S94 



INDEX 



Gneisses, structure of, 143 



Gueissoid granite, N. Garden, Ya., 



chemical analyses of, 194 



weathering of, 192 



Granite, chemical composition of, 62 



classification and nomenclature, 



63 

 color of, 63 



Corsican, weathering of, 236 

 Granite described, 61 



District of Columbia, chemical 

 analyses of, 186 

 mechanical analyses of, 



190 

 weathering of, 185 

 geological age, 64 

 Greenville, Ga., analyses of, 195 



weathering of, 195 

 -Liparite group, 61 

 mineral composition of, 61 

 mode of occurrence, 64 

 structure of, 62 

 Stone Mt., exfoliation of, 231 

 weathering of, 228 

 Granitell defined, 63 

 Granophyr, 66 

 Grauwacke, 116 

 Greensand, 116 

 Greenstone, 76 

 Greywacke, 116 

 Greisen defined, 64 

 Ground moraine, mechanical anal- 

 yses of, 342 

 nature of material, 341 

 Gruss, 289 

 Guano, analysis of, 132, 361 



origin of, 131 

 Gypsum, composition, origin and 

 occurrence, 109 



Halleflinta, 146 



Hardness of minerals, scale of, 12 



Hardpan, defined, 373 



Harzburgite, 92 



Heat and cold, effect on rocks, 158 



Hematite, 100 



as a rock constituent, 26 

 Hornblende as a rock constituent, 18 



decomposition of, 19 

 Hornblendite, 95 

 Horseback, 50 

 Hyalomelan, 87 

 Hyalotrachyte, 73 



Hydrargillite a product of weather- 

 ing, 270 



in soils, 362 

 Hydration, 166 



importance of, 166 



Hydration, incidental to weathering, 



238 

 Hydraulic limestone, 127 

 Hydrometamorphism defined, 140 

 Hyperite, 82 

 Hypersthene, 21 

 Hypersthenite, 95 



lee, mechanical action of, 177 

 Igneous rocks, 55 



Induration of rocks on exposure, 240 

 Insects, effects on soils, 378 

 Intrusive rocks, 56 



Iron as a constituent of the earth's 

 crust, 5 



ores, 25 



pyrite as a rock constituent, 26 

 weathering of, 165 



salts, solubility of, 225 

 Itacolumite, 116 



Jasper, 104 



Jointing as influencing weathering, 

 230 



Kalk-diabase, 86 



Kames, 50 



Kaolin, 108 



chemical analyses of, 298 

 composition of, 118-119, 298 

 distinguished from kaolinite, 



297 

 deposits, origin of, 254 

 mechanical analyses of, 297 

 origin of, 118 



Kaolinization defined, 17 



Kersantite, 78 



Keratophyr, 72 



Kinzigkite, 148 



Kissimmee valley, swamp deposits, 

 304 



Kugel-porphyry, 66 



Laccoliths, 46 



Labradorite as a rock constituent, 16 



Lake Agassiz, 278 



Lakes, filling of, 302, 314 



transient nature of, 314 

 Lapilli, 122 

 Laterite, 121, 298 



composition of, 299 

 Laurvikite, 75 



Lava, cause of structural features- 

 57 



defined, 46 

 Leda clays, 322 

 Leopardite, 66 

 Leucite as a rock constituent, 18 



