INDEX 



961 



Hugi, F. J., 287 

 Human period, 931 



life of, 935 

 Human relics, 913 



in California, 811 

 Huntington, E., 837, 894 

 Huronian systems, 457 

 Hustedia mormoni, 658 

 Hyatt, A., 705 

 Hybocrinus tumidus, 530 

 Hydration, 33, 102, 203 

 Hydraulic limestone, 84 

 Hydrosphere, 4, 201 



geologic activity of, 7 



mass of, 6 



origin of, 433 

 Hydrozoa, Cambrian, 499 



Ordovician, 531 

 Hyolithes americanus, 498 

 Hypersthene, 78 

 Hypogene rocks, 84 

 Hypothyris cuboides, 587 

 Hypsipteura gregaria, 741 

 Hypsometric hypotheses of glacial 



climate, 895 

 Hyracotherium, 790 



venticolum, 791 



Ice crystals, structure of, 278 



glacial, 229, 275 



in soil, 223 



on lakes and ponds, 223 

 rivers, 226 

 the sea, 226 



ramparts, 225 



texture of, 230 



wedge work of, 223 

 Icebergs, 274, 275 

 Iceland spar, 78 

 Ice-packs, 227 

 Ice-sheets, development of, 861 



erosion by, 863 



in Europe, 846, 848 

 North America, 846 



slope of, 862 



thickness of, 861 



work of, 868 

 Ichthyornis victor, 768 

 Ichthyosaurs, Cretaceous, 765 



Jurassic, 716 



Triassic, 694, 701 

 Ichthyosaurus quadriscissus, 718 

 Iddings, J. P., 59, 393 

 Idonearca nebrascensis, 768 

 Igneous activity, Cretaceous, 755 



Igneous activity continued 



Miocene, 813 



Mississippian, 601 



Oligocene, 800 



Pleistocene, 911 



Tertiary, 778, 813, 839 



Triassic, 682 

 Igneous rocks, 12, 13, 15 



Carboniferous, 642 



composition of, 23 



Cretaceous, 754 



Devonian, 571 



disruption of, 31, 33 



in Illinois, 601 



Ordovician, 513 



Pleistocene, 911 



Silurian, 545 



Tertiary, 778, 812, 839 



Triassic, 682 



Illinois glacial epoch, 874, 876 

 Illinois, oil and gas in, 639 

 Ilmenite, 78 



Ilyanassa (?) porcina, 827 

 Imbrication of drift sheets, 878 

 Immediate run-off, 110 

 India, in Permian, 696 



Permian glacial formations of, 



667 



Infusorial earth, 38, 84 

 Initial atmospheric stage, 432 

 Inoceramus vanuxemi, 768 

 Inorganic deposits of sea, 327 

 Insectivora, Eocene, 787, 792 

 Insects, Devonian, 595 



Eocene, 794 



Jurassic, 720 



Oligocene, 801 



Ordovician, 534 



Pennsylvanian, 654 

 Interglacial epochs, 874 



life, of 916 

 Interior of earth, 10 

 Intermediate rocks, 24 

 Intermittent streams, 113 

 Internal density, changes in, 360 



heat, 361, 363, 364 

 Intrusion and metamorphism, 51 

 Intrusions of lava, 367 

 lone formation, 811 

 lowan glacial epoch, 874 

 "Iron age," 924 

 Iron in igneous rocks, 23 

 Iron ore, 38, 69 



Clinton, 538 



in Proterozoic, 459, 473 



