476 



INDEX. 



Saline springs, 171, 172, 173, See also 



Rock-salt. 

 Salt, quantity of in the ocean, 5. 

 works of Bex, 175 ; of the Taren- 



taise, ib. 



Sand, inundations of, 339; in Lybia, ib.; 



in Cornwall, ib.; in Guadaloupe, 330. 

 Sandstone. See New red sandstone, Old 



red sandstone, and Molasse. 

 Sapphire, crystallized alumine or clay, 



32. 



Saturn, density of, 364. 



Saurian animals, or lizards, fossil re- 

 mains of, 24. 



Saussure, account of his ascent up Mont 

 Blanc, 60; the fatigue is supposed to 

 have abridged his life, 61. 



iSaussurite, crystallized serpentine com- 

 bined with jade or felspar, 78; one of 

 the hardest and heaviest of rocks, 79 ; 

 blocks of it scattered in the valley of 

 the Rhone, ib. ; immense beds of it 

 in the valley of Sass, ib. ; also in the 

 Apennines, ib. 



Scaglia, a mode of chalk, 201 ; account 

 of, in the Tyrolese, 205. 



Scattered blocks of granite, in the Alps, 

 355, 356; in Cumberland and Wales, 

 314. 



Schist. See Slate. 



Sea, encroachments of, 462. 



Seams, or partings in rocks, how to be 

 distinguished from strata, 45. 



Secondary rock formatio7is, abound in 

 remains of testaceous animals, 157; 

 the floetz or flat rocks of Werner, ib. 



strata (Chap. XI.) 158; min- 

 eral and fossil characters of, ib. ; suc- 

 cession and tabular arrangement of, 

 158; section of, 160; secondary strata 

 of Germany, 163. 



Sedgvnck, Professor, on the protrusion 

 of trap rocks, 137, 139 ; on red sand- 

 stone and magnesian limestone, 167, 

 168 ; observations on the study of geo- 

 logy, 366. 



Selenite, or crystallized gypsum, 37. 



Septaria, or balls of imperfect ironstone, 

 occur in London clay, 222; Parker's 

 cement made of them, ib. 



Serpentine, analysis of, 36 ; description 

 of, 77; localities of, 78; passage of 

 into potstone, jade and diallage, ib.; 

 remarkable position of, in the Apen- 

 nines, 79; serpentine sometimes pass- 

 es into trap when the latter rock is in 

 contact with limestone, ib. ; minerals 

 associated with it allied to talc, 77; 

 sometimes magnetic, ib. ; a beautiful 

 variety in Anglesea, approaching to 

 noble or precious serpentine, 78. 



Sixt, valley of, 342. 



Shale, soft slate u^ith an excess of car- 

 bon, 150; called also slate clay. 



Sheep, varieties of, might be mistaken 

 for distinct species, were their skins 

 only found in a fossil state, 241. 



Shell marl, 328; remains of land quad- 

 rupeds found in it, ib. 



Sienite, a variey of granite in which 

 hornblende supplies the place of mica, 

 58; occurs in Malvern and in Charn- 

 wood Forest, 80; when hornblende is 

 abundant, is denominated greenstone, 

 129, 131. 



Sienitic granite, 65; its passage into 

 greenstone and trap, ib. and 130. 



Silez, or siliceous earth, 32; flint, chert, 

 opal, agate, &c., modifications of, 34. 



Sill, synonymous with stratum, 138. 



Silver ore, vein of, at Uspalata, 290; ex- 

 tends ninety miles, ib. 



Simple minerals composing rocks, enu- 

 merated, 31,33. 



Skeletons, human, in Guadaloupe sand- 

 stone, 14; in various caverns ia 

 France and Germany, 305 — 307. 



Sky, Isle of, the crystalline limestone 

 there, more like' the secondary or 

 lias, 75. 



Slate, called also clay slate and argillace- 

 ous schistus, 37; roof slate, the purest 

 form of, ib. ; component parts of, 38. 



(Chap. VII.) 82; cleavage of, 84; 



when magnesia prevails, passes into 

 talcy slate and chlorite, ib.; carbona- 

 ceous matter first discovered in slate 

 rocks as they approach the secondary 

 strata, 85; impressions of vegetables 

 in slate rocks, ib. ; impressions of 

 ferns in the slate of Mont Blanc and 

 Mont Cenis, ib.; effects ol' crystalli- 

 zation evident in slate, ib. ; localities 

 of, ib. ; mountains of, have often a 

 sharp, serrated outline, ib. ; the most 

 metalliferous of rocks, principally 

 lead and copper, 86. 



clay, or shale, a soft kind foimd in 



coal strata, 84; differs from clay slate, 

 ib. ; more properly called shale (which 

 see) ib. 



Slaty, or laminar, composed of straight 

 parallel thin plates, 39. 



Soda exists in great abundance in sea 

 water and rock salt, 33. 



Soil, formation of, 337. 



Solar radiation, Sir W. Herschel's ob- 

 servations on, 360. 



Stalactites, described, 310. 



Stalagmites, described, 310, 



Statuary marble, localities of a spurious 

 sort in Scotland, 75. 



Stonesficld slate, 185; description of, 

 186 ; extraordinary fossil remains in, 

 23, 187. 



Strata, 39. 



seams, 45. 



Stratif cation (Chap. IV.) 41 ; the knowl- 

 edge of, most important for geologists, 



