398 INDEX. 



Schistose group of Norway, 74. 



rocks, structure of, in Cornwall, 104?. 



. . Scotland, 104. 109. 



. Ireland, 106. 112. 



-, position of, next granite, in Cornwall, 125. 129. 132. 



Scotland, 129. 132. 



-, dip of, next granite, 123. 



Scotland, granite of, 25. 



, Western Isles of, the primary schists of, 67. 



Sea-level, alterations of, in Cornwall, 272. 



Sedgwick, Professor, on the dip of slate next granite in Cornwall, 124. 



, on granite-veins of Wicka Pool, 151. 



, on veins of segregation, 355. 



Sedgwick and Murchison on Caithness, 261. 282. 

 Segregation, veins of, in Cornwall, 355. 

 Serpentine, Cornish, 46. 



in the gneiss of Scotland, 70. 



Shorl-rock, different kinds of, 15. 



, convoluted appearance of, 338. 



, beds of, in slate, 53. 



Shorl-schist of the Erzgebirge, 85. 



Sicily, trap -rocks in the strata of, 273. 



Skye, dykes of trap-rocks in, 275. 



Slate, angular portions of, in granite, not fragments, 349. 



Slate-veins analogous to granite-veins, 352. 



Strata, primary, the determination of the dip of, 106. 



, sedimentary and primary, compared, 233. 



, deposition of, on inclined planes, 259. 



, inclined, great thickness of, 265. 



, primary, the nature of, doubtful, 290. 



, not stratified, 371. 



, objections to the metamorphosis of, 311. 



, altered appearance of, next trap, 301. 



, primary, not raised from horizontal positions, 372. 

 -, not altered sedimentary rocks, 378. 



, the apparent dislocations of, 337. 



Stratification, an enquiry into the nature of, 230. 



and structure often confounded, 247. 



Stratified and rounded masses of granite, 198. 



rocks, the alternation of, next trap, 222. 



Stratum, definitions of the term, 231. 

 Structure of the primary rocks, 91. 



rocks of the same nature in every group, 247. 



Studer, M., on the granite and altered rocks of the Alps, 326. 



T. 



Talc-schist, Cornish, the nature of, 47. 



- in gneiss of the Western Isles, 70. 



