INDEX 



393 



Dikes, 464 



Diorite, analyses of, 207 



-andesite group, 76 



origin through metamorpHsm, 

 136 



weathering of, 207 

 Diorites, 76 



chemical composition of, 77 



classification of, 77 



colors of, 77 



mineral composition of, 76 



structure, 77 

 Distiutegration without decomposi- 

 tion, 227 

 Ditroite, 75 

 Dolerite, 86 



weathering of, 270 

 Dolomite, 126 



as a rock constituent, 24 



chemical composition of, 127 



origin of, 138 



weathering of, 236 

 Dolomites, crystalline, chemical and 

 mineral composition, 141 

 colors of, 141 

 nomenclature, 142 

 Drift, galcial, 277 

 Drumlin, 50, 314 

 Dunite, 92 

 Dust in snowfall, 332 



soil, chemical analysis of, 333 

 mechanical analysis of, 333 

 Dunes, sand, 50, 334 

 Dynamic metamorphism defined, 136 



Earth 's crust, thickness of, 2 



Earthworms, effect on soil, 381 



Eclogite, 148 



Effusive rocks, characteristic struc- 

 ture, 57 

 defined, 56 



Elseolite syenite, 73 



weathering of, 196 



Elements constituting rocks, 4 



Enstatite, 21 



Eozoon canadense, nature of, 138 



Epidiorite, 84 



Epidote as a rock constituent, 23 



Erosion, material lost by, 175 



Esker, see glacial deposits, 277 



Eukrite, 84 



Exfoliation of granite, 231 



Expansion and contraction, effects 

 of, 158 

 of minerals, coefficient of, 255 

 of rocks by heat, amount of, 159 



Fault, definition of, 49 

 Eeldspars as rock constituents, 13 



Feldspars, decomposition of, 17 



importance of, 16 



weathering of, 223 

 Felsite-pitchstone, 66 

 Felsophyr, 66 

 Felstone, 66 

 Fiorite, 103 

 Flint, 103 



Flood plains of rivers, 277 

 Foliated or schistose rocks, 142 

 I^orellenstein, 82 

 Forests, influence of, 266 

 Fossiliferous limestone, structure of, 



127 

 Fourchite, 75 



Foyaite-phonolite group, 73 

 Frontal moraine, 343 



aprons, 344 

 Frost action on soils, 356 



heaving effect of, 382 



protective action of, 264 



Gabbro-basalt group, 80 

 Gabbros, the, 80 



chemical composition, 81 



classification of, 82 



colors, 82 



mineral composition, 80 



structure, 81 

 Geest, 289 



Gem sands, origin of, 253 

 Geyserite, 103 



Glaciated area, extent of, 339 

 Glacial deposits, 278, 338 



classification of, 340 

 thickness of, 344 



drift, section through, 345 



ice, disintegrating action, 179 

 sheet, drifting power of, 



sheets, effect on landscape, 

 279 

 lakes, filling of, 277 

 soil, composition of, 352 

 Glauconite as a rock constituent, 



28 

 Glauconitic sand, 116-117 

 Glaueophane schist, 148 

 Gneisses, the, 142 



the age and occurrence of, 



143 

 classification and nomenclature, 



143, 146 

 colors of, 143 



mineral and chemical composi- 

 tion, 142, 145 

 origin of, 144 



