208 Prof. Favre on the Origin of 



the name of the Glacier of the Rhone has been given. This glacier 

 evidently discharged itself into the Swiss plain by the valley 

 which extends from Martigny to Villeneuve, and had a mini- 

 mum thickness of 2300 to 2600 feet *. 



This great glacier extended itself over the plain. It covered 

 all the bottom of the basin of Lake Leman with moraines, 

 boulders, clay, and scratched pebbles. The distribution of these 

 materials has often been studied ; they are spread over the two 

 banks of the lake ; but I do not think that any conclusion can be 

 drawn from their examination, either for or against the hypo- 

 thesis which I am desirous of examining. 



In the course of its slow but continuous movement, the enor- 

 mous glacier abutted eventually against the Jura. As M. Char- 

 pentier has stated, it is remarkable that the maximum height of 

 the traces which it has left should be near Chasseron, a moun- 

 tain situated to the north-west of Yverdun, just opposite the 

 valley of the Rhone. The blocks there attain an elevation of 

 3000 feet above the Lake of Neuchatel f- 



Thence the upper limit of the boulders falls successively to- 

 wards the north and south, in such a manner that we may apply 

 the term median to the line which connects the mouth of the 

 Rhone near Villeneuve with Chasseron. North of the median line 

 the higher line of the blocks rejoins the plain in the environs of 

 Soleure. The glacier terminates there, and has left at its ex- 

 treme limit the remarkable blocks of Steinhof, near Soleure. 

 South of the median line the glacier has left incontestable traces 

 over all the southern extremity. of the Swiss plain. It has gone 

 beyond the limit of this plain in passing Mont Sion, south of 

 Geneva, and the defile of Fort de PEcluse. These facts have 

 long been known; but it is a matter of surprise (reasoning 

 according to the hypothesis of the excavation of the basin of the 

 lake by the glacier) that the lake has not been hollowed out in 

 the direction of the median line — that is to say, from the mouth 

 of the Rhone to Chasseron — but in a curve which bears no rela- 

 tion to that line. 



This bend in the lake nearly follows the base of the great 

 mountains which are situated on the southern bank, at least so far 

 as the large lake is concerned. The depth of the basin is evidently 

 connected with the neighbourhood of the mountains, and the 

 inclination of the strata ; it is thus that near Meillerie, where 

 the mountains are elevated and the strata vertical, the lake at- 



* Charpentier, ' Essai sur les Glaciers,' pp. 270,271. I am led to 

 believe that the glacier rose above this limit, and that if blocks are 

 not met with above it, it is owing to their having rolled towards the 

 bottom. 



t Charpentier, ibid. 



