294 M. Renoir on the Glaciers of the Vosges. 



tuted immense masses, but distinct, and generally not con- 

 tinued from one chain to another, and perhaps even from one 

 mountain to another. 



With regard to the mode of the transportation of blocks, I be- 

 lieve that if they had slidden, as has been asserted, by their own 

 weight over an inclined and continuous surface of ice from the 

 summits of the Alps, as far, for example, as the first southern 

 slopes of the Jura, the face exposed to the friction in all those 

 of large size would necessarily be polished, but I have never 

 observed this effect in any of them. 



If there still issue from beneath our glaciers, reduced as they 

 now are, rivers of which, in the favourable season, many are 

 of great power from their origin, how much greater must those 

 have been which emanated from those immense masses of ice 

 which covered perhaps entire countries, particularly during 

 the melting which reduced them to their present condition, a 

 melting which would be rapid, if the return of heat was sud- 

 den. Now, the torrents of our glaciers sometimes carry along 

 with them, from beneath the latter, such considerable quanti- 

 ties of sand, coarse gravel, and even pebbles, that the country 

 at a distance is covered with them ; may we not, then, be 

 permitted to ascribe to the great currents which proceeded 

 from the ancient masses those great mixtures of sand and 

 rolled pebbles which still encumber our lower valleys, and 

 which may be traced without interruption to the height of 

 existing glaciers, or the places which have borne ancient ones, 

 without having recourse to the hypothesis of a deluge, the ef- 

 fects of which would be different from what we now witness. 



After the secretary of the Society had read the above pa- 

 per, M. Constant Prevost stated that he had seen on the road 

 to Chambery the surfaces of calcareous rocks deeply furrowed. 

 On these surfaces he had observed pebbles foreign to the 

 country, and in particular a block of greenish slate, v/hich 

 might be fifteen feet in diameter. He was of opinion that 

 these effects might be produced by causes analogous to those 

 just described. 



At the request of M. de Roissy, M. Leblanc gave some ex- 



