INDEX. 



315 



Stokes, Mr., on lapidification of fossil 



wood, 60. 



, on structure of Orthocerata, 268. i 



Stone-lilies, fossil, 215, 21G. 

 Stonesfield slate, fossils of, 222. 

 Strata, term defined, 15. 



, original horizontally of, 30. 51. j 



, thinning out of, explained, 31. 



, parallelism of, 30. 



, ripple-marked, 33. 



, gradual deposition of, indicated 



by fossils, 35. 42. 216. 



, their mineral composition, 25. 



, consolidation of, 50. 



, horizontal at great heignts, 62. 



, sometimes reversed, 73. 159. 



age of, how determined, 159. 271. I 



281. 294. 

 , fbssihferous, chronological ar- ! 



rangement of, 157. 163. 



, oldest sometimes horizontal, 2G9. 



, conversion of fossihferous into 



metamorphic, 295. 



Strathaird, fissures caused by decom- 

 posed trap dikes, 104. 

 Stratheden, trap rocks of, 279. 

 Slrathmore, valley of, 65. 2G2. 

 Stratification, forms and causes of, 15. 



28. 32, 33. 35. 64. 74. 



, proof of aqueous origin, 16. 



, of deposits in lakes and estuaries, 



15, 16. 



, planes of, how far parallel, 30. 



, distinct from cleavage, 137. 



Stratum defined, 15. 



Strickland, Mr., on tertiary strata, 173. 



Strike and dip explained, 69. 



, sometimes not altered by intruded 



granite, 128. 

 Stromboli, 273. 276. 283. 

 Studer, M., on alternation of gneiss and 



fbssiliferous rocks in the Alps, 298. 

 Stutchbury, Mr., on fossil reptiles, 242. 

 Subapennmes, interstratified tuffof, 276. 

 Subsidence of land, 63, 64. 



, in Cretaceous period, 193. 



, in Wealden period, 204. 212. 



, in Carboniferous period, 257. 



Succinea elongata, 45. 



Suffolk, freshwater strata in, 173. 



, Crag of, described, 173. 



Suishnish, trap rocks of, 105. 

 Superior, Lake, recent deposits in, 52. 

 Superposition, relative age of strata 



shown by, 159. 

 Sutton, section at, 175. 

 Sweden, gradual rising of land in, 63. 



, Recent and Tertiary strata of, 171. 



, Silurian strata, horizontal in, 62. 



267. 269. 



Swiss Alps, altered rocks of, 296. 

 Syenite described, 121. 

 Syenitic greenstone described, 96. 101. 

 Synclinal line described, 66. 72. 



Table Mountain, stratification of, 62. 



Table Mountain, granite veins in, 125. 



Talc, 102. 



Talcose gneiss, 135. 



Talcose granite, 122. 



Talcose schist, 135. 



Tattingstone, crag strata at, 174. 



Tephrine, 101. 



Tercis, chalk of, 197. 



, chalk and volcanic tuff, alternat- 

 ing at, 277. 



Terebellum fusiforme, 179. 



Terebrahdce, fossil figures of, 183. 192. 

 220. 266. 



Teredina, fossil wood bored by, 38. 



Teredo navalis, wood bored by, 38. 



Terminology, 199. 



Tertiary formations, their relative posi- 

 tion, fossils, &c., 164. 



, divisible into four groups, 165. 



, how classified, 165. 



, of different countries described, 



169. 



, how distinguished from Recent, 



170. 



, volcanic rocks, 275. 



, plutonic rocks, 284. 



Testacea. See Shells. 



Thermal ocean, theory of, 155. 



Thinning out of formations, 162. 



Thirria, M., on the Oolite, 233. 



Thun.lakeof, land shells drifted into, 43. 



Thurmann, M., on the Swiss Jura, 71. 

 218. 



Tisbury, fossil coral from, 214. 



Toadstone, 101. 



Tourmaline, 102. 



Tournedos, chalk needles at, 194. 



Trachyte described, 96.101. 



, analogy in composition of granite 



and, 123. 



and basalt, relative position of, 274. 



Transition strata and fossils, 152. 154.264. 



Trap conglomerates, 116. 



Trap dikes described, 103. 



, rocks altered by, 104, 107. 



, their abrupt termination caused 



by denudation, 115. 273. 



Trap rocks described, 89. 



, name whence derived, 89. 



, step-like appearance of, 90. 



, changes caused by, 104. 107. 



, intrusion of, between strata, 110. 



, their relation to modern lavas, 114. 



117. 



, pass into granite, 123. 



, regarded by Werner as aqueous 



deposits, 153. 



, on the different ages of, 271. 



. See also Volcanic rocks. 



Trap tuff described, 98. 



Trass, 101. 



Travertin deposited by springs, 50. 



Tree-ferns, figures of, 249. 



Trees in Coal strata, erect position of, 257. 



Treuil coal-mine, vertical trees in, 258. 

 Trigonia gibbosa, 218. 



