600 



INDEX. 



Hypothyris cuboides, ii, 475. 476 

 Hypsipleura gregaria, iii, 136 

 Hypsometric hypotheses of gla- 

 cial climate, 111, 424 

 Hyracodon, iii, 253 

 Hyracotherium, in, 235 



venticolum, iii, 235 

 Hyrochinus, in, 235 



Ice, glacial (see Glaciers) 



ground, i, 119 



of lakes, i, 389 



of rivers, i, 118 

 Icebergs, i, 307 

 Ice-caps, i, 249, 250 

 Ice crystals, arrangement in 



glacier ice, i, 311 

 Ice-fall, i, 264 

 Iceland spar, i, 463 

 Ice-sheet, Cordilleran, iii, 330, 

 332 



Greenland, rate of move- 

 ment, iii, 430 



Keewatin, iii, 330, 332 



Labradorean, iii, 330 



stages in history of, iii, 358 



work of, iii, 358 

 Ice-sheets, and continental bor- 

 ders, iii, 529 



development and thickness of, 

 iii, 355 



distribution of, iii, 329 



formations made by, iii, 359 



map of, iii, 330 



rate of growth of, iii, 429 



slope of, iii, 356 

 Ichthyopterygians, Triassic, iii, 



46 

 Ichthyosauria, iii, 42 



Cretaceous, iii, 180 



Jurassic, iii, 86, 87 



Triassic, iii, 45, 46 

 Ichthyosaurus quadriscissus, iii, 



88,89 

 Ichthyornis, iii, 182, 184 



victor, iii, 184 

 Ictops, iii, 253 

 Idaho formation, iii, 299 

 Iddings, J. P., cited, i, 412, 451, 

 573. 614, 636; iii, 272; 

 (and Weed), iii, 156, 159 

 Idonearca antroso, iii, 187 



nebrascensis, iii, 189 



vulgaris, iii, 187 

 Ignacio quartzite, iii, 573 

 Igneous activity, Cretaceous, iii, 

 167 



Eocene, iii, 212 



Miocene, iii, 270 



Pleistocene, iii, 459 

 Igneous intrusions and shear 



zone, ii, 130 

 Igneous rocks, Animikean, ii, 184 



Cambrian, ii, 252 



Carboniferous, ii, 588 



Comanchean, iii, 124 



composition of, i, 395 



Crazy mountains, iii, 168 



Cretaceous, iii, 167 



Deccan, iii, 171 



Igneous rocks, Devonian, ii, 

 439 



gases in, ii, 95 



heavy and light crystals in, ii, 

 121 



Huronian, ii, 192 



Jurassic, iii, 67, 76 



Keweenawan, ii, 192 



leading mineral of, i, 399 



Lower Carboniferous, ii, 515 



Miocene, iii, 270 



Newark, iii, 10 



Oligocene in Europe, iii, 251 



origin of, i, 393 



Pleistocene, iii, 459, 477 



Pliocene, iii, 310, 317 



relations to stratified rocks, i, 

 16 



Silurian, ii, 394 



structural features of, i, 498 



Triassic, iii, 10, 28 

 Iguanodon, iii, 99 

 Ilex, iii, 173 



Illaenus americanus, ii, 349 

 Illinoian drift, iii, 383, 390 



glacial stage, iii, 391 

 Illinois, lead in, ii, 337 



zinc in, ii, 337 

 Ilmenite, i, 463 

 Ilyanassa, iii, 295 



percina, iii, 294 

 Incrustation, i, 223 

 Independence shales, iii, 558 

 India, Archean of, ii, 159 



Cambrian of, ii, 272 



Cambrian fossils of, ii, 300 



Cretaceous, Lower, iii, 129 

 Upper, iii, 170 



Devonian of, ii, 448 



Eocene of, iii, 217 



Jurassic of, iii, 77 



Miocene of, iii, 280 



Pennsylvanian of, ii, 590 



Permian of, ii, 634 



Proterozoic of, ii, 215 

 Indian Territory, section of 



strata in, iii, 562 

 Indiana, section of strata in, iii, 



556 

 Infusorial earth, i, 470 

 Initial atmosphere, nature of, ii, 



95 

 Initiation of vulcanism, ii, 99 

 Inoceramus, iii, 91. 189. 190 



vanuxemi, in, 189 

 Inorganic deposits, in deep sea, 



1,380 

 Insectivora, iii, 229 



Eocene, iii, 239 

 Insect life, Carboniferous, ii, 610 



Devonian, ii, 494 



Eocene, iii, 240 



Jurassic, iii, 104 



Mississippian, ii, 538 



Oligocene, iii, 252 



Ordovician, ii, 346 

 Interglacial epochs, iii, 383-393 

 life of, iii, 490 



faunas, iii, 493 



floras, iii, 493 



Interior of earth, i, 14 (see also 

 Vulcanism) 



densities, based on Laplace's 

 law. i, 564 



heat of, i. 562, 564 



pressures, 1, 564 

 Interior heat, sources of, ii, 99 

 Intermittent springs, i, 235 

 Internal heat (see Internal tem- 

 perature) 

 Internal temperature, i, 562 



affected by ground-water, i, 

 57o 



at center of earth, i, 571 



on accretion hypothesis, 1, 564, 

 567 



on convection hypothesis, i, 

 559 



on Laplacian hypothesis, i, 559 

 Intrusions, i, 591 

 Iocrinus subcrassus, ii, 359 

 lone formation, iii, 264, 317 

 Iowa, lead in, ii, 337 



section of strata in, iii, 558 



zinc in, ii, 337 

 Iowan drift, iii, 383, 387. 390 



glacial stage, iii, 391 

 Iphidea labradorica, ii, 297 

 Iron age, iii, 504 

 Iron in meteorites, ii, 27 

 Iron ore, Clinton, ii, 377 



Cretaceous of Europe iii, 

 170 



Lake Superior region, ii, 190 



Lias, iii, 73 



Lower Cretaceous of Europe 

 iii, 128 



Middle Jurassic, of England, 

 iii, 73 



Pennsylvanian, ii, 580 

 Iron-ore beds, origin, i, 425 

 Iron oxide, i, 400 

 Iron pyrites, i, 463 

 Ironstone, i, 425, 470 

 Ironwood formation, ii, 186, 188 

 Irruptions, 1, 591 

 Irving, R. D., cited, ii, 138, 145, 

 157, 182, 193, 195, 197, 205; 

 (and Van Hise), 180, 188, 

 198; iii, 344, 367 

 Ischadites, ii, 363 

 Ischyrodonta decipiens, ii, 354 

 Ishpeming formation, ii, 176, 186 

 Island glaciation, iii, 336 

 lsocardia, iii, 295 



markoei, iii, 292 

 Isoclinal folds, i, 504 

 Isodectes, ii, 650 

 Isoseismals, i, 532 

 Isostasy, ii, 200, 236 

 Isostatic adjustments due to 



gradation, ii, 236 

 Isotelus gigas, ii, 351 



maximus, ii, 349 

 Itacolumite, i, 470 

 Italy, Jurassic of, iii, 71 



lateral moraines in, i, 303 



Pliocene of, iii, 319 



Triassic of, iii, 36 

 Izard limestone, iii, 561 



