392 



INDEX 



Bog deposits, depth of, 306 

 Bone breccia, 132 



Boss-like form induced by weather- 

 ing, 231 

 Bosses, 46 



Botryoidal structure, 34 

 Boulder clay, 340 

 Boulders, discoloration of, 244 



of decomposition, 230 

 Breccia, 115 



formed by weathering, 237 

 Bronzite, 21 

 Bronzitite, 95 

 Brown iron ore, 101 

 Gabook, origin of, 228 

 Calcareous group of rocks, 121, 124 



rocks, weathering of, 216 

 Calcite as a rock constituent, 24 

 Calcium as a constituent of the 



earth's crust, 6 

 Calcite, mode of weathering, 236 

 Calcium carbonate, amount annually 



removed in solution, 171 

 Calc sinter, 104 



tufa, 104 

 Carbon as a constituent of the 



earth's crust, 7 

 Carbonaceous group of rocks, 129 

 Carbonates, production of in wea- 

 thering, 253 

 Carbonic acid, amount brought down 

 by rainfall, 157 

 in the atmosphere, 156 

 in water, influence of, 169 

 Ceylon, weathering of granite in, 



228 

 Chalcedony, 103 

 Chalk defined, 125 



cavities in, formed by weather- 

 ing, 247 

 Champlain clays, 118, 322 

 Chemical action of water, 165 



composition of rocks, 41 

 Chert, 103 



weathering of, 215 

 Chinese loess, 315 

 Chlorides, 111 



Chlorite as a rock constituent, 27 

 ('hrysotile^ 107 



Citric acid, solvent action of, 181 

 Clastic rocks, 112 

 Clays, aqueo-glacial, 288, 322 

 boulder, 340 

 Champlain, 322 



mineral nature of 323 

 origin of, 323 

 chemical analyses of, 324 

 Clay, defined, 117 



Clay, effect on soils, 368 

 -iron-stone, 106 

 slates, 119 

 Climate, influence on weathering, 



263 

 Clinton iron ores, origin of, 254 

 Coastal plain deposit, 300 

 Coal, anthracite, composition and 

 origin, 131 

 bituminous, 130 

 Colluvial deposits, 307 

 Color changes due to weathering, 

 243, 244 

 of rocks, 42 

 of soils, 373 

 Concretions, formation of, 32 

 Concretionary structure, influence on 



weathering, 232 

 Conductivity of rocks, 162 

 Conglomerate, 115 

 Contact metamorphism defined, 136 

 Coprolite nodules, 132 

 Coquina, 125 



Corsica, granite weathering in, 236 

 Creeping of soil cap, 274 

 Cumulose deposits, 301 



rate of formation, 305 

 Crystalline schists, the, 146 

 Daubree's experiment, 176 

 Decay, time limit of, 260 

 Decomposition of rocks, see weather- 

 ing, 150 

 during trituration, 176 

 Delta deposits, character of materi- 

 als, 309 

 mechanical analyses, 310 

 Deoxidation, 166 

 Desert varnish, 244 

 Deweylite, 108 



Diabase, Chatham, Va., analyses of, 

 204 

 weathering of, 203 

 mandelstein, 85 



Medford, Mass., chemical an- 

 alyses of, 200 

 porphyrite, 85 

 weathering of, 198 

 weathered, mechanical analyses 

 of, 199 

 Diabases, the, chemical composition, 



classification, 84 



colors, 84 



mineral composition, 82 



structure, 83 

 Diallogite, 95 



Diamond Head, Oahu, sand of, 329 

 Diatomaceous earth, 123 



