M. Charpentier on the Glaciers of the Cantmi Vallais. 213 



dams through the lakes, without these lakes being for the most 

 part filled up. 



This view is equally insufficient to account for the extraordi- 

 nary position of immense single blocks, which we sometimes find 

 planted vertically in the soil, in the valleys or on the sides of a 

 mountain, and split up throughout their whole extent from top 

 to bottom, — a phenomenon which would force us to believe that 

 these blocks had fallen perpendicularly from a certain height, 

 on the very spots where we now see them, and had been rent 

 asunder by the fall, into the several fragments lying near one 

 another. 



It is further remarked, that the blocks which are derived from 

 one of our large valleys, are never mixed with those having their 

 origin in another neighbouring valley. This fact, which had 

 been already observed by Escher, does not harmonize with the 

 effects of the action of water, even though that action had taken 

 place in both valleys at the same time. It is impossible to un- 

 derstand how the stones carried away by both floods, should not 

 be mixed, at that point, at least, where the flowing of the water 

 had continued sufficiently long to admit of the deposition of 

 stones ; and more especially where the Jura was encountered, 

 when a reverberation or whirling must have taken place, well 

 calculated to produce this mixture. I have also to add, that 

 the blocks proceeding from a lateral into a principal valley, are 

 not mingled, but that the blocks of the two valleys form sepa- 

 rate dams. 



All chains of mountains which have affbrded erratic blocks, 

 present, on all the fixed rocks which have not subsequently suf- 

 fered from weathering and decomposition, the remarkable phe- 

 nomenon of rounded and i:)olished surfaces Apparently these 

 are the consequence of friction, and as we every where see how 

 the rocks in the beds of mountain-streams and rivulets become 

 smoothed by the stones carried down by the water, it has been 

 concluded, that the smooth and polished surfaces of the rocks of 

 our great valleys, have been produced by that great flood which 

 is believed to have transported the blocks now under considera- 

 tion, so that these last must to a certain extent have acted in the 

 manner of emery. This explanation is also grounded on the 

 fact, that the polished surfaces occur only to the height reached 



