INDEX. 



ABERDEENSHIRE, granite of, 123. 

 Acephalous mollusca, 44. 



Acrodus nobilis, 226. 



Actinoceras Simmsii, 268. 



Actinolite, 102. 134. 



Agassiz, on fossil fish, 180. 225, 226 

 237. 241. 246. 263. 



Age of aqueous strata, how deter- 

 mined, 159. 



, of volcanic rocks, 271. 



, of the plutonic rocks, 281. 



, of the metamorphic rocks, 293. 



Airdnamurchan, trap veins in. 104. 



Albite, 102. 



Alluvium described, 83. 



, passes into regular strata, 84. 



, marine, 85. 



Alps, reversed position of strata in, 73. 

 297. 



, curved strata of, 73, 74. 



, metamorphic rocks of the, 287. 



296. 



Altered rocks, 21. 107. 123. 140. 143. 

 286. 293. 



Alternations of coarse and fine strata, 

 how formed, 16. 29. 



, of marine and freshwater forma- 

 tions, 49. 



Alumine in rocks, how to detect, 26. 



Amblyrhynchus cristalus, 229. 



America, Recent and Tertiary strata 

 of, 171. 



Silurian strata in, 268. 



Amici, Professor, on recent Charae, 48. 



Ammonites, figures of, 189. 220. 238. 246. 



Ampelite, 134. 



Amphibolite, 93. 134. 



Ampullaria glauca, 46. 



Amygdaloid described, 96. 



Ananchytes ovatus, 185. 



Ancylus elegans, 45. 



Andes, geological structure of, 284, 285. 



, tertiary plutonic rocks of, 286. 



Anglesea, rocks altered by a dike in, 



Anodonta, figures of, 44. 

 Anoplotherium, 180. 

 Ansted, Mr., on Cambrian fossils, 270. 

 Anticlinal line explained, 66. 72. 

 Antrim, rocks altered by dikes in, 107. 



, on age of trap rocks of, 278. 



Apennines, age of metamorphic rocks 



of, 295. 



Apes, fossil, 180. 

 Apiocrinites rotundus, 216. 

 Aa* 



Aqueous rocks described, 15. 159. 



Arbroath, section from, to the Gram- 

 pians", 65. 



Arenaceous rocks described, 25. 



Argillaceous rocks described, 26. 133. 



Arran, dikes in, 104. , 



, geology of, 291, 292. 



, section of, 292. 



Arthur's seat, strata altered in, 109. 



Asapkus, figures of, 266, 267. 



Ashby, faults in coal-field of, 81. 



Ashes, volcanic, hollows filled up by, 

 30, 31. 



, wide dispersion of, 273, 274. 



Astarte, 176. 



Atlantis, 210. 



Auch, ape fossil near, 180. 



Augite and hornblende, analogy of, 92, 

 9o. 



, analysis of, 102. 



Augite rock, 99. 



Augitic porphyry, 99. 



Auricula, 45. 



Autreppe, unconformable strata, 74, 75. 



Auvergne, volcanos of, 18. 91. 276. 



, freshwater strata of, 43. 



Auvergne, rocks decomposed by car- 

 bonic acid in, 147. 



, tertiary red sandstone of, 243. 



, calcareous springs of, 302. 



Amcula, figures of, 224. 238. 



JBacillaria in tripoli, 39. 



Baculites, figures of, 184. 



Bakewell, Mr.,on structure ofrocks, 139. 



Bala limestone, 270. 



Baltic, rocks drifted by ice in, 87. 



Basalt described, 95. 100. 



, columnar, 110. 



, sandstone rendered columnar by, 



140. 

 and trachyte, relative position of, 



274, 275. 



Basin, or trough, described, 66. 

 Basset, term explained, 72. 

 Bayfield, Captain, on transportation of 



rocks by ice, 72. 



, on worn limestone pillars, 194. 

 Beaumont, M. E. de, on lias of the Vos- 



ges, 225. 

 , on metamorphic rocks in the Alps, 



287. 298. 

 Beck, Dr., on recent and tertiary fossil 



shells, 167. 



, on classification of tertiary strata, 



168. 



(305) 



