421 



Geology, great divisions of, 8. 

 historical, 256. 

 structural, 173. 

 Geyser, Great, 147. 

 Great, phenomena of eruption 



of, 147. 



Geysers defined, 146. 

 cause of eruption of, 151. 

 of Iceland, 146. 

 of Yellowstone Park, 147. 

 Gigantitherium (gigantic beast), 



343. 



Glacial (icy), 385. 

 cold, cause of, 402. 

 epoch, 386. 



epoch, explanation of phenom- 

 ena of, 358. 



erosion, general results of, 396. 

 Glaciers as a geological agent, 60. 

 characteristic signs of, 62. 

 denned, 52. 

 erosion of, 61. 



evidences of former greater ex- 

 tension of, 62. 

 in the Sierra, 56. 

 lower limit of, 53. 

 motion of, 58. 



size of, in various regions, 56. 

 structure of, 56. 

 transportation and deposit by, 



61, 62. 

 Globigerina (globule-bearing),117. 



ooze, 117. 



Glyptodon (sculptured tooth), 400. 



Goniatite (angled stone : a family 



of shelled cephalopods with 



angled sutures), 290, 317. 



Gorge formed by recession of falls, 



21. 



Gracilis (graceful), 274. 

 Gradual oscillation of the earth- 

 crust, 164. 

 Grahamite : a form of asphalt, 



313 



Granite,' 212. 

 Granitic rocks, composition of, 



211. 



rocks, mode of occurrence, 212. 

 Graphic granite, 212. 

 Graptolites (stone-writing), 276. 

 Ground-water, perpetual, 68. 

 Gulf Stream, geological agency 

 of, 48. 



Gulf Stream, origin and cause of, 

 47. 



Gyrnnosperm (naked seed : a class 

 of plants including conifers 

 and cycads), 287, 304. 



Halysites (stone chain) catenulata 

 '(like a little chain), 276. 



Halysitid (stone chain), 275. 



Hamite (stone hook), 354. 



Hesperornis (western bird), 358. 



Hipparion (little horse), 381. 



Hippurite (horse-tail), 353. 



Historical geology, 256. 



History, general principles of, 



256. 

 geological, divisions of, 259. 



Horse, genesis of, 382. 



Hybodont (hybodus, hump-tooth : 

 a family of shark-like fishes), 

 318. * 



Hydrothermal fusion (fusion by 

 heat and water), 133. 



Hydrozoa (water-animals), 275. 



Hypsilophodon, 355. 



Ice, agency of, 52. 



Icebergs as a geological agent, 66. 



effect of, compared with gla- 

 ciers, 66. 



how formed, 64. 



of Greenland, 64. 



of the Antarctic, 66. 

 Ice-sheet moraine, 388. 

 Ichthyornis (fish-bird), 358. 

 Ichthyosaur (fish-lizard), 334. 

 Ideal section of earth-crust, 261. 

 Igneous agencies, 131. 



rocks, 210. 



rocks, characteristics of, 210. 



rocks, classification of, 211. 



rocks, extent of, on the surface, 

 211. 



rocks, modes of occurrence of, 

 211, 216. 



rocks, origin of, 210. 



rocks, sub-groups of, 213. 

 Iguanodon (iguana-toothed), 336. 

 Indusium (an inner garment), 371. 

 Insects, 290. 

 Intercalary beds, 219. 

 Invertebrates, age of, 271. 

 Iron accumulations, 88. 



