29t> M. Renoir on the Glaciers of the Vosges. 



deposits, of which I have spoken, we likewise find blocks of 

 large dimensions, sometimes exceeding twenty cubic metres, 

 the transportation of which ^ in the places rohere they are found, 

 cannot he explained by means of the same forces which have con- 

 veyed the others''' Thus, in order to explain the great height 

 at which these collections are found, M. Hogard has recourse 

 to another hypothesis, — that' of a change of level in the diffe- 

 rent parts of the valley, subsequently to the transportation of 

 these debris. 



The strongest consideration indicative of the origin of all 

 these remains, is derived from considering them collectively. 

 In fact, if we see in our valleys only collections of stones which 

 we ascribe to moraines, we might, perhaps, in conformity to 

 one of the old systems, regard them as the remains of the 

 banks of ancient lakes. But in regard to these huge tran- 

 sported blocks, deposited at great heights on the declivities of 

 mountains, their transportation by means of water and muddy 

 currents, would always remain incomprehensible ; for we can- 

 not cite as an example, even on a small scale, the last break- 

 ing up of the Dent-du-Midi in the Valais. In that case, the 

 blocks only descended in obedience to the law of gravitation, 

 aided merely by a muddy current, and in reality they surmounted 

 no obstacle nor ascended again ; on the contrary, the residuum 

 and debris were extended in the manner of avalanches, with- 

 out any resemblance to the forms of a moraine. But do we 

 here find only the forms of a moraine and transported blocks ? 

 Shall we regard these lateral banks, all of them inclined, and 

 often considerably so, as having contained the waters of lakes \ 

 Can the latter ever have inclined surfaces ? Shall we say 

 that they have been deposited by currents having this inclina- 

 tion ? In such a case the currents must have been very ra- 

 pid, and could not have formed, in the midst of their course, 

 heaps of stones corresponding to the bottom of the valley- 

 Lastly, these round surfaces, small as well as large, polish- 

 ed on the faces which must have been opposed to the cur- 

 rents, quite as perfectly, as on those which would have been 

 directly exposed to them ; equally worn on every part of the 

 same heterogeneous rock, without any difference resulting from 



