SIG 



INDEX. 



Tripoli composed of infusoria, 39. 

 Trochus, and cast of the same, 65. 

 Tronslad Strand, section on beach at, 129. 

 Trough, or basin, described, 66. 

 Tuff; volcanic, 19. 98. 



• , imbedding of fossils in, 273. 



Tufacebus conglomerates, 98. 

 Turner, Dr., on combinations formed by 



mineral matter when in a nascent 



state, 58. 



, on source of silex in solution, 59. 



Turrilites costatus, 184. 

 Tuscany, volcanic rocks of, 276. 



, calcareous springs of, 302. 



Tynedale fault, 78. 



Unconformable stratification, 74. 

 Underlying rocks, term proposed for 



granites, 21. 129. 

 177110 Litloralis, 44. 



Upheaval of extensive masses of hori- 

 zontal strata, 62. 



Upper New Red sandstone and fossils, 

 237. 



Val di Noto, volcanic rocks of the, 115. 



Valley of Bray, 182. 211. 



Valleys of denudation, 80. 



Valorsine granite, veins of the, 127. 298. 



Valvaia, 45. 



Veins, granitic, 123. 



, metalliferous, 128. 



, of segregation, 129. 



. .See Dikes. 



Velay, volcanic rocks of, 18. 



Vertical strata parts of great curves, 64. 



Vesuvius, 273. 276. 



Vicentin, columnar basalt in the, 112. 



Virlet, M., on corrosion of rocks by 



gases, 147. 

 , on cretaceous rocks of the Morea, 



199. 



, on volcanic rocks of the Morea, 



277. 278. 

 Vivarais, volcanic rocks of, 18. 

 Volcanic eruptions, number of in a 



century, 283. 

 Volcanic dikes described, 103. 



• , rocks altered by, 107. 



Volcanic grits, 98. 



Volcanic rocks described, 18. 89. 92.99. 



• produce a fertile soil, 90. 



, analysis of minerals found in, 102. 



, their fusibihty, 99. 



, their relation to trap, 114. 117. 



, denudation of shown by dikes, 1 15. 



, submarine, 19. 115. 



, on the different ages of, 19. 271. 



, age of, how determined, 271. 



■ , iSee also Trap rocks. 



Volcanic tuff" described, 19. 99. 



, imbedding of fossils in, 273, 274. 



Volcanos, extinct, of different coun- 

 tries, 18, 19. 91. 



, cones and craters of, how formed, 



91. 



, all near the sea, 116. 



Vollzia brevifoUa, 237. 

 Volutes, figures of 177. 179. 

 Von Buch, on rise of land in Sweden, 

 63. 



, on granite of Norway, 129. 289. 



, on altered Oolite, 288. 



Von Dechen, M., on granite veins, 127. 

 , on isle of Arran, 294. 



Wacke described, 101. 



Waller cited, 155. 



Water, sorting power of, 30. 



, levelling power of, 30, 31. 



Watt, G., experiments of, 146. 



Wealden strata, position and subdivi- 

 sions of 200. 



, fossils of 201 to 204. 209, 210, 



211. 



, passage of beneath chalk, 203. 



, how formed, 204. 208. 



, extent of 209. 



, age of 211. 



Webster, Mr., on dirt-bed in Portland, 

 206. 



Weinbiihla, granite of covering chalk, 

 291. 



Wenlock formation, 267. 

 Werner, his classification of rocks, 152. 

 West Indies, recent and tertiary strata 

 in, 171. 



Westphalia, cretaceous rocks of, 193. 

 Whin-Sill, intruded trap, 110. 

 Whinstone, 101. 



White Mountains, granite veins in, 283. 

 Whitestone, 135. 



Witham, Mr., on fossil coal plants, 56. 

 260. 



Wood, recent and fossil, drilled by per- 

 forating mollusca, 38. 



, fossil, magnified portion of, 56. 



, experiments to illustrate the petri- 

 faction of 57. 



, rate of its lapidification, 60. 



Wrekin, trap tuffs of the, 280. 



Yarmottth sands, new channel in, 178. 

 Yorkshire, Oolite of 223. 



Zamia, fossil, in Portland, 205. 



, recent, figure of 205. 



Zechstein and fossils of 240, 241. 

 Zoophytes, limestone formed by, 50. 

 ; fossil, in Oolite, 214. 216. 



THE END. 



