 20; Arkansas. 28, 
 80; California, 82; Colorado, 81;
 
 INDEX 
 
 439 
 
 Coal, distribution continued. 
 
 Dakota, 31 ; Eastern Interior field, 26 ; 
 Illinois, 27 ; Indiana, 27 ; Indian Ter- 
 ritory, 29; Iowa, 29; Kansas, 29; 
 Kentucky, 27; Maryland, 22; Michi- 
 gan, 27 ; Montana, 31 ; New Mexico, 
 81 ; Northern Interior field, 27 ; Ore- 
 gon, 82 ; Pacific coast field, 31 ; Penn- 
 sylvania, 22; Rhode Island field, 25; 
 Eocky Mountain field, 80; South 
 Dakota, 31 ; Southwestern field, 29 ; 
 Texas, 30 ; Triassic area, 25 ; United 
 States, 18 ; Washington, 32 ; Western 
 Interior field, 29. 
 elementary analysis, 14. 
 faulting, 18. 
 
 formation of, chemical changes during, 12. 
 geologic distribution in United States, 19. 
 heat and pressure, effect on, 14. 
 kinds of, 8. 
 origin of, 9. 
 outcrops, 15. 
 price per ton, 84. 
 production of, 88. 
 
 proximate analysis of, explained, 6. 
 proximate analyses of United States coals, 6. 
 references on, 35. 
 rocks associated with, 16. 
 seams, see Coal beds, 
 semi-bituminous, defined, 5. 
 Triassic, distribution, 19. 
 Coal beds, pinching of, 16. 
 splitting of, 17. 
 structural features, 15. 
 swelling of, 16. 
 thickness of, 16. 
 Coal-blossom, 16. 
 Coal-brasses, 200. 
 Coal-breaker, 24. 
 Cobalt, Missouri, 404. 
 ores, 404. 
 
 production of, 406. 
 references on, 407. 
 uses, 406. 
 
 Cobaltite, as mineral pigment, 188. 
 Coke, natural, see Carbonite. 
 
 production of, 85. 
 Colemanite, 184. 
 
 Colorado, anthracite coal, analysis of, 8 ; coal, 
 31 ; coking coal, analysis of, 7 ; cop- 
 per. 298 ; desilverized lead, 807 ; fire 
 clay, 103 ; lignite, analysis, 6 ; limon- 
 ite, 271 ; magnetite, 256 ; manganese, 
 888 ; petroleum, 53 ; Portland cement 
 materials, 119 ; stoneware clay, 108 ; 
 topaz,194; tungsten,415; uranium,416. 
 Comb structure, 287. 
 Comstock lode, Nevada, 844. 
 Conglomerate, copper-bearing, 288. 
 Connecticut, barite, 170 ; garnet, 163 ; kaolin, 
 101 ; lithium minerals, 188 ; tungsten 
 in, 415. 
 
 Contact deposits, copper ores, 298, 279. 
 
 examples of, 285. 
 
 Contemporaneous ores, in igneous rocks, 
 224. 
 
 in sedimentary rocks, 225. 
 Copper, 278. 
 
 in hot spring deposit, 228. 
 
 in iron ores, 252. 
 
 mode of occurrence In United States, 
 279. 
 
 native, 278, 279, 287, 289, 296. 
 
 ores of, 278. 
 
 production, 299. 
 
 references on, 801. 
 
 with mercury, 898. 
 Copper ore, analysis, California, 298. 
 analyses of, Montana, 285. 
 distribution, 281; Alaska, 298; Appala- 
 chian region, 294 ; Ariz., 290 ; Bis- 
 bee, Ariz., 290; California, 297; 
 Clifton, Ariz., 293; Colorado, 298; 
 Connecticut, 296; Globe, Ariz., 294; 
 Idaho, 298; Jerome district, 292; 
 Michigan, 287 ; Montana, 282 ; New- 
 Jersey, 296; New Mexico, 298; 
 Pennsylvania, 296; Utah, 296 ; Wyo- 
 ming, 298. 
 
 Copper ores, gold and silver bearing, 828. 
 impurities, 280. 
 superficial alteration, 280. 
 Coquina, 80. 
 
 Corniferous limestone, gas in, 55. 
 Cornwall, England, tin veins, 285. 
 Cornwall, Pa., magnetite, 256. 
 Corsicana, Texas, petroleum, 52. 
 Corundum, ore of aluminum, 875. 
 as abrasive, 163. 
 distribution, 168. 
 Georgia, 164. 
 North Carolina, 164. 
 mechanical concentration, 165. 
 origin, 164. 
 
 Cottonwood district, Utah, SOT. 
 Covellite, 285, 286. 
 
 carrying platinum, 408. 
 Creede, Colo., 807. 
 Crested Butte, Colo., 15. 
 Cretaceous, glass sand in, 176; greensand In, 
 155 ; lignite, 19 ; limestone for lime, 
 116; mercury, 892; petroleum, 58; 
 phosphate, 158; shale for Portland 
 cement, 119. 
 
 Crimora, Va., manganese, 885. 
 Cripple Creek, Colo., gold, 388. 
 Crustification, defined, 286. 
 Cryolite, 875. 
 
 Crystal Falls district, hematite, 261. 
 Culm, defined, 24. 
 
 uses, 24. 
 
 Cuprite, 278, 291. 
 Cut-off, in quarries, 74.
 
 440 
 
 INDEX 
 
 Dakota, lignite In, 81. 
 Dead Sea, analysis of water, 124. 
 Descension theory, 240. 
 Devonian, phosphate in, 153. 
 Diamond, properties of, 192. 
 
 South Africa, 192. 
 
 United States, 192. 
 Didymium in inonazite, 191. 
 Dismal Swamp, analysis of peat from, 6. 
 Disseminated ores, 242. 
 Dolomite, see Gangue. 
 
 defined, 78. 
 
 petroleum in, 51. 
 Douglas Island, Alaska,, 864. 
 Dredging gold, 848. 
 Drift mining, gold, 847. 
 Duck Elver, Tenn., phosphate deposits, 151. 
 Ducktown, Tenn., copper at, 295. 
 Dune soils, 214. 
 
 Eagle Pass, Texas, coal, 80. 
 Earthenware clay, defined, 99. 
 Earth's crust, zones in, 228. 
 Eldridge, on Florida phosphate, 149. 
 Embolite, 825. 
 
 Emerald, distribution, Brazil, 194 ; Ceylon, 198 ; 
 Hindostan, 193; North Carolina, 198; 
 Siberia, 193. 
 
 lithia, 194. 
 
 properties, 198. 
 Emery, defined, 168. 
 
 Massachusetts, described, 164. 
 
 New York, mentioned, 164. 
 Emmons, cited, 280. 
 Enargite, 278, 279, 284, 872. 
 England, fuller's earth in, 175. 
 Epidote, 295, 826. 
 
 in contact deposits, 235. 
 
 Faults, effect on oil reservoir, 58. 
 
 relation to oil springs, 58. 
 Feather Eiver, Calif., gold in, 849. 
 Ferric sulphate, as a solvent of ores, 244. 
 
 effect on pyrite, 244. 
 Ferro-chromium, 401. 
 Ferro-nickel, 401. 
 Ferro-titanium, 414. 
 Fertilizers, apatite, 147. 
 
 listed, 147. 
 
 production of, 156. 
 
 references on, 157. 
 
 See Phosphate, Guano, Gypsum, and 
 
 Greensand. 
 
 Findlay, Ohio, oil pressure at, 45. 
 Fire clay, analysis of, 98. 
 
 defined, 99. 
 
 distribution in United States, 102. 
 
 under coal, 16. 
 
 Fissure veins, apex, 239. 
 
 bonanzas, 237. 
 
 boundaries of, 236. 
 
 comb structure, 237. 
 
 filling of, 240. 
 
 foot wall, 239. 
 
 hanging wall, 289. 
 
 linked, 239. 
 
 lode, 239. 
 
 ores common in, 237. 
 
 secondary banding, 286. 
 
 selvage in, 237. 
 
 strike of, 239. 
 
 Fixed carbon, effect of, in coal, 8. 
 Flagstone, defined, 85. 
 Flats, 312. 
 
 Flint clay, defined, 99. 
 Florence oil field, Colorado, 58. 
 Florida, ball clay, 103 ; phosphate, 148 ; phos- 
 phate, uses, 154. 
 Fluorspar, characters, 171. 
 
 distribution, Arizona, 173 ; Illinois, deposits 
 described, 172 ; Kentucky, 178 ; Ten- 
 nessee, 173. 
 
 gangue mineral, 172. 
 
 gems, 195. 
 
 occurrence, 171. 
 
 origin, 178. 
 
 production, 178. 
 
 references on, 178. 
 
 uses, 178. 
 Foot wall, 239. 
 
 Fort Dodge, Iowa, gypsum at, 140. 
 Foster, on Lake Superior ores, 262. 
 Fountain head, 209. 
 France, buhrstones, 161. 
 Franklinite, 303, 804, SOS, 810. 
 Fredonia, N.T., gas, 40. 
 Freestone, defined, 85. 
 Freiberg, Saxony, banded veins at, 237. 
 Fuel ratio, 8. 
 Fuller's earth, analyses of, 175. 
 
 difference from clay, 174. 
 
 distribution, Alabama, 175; Arkansas, 175; 
 England, 175; Florida, 175; Ne- 
 braska, 175; New York, 175; South 
 Dakota, 175. 
 
 geological distribution, 175. 
 
 production of, 176. 
 
 properties, 174. 
 
 references on, 176. 
 
 Gaffney, S.C., tin, 411. 
 Galena, as a contact ore, 285. 
 
 mentioned, 803, 305, 306, 811, 812, 818, 815, 
 
 329, 365, 870,871, 372, 878, 412. 
 Galicia, ozokerite in, 59. 
 Galvanic action, ore precipitation by, 285. 
 Gangue minerals, barite, 811, 315, 336, 842, 365, 
 
 867, 872. 
 Cftloite, 811, 812, 815, 842, 865, 390, 893, 396.
 
 INDEX 
 
 441 
 
 jQaugue minerals continued. 
 chert, 315, 365. 
 
 dolomite, 811, 815, 339, 342, 367. 
 epidote, 295, 412. 
 fluorite, 311, 839, 410, 412. 
 garnet, 295. 
 lepidolite, 410. 
 marcasite, 312, 818. 
 muscovite, 410. 
 orthoclase, 839, 844. 
 quartz, 811, 885, 836, 339, 342, 844, 867, 370, 
 
 872, 873, 390, 896, 412. 
 rhodochrosite, 842, 370, 883. 
 topaz, 410, 412. 
 zinnwaldite, 412. 
 Garnet, as an abrasive, 163. 
 as a gem, 194. 
 
 distribution, Arizona, 195 ; Connecticut, 
 mentioned, 163; India, 194; New 
 Mexico, 195 ; New York, mentioned, 
 168 ; North Carolina, 195 ; Tennessee, 
 163. 
 
 In contact deposits, 235. 
 uses as abrasive, 163. 
 Gash veins, in Wisconsin, 240. 
 
 defined, 240. 
 
 Gasoline, in petroleum, 42. 
 Genthite, 404. 
 
 Georgia, asbestos, 167 ; bauxite, 376 ; corun- 
 dum, 164 ; graphite, 179 ; manganese, 
 886; ocher, 187; phosphate, 154; 
 stoneware clay, 103. 
 German silver, 321. 
 Germany, buhrstones from, 161. 
 Gibbsite, 875. 
 
 analysis of, 60. 
 
 occurrence, 59. 
 
 properties, 59. 
 Glacial soils, 214. 
 Glass sand, analyses of, 177. 
 
 distribution, Illinois, 177 ; Iowa, 177 ; Mary- 
 land, 177; Massachusetts, 177; New 
 Jersey, 177 ; Pennsylvania, 177 ; West 
 Virginia, 177. 
 
 effect of clay in, 176. 
 
 effect of iron oxide on, 176. 
 
 geologic distribution, 176. 
 
 production, 177. 
 
 properties, 176. 
 
 references on, ITS. 
 Glauber salt, 136. 
 Globe, Ariz., copper, 294. 
 Gold, gravels, 346. 
 
 gravels, Pacific Coast, 847. 
 Gold Hill, N.C., copper at, 295. 
 Gold, in beach sands, 849. 
 
 native, 825, 836, 889, 865. 
 Gold ores, chlorination process, 880. 
 
 classification, 327. 
 
 cyanide process, 830. 
 
 distribution, Alaska, 353; Alaska, placer 
 
 deposits, 856; Black Hills, 850; Crip- 
 ple Creek, Colo., 888 ; Cordilleran re- 
 gion, 332 ; Homestake belt, 8. Dak., 
 351 ; Idaho, 887 ; Mercur, Utah, 836 ; 
 Michigan, 852 ; Montana, 887 ; Mother 
 Lode belt, Calif., 838; Nevada Co., 
 Calif., 334; Oregon, 885; Pacific coast 
 belt, 332 ; Washington, 835. 
 
 eastern crystalline belt, 852. 
 
 extraction, 829. 
 
 free milling, defined, 829. 
 
 geologic distribution, 829. 
 
 gold-milling centres, 830. 
 
 igneous rocks associated with, 826. 
 
 in igneous rocks, 826. 
 
 in metamorphic rocks, 326. 
 
 in propylitic veins, 826. 
 
 listed, 825. 
 
 mode of occurrence, 326. 
 
 production of, 858. 
 
 quartzose, 328. 
 
 quartz veins, 826. 
 
 references on, 860. 
 
 refractory, defined, 829. 
 
 sands in arid region's, 849. 
 
 secondary enrichment of, 327. 
 
 siliceous, Cambrian, South Dakota, 852. 
 
 uses of, 857. 
 
 valuation of, 830. 
 
 wall rocks, 826. 
 
 weathering of, 827. 
 
 with mercury, 893. 
 
 with platinum, 408. 
 
 Gold-silver ores, distribution, Bohemia district, 
 Ore., 845; Boulder Co., Colo., 845; 
 Central Belt, 335; Clear Creek Co., 
 Colo., 845; Comstock lode, Nev., 
 844 ; Eastern Belt, Tertiary ores, 337 ; 
 Gilpin Co., Colo., 845 ; Monte Cristo, 
 Wash., 345; Ouray, Colo., 842; Owy- 
 hee Co., Ido.,345; San Juan region, 
 Colo., 841 ; Silverton, Colo., 841 ; Tel- 
 luride, Colo., 842 ; Tonopah, 843. 
 Gold veins, associations with igneous rock, 280. 
 Gossan, defined, 242. 
 
 leaching of, 244. 
 Grahamite, analysis of, 60. 
 
 occurrence, 59. 
 
 Grand Eapids, Mich., gypsum at, 142. 
 Granites, 75. 
 
 characteristics of, 75. 
 
 color of, 75. 
 
 distribution, California, 77 ; Central States, 
 77 ; eastern crystalline belt, 77 ; Min- 
 nesota, 77; Missouri, 77; Montana, 
 77; Oregon, 77; South Dakota, 77; 
 Texas, 77 ; United States, 77 ; Wash- 
 ington, 77 ; western states, 77. 
 
 durability of, 75. 
 
 geologic range, 76. 
 
 uses of, 77. 
 
 weight of, 75.
 
 442 
 
 INDEX 
 
 Graphite, amorphous, 179. 
 
 amorphous, Khode Island, 179. 
 analysis, 178. 
 artificial, 180. 
 as mineral pigment, 188. 
 distribution, Alabama, 179; Ceylon, 179; 
 Ceylon, origin, 179; Georgia, 179; 
 Michigan, not such, 179; Montana, 
 179; New Hampshire, 179; New 
 York, 179; North Carolina, 179; 
 Pennsylvania, 179 ; Wisconsin, not 
 such, 179. 
 occurrence, 178. 
 production, 180. 
 properties of, 178. 
 references on, 181. 
 uses, 179. 
 
 Grass Valley, Calif, 834. 
 banded veins at, 287. 
 Gravels, auriferous, 846. 
 Gravity of petroleum, 41. 
 Great gossan lead, 295. 
 Great Salt Lake, analysis of water, 124. 
 Greenland, cryolite in, 378. 
 Greensand, analyses, 156. 
 defined, 155. 
 distribution, 155. 
 source of Texas limonite, 271. 
 Virginia, uses of, 155. 
 Greisen, tin bearing, 410. 
 .Grindstones, distribution, 159. 
 
 properties of, 158. 
 Ground water, 208. 
 
 movements of, 208. 
 Guano, 156. 
 bat, 155. 
 
 bat, analysis, 156. 
 bat, Texas, 155. 
 kinds, 155. 
 Peru, 165. 
 West Indies, 165. 
 Gumbo clay, defined, 99. 
 Gypsite, defined, 189. 
 
 distribution, Kansas, 141 ; Oklahoma, 142 ; 
 
 Texas, 142; Wyoming, 142. 
 origin of, 140. 
 
 Gypsum, absence from Kansas salt beds, 130. 
 analyses before and after calcination, 144. 
 analyses of, 148. 
 as mineral pigment, 187. 
 calcination process, 144. 
 composition, 139. 
 
 distribution, Arizona, 142 ; California, 142 ; 
 Colorado, 142 ; Idaho, 142 ; Iowa, 140 ; 
 Kansas, 141 ; Michigan, 142 ; Mon- 
 tana, 142 ; Nevada, 142 ; New York, 
 142 ; Ohio, 142 ; South Dakota, 142 ; 
 Vermont, 142 ; Virginia, 142. 
 formed from pyrite, 140. 
 formed from sea-water, 140. 
 geologic distribution, 189. 
 occurrence, 189. 
 
 origin, 189. 
 production of, 145. 
 references on, 146. 
 uses, 143. 
 volcanic origin of, 140. 
 
 Hamilton shales, for Portland cement, 118. 
 
 Hanging wall, 239. 
 
 Hayes, on Arkansas bauxite, 879. 
 
 on Georgia bauxite, 876. 
 
 on Tennessee phosphates, 158. 
 Hematite, 259. 
 
 analysis, Lake Superior, 264. 
 
 as mineral pigment, 186. 
 
 distribution, Alabama, 268; Lake Superior 
 region, 259; Missouri, 269; Utah, 
 268; Wyoming, 268; United States, 
 259. 
 
 in contact deposits, 285. 
 
 with mercury, 398. 
 
 See Clinton ore. 
 
 Hermann, on weight of stones, 71. 
 Hindostan, emerald in, 193. 
 Hindostan stone, 160. 
 Holston Valley, Va., gypsum, 142. 
 Horn silver, 325. 
 Hot spring, gold-bearing, 228. 
 Hot spring deposits, see Stibnite, Pyrite, 
 
 Copper. 
 
 Hot Springs, 204. 
 Hubnerite, 414. 
 Humus, 213. 
 Hungary, opal in, 195. 
 Huronian, iron ores in, 261. 
 Hydraulic limes, see Lime. 
 Hydraulic mining, 348. 
 
 Idaho, auriferous lead ores in, 829 ; copper, 
 298; nickel, 405; silver-lead ores, 372. 
 
 Idaho basin, Idaho, 337. 
 
 Igneous rocks, miscellaneous, for building, 78. 
 
 Illinois, brick clays, 104; bituminous coal, 
 analysis of, 7 ; coal field, 26 ; glass 
 sand, 177; natural rock cement, 118; 
 ocher, 187 ; sienna, 187 ; stoneware 
 clay, 108. 
 
 Ilmenite, 257, 418. 
 
 India, garnet in, 194. 
 source of mica, 186. 
 
 Indiana, Brazil coal, analysis of, 7 ; brick clays, 
 104 ; cannel coal, analysis of, 7 ; coal 
 field, 27 ; petroleum, distillates from, 
 42 ; natural gas, 55 ; natural gas analy- 
 sis, 48 ; petroleum, 50 ; Portland ce- 
 ment materials, 119 ; stoneware clay, 
 103 ; whetstones mentioned, 160. 
 
 Indian Territory, coal field, 29; natural gas, 
 55. 
 
 Infusorial earth, defined, 162. 
 
 distribution, California, 162 ; Maryland, 162 ;
 
 INDEX 
 
 443 
 
 Infusorial earth, distribution continued. 
 
 Missouri, 162; Nevada, 162; New 
 England, 162 ; New York, 162 ; Vir- 
 ginia, 162. 
 
 German deposits, 162. 
 
 uses, 162. 
 
 Iowa, bituminous coal, 7; coal in, 29; glass 
 sand in, 177 ; gypsum, 140 ; lime rock 
 in, 116 ; limonite in, 271 ; lithographic 
 stone in, 182 ; stoneware clay in, 103 ; 
 zinc ores in, 311. 
 Iridium, properties and occurrence, 410. 
 
 uses, 410. 
 
 with platinum, 407. 
 Iron, in copper ores, 280. 
 Iron Mountain, Calif., copper, 298. 
 Iron ores, distribution, Alabama, 266, 271; 
 Arkansas, 271 ; California, 256 ; Colo- 
 rado, 256, 257 ; Iowa, 271 ; Kentucky, 
 278 ; Michigan, 256, 261, 265 ; Minne- 
 sota, 257, 261, 264, 271 ; Missouri, 
 269; New Jersey, 256, 257; New 
 Mexico, 256, 268; New Tork, 255, 
 257, 258, 266, 273; North Carolina, 
 255; Ohio, 266, 273; Oregon, 271; 
 Pennsylvania, 256, 273; Sweden, 270 ; 
 Texas, 271; Utah, 256, 268; Ver- 
 mont, 271 ; Virginia, 271 ; Wisconsin, 
 261, 266, 271 ; Wyoini 
 
 distribution in United States, 254. 
 
 geologic distribution, 254. 
 
 impurities in, 252. 
 
 magnetite, modes of occurrence, 254. 
 
 magnetites, origin of, 256. 
 
 modes of origin, 253. 
 
 non-titaniferous, 254. 
 
 production of, 278. 
 
 references on, 276. 
 
 See Hematite and Limonite. 
 Iron oxide, effect on clay, 95. 
 
 in soils, 214. 
 Irving, on Lake Superior ores, 262. 
 
 Japan, solfataric sulphur in, 196. 
 Jenney, on Missouri lead zinc ores, 817. 
 Jennings, La., petroleum, 52. 
 Jerome, Ariz., copper, 292. 
 Jet, 4. 
 
 Joplin, Mo., zinc ores, 808, 314. 
 Josephinite, 408. 
 
 Jurassic, gold, 333; lithographic stone, 
 sulphur in, 197. 
 
 Kansas, coal, 29 ; gypsite, 141 ; gypsum, 141 
 lime rock, 116 ; natural gas, 55 ; petro 
 leum, 52 ; petroleum, distillates from 
 42 ; Portland cement materials, 119 
 salt, 130. 
 
 Kaolin, denned, 99. 
 analysis of, 98, 101. 
 
 distribution, Alabama, 101; Connecticut, 
 101 ; Maryland, 101 ; North Carolina, 
 101; Pennsylvania, 101; Virginia, 
 101. 
 origin, 93. 
 
 Kaolinite, 92. 
 analysis of, 98. 
 product of metasomatism, 326. 
 
 Kemp, cited, 230, 246, 257, 810, 407. 
 
 Kentucky, ball clay in, 103; bat guano, 155; 
 bituminous coal, analysis of, 7 ; coal 
 field, 27 ; fluorspar, 178 ; lithographic 
 stone, 182; molding sand, 190; natu- 
 ral gas, 56 ; natural rock cement, 118 ; 
 stoneware clay, 103. 
 
 Kerosene, in Wyoming petroleum, 58. 
 
 Kerosene shale, 57. 
 
 Keweenaw series, Michigan, 287. 
 
 Klondike Kiver, Alaska, 854, 856. 
 
 Knox dolomite, 876. 
 
 Kunzite, as gem, 195. 
 
 Lake asphalt, 59. 
 
 Lake Superior ores, 259. 
 
 analyses, 264. 
 
 character, 260. 
 
 development, 265. 
 
 origin, 263. 
 
 Lanthanum, in monazite, 191. 
 Lateral secretion theory, 240. 
 Lead, desilverized, occurrences, 807. 
 
 gangue minerals of, 804. 
 
 ores of, 303. 
 
 production of, 821. 
 
 references on, 828. 
 
 uses of, 319. 
 
 with mercury, 898. 
 Lead ores, Colorado, 307. 
 
 disseminated, 306. 
 
 distribution, Appalachian belt, 806; Mis- 
 souri, 806, 814; Rocky Mountain 
 states, 818. 
 
 gold and silver bearing, 828. 
 
 impurities in, 804. 
 
 modes of occurrence, 804. 
 
 superficial alteration, 805. 
 Leadville, Colo., 364. 
 Lepidolite, 183. 
 
 Lesley, on origin of petroleum, 44. 
 Lift, in quarries, 74. 
 Lignite, 4. 
 
 age of, 4. 
 
 areas in United States, 19. 
 
 Gulf States area, 30. 
 
 properties of, 4. 
 Lime, effect on clay, 96. 
 
 effect on soils, 215. 
 
 In iron ores, 252. 
 
 properties, 110. 
 
 references on, 121. 
 
 uses of, 119.
 
 444 
 
 INDEX 
 
 JJmes, hydraulic, distribution, 117. 
 
 properties of, 112. 
 Limestone, analyses, 109. 
 
 burning, changes in, 110. 
 
 Cretaceous, for building, 80. 
 
 distribution in United States, 80. 
 
 for lime, distribution, 116. 
 
 for Portland cement, 114, 118. 
 
 general characteristics, 78. 
 
 lithographic, 181. 
 
 varieties, 78. 
 
 See Building stones. 
 Limonite, 269. 
 
 advantage of using, 272. 
 
 analyses of, 272. 
 
 bog ores, 269. 
 
 Cambro-Silurian, 271. 
 
 distribution, Appalachian, 271; Arkansas, 
 271 ; Colorado, 271 ; Iowa, 271 ; Min- 
 nesota, 271 ; Oregon, 271 ; Texas, 
 271 ; Wisconsin, 271. 
 
 Great Gossan Lead, 271. 
 
 manganiferous, 271. 
 
 residual, 270. 
 
 with mercury, 393. 
 Lindgren, cited, 280. 
 
 on Colorado gold ores, 887. 
 Linked veins, 239. 
 Linnaeite, 404. 
 Lipari, pumice from, 162. 
 Litharge, 819. 
 
 Lithium, distribution, California, 188 ; Connec- 
 ticut, 183 ; South Dakota, 183. 
 
 industry, 183. 
 
 minerals as sources of, 183. 
 
 production, 183. 
 
 Lithographic stone, analyses, 181. 
 
 definition, 181. 
 
 distribution, Bavaria, 182 ; Iowa, 182; Ken- 
 tucky, 182. 
 
 physical properties, 182. 
 
 references on, 183. 
 Lithophone paint, 170. 
 Lode, 239. 
 Loess, defined, 99. 
 Louisiana, petroleum, 52; salt, 129; sulphur, 
 
 197. 
 
 Lower Carboniferous, fluorspar in, 172. 
 Lower Helderberg, limestone for lime, 116. 
 
 Magmatic segregation, 224. 
 
 in acid rocks, 225. 
 
 in basic rocks, 224. 
 
 of copper, 279. 
 
 Magmatic water, effects of, 280. 
 Magnesia, effect on clay, 96. 
 
 in iron ores, 252. 
 
 in natural cements, 113. 
 
 in soils, 214. 
 
 Magnesite, California, 184. 
 
 occurrence and properties, 188. 
 
 production, 184. 
 
 references on, 184. 
 
 uses, 184. 
 Magnetite, as a contact ore, 235. 
 
 non-titaniferous, 254. 
 
 sand, 258 ; nee Iron ores. 
 
 titaniferous, 257. 
 analyses, 258. 
 distribution, 257. 
 origin, 257. 
 
 Maine, molybdenum, 408 ; topaz, 194. 
 Malachite, 278, 231, 291, 293, 871. 
 Malay peninsula, tin from, 412. 
 Maltha, analysis of, 60. 
 
 Manganese, distribution, Arkansas, 887 ; Cali 
 fornia, 887; Colorado, 888; eastern 
 area, 885; Georgia, 385; Utah, 888; 
 Virginia, 886. 
 
 in iron ores, 252. 
 
 ores of, 883. 
 
 origin, 884. 
 
 production, 888. 
 
 references on, 889. 
 
 uses, 388. 
 Marbles, distribution in United States, 81. 
 
 general characteristics, 78. 
 
 See Building stones. 
 Marl, for Portland cement, 114, 119. 
 Marquette range, 261, 263. 
 Marsh gas, in natural gas, 42. 
 
 properties, 42. 
 Marshes, salt, cause of, 127. 
 Maryland, coal, referred to, 37 ; glass sand, 177 ; 
 infusorial earth, 162; kaolin, 101; 
 marble, 82 ; natural rock cement, 118. 
 Marysville, Mont., 887. 
 Massachusetts, emery in, described, 164 ; glass 
 
 sand, 177 ; marble, 82 ; pyrite, 199. 
 Mechanical concentration, 289, 810, 318, 
 
 315. 
 
 Mediterranean Sea, analysis of water, 124. 
 Melaconite, 278, 295. 
 Mendeljeff, on petroleum origin, 46. 
 Menominie range, 261. 
 Mercur, Utah, 836. 
 Mercury, 890. 
 
 associated minerals, 893. 
 
 distribution, California, 890; Oregon, 392; 
 Texas, 892. 
 
 extraction, 894. 
 
 mode of occurrence, 890. 
 
 ores of, 890. 
 
 origin, 893. 
 
 production of, 394. 
 
 references on, 395. 
 
 uses, 393. 
 
 Merrill, G. P., on chrysotUe veins, 169. 
 Mesabi range, Minnesota, 261, 262. 
 Mesozoic, auriferous gravels, 827 ; clays of, 100; 
 petroleum, 53 ; quartzose ores, 328.
 
 INDEX 
 
 445 
 
 Metals, disseminated in granite, 226. 
 
 disseminated in limestone, 226. 
 
 disseminated in quartz-porphyry, 226. 
 
 distribution in rocks, 226. 
 
 precipitation, conditions governing, 232. 
 Metasomatism, defined, 233. 
 
 pressure accompanying, 233. 
 
 temperature during, 233. 
 
 variation in process of, 233. 
 Meteoric waters, importance in secondary con- 
 centration, 230. 
 
 Mexico, opal in, 195; solfataric sulphur in, 196. 
 Mica, distribution, North Carolina, 185. 
 
 in kaolin, 100. 
 
 mode of occurrence, 186. 
 
 production of, 186. 
 
 references on, 186. 
 
 species of economic value, 185. 
 
 value of, 186. 
 Micanite, 185. 
 
 Michigan, bituminous coal, analysis of, 7; 
 brick clays, 104 ; coal field, 28 ; cop- 
 per ores, 28T ; gold, 852 ; graphite, so- 
 called, 180; gypsum, 142; iron ore, 
 261 ; magnetite, 256 ; Portland cement 
 materials, 119 ; salt in, 129. 
 Millerite, 404. 
 Millstones, characters, 161. 
 
 distribution, 161. 
 Mine Hill, N.J., zinc ore, 309. 
 Mine waters, analyses of, 227. 
 
 vadose, 227. 
 Mineral pigments, 186. 
 
 asbestos, 188. 
 
 barite, 187. 
 
 graphite, 188. 
 
 gypsum, 187. 
 
 hematite, 186. 
 
 ochers, 186. 
 
 production, 188. 
 
 references on, 189. 
 
 slate, 187. 
 
 Mineral springs, volume of discharge, 205. 
 Mineral waters, analyses, 206. 
 
 classification, 205. 
 
 defined, 204. 
 
 distribution, 205. 
 
 origin and occurrence, 204. 
 
 production of, 206. 
 
 references on, 207. 
 
 thermal springs, 204. 
 Mineralizing vapors, 284. 
 
 in contact deposits, 285. 
 Minerals, in contact deposits, 285. 
 Minnesota, hematite, 261, 264 ; limonite, 271. 
 Miocene, petroleum, 58 ; phosphate, 150. 
 Mississippi, lignite in, 80. 
 Mississippi delta, soils of, 214. 
 Missouri, bituminous coal, analysis of, 7 ; ball 
 clay, 103 ; barite, 170 ; hematite, 269 : 
 Infusorial earth, 162 ; lime rock, 116 ; 
 stoneware clay, 103. 
 
 Moisture in coal, 8. 
 Molding sand, analysis, 189. 
 
 distribution, 190. 
 
 mechanical composition, 189. 
 
 references on, 190. 
 Molybdenite, 339, 408. 
 Molybdenum, 403. 
 
 in Maine, 403. 
 
 in western states, 408. 
 
 ores and occurrences, 408. 
 
 production of, 403. 
 
 references on, 403. 
 
 uses, 403. 
 Monazite, analyses, 191. 
 
 composition, 190. 
 
 distribution, Brazil, 190; North Carolina, 
 190 ; South Carolina, 190. 
 
 magnetic separation of, 191. 
 
 occurrence, 190. 
 
 production of, 191. 
 
 references on, 191. 
 
 uses, 191. 
 
 Montana, asbestos, 168 ; silver, 284 ; coal, 81 ; 
 copper ores, 282 ; graphite, 179 ; lignite 
 analysis from, 6 ; molybdenum, 403 ; 
 sapphire, 198 ; silver-lead ores, 878. 
 Monte Cristo, Wash., 835. 
 
 direction of veins at, 288. 
 Montezuma, Colo., zinc concentrates, 819. 
 Moss agate, as gem, 195. 
 Mother lode, California, gold, 338. 
 Muscovite, as source of mica, 185. 
 
 Naphthas, In petroleum, 42. 
 
 Natural gas, analyses of, 43. 
 
 anticlinal theory, 48. 
 
 distribution, California, 56; Indiana, 55; 
 Indian Territory, 55; Kansas, 55; 
 Kentucky, 56 ; New York, 54 ; Ohio, 
 55; Pennsylvania, 54; Texas, 66; 
 West Virginia, 55. 
 exhaustion of, 54. 
 geologic distribution, 48. 
 history of development, 40. 
 occurrence of, 48. 
 pressure in well, 44. 
 properties of, 42. 
 references on, 67. 
 uses of, 66. 
 
 Natural rock cements, see Cements. 
 Nebraska, fullers earth in, 175. 
 Nevada, infusorial earth, mentioned, 162 ; mag- 
 maticaUy segregated ores in, 225 ; sol- 
 fataric sulphur, 197 ; silver-lead ores, 
 373 ; tungsten in, 415. 
 Nevada City, Calif., 834. 
 
 Newberry, on temperature petroleum forma- 
 tion, 47. 
 
 New Brunswick, albertite in, 69. 
 New Caledonia, nickel supply from, 405.
 
 446 
 
 INDEX 
 
 New England, Infusorial earth, mentioned, 162. 
 lime rock in, 116. 
 
 New Hampshire, graphite in ; 179 ; whetstones 
 mentioned, 160. 
 
 New Jersey,ballclay,108; copper,296; glass sand, 
 177 ; greensand, 155 ; magnetite, 256 ; 
 molding sand, 190 ; Portland cement 
 materials, 118 ; stoneware clay, 103. 
 
 New Mexico, anthracite coal, analysis of, 8 ; 
 bauxite, 379; coal, 30, 81; copper, 
 298; garnet, 195; magnetite, 256; 
 molybdenum, 403; silver-lead ores, 
 873 ; turquoise, 194 ; vanadium, 416. 
 
 New York, Clinton ore, 266 ; emery, mentioned, 
 164; fuller's earth, 175; garnet, 163; 
 graphite, 179 ; gypsum, 142 ; infuso- 
 rial earth, mentioned, 162 ; limestone ; 
 116 ; magnetite, 255 ; marble, 82 ; mill- 
 stones, 161 ; molding sand, 190 ; natu- 
 ral gas, 54 ; natural rock cement, 118 ; 
 petroleum occurrence, 48; Portland 
 cement materials, 118 ; production of 
 gypsum, 145; pyrite, 199; salt, 127; 
 siderite, origin of, 273 ; sienna, 187 ; 
 talc, 202 ; whetstones, mentioned, 160. 
 
 New Zealand, magnetite sand, 258. 
 
 Niccolite, 404. 
 
 Nickel ores, 404. 
 
 Nickel, analysis of, 405. 
 
 distribution, Missouri, 404 ; North Carolina, 
 404; Ontario, Canada, 404; Pennsyl- 
 vania, 404; western states, 404. 
 production of, 406. 
 references on, 407. 
 uses of, 405. 
 
 Nile Valley, alluvial soils, 214. 
 
 Nitrogen, in natural gas, 214. 
 in soils, 214. 
 
 Norite, New York, 78. 
 
 North Carolina, asbestos, 167; barite, 170; 
 corundum, 164 ; emerald, 198 ; garnet, 
 195 ; graphite, 179 ; kaolin, 101 ; mag- 
 netite, 255 ; mica in, 185 ; millstones 
 in, 161 ; monazite in, 190 ; phosphate 
 in, 154 ; pyrophyllite, 203 ; rubies, 193 ; 
 talc, 201 ; tin, 411 ; Triassic coal, 25. 
 
 North Dakota, Portland cement materials, 119. 
 
 Norway, titanium in, 418. 
 
 Novaculite, 160. 
 origin, 160. 
 
 Nuggets, gold, 846. 
 
 O 
 
 Ocher, as mineral pigment, 186. 
 classification, 187. 
 composition, 187. 
 distribution, 1ST. 
 origin, 187. 
 
 Ochsenius, on origin of salt, 125. 
 
 Ogdensburg, New Jersey, zinc ore, 309. 
 
 Ohio, brick clays, 104; brines, 129; Clinton 
 ore, 266 ; gypsum, 142 ; Hocking 
 Valley coal, analysis of, 7 ; molding 
 
 sand, 190 ; natural gas analysis, 43 ; 
 natural gas, 55 ; natural rock cement, 
 118 ; petroleum, 50 ; Portland cement 
 materials, 119 ; siderite, 273 ; stoneware 
 clay, 103 ; whetstones, mentioned, 160. 
 Oil rock, capacity of, 44. 
 Oil shales, analysis, 57. 
 distillation of, 57. 
 geographic distribution, 57. 
 properties, 56. 
 references on, 67. 
 Oil springs, 52. 
 Oilstones, defined, 159. 
 
 distribution, 160. 
 Oklahoma, gypsite in, 142. 
 Oliphant, on petroleum distillates, 42. 
 Ontario, anthraxolite in, 59. 
 Ontario, nickel, 404. 
 Onyx marbles, 83. 
 characters, 83. 
 distribution, 83. 
 for lithographic work, 182. 
 references on, 91. 
 Oolitic, limestone, defined, 80. 
 Opal, composition and occurrence, 195. 
 
 distribution, Hungary, 195; Mexico, 195; 
 
 Oregon, 195 ; "Washington, 195. 
 Orange Spring, Fla., 205. 
 Ordovician, lead in, 306 ; limestones, 116. 
 Ore deposits, bedded, 241 ; bonanzas, forma- 
 tion of, 245; chamber deposits, 242; 
 classification of, 246 ; contact de- 
 posits, 241 ; contemporaneous origin 
 of, 224; disseminations, 242; Fahl- 
 band, 241 ; fissure veins, 286 ; forms 
 of, 236 ; impregnations, 241 ; linked 
 veins, 239 ; ore channel, 241 ; origin 
 of, 224; oxidation, 243; oxidation, 
 depth of, 244, references on, 249 ; sec- 
 ondary alteration in, 242 ; secondary 
 enrichment, 245; weathering, 242; 
 weathering, chemical changes, 243 ; 
 weathering, conditions affectingdepth, 
 243 ; weathering, minerals affected, 242. 
 Oregon, coal, 32 ; gold ores, 335 ; limonite, 27 ; 
 mercury, 392; nickel, 404; opal in, 
 195 ; solfataric sulphur, 197. 
 Ores, concentration in rocks, 225. 
 
 value of, 245. 
 
 Organic matter, as reducing agent, 317. 
 Oriskany, glass sand in, 177 ; limonite in, 271 ; 
 
 phosphate in, 153. 
 Orpiment, 898. 
 
 Orton, on petroleum origin, 47. 
 Osmium, properties and occurrence, 409. 
 uses, 409. 
 
 with platinum, 407. 
 
 Osmotic pressure, ore precipitation by, 236. 
 Onray, Colo., 807, 842. 
 Ozark region, 314. 
 Ozokerite, properties, 59. 
 occurrence, 59.
 
 INDEX 
 
 447 
 
 Palladium, properties and occurrence, 409. 
 uses, 409. 
 
 with platinum, 407. 
 Paper clay, defined, 99. 
 Paraffin, 56. 
 Paragenesis, 313, 815. 
 Park City, Utah, 807. 
 Peace River, Fla., phosphate, 148. 
 Peale, on mineral waters, 205. 
 Peat, analyses of, 4, 6. 
 defined, 3. 
 references on, 88. 
 sections in bog, 8. 
 
 Peckham, on temperature petroleum forma- 
 tion, 47. 
 
 Pegmatite, tin-bearing, 410. 
 Pennsylvania, anthracite coal, 8, 22; barite, 
 170 ; bituminous coal, 7 ; cement ma- 
 terials, 117, 118 ; chromite, 401 ; Clin- 
 ton ore, 266 ; copper, 296 ; fire clays, 
 102 ; glass sand, 177 ; graphite, 179 ; 
 iron ore, 256, 273 ; kaolin, 101 ; mag- 
 netite, 256 ; natural gas, 54 ; ocher, 
 187 ; petroleum, 50 ; phosphate, 154 ; 
 Portland cement materials, 118 ; ser- 
 pentine, 84; siderite, 273; sienna, 
 187 ; stoneware clay, 103 ; titanium, 
 414; zinc, 811. 
 
 Penokee-Gogebic range, 261, 262. 
 Penrose, on Georgia manganese, 886. 
 Pentlandite, 404. 
 Permian, gypsum, 141; rock salt, 127; salt, 
 
 130. 
 
 Persia, turquoise, 194. 
 Petroleum, analyses, 41. 
 anticlinal, 43. 
 asphaltic, 40, 42. 
 
 uses, 42. 
 boiling point, 42. 
 distillates, percentages of, 42. 
 distribution, Alaska, 54; Appalachian field, 
 48; California, 52; Colorado, 53; 
 Kansas, 52 ; Ohio-Indiana, 50 ; Penn- 
 sylvania, 50 ; Texas-Louisiana, 61. 
 flashing point, 41. 
 geologic distribution, 48. 
 gravity of, 41. 
 
 gushers, in Beaumont field, 45. 
 history of development, 89. 
 movement in rocks, 47. 
 nitrogen in, 40. 
 origin, inorganic theory, 46. 
 
 organic theory, 46. 
 paraffin in, 42. 
 pool, defined, 44. 
 pressure in well, 44. 
 production, 62. 
 properties of, 40. 
 references on, 66. 
 rock pressure, 45. 
 sands, defined, 44. 
 
 solidification temperature, 41. 
 
 uses of, 56. 
 
 wells, depth of, 45. 
 Phlogopite, as source of mica, 185. 
 Phosphate, analyses, 154. 
 
 distribution, Alabama, 153 ; Arkansas, 153 ; 
 Florida, 148; Georgia, 153; North 
 Carolina, 153; Pennsylvania, 153; 
 South Carolina, 150 ; Tennessee, 150. 
 
 geological distribution, 148. 
 
 impurities, 158. 
 
 land pebble, 149. 
 
 mode of occurrence, 147. 
 
 river pebble, 149. 
 
 rock, 148. 
 
 soft, 149. 
 
 uses, 154. 
 
 Phosphoric acid, in soils, 214. 
 Phosphorus, in copper ores, 280. 
 
 in iron ores, 252. 
 Pipe clay, defined, 99. 
 Pipe lines, West Virginia, 55. 
 Pitches, 812. 
 Placers, 827. 
 Plaster of Paris, 144. 
 Plasticity, clay, 96. 
 Platinum, associated metals, 407. 
 
 composition, 407. 
 
 distribution, California, 408; Wyoming, 
 408. 
 
 native, 407. 
 
 ores, 407. 
 
 production, 408. 
 
 references on, 408. 
 
 uses, 408. 
 
 Pleistocene, clays, 100 ; glass sand, 176 ; stone- 
 ware clays, 103. 
 Pneumatolysis, defined, 284. 
 Polybasite, 325, 344, 368. 
 Portland cement, see Cement. 
 Posepny, on ore deposits, 246. 
 
 on vadose water, 281. 
 Potash, in soils, 214. 
 
 Potsdam, glass sand, 177 ; sandstone, 87. 
 Pottery clay, defined, 99. 
 
 distribution, 103. 
 
 Pozzuolano, Italy, cement from, 111. 
 Pratt, on chromite, 400. 
 
 on chrysotile veins, 169. 
 
 on corundum, 168. 
 Pre-Cambrian, auriferous gravels, 827; clays, 
 
 100 ; gold, 829 ; iron ores, 260. 
 Precious stones, defined, 192. 
 
 occurrence, 192. 
 
 production, 195. 
 
 references on, 195. 
 Proctor, Vt., marble, 82. 
 Proustite, 825. 
 Psilomelane, 883. 
 
 Pulpstones, properties and uses, 159. 
 Pumice, 161. 
 
 sources, 162.
 
 448 
 
 INDEX. 
 
 Pumpelly, cited, 262. 
 Pyrargyrite, 825. 
 Pyrite, 2S6, 839, 871, 412. 
 
 analysis, 199. 
 
 as contact mineral, 285. 
 
 distribution, Massachusetts, 199 ; 
 York, 199 ; Virginia, 199. 
 
 In hot spring deposit, 228. 
 
 occurrence, 199. 
 
 references on, 200. 
 
 uses, 200. 
 Pyrolusite, 888. 
 Pyromorpnite, 808. 
 Pyrope, as gem, 194. 
 Pyrophyllite, composition, 203. 
 
 North Carolina, 203. 
 
 uses, 208. 
 
 Pyroxene, as gangue mineral, 295. 
 Pyrrhotite, 404. 
 
 as contact ore, 285. 
 
 Ducktown, Tenn., 295. 
 
 in Virginia pyrite deposits, 199. 
 
 Sudbury, Ont., 405. 
 
 Quarries, bedding planes In, 74. 
 Quarrying, structural features affecting, 74. 
 Quarry water, 73. 
 Quartz, crystalline, uses, 168. 
 
 in kaolin, 100. 
 Quicksilver, 390, 391, 898. 
 Qulncy, Mass., granite, 77. 
 
 Realgar, 398. 
 
 Bed Sulphur Springs, Va., 206. 
 
 Regolitb, 213. 
 
 Replacement, defined, 283. 
 
 Residual soils, 218. 
 
 Residuum, petroleum, 42. 
 
 Retort clay, defined, 99. 
 
 Rhlgolene, 56. 
 
 Rhode Island, coal field, 25 ; graphite, 179. 
 
 Rhodium, with platinum, 407. 
 
 Rico, Colo., 807. 
 
 banded veins at, 287. 
 
 zinc concentrates, 819. 
 Rift, 74. 
 Road materials, 21T. 
 
 day, behavior under traffic, 21T. 
 
 gravel, characteristics, 217. 
 
 methods of testing, 218. 
 
 references on, 218. 
 
 requisite qualities, 218. 
 
 sand, characteristics, 217. 
 
 shale, 217. 
 
 Rock crystal, as gem, 195. 
 Rock pressure, Orton on, 45. 
 Eock salt, occurrence, 125. 
 Rocky Mountain region, yield of silver, 
 882. 
 
 coal fields of, 80. 
 
 Enby, properties, 198. 
 
 Arizona, 193 ; North Carolina, 193 ; United 
 
 States, 193. 
 Ruby silver, 325. 
 Ruthenium, with platinum, 407. 
 Rutile, 413. 
 
 Salina, gypsum, 142 ; salt, 129. 
 
 Salines, 124. 
 
 Sail Mountain, Ga., amphibole asbestos, 167. 
 
 Salt, analyses of salt and brines, 131. 
 
 analyses of sea waters, 124. 
 
 association with gypsum, 126. 
 
 distribution, California, 130; Kansas, 130; 
 Louisiana, 129; Michigan, 129; New 
 York, 127 ; Texas, 130 ; Utah, 180. 
 
 extraction, 181. 
 
 impurities, 126. 
 
 occurrence in waters, 124. 
 
 production, 132. 
 
 references on, 134. 
 
 rock, origin, 125. 
 
 sources of, 124. 
 
 uses, 132. 
 
 San Bernardino Hot Springs, Calif., 204. 
 Sandberger, on dissemination of metals, 226. 
 Sandstone, 84. 
 
 arkose, 85. 
 
 Berea, 87. 
 
 bluestone, 85. 
 
 distribution, 86. 
 
 flagstone, 85. 
 
 general properties, 84. 
 
 Potsdam, 87. 
 
 varieties of, 85. 
 Sandusky, Ohio, gypsum, 142. 
 San Juan region, Colorado, gold-silver, 841. 
 Sap, 78. 
 Sapphire, 198. 
 
 distribution, Montana, 193 ; North Carolina, 
 193 ; Siam, 193. 
 
 properties, 193. 
 Sagger clay, defined, 99. 
 Saucon Valley, Pa., zinc ores, 811. 
 Scheelite, 414. 
 
 Schrauf, on mercury origin, 398. 
 Sea water, pyrite precipitation from, 226. 
 
 limonite precipitation from, 225. 
 
 manganese precipitation from, 225. 
 Selvage, 237. 
 
 Semi-bituminous coal, defined, 5. 
 Senarmontite, 896. 
 Sericite, 826. 
 Serpentine, for building, 88. 
 
 characteristics, 88. 
 
 distribution, 84. 
 
 Seward peninsula, Alaska, 357 ; tin in, 412. 
 Shale, analysis of, 98. 
 Shutes, 237. 
 Siam, sapphire, 198. 
 Siberia, emerald, 198 ; turquoise, 194. 
 Sicily, sulphur, 197.
 
 INDEX 
 
 449 
 
 Biderite, 272, 873. 
 
 distribution, Kentucky, 273; New York, 
 278 ; Pennsylvania, 278. 
 
 geologic distribution, 272. 
 
 mode of occurrence, 272. 
 Sienna, defined, 187. 
 Silica, as an abrasive, 168. 
 
 deposition from water, 893. 
 
 effect on clay, 95. 
 
 in iron ores, 262. 
 
 in soils, 214. 
 
 Silurian, manganese in, 887. 
 Silver, Butte, Mont., 284. 
 
 ores of, 825. 
 
 production, 858. 
 
 uses of, 857. 
 
 with mercury, 893. 
 Silver Cliff, Colo., analyses of mine waters, 
 
 227. 
 
 Silver glance, 825. 
 Silver ores, classification, 827. 
 
 distribution of, see Gold-silver. 
 
 extraction, 829. 
 
 geologic distribution, 829. 
 
 mode of occurrence, 826. 
 
 production of, 858. 
 
 references on, 860. 
 
 secondary enrichment, 327. 
 
 wall rocks, 826. 
 
 weathering of, 827. 
 Silver-lead ores, 864. 
 
 assays of, 872, 878. 
 
 distribution, Aspen, Colo., 867 ; Co2ur 
 d'Alene, Ido., 872; Eagle Elver, 
 Colo., 869 ; Eureka, Nev., 873 ; Glen- 
 dale, Mont., 873; Leadville, Colo., 
 864 ; Neihart, Mont., 373 ; New Mex- 
 ico, 373 ; Park City, Utah, 8TO ; Bed 
 Mountain, Colo., 869 ; Rico,Colo.,369; 
 South Dakota, 373 ; Ten Mile district, 
 Colo., 369 ; Tintic district, Utah, 872. 
 
 references on, 874. 
 Silverton, Colo., 841. 
 Slate, as mineral pigment, 187. 
 
 quarrying, waste in, 88. 
 
 uses, 89. 
 Slates, for building, 87. 
 
 bleaching of, 88. 
 
 cleavage, 87. 
 
 distribution, 88. 
 
 Smithsonite, 808, 305, 810, 812, 819. 
 Smut, of coal, 16. 
 Soapstone, 201. 
 
 in southern Appalachians, 201. 
 
 Soda, in soils, 214. 
 
 Soda niter, properties, 186. 
 
 references on, 186. 
 Sodium sulphate, 186. 
 Soils, 213. 
 
 seolian, 214. 
 
 alkali in, 215. 
 
 2r 
 
 alluvial, 214. 
 
 chemical properties, 214. 
 
 defined, 213. 
 
 distribution, 216. 
 
 dune, 214. 
 
 flocculated, 215. 
 
 glacial, 214. 
 
 loamy, properties, 218. 
 
 loess, 216. 
 
 marsh, 216. 
 
 origin, 213. 
 
 physical properties, 215. 
 
 prairie, 216. 
 
 puddled, 215. 
 
 references on, 216. 
 
 residual, 218. 
 
 sandy, 215. 
 
 structure, 215. 
 
 subsoil, 216. 
 
 temperature, 216. 
 
 texture of, 215. 
 
 transported, 218. 
 
 volcanic, 214. 
 
 Solenhofen, Bavaria, lithographic stone, 182. 
 Solid bitumens, 57. 
 South Carolina, monazite, 190 ; phosphate, 150 ; 
 
 tin, 411. 
 
 South Dakota, fire clay, 103 ; gold. 350 ; fuller's 
 earth, 175; lithium, 183; Portland 
 cement materials, 119; silver-lead 
 ores, 878 ; tungsten, 415. 
 Specularite, as contact ore, 285. 
 Sperrylite, 407. 
 Spessartite, as gem, 194. 
 Sphagnum, 8. 
 Sphalerite, 303, 805, 311, 812, 818, 315, 819, 
 
 872, 873. 
 
 Spodumene, 188. 
 
 Spurr, on magmatic segregation, 225. 
 Stannite, 410. 
 
 Stassfurth, Prussia, salt at, 126. 
 Steamboat Springs, Nev., 892. 
 Stephanite, 825, 844. 
 Stevenson, on anthracite formation, 15. 
 
 in hot spring deposit, 228. 
 Stoneware clay, analysis of, 98. 
 
 defined, 99. 
 
 distribution of, 108. 
 Stream tin, 410. 
 
 Strontian Island, celestite on, 201. 
 Strontium, minerals containing, 200. 
 
 references on, 201. 
 
 uses, 201. 
 Subcarboniferous, salt, 129 ; limestone for 
 
 lime, 116; zinc, 814. 
 Subsoil, 216. 
 
 Sudbury, Ont., nickel, 405. 
 Sulphides, in contact deposits, 235. 
 Sulphur, distribution, Louisiana, 197 ; Japan, 
 196; Mexico, 196; Oregon, 197; 
 Utah, 196.
 
 450 
 
 INDEX 
 
 Sulphur continued. 
 
 geologic age, 197. 
 
 gypsum type, 197. 
 
 in coal, 9. 
 
 in 
 
 origin," 197. 
 
 production, 198. 
 
 references on, 198. 
 
 solfataric type, 196. 
 
 uses, 198. 
 
 Sussex County, N.J., zinc ores, 808. 
 Sweet Springs, W. Va., 204. 
 Sylvanite, 325, 839. 
 
 Table Mountain, Calif., 847. 
 Talc, 201. 
 
 analyses of, 202. 
 as alteration product, 201. 
 distribution, New York, 202; North Caro- 
 lina, 201. 
 
 origin and occurrence, 201. 
 production, 203. 
 references on, 203. 
 uses, 202. 
 Tellurides, 825. 
 
 unknown in contact deposits, 235. 
 Tellurium in copper, 280. 
 Tennantite, 285. 
 
 Tennessee, ball clay, 103; barite, 170; fluor- 
 spar, 173 ; Jellico coal, analysis of, 7 ; 
 garnet, 163; phosphate, 150; stone- 
 ware clay, 103. 
 
 Terlingua, Texas, mercury, 392. 
 Terra alba, 143. 
 Terra-cotta clay, defined, 99. 
 Tertiary, fuller's earth, 175; gold-silver ores, 
 887 ; glass sand, 177 ; greensand, 155 ; 
 lignite, 19 ; limonite, 271 ; phosphates, 
 148, 153 ; sulphur, 197. 
 Tetrahedrite, 278, 285, 297, 321, 331, 339. 
 Texas, bat guano, 155 ; bituminous coal, analy- 
 sis, 7; coal, 29; fertilizer, 155; 
 gypsite, 142; lignite, 6,30; lime rock, 
 116; limonite, 271; mercury, 892; 
 natural gas, 56 ; petroleum, 51 ; Port- 
 land cement materials, 119 ; salt, 130 ; 
 stoneware clay, 108. 
 Thermal springs, origin, 204. 
 Thorium, in monazite, 190, 191. 
 Tin, association with granite, 226. 
 
 distribution, Alaska, 412 ; Black Hills, 411 ; 
 Malay Peninsula, 412 ; North Caro- 
 lina, 411 ; South Carolina, 411. 
 mode of occurrence, 410. 
 ores, 410. 
 
 production of, 412. 
 references on, 418. 
 uses of, 412. 
 Titanic acid, in clay, 96. 
 
 Titanium, distribution, Norway, 418 ; Penn- 
 sylvania, 414 ; Virginia, 414. 
 
 in iron ores, 252. 
 occurrence, 418. 
 ores, 413. 
 
 references on, 414. 
 uses, 414. 
 
 Tonopah, Nev., 848. 
 
 Topaz, distribution, Brazil, 194; California, 
 194; Ceylon, 194; Colorado, 194; 
 Maine, 194 ; Urals, 194. 
 properties, 194. 
 Torbanite, 57. 
 Tourmaline, as gem, 195. 
 
 with tin, 412. 
 Transported soils, classification, 214. 
 
 origin, 213. 
 Trap, 78. 
 
 Travertine, defined, 80. 
 Trenton, limestone for lime, 116; petroleum 
 
 in, 51. 
 
 Triassic, coal, 25; magnetite, 256. 
 Trinidad, asphalt in, 59. 
 
 analysis of, 60. 
 Tripoli, see Infusorial earth. 
 Tully limestone, for Portland cement, 118. 
 Tungsten, analysis, Arizona, 415. 
 
 distribution, Arizona, 415 ; Black Hills, 415 ; 
 Colorado, 415; Connecticut, 415; 
 Nevada, 415. 
 ores, 414. 
 production, 415. 
 references on, 416. 
 uses, 415. 
 
 Turquoise, distribution, Arizona, 194; Asia 
 Minor, 194; New Mexico, 194; Per- 
 sia, 194 ; Siberia, 194. 
 properties and occurrence, 194. 
 Type metal, 897. 
 
 U 
 
 Uintaite, 69. 
 Ulexite, 184. 
 Umber, defined, 187. 
 Underground waters, 207. 
 references on, 211. 
 sources of, 207. 
 Urals, topaz in, 194. 
 Uranium, distribution, Colorado, 416; Utah. 
 
 416. 
 
 ores, 416. 
 production, 416. 
 references on, 417. 
 uses, 416. 
 
 Utah, coal, 81 ; copper, 296 ; desilverized lead, 
 307; hematite, 268; magnetite, 256; 
 manganese, 888 ; molybdenum, 40? ; 
 Portland cement materials, 119 ; salt, 
 130; silver-lead ores, 372; sulphur, 
 196 ; uranium, 416. 
 
 Vadose water, defined, 227. 
 Vanadium, distribution, Arizona, 416; New 
 Mexico. 416.
 
 INDEX 
 
 451 
 
 Vanadium continued, 
 
 ores, 416. 
 
 production, 416. 
 
 references on, 417. 
 
 uses, 416. 
 Van Hise, on Lake Superior ores, 262. 
 
 on meteoric waters, 228. 
 
 on ore deposit classification, 246. 
 Veins, see Fissure veins. 
 Vermilion, as mineral pigment, 188. 
 Vermilion Range, Minn., 261. 264. 
 Vermont, asbestos, 168 ; marble, 82 ; -whet- 
 stones, 160. 
 
 Vesuvianite, in contact deposits, 235. 
 Virgilina, Va., copper, 291. 
 Virginia, arsenic, 398; asbestos, 107; barite, 
 170 ; brines, 129 ; coal, 25 ; green- 
 sand, 155; gypsum, 142; infusorial 
 earth, 162 ; kaolin, 101 ; limonite, 
 271 ; pyrite, 199 ; titanium, 414. 
 Virginia City, Nev., 344. 
 Vogt, on magmatic segregation, 224. 
 Volcanic ash, 161. 
 
 United States deposits, 162. 
 
 soils, 214. 
 
 W 
 
 Wad, 383. 
 
 Warm Springs, Tenn., 204. 
 Warm Sulphur Springs, Va., 205. 
 Washington, arsenic, 398 ; bituminous coal, 
 analysis of, 8 ; coals, 82 ; gold, 835 ; 
 lignite, analysis, 6 ; molybdenum, 
 403 ; nickel, 404. 
 Water, artesian, 209. 
 
 as carrier of ores, 226. 
 
 circulation of meteoric, 229. 
 
 distribution in earth's crust, 228. 
 
 hot, agent in ore formation, 228. 
 
 in clay, 96. 
 
 mine, analyses, 227. 
 
 mineral, 205. 
 
 of igneous origin, 229. 
 
 of meteoric origin, 228. 
 
 underground, source of, 228. 
 Water lime beds, cement rock in, 117. 
 Water table, 208. 
 
 Watson, on Georgia manganese, 386. 
 Weathering, building stones, 70, 75, 79, 85. 
 
 ore deposits, 242. 
 Weed, cited, 228, 280, 246. 
 
 West Virginia, brines, 129 ; gas, 55 ; glass sand, 
 
 177 ; grahamite, 59 ; natural gas, 55 ; 
 
 petroleum, 48. 
 Westerly, E.I., granite, 77. 
 Whetstones, defined, 159. 
 
 distribution, 160. 
 
 White, I. C., on anticlinal theory, 48. 
 White lead, as mineral pigment, 188. 
 White metal, 320. 
 Whiting, as mineral pigment, 188. 
 Whitney, on Lake Superior ores, 262. 
 Willemite, 303, 804, 308, 310. 
 Winslow, on Missouri lead and zinc, 226. 
 Wisconsin, Clinton ore, 266; graphite, 180; 
 
 hematite, 261, 264; limomite, 271; 
 
 natural rock cement, 118; zinc ores, 
 
 812. 
 
 Wolframite, 414. 
 Wollastonite, 235. 
 Wulfenite, 403. 
 Wyoming, asbestos, 168 ; copper, 298 ; gypsitc, 
 
 142; hematite, 268; magnetite, 256; 
 
 nickel, 404 ; petroleum, 53 ; platinum, 
 
 408. 
 
 Y 
 
 Yellow ocher, see Ocher. 
 Yukon valley, Alaska, 358. 
 
 Zinc, Butte, Mont., 285. 
 ores of, 808. 
 production of, 821. 
 with mercury, 898. 
 uses of, 320. 
 Zincite, 303, 308, 810. 
 Zinc ores, analysis of, Leadville, 818. 
 Missouri, 815. 
 New Jersey, 308. 
 
 distribution, Creede, Colo., 819 ; Iowa, 311 ; 
 Missouri, 314 ; New Jersey, 808 ; New 
 Mexico, 819 ; Pennsylvania, 311 ; Vir- 
 ginia-Tennessee, 809 ; Wisconsin, 311. 
 impurities in, 304. 
 mechanical concentration, 313. 
 references on, 828. 
 residual, 310. 
 superficial alteration, 305. 
 Zinc oxide, manufacture in Colorado, 818. 
 Zone of flowage, 228. 
 Zone of fracture, 228.
 
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