oil PROCEEDINGS OF THE GEOLOGICAL SOCIETY, 



and that no sedimentary rocks formed high mountains. Again, it 

 was formerly supposed that the crystalline rocks, particularly 

 granite, owed their origin to igneous action. Now it is \vell 

 known that these granites are chiefly arranged in layers and, 

 as it were, stratified, as those of the Pinster Aarhorn and of St. 

 Crothard. The granite passes into gneiss, and the gneiss into mica- 

 schist and talc-schist, and this is again closely connected with the 

 green and grey slates ; and it is well known that many of these 

 rocks formerly considered as plutonic, are really metamorphosed 

 sedimentary rocks. Like Prof. Theobald, the author adopts 

 Studer's view that the Alps, instead of consisting of a central 

 chain with several parallel lateral chains, are composed of a num- 

 ber of mountain-groups forming so many ellipticad central masses 

 of crystalline rocks, the intervening spaces or troughs being occu- 

 pied generally by the sedimentary rocks. 



He then describes these various central masses, thirty-five iu 

 number, having their respective belts of sedimentary rocks vari- 

 ously contorted and disturbed, and often inverted, wrapping round 

 them. This is followed by an account of the sedimentary rocks 

 themselves, the erratic appearances in the Alps, and an explanation 

 of the Alpine lakes, showing that the valleys and depressions in 

 which these lakes lie were owing to causes existing before the 

 glacial period ; amongst these causes not only the accidental form 

 of the surface is to be noted, but also the nature and constitution 

 of the ground and soil. 



With regard to the striking difference in the features of the 

 Italian lakes and those in the interior of Switzerland, he considers 

 that, while the former owe their existence to longitudinal cracks 

 or crevices in the mountain-chains at right angles to their direc- 

 tion, the Swiss lakes are for the most part washed-out or exca- 

 vated lakes ; and this excavation he attributes to mighty floods, 

 caused by the elevation of the Alps, rushing against and tearing 

 away the softer material of the Molasse and other Tertiary de- 

 posits, against which they were directed ; for previously to the 

 last elevation of the Alps these Tertiary formations were covered 

 by the waters of the sea. This excavation took place before the 

 glacial period, but could not have been caused by the action of 

 rivers, such as they now are. He does not admit that they are 

 the result of local depressions, although this is the view taken of 

 their origin by Prof. Studer. And the reason why they were not 

 filled up by the gravel and other material Avashed down from the 

 Alps during the glacial period Avas that they Avere covered by 

 glaciers over Avhich these materials as Avell as the Alpine boulders 

 AV'ere carried, and which afterwards melted away, leaving the lake- 

 basins in the same condition as they were in before. 



Another important work on Swiss geology, published during the 

 past year, is that of Prof Heer of Zurich, entitled ' The Primeval 

 World of Switzerland' ('Die Urwelt der Schweiz'). You Avill 

 remember that in the year 1862 the Council awarded the balance 

 of the .proceeds of the Wollaston Pund to Prof. Heer to assist him 



