~ 942 
Clay, absorbent power of plastic, 299 
Clay, origin of, 81 
Clay-ironstone, 83, 116, 175 
Clay-rocks, 160, 161 
Clay-slate, 121,126; formation of by meta- 
morphism, 304 
Cleavage, 121; nature of, 310, 521; in- 
fluenced by nature of the rock, 311; 
relation to foliation, 307, 579, 582, 586 
Cleidophorus, 665, 669* 
Cliff-debris, 154 
Climacograptus, 663 
Climate, geological relations of, 21; influ- 
ence of man upon, 471; affected by the 
sea, 426; submarine, 421; past alterna- 
nations of, 21, 29; indicated by fossils, 
613; Paleozoic, 21; Jurassic, 784; 
Cretaceous, 803 ; Tertiary, 837, 869, 871, 
872; proofs of gradual refrigeration of 
in late Tertiary time, 872, 883 
Climatius, 714 
Clinkstone, 139 
Clinometer, 509 
Clinton Group, 692 
Cliona, 676 
Clisiophyllum, 722 
Clouds, formation of, 329 
Clyde shell-beds, 895 
Clymenia, 698 
Clypeus, 773 
Coal, kinds of, 171; mode of occurrence 
of, 720; formation of, 305, 490; jointing 
of, 502; altered by eruptive rock, 173, 
573, 575; alters eruptive rock, 576 ; 
effects of plication on, 306, 520; as- 
sociated with fireclay, 490, 720; with 
marine limestones, 741, 745, 749 
Coal-measures, 737, 743 
Coal-seams, persistence of, 492; 
poraneous channels in, 480, 483 
Coals of various geological ages, as Old 
Red Sandstone, 714; Carboniferous, 
720; Permian, 756; ‘Triassic, 768; 
Jurassic, 792; Cretaceous, 802, 828, 
834; Eocene, 851; Oligocene, 859, 861 ; 
Miocene, 868 
Coast-lines of the continents, 41; form of 
as an index of depth of sea, 449 
Coblenzien, 702 
Coccosteus, 666, 698, 709*, 710 
Cochliodus, 724 
Cockroach, early form of, 732 
Calacanthus, 749 
Celaster, 696 
Ceelenterates as fossils, 611 
Canites, 678 
Coanopithecus, 840 
Colcoptera fossil, 752, 787, 
Colloid minerals, 61 
Colobus, 864 
Colonies, Barrande’s doctrine of, 627, 849 
Colorado Group, 832 
Colorado, river gorges of, 378, 923 
Colorado, subaerial denudation in basin 
contem- 
798, 868 
INDEX. 
of the, 321, 378, 922; river gorges or 
caiions of, 378, 9238 ; table-lands of, 922 
Cee ‘of rocks ‘by eruptive masses, 
73 
Columbia, British, Cretaceous rocks of, 831 
Comoseris, Vise 
Compact structure of rocks, 87, 88 
Compression of rocks, 314, 519, 747; 
effects of relief from, 273, 309, 311, 314 
Compsemys, 832 
Compsognathus, 779 
Conchicolites, 664 
Conchoidal fracture, 91 
Concretionary structure, 89, 487 
Concretions, 62, 89 
Condensation of water, importance of in 
geology, 329 
Condros, psammites de, 701 
Cone de déjection, 280 
Cone-in-cone structure, 313 
Cones, voleanic, 214, 225, 243, 248, 258 
Conformable strata, 599 
Congeria, 866, 874*, 876 
Congerian Stage, 876 
Conglomerate, 156; associated with sand- 
stone rather than with shale, 491; oc- 
currence of in schist, 125; inconstancy 
of, 492; pillars of, eroded by rain, 341 ; 
joints i in, 504 ; voleanic, 163 
Conglomerated structure, 87 
Conifers, earliest known forms of, 709, 730 
Coniosaurus, 808 
Coniston grits and flags, 684; limestone, 
670), 684 
Conocardium, 723* 
Conocoryphe, 649*, 651, 664 
Conodonts of Pander, 666 
Conservative action in geology, 316 
Contact-metamorphism . (see Metamor- 
phism) 
Contactschiefer, 578 
Contemporaneity, geological, 617 
Contemporaneous eruptive rocks, 535, 562 
Contemporaneous veins, 90, 556 
Continental conditions, indications of, 711, 
757 
Continents, grouping of the, 35; antiquity 
and permanence of the, 22, 35, 54, 288, 
911; intermittent and often repeated 
elevation of, 287, 912; inland sand 
wastes of, 325 
Contortion (see Plication) 
Contraction, terrestrial, 261, 274, 286, 912 
Contraction of rocks, 294, 319 
Conularia, 651*, 666, 724% 
Conus, 840, 841%, 855, 865 
Cooling, secular, of globe, 286 
Copper, native, in fossils, 453 
Copper ores in Kupferschiefer, 751 
Coprolites, 169 
Corallian, 794 
Coralline Crag, 873 
Coralline Oolite, 794 
Coral Rag, 794 
