212 M. Charpentier on the Glaciers of the Canton Vallais. 



the belief that the whole mass of these blocks has been conveyed 

 by water. I shall in another place speak of the origin of these 

 small stratified accumulations of sand and mud. 



Although most of the blocks now under consideration exhibit 

 a rounded form, yet we occasionally find them having not only 

 a flattened figure, but even presenting no rounding, and having 

 edges and angles which have suffered no smoothing whatever. 

 It would be impossible to understand how these blocks could be 

 pushed forwards to the foot of the Alps, and driven up to the 

 ridgesof the Jura, without having lost their fresh condition and 

 the sharpness of their edges and angles. 



The deposits of erratic blocks have generally a prevailing ex- 

 tension in one direction, so that we cannot better compare them 

 than to dams or walls ; or they sometimes form small rather co- 

 nical hills, which are either isolated or stand in a row. These 

 deposits never occur, on the contrary, in the form of spreading 

 and flat alluvial masses or plateaux. 



The dams already mentioned run horizontally, frequently se- 

 veral behind one another, on the declivities and at the foot of 

 the mountains, and their direction is, in the first case, parallel to 

 that of the valley. Those, however, which run at the foot of 

 mountains enclosing a valley, turn away from the mountains at 

 their lower end, cross in an oblique direction through the valley, 

 and would unite in the middle of the latter, if they were not in- 

 terrupted by the stream running there. 



The surface between two such dams always consists of fixed 

 rock, which is covered only by a Utile earth, or by some scat- 

 tered blocks. Sometimes two or more dams are so near one an- 

 other, that they form together a single dam, with two or more 

 crests. 



^ This internal and external constitution of such deposits, can- 

 not be explained by assuming that their component materials 

 were transported by water to their present situation. Water 

 would have deposited the blocks, especially on the flat surfaces 

 of valleys, and at the base of the Alps, as a spreading flat allu- 

 vial mass. 



It would also be impossible to conceive how, by such an as- 

 sumption, we could explain the passage of the materials of these 



