CHAP. XV. THEORIES OF CHARPENTIER AND GUYOT. 297 



mun}^ valleys receding far into the Alps, were under water. 

 He thought it impossible that the glacial detritus of the 

 Ehone could ever have been carried to the Lake of. Geneva, 

 and beyond it by a glacier, or that so vast a body of ice 

 issuing from one narrow valley could have spread its erratics 

 over the low country of the Cantons of Vaud, Friburg, Berne, 

 and Soleure, as well as the slopes of the Jura, comprising a 

 region of about a hundred miles in breadth from southwest 

 to northeast, as laid down in the map of Charpentier. He 

 therefore imagined the granitic blocks to have been trans- 

 lated to the Jura by ice-floats when the intermediate country 

 was submerged.* It may be remarked that this theory, pro- 

 vided the water be assumed to have been salt or brackish, 

 demands quite as great an oscillation in the level of the land 

 as that on which Charpentier had speculated, the only differ- 

 ence being that the one hj^pothesis requires us to begin with 

 a subsidence of 2500 or 3000 feet, and the other, with an 

 elevation to the same amount. We should also remember 

 that the crests or watersheds of the Alps and Jura are about 

 eighty miles apart, and if once we sujDpose them to have been 

 in movement during the glacial period, it is very probable 

 that the movements at such a distance may not have been 

 strictly uniform. If so, the Alps may have been relatively 

 somewhat higher, which would greatly have facilitated the 

 extension of Alpine glaciers to the flanks of the less elevated 

 chain. 



Five years before the publication of the memoir last men- 

 tioned, M. Guyot had brought forward a great body of new 

 facts in support of the original doctrine of CharjDentiei', that 

 the Alpine glaciers once reached as far as the Jura, and that 

 they had deposited thereon a portion of their moraines.f 

 The scope of his observations and argument was laid with 



® Quarterly Geological Journal, 1850, f Bulletin de la Societe des Sciences 



vol. vi. p. 65. Naturelles de Neufchatel, 1845. 



