INDEX. 



Fit ton, Dr., on the Green-sand, 181. 



191, 192. 



, on the Maestricht beds, 189. 



, on the Wealden strata, 200, 201. 



205. 209. 



, on the Portland dirt-bed, 206, 207. 



Fleming, Dr., on fossil fish of Old Red 



sandstone, 263. 



, on trap rocks, 279, 280. 



Flint, sponge fossil in, 185. 



, in chalk, its origin, 190. 



Flotz rocks of Werner, 153. 

 Footsteps, fossil, 238, 239. 

 Foraminifera of the Chalk, 41. 

 Forfarshire, geology of, 65. 262. 



, decomposition of rocks in, 242. 



Formation, term explained, 16. 

 Formations, fossiliferous, arrangement 



of, 157. 163. 



Forth coal-field, trap rocks of, 279. 

 Fortis, on columnar basalt, 112. 

 Fossil, term defined, 16. 

 Fossils in stratified rocks, 16. 



, height at which they are found, 17. 



, their arrangement in strata, 35. 



, parasitic, prove gradual deposi- 

 tion, 36. 



, freshwater and marine, 42. 



, their absence in some rocks, how 



explained, 52. 302. 



, mineralization of, 55. 



, casts and impressions of) how 



formed, 55. 

 Fossiliferous strata, conversion of into 



metamorphic rocks, 295. 

 , why most calcareous, 301. 

 Fournet, M., on disintegration of rocks, 



Fox, Mr. R. W., his experiments on 

 lamination, 142. 



Fox, Rev.W.D., on fossil mammalia, 180. 



Freshwater formations, how distin- 

 guished from marine, 42. 



, land shells numerous in, 43. 



, fossils numerous, but species few 



in, 44. 



, figures of shells most common in, 



44, 45, 46. 



, Cypris fossil in, 47. 



, Charae fossil in, 48. 



, vertebrated animals in, 48. 



, alternating with marine, causes 



of, 49. 



Fresh water strata of the Coal, 244.256. 



Frontispiece described, 22. 



Fusus contrarius, 175. 



Gabbro, 100. 



Gaillonella, fossil in tripoli, 39. 41. 



Galapagos islands, living marine reptile 



of, 229. 



Ganges river, deposits in estuary of, 16. 

 Garnet, 102. 



. , in altered rocks, 107. 301. 



Gases, subterranean, rocks altered by, 



146, 147. 



Gault, 191. 



Gavarnie, curved strata near, 74. 



Geology defined, 13. 



Gestellihorn, section at base of the, 298. 



Giant's Cause way, volcanic rocks of, 19. 



Glen Tilt, junction of granite, schist, 



and limestone in, 123. 125. 

 Globular structure, 110. 

 Gneiss described, 132. 

 Gold mine, slaty structure in refuse of, 



142. 



Goniatites evolutus, 254. 

 Goppert, Prof, his experiments on fbs- 



silization of plants, 57. 

 Gosforth, tree in coal strata at, 56. 259. 

 Graham island, 116. 

 Grampians, vertical conglomerates in 



the, 64. 



, section from to the sea, 65. 



, dikes of granite in, 125. 



, decomposed rocks of, 242. 



, rarity of limestones in the, 301. 



Granite, of igneous origin, 20. 148. 



, of different ages, 23. 126. 281. 



, general aspect, structure, and 



composition of, 119. 



, varieties of, 120, 121. 



, passage from trap to, 123. 



, analogy in composition of trachyte 



and, 123. 



, veins, 123. 



, finer grained in veins, 126. 



, isolated masses of, 128. 



, whether it ever overlies fossilife- 

 rous rocks, 129. 291. 

 , rocks altered by, 20. 143. 145. 



284. 289. 



, on the most ancient, 290. 



, protrusion of solid, 291. 



, of Arran, age of, 291. 



. See also Plutonic rocks, and 



Hypogene rocks. 

 Graphic granite described, 120. 

 Graptolites, 268. 

 Grateloup, Dr., on chalk of S. of 



France, 197. 

 Grauwacke, term, 264. 



, different ages of, 264. 



Graves, M., on valley of Bray, 210. 

 Gray, Mr., cited, 45. 

 Greenland, subsidence of part of, 63. 

 Green-sand formation, 191. 



, fossils of, 192. 



, its origin, 192. 

 Greenstone described, 96. 100. 

 Greystone, 100. 

 Grit defined, 26. 



Grypheea, figures of, 36. 218. 225. 

 Gryphite limestone, 225. 

 Guadaloupe, human skeletons of, 171. 

 Guidoni, M., on altered oolite, 295. 

 Gusigny, section at, 75. 

 Gypsum, composition of, 28. 

 Gyrogonites, 48. 



Hall, Sir J., on curved strata, 67. 



