Prof. B. Studer on the Origin of the Swiss Lakes. 491 



tigny to Geneva, and in that which is prolonged from the Lake 

 of Annecy to Faverges. As the latter circle appears to be de- 

 pendent on Mont Blanc, so that of Eastern Switzerland bounds 

 the spreading foot of the Verrucano of Glaris. 



Those valleys which have cracked the Alpine strata are gene- 

 rally regarded as traces of the upheavals, dislocations, and twist- 

 ings which that country has undergone ; and one of the most 

 powerful of these revolutions must be more recent than the Mio- 

 cene period, as the strata of the Nagelflue and Molasse have 

 been so much affected by it as to have acquired greatly inclined 

 and even vertical positions. On the other hand, we cannot over- 

 look a certain connexion between the basins of the lakes and the 

 valleys in which they are situated. These basins appear as the 

 remains of the original depth of the valleys, before their bottoms 

 were partially filled up by rivers. It has always been admitted 

 that originally the basin of the Lake of Geneva extended on one 

 side as far as St. Maurice, and on the other beyond Carouge ; 

 it has also been supposed that the two basins of the lakes of 

 Brienz and Thun only formed a single one^ which extended up- 

 wards as far as Meiringen, and downwards to the vicinity of the 

 Belpberg, and perhaps further ; and, lastly, that the three lakes 

 of the Jura were not separated as at present by marshes, and 

 that the great basin which contained them must have extended 

 from Entreroches and Payerne as far as below Soleure. 



The connexion between the basins of the lakes and the tilting 

 of the calcareous and Miocene beds of the Alpine and Jurassic 

 ranges being admitted, we find ourselves face to face with the 

 difficulty already indicated, namely, the transportation of the 

 ancient alluvium beyond the Alps across the lakes; and after 

 having got rid of the proposed solutions, we have only, it seems 

 to me, two ways to escape from this difficulty — two solutions, 

 moreover, which do not mutually exclude each other, and which 

 may be applied according to the configuration presented by the 

 different localities. 



We may suppose the deposits of the ancient alluvium to have 

 been produced by rivers which have no lakes to traverse ; and 

 these rivers having frequently changed their course, thi3 expla- 

 nation may be adapted to cases which at the first glance seem to 

 be opposed to it. The beds of sand and gravel which, at the 

 mouth of the Kander in the Lake of Thun, support the moraine 

 of Stratligen, are undoubtedly an ancient deposit of the Kander 

 and the Simme ; the great plain between Thun and Thierachern 

 must have had the same origin. All the pebbles on the shore of 

 the lake, as far as the Schadau, are derived from the valleys to 

 the westward of the lake ; the ridges of Nagelflue east of the 

 Aar have not furnished a single one. In the same way the 



