244 



GENERALIZATIONS. 



tains, they have been designated orographic lakes, in contra- 

 distinction to those lakes which have been produced by erosion. 

 In order to explain the stratification of the Swiss moun- 

 tains, some sections may here be noticed 

 Fig. 366. which Prof. Heer has borrowed from 



Studer's 'Geology of Switzerland' 

 (vol. ii. p. 324) : 



I. A section through the Jura in the 

 direction from Soleure to Pfirt. The 

 examination of this section shows the 

 numerous undulations of the moun- 

 tains, the open and denuded arches, 

 and the basin- and combe-valleys which 

 environ them. Here and there (as, 

 especially, between Moutiers and Soy- 

 hiere) the mountain-chains are broken 

 through by clefts which have revealed 

 their internal structure. They show 

 that here the Keuper forms the nucleus 

 of the mountains, and that it is followed 

 by the Lias, and then by the Brown 

 and White Jura. In the broad valley 

 of Delsberg the beds of the White Jura 

 are covered by the Eocene deposit of 

 the pea-ore ; and over this is the Mio- 

 cene, which also cccupies the bottom 



> of the valley of Moutiers. 



II. A second very instructive ex- 

 ample is furnished by the section from 

 the Lake of Wallenstadt towards Ap- 

 penzell (Studer, Geol. der Schweiz. ii. 

 p. 193). Even in the Kurfirsten the 

 Jurassic and Cretaceous beds are un- 

 settled ; and in the Appenzell Alps they 

 are thrown together in so confused a 

 manner that it was only by untiring 

 investigations, continued for years, that 

 Prof. Escher de la Linth succeeded in 

 disentangling this Gordian knot. The 



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