Presented hi/ (he Glaciers of Sivitzerland. 347 



It is clear that the stones imbedded in the ice must ad- 

 vance simultaneously with the glacier, and that they cannot 

 advance without being rubbed, and, according to the degree 

 of their own hardness, and that of the walls, produce fur- 

 rows and strisB in the latter, or receive such themselves (de- 

 tached stones, polished,^ furrowed, and striated). The mud 

 mentioned appears as the necessary produce of the friction 

 of the stones against the rock ; accordingly, we observe it 

 everywhere in the rivulets which issue from beneath glaciers. 



The mode of producing polish, furrows, and striae, is thus 

 exhibited so distinctly to the eye, that every one, I should 

 imagine, ought to yield to the evidence of facts, and admit 

 that glaciers have the power of producing the phenomena 

 mentioned in all parts of their bed. 



With regard to the deep and undulated canals, I confess 

 that in such canals, which are very frequent in the bottom 

 of our glacier beds, but rarely accessible to minute examina- 

 tion, I have not hitherto remarked the striated appearances 

 mentioned by M. Durocher. But, the flexibility of the ice 

 once admitted, there is not the least difficulty in conceiving 

 their production in such a canal, as soon as it is left by the 

 water and filled again by the ice. The frequent change of 

 water-courses under the glaciers is a phenomenon too well 

 known to render it necessary to enter into details on this 

 subject. 



It appears to me, therefore, that M. Durocher's objections 

 to the theory of M. de Charpentier, which ascribes the fur- 

 rowing to glaciers, are refuted by the examination of what 

 we witness taking place in glaciers still existing. 



Let us now see if facts are not to be found which require 

 properties in the furrowing agent, which are opposed to those 

 of a current of water or mud. It appears to me that there 

 are several. 



1^^, The large furrows, as well as the fine striae we see in 

 countries now destitute of glaciers, are by no means, in ge- 

 neral, rectilinear ; on the contrary, they follow, in lines ge- 

 nerally almost horizontal, exactly the irregular circumfer- 

 ence, often very sinuous, and even almost at a right angle 

 with the walls. The instrument by which these furrows 



