572 



INDEX 



Tirolic series, 443, 447. 



Titanic ht/iys, 405. 



Titanotheres, 506, 509. 



Titanotheriuni, 509. 



Tombigbee stage, 475. 



Topography, 301. 



Toronto stage, 529, 53of. 



Torosaurus, 492. 



Torridon sandstones, 363. 



Toxaster, 487, 489*. 



Toxodon, 523*. 



Toxodontia, 523. 



Trachyceras, 451*, 452. 



Trachyte, 199 ; amphibole, 199 ; mica, 



199; pyroxene, 199; quartz, 198. 

 Tracks of animals, fossil, 182, 227, 228*. 

 Transferred drainage, 329. 

 Transition rocks, 368. 

 Transportation by glaciers, 113 ; by rain, 



78 ; - by rivers, 100 ; by wind, 86. 

 Transverse streams, 317, 318 ; valleys, 



317- 



Trap, 201. 



Travertine, I28f , 209-}-. 



Tremolite, 20. 



Trenton epoch, 355; series, 375; stage, 

 375. 376I-. 



Triarthrus, 381*, 383*. 



Triassic period, 355, 443t- 



Triclinic system of crystals, 10. 



Triconodon, 493. 



Trigonia, 463*, 465, 466*. 



Trigonoceras, 426. 



Trigotiolestes, 505. 



Trilobita, 372; Cambrian, 372; Carbo- 

 niferous, 424; Devonian, 400; Ordo- 

 vician, 381 ; Palaeozoic, 367 ; Permian, 

 432; Silurian, 391. 



Trimetric system of crystals, 10. 



Trinity stage, 475, 476!. 



Trinucleus , 381, 383*. 



Trochoceras, 392*, 393. 



Trocholites, 384. 



Tropics, glaciers in, 106. 



Trough faults, 248. 



Trough, glacial, 112*. 



Tufa, 51 ; calcareous, 151, 209. 



Tuff, sit, 52, 203, 297; andesite, 203; 

 basalt, 203 ; rhyolite, 203. 



Tuffs, fossils in, 53. 



Tulip-trees, fossil, 521. 



Turbo, 521*. 



Turrilites, 490. 



Turtles, 455, 469, 491, 495, 503, 508. 



Tuscaloosa stage, 475. 



Twins (of crystals) 14 ; polysynthetic, 14. 



Typhis, 521*. 



Typotheria, 523. 



Uinta Mountains, 314, 325, 334 ; Al- 



gonkianof, 363; Jurassic of, 458; origin 



of, 483. 

 Uinta stage, 496, 5067. 

 Uintacrinus, 487, 489*. 

 Uintatlierinm, 506. 

 Ultrabasic rocks, 202. 

 Unconformity, 269, 270*, 271*, 349, 362, 



366, 478, 497, 498. 

 Unconformity, obliteration of, 363. 

 Underclay, 413. 

 Underground waters, geological work 



of, 88. 

 Undina, 467. 

 Undulating folds, 239. 

 Unstratified rocks, 218, 2747. 

 Upper Barren Measures, 428, 429. 

 Upper Pentamerus stage, 385. 

 Upper Productive stage, 409. 

 Upthrow of fault, 243. 

 Utica stage, 375, 3767. 



Valley trains, 528. 



Valleys, anticlinal, 318 ; longitudinal, 317 ; 

 synclinal, 318 ; transverse, 317. 



Veins, igneous, 279; lead, 267; metal- 

 liferous, 266; mineral, 247, 26sf; for- 

 mation of, 267 ; sediment-filled, 268. 



Vein stuff, 266. 



Velocity of streams, 97. 



Vertebraria, 437. 



Vertebrata, Carboniferous, 426; Creta- 

 ceous, 490 ; Devonian, 403 ; Jurassic, 

 467; Mesozoic, 442 ; Ordovician, 384 ; 

 Palaeozoic, 367 ; Permian, 435 ; Silu- 

 rian, 393 ; Triassic, 452. 



Vesicular texture, 189. 



Vesuvius, 37, 38, 43* 55*; origin of, 

 520. 



Vicksburg stage, 496. 



Volcanic, activity, causes of, 58 ; agglom- 

 erate, 51, 203t; ashes, 51; bombs, 51; 

 breccia, 51, 2037; cones, 54. 



