M. Renoir on the Glaciers of the Vosges, 291 



solubility in water, hardness, the presence of crystals, fossils, 

 &c., and presenting all the characters of rocks which are still 

 polished every day by our glaciers ; in particular, fine and pa- 

 rallel striae, constantly running in the direction of the gene- 

 ral movement, and similar to what diamond points fixed to- 

 gether in a large frame, would trace upon polished marble ; 

 striae which could not therefore be traced otherwise than by 

 angular fragments of hard rock, fixed in a solid body having 

 a regulated movement, such as takes place in the mass of a 

 glacier. And let it not be said that these surfaces have been 

 worn by the friction of blocks in their passage, for in that case 

 they would not rise into nipple-like prominences, often form- 

 ing a hemisphere of rather small diameter. Let it not more- 

 over, be said, that the stria? have been engraved by the hard 

 angular points which often project from the surface of these 

 blocks ; in such a case, they could not exhibit the sustained 

 direction now observed, since a block rubbing upon a rock and 

 driven forward by a violent current, rolls upon itself, or continu- 

 ally turns upon the rubbing surface, by continually changing 

 its direction. When, therefore, we see so many proofs accumu- 

 lated in the same point, as in the valley of Giromagny, it is 

 impossible to resist conviction, and there is scarcely anything 

 save a geometrical demonstration, that could be attended with 

 greater weight. 



A proof of another kind is derived from the state of the soil 

 at the bottom of the two dechvities of the chain. M. Henry 

 Hogard, observing that no debris of calcareous rocks was found 

 in the ancient alluvium which covers the soil at the bottom 

 of the north declivity, remarks : 



" The current which has carried along the blocks of which 

 I speak (boulders), has followed the direction from SE. to 

 NW. ; it ran parallel to the general direction of the valleys of 

 the Vosges, in which the deposits of ancient alluvium have 

 been made by the movements of the waters which flowed, as 

 they do now, towards the north-west. Of this fact we may 

 be convinced by studying the nature of the deposits, and of the 

 materials composing them" 



" Thus we see the rocks of the high regions descend to- 



