160 Geological Notes on the 



striking contraction of the valley at St Maurice, the bold 

 precipices overhanging that town shew no such appearances. 

 Here, nevertheless, there are memorials of some mechanical 

 agency of the kind speculated upon, for a low hill between 

 St Maurice and Bex presents smoothened surfaces above the 

 soil in many parts. I cannot say that my observations in 

 the valley of the Rhone very greatly favoured the idea of its 

 supposed glacier, though I am far from saying that they were 

 either extensive or minute. One particular in the smooth- 

 ings which have been pointed out by Professor Forbes in the 

 high valley of the Sallench escascade (Pissevache) struck me 

 forcibly, that they were not sloping in the direction of the 

 valley, but maintained a horizontal tendency, even at the 

 place where the walls of the valley turn round to join the 

 valley of the Rhone. In that case, it certainly appeared to 

 me that ice borne upon a sea at the proper level was the 

 more plausible hypothesis. 



At Monthey, two miles below St Maurice, and exactly 

 opposite the village of Bex, there is a prominent hill, on the 

 face of which, from 200 to 250 feet up, is presented the zone 

 of blocks of w^hich Professor Forbes has given so interesting 

 a description. For several miles along the hill-side, gene- 

 rally about one level, these blocks occur — enormous, undressed 

 masses of granite and other primitive rocks, resting on the 

 secondary formation which constitutes the hill. Mr Forbes 

 has been unable to surijiise for them any other explanation, 

 than that they are the remains of a moraine formed by the 

 supposed ancient glaciers of the Rhone valley. It is re- 

 markable, however, that they are just about the height of the 

 great superior terrace at Vevay, so that we may suppose the 

 sea to have once had this very spot for its margin. In that 

 case icebergs might transport the blocks from the skirts of 

 glaciers in the higher parts of the Rhone valley, and being, 

 as was very likely, intercepted by the projecting hill on their 

 way out to the open sea, might deposit them here. Perhaps 

 a rigid ascertainment of the levels of the Vevay terrace and 

 the zone of blocks might enable us to treat this hypothesis 

 with somewhat greater confidence. 



The zone of blocks on the face of the Jura mountains above 



