INDEX. 



511 



Siebengebirge, different in structure from other 



groups in Germany, except one in Nassau, and 



another near Montabaur, 435. 

 , absence in, of substances which 



in Hungary and Central France accompany 



trachyte, 440. 

 • , non-occurrence of basalt frag- 



ments in the trachyte tuff of the, 441. 



, notice of a geological mapof, 472. 



, notice of authors who have de- 



scribed the, 4;i3. 

 , the, the nearest point to En- 



gland where volcanic phenomena nearly re- 

 sembling those of modern eruptions are to be 

 seen, 434. 

 , trachyte tuff of the, (wood-cut). 



440 — 443 ; its localities and characteristics, 

 441, 442. 

 -, volcanic eruptions of, 468. 



Silesia, Prof. Pusch on the beds below the chalk in, 

 329. 



Siliceous deposits of the brown-coal formation 

 in the environs of Bonn, 448. 



Siliceous stone in sand, concretion of, formed sub- 

 sequent to deposition of the sand, 232. 



. , white, containing casts of shells 



and vegetable stems, occurrence of, at Marien- 

 forst in the environs of Bonn, 4j4. 



Similarity of deposits of different epochs ; — 

 of Wealden, to new red sandstone, and to beds 

 above, and below, the chalk, 333; — of green- 

 sand, above, and below, the chalk, to that of the 

 Portland series, 333; of part of the Wealden 

 to the coal formations, 333. 



, inference from this similarity, 333. 



Sithe-stones, mode of preparing at Blackdown, 

 237. 



, workmen said to be consumptive, 238. 



Skiddaw Forest, granite of, overlaid by crystal- 

 line slates, 48. 



■-, slates of, probably owe their 



structure to action from below, 65. 



Sate, siliceous, pebbles of, in the Lower green- 

 sand conglomerate of Kent, 117. 



Smith, Rev. Gerard E., fossils of Kent, collected 

 and drawn by, 112. 



Smith, Rev. Gerard, E., examines the Wealden 



cliffs in Kent, 161, 

 ■ , remarks by, on the spiral 



termination of certain Hamites, 337. 

 Smith, William, his map of Kent referred to, 107. 

 ■ ■ , his statement respecting " sand in- 



" eluding the Portland-stone," explained, 265, 



note. 

 Soda, carbonate of, at Serroor in the Dukhun, its 



form and mode of occurrence described, 426. 

 " and at other places, 



426. 



— , muriate of, impregnates many of the wells 

 at Ahmednuggur, 425. 



also 



a rivulet called the Salt Brook at Ahmednug- 

 gur, 425. 



, streams impregnated with, at 



other places described, 426. 



Solway Firth, boulders of Carrock Fell syenite, 

 on the sliores of, 388. 



South Wales and North Devon, grey wacke series 

 of, probably elevated after completion of car- 

 boniferous-series, 57. 



does 



not conform, in direction, to other greywacke 

 chains, 57. 



of, parallel to that of the coal basin of Soutii 



Wales, 57. 

 South Western coal, notice of total break between 



coal measures and red sandstone series of the, 



401. 

 Sowerby, James, F.L.S. {deceased), observations 



by, (1812), on the probable existence of fresh- 

 water formations, 324, note. 

 Sowerby, James De Carle, F.L.S., fossils of beds 



between the chalk and Oxford oolite, drawn 



and engraved by, 105. 

 , descriptive notes by, on 



the shells figured in Plates XI. to XXIII. of 



this volume, 335—348. 

 Sphenopteris gracilis, a new species of fern from 



the Wealden, (wood-cut,) 181. 

 Springs near Weymouth, temperatures of, 44, 



note. 



