318 



INDEX. 



Tripoli composed of infusoria, 39. 

 Trochus, and cast of the same, 55. 

 Tronstad Strand, section on beach at, 129. 

 Trough, or basin, described, 66. 

 Tuff, volcanic, 19. 98. 



, imbedding of fossils in, 273. 



Tufaceous 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. 



Unio litloralis, 44. 



Upheaval of extensive masses of hori- 

 zontal strata, 62. 



Upper New Red sandstone and fossils, 



Val di Noto, volcanic rocks of the, 115. 



Valley of Bray, 182. 211. 



Valleys of denudation, 80. 



Valorsine granite, veins of the, 127. 298. 



Valvata, 45. 



Veins, granitic, 193. 



, 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 fusibility, 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. 



, See 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 brevifolia, 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. 



Weinbuhla, 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. 



W T hite 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. 



Yarmouth 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. 



