INDEX. 



425 



Species, geographical distribu- 

 tion of, 118. 

 origin of geographical diversity 



of, 130. 

 Sphenothallus (wedge frond), 



' 274. 

 Springs, 69. 

 great, 69. 

 mineral, 71. 

 Squalodont (shark - toothed : a 



family of true sharks), 318. 

 Stalactites and stalagmites, 72. 

 Stegosaur (covered lizard), 346. 

 Strata, crumpling of, 185. 



folding of, 185. 

 Stratification explained, 27. 

 Stratified rocks, classification of, 



205. 



rocks, divisions and subdivi- 

 sions of, 207. 

 rocks, how relative age of, is 



determined, 205. 

 Strike and dip defined, 187. 

 Strombodes pentagonus (five- 

 angled strombus-like ani- 

 mal), 275. 



Structural geology, 173. 

 Sub-carboniferous, 297. 

 Submarine banks, 41. 

 Subsidence of crust, gradual, 



169. 

 of Pacific bottom, amount of, 



107. 



of Pacific bottom, time of, 107. 

 of river deltas, 169. 

 Succinifer (amber-bearing), 371. 

 Sulphur, deposits of, 76. 

 Swamp, Great Dismal, 86. 

 Syenite, 212. 



Syncline and anticline defined, 

 188. 



Table-mountains, 247. 

 Tachylite, 214. 



Taxodium, bald cypress of South- 

 ern swamps, 368. 

 Teleost (complete bone), 291. 

 Terraces, 392. 

 Tertiary period, 364. 



period, animals of, 370. 



period, coal of, 366. 



period, crust-movements during 

 and closing, 384. 



Tertiary period, lake deposits of, 

 377. 



period, life-system of, 368. 



period, mammals of, 375. 



period, physical geography of, 

 366. 



period, plants of, 368. 



period, subdivisions of, 364. 



system, areas of, 365. 

 Theromorpha (beast-like), 328. 

 Tides and waves, agency of, 41. 



and waves, effect on coast-line, 



42. 



Toxoceras (bow-horn), 354. 

 Trachyte, 139, 214. 

 Transporting power of water, 26. 

 Trappean rocks, 213. 

 Triceratops (three-horned face), 



362. 

 Triassic period, 325. 



period, animals of, 326. 



period, life-system of, 325, 



period, plants of, 326. 

 Trigonia (three-angled), 331. 

 Trilobite (three-lobed stone), 283. 

 Tufa, 139, 223. 

 Turrulite (stone tower), 354. 



Unconformity, 190. 

 Unstratified rocks, 210. 



Vegetable accumulations, 84. 

 Veins, age of, 236. 



contents of, 234. 



fissure, 234. 



irregularities of, 236. 



metalliferous, 234. 



mineral, 233. 



origin of, 237. 



structure of, 235. 



surface changes of, 237. 

 Volcanic cinders, ashes, etc., 135. 



dikes, 141. 



eruptions, cause of, 144. 



eruptions, phenomena of, 135. 



gases and vapors, 139. 



phenomena, secondary, 145. 



rocks, 214. 



rocks, age of, 219. 



rocks, different kinds of, 215. 



rocks, intercalary beds of. 219. 



rocks, modes of eruption, 215. 



rocks, modes of occurrence, 216. 



