INDEX. 
‘Trochosmilia, 804 
Trochus, 679*, 792, 806, 865 
Trogontherium, 874 
Trophon, 873, 874, 875*, 895* 
Tubicaulis, 757 
Tufa, calcareous, formed in bitter lakes, 
400 
Tuff, 161, 244, 565; non-voleanic frag- 
ments in, 206, 216, 245, 253, 574 
Tuff-cones and coniferous wood, 731 
Tulip-tree, fossil forms of, 804, 871 
Tunbridge Wells Sand, 817 
Tundras of Siberia, 457 
Turbinolia, 851, 860 
Turbo, 753, 762, 806 
Turf, protective influence of, £56 
Turonian, 814, 821, 826, 829 
Turrilepas, 664 
Turrilites, 807, 808* 
Turritella, 762, 806, 840, 874, 881 
Turtles, earliest known, 776 
Tuscany, delta growth in, 390; travertine 
of, 354 
Tylodon, 840 
Type-fossils, 615 
Typhis, 855 
Uinta Group, 853 
Uinta Mountains, 288 ; structure of, 914 
Ulmus, 862 
Uneites, 696, 698* 
Unconformability, 599 
Under-clays of Coal-measures, 491 
Undercliff, origin of, 357 
Underground circulation of water, 346 
(see Springs) 
Unio, 790, 817, 856, 875 
United States (see America, North) 
Unstratified rocks, 109 
structure, 88 
Upheaval, secular, 274; results from sub- 
sidence, 912; increases towards the 
poles, 280; relation of to earthquakes, 
273; proofs of intermittent, 280; causes 
of, 284; connected with denudation, 287 ; 
at volcanic vents, 232, 251; gives rise 
to faults, 315; attributed to local hydra- 
tion of anhydrite, 333; influence of on 
flow of rivers, 364; indicated by river 
terraces, 384; affects denudation, 447, 
911, 912 
Uralite, 77 
Uranus, 8 
Uraster, 789 
Urgonian, 824 
Urocordylus, 733 
Ursus, 875, 898 
Utah, salt lakes of, 111, 595, 400; efflores- 
cences of, 327; Carboniferous marble of, 
114; “laccolites” of, 546; granite of, 
553, 646; Cretaceous, 832; Tertiary, 
869; volcanic phenomena of, 209, 210, 
244 



969 
Utica Group, 692 
Valleys, longitudinal and transverse, 38; 
sometimes originated by earthquakes, 
272; usually by erosion, 926; subaerial 
origin of, 283, 446; sometimes formed 
or deepened by falling in of cavern roofs, 
357; rate of erosion of, 446, 879, 920; 
relation of to anticlines and synclines, 
914; persistence of, 922 
Valwata, 796 
beso from volcanoes, 198, 211, 235, 
Variolite, 145 
Vectisaurus, 817 
Vegetable substance, alteration of into 
coal, 305 
Veins and dykes, 551; mineral, 591 (see 
Mineral Veins); of segregation, 132; 
of intrusion, 551 
Veinstones, 592 
Venice, delta formation at, 390 
Ventriculites, 804* 
Venus, 806, 865 
Venus, planet, 8 
Vermetus, 849 
Vermicularia, 820 
Vermilia, 723 
Vermilion Creek Group, 853 
Vertebrate life, earliest traces of, 666 
Vesicular structure, 88 - 
Vesuvianite, 79 
Vesuvius, phenomena of, 200, 202, 206, 208, 
209, 211, 212, 213, 215, 216, 217, 220, 
222, 223, 225, 227, 228, 229, 230, 231, 
232, 233, 248, 249 
Viburnum, 849, 868 
Vichy, alkaline water of, 351 
Vienna basin, Oligocene deposits of, 861 ; 
Miocene, 866; Pliocene, 876 
Vienna Sandstone of Alps, 830, 838, 851 
Vincularia, 723 
Vine, fossil forms of, 855, 866 
Virgulian group, 795, 797 
Viridite, 107 
Vistula, sediment in water of, 370 
Vitreous structure, 99, 104, 105, 131; ba- 
salt, 100, 105, 149, 213 
Vitrophyre, 90 
Vivarais, volcanoes of, 209 
ae: 84; as a petrifying medium, 
Voleanello, Island of, 242, 248 
Volcanic action, 208 ; active, dormant, and 
extinct phases of, 208; sites of, 209; 
Conditions for, 210; influence of steam 
in, 218; periodicity of, 211 ; alternations 
in character of, 247, 253; premonitory 
symptoms of eruption, 212; fissures, 212, 
221, 255, 261; explosions, 215, 219, 226, 
252; showers of dust, 216; outpouring 
of lava, 219 (see Lava); subsidence and 
elevation, 232, 243, 251; torrents of 
