76 Professor Favi'e's Geological Besearches 



the anthraciferous rocks, and the frequently crystalline ap- 

 pearance of the latter, that has led M. Gras to refer the 

 gi'eater part of the crystalline rocks of the Alps of Dauphine 

 to the carboniferous period.* Oftener than once I have 

 asked myself whether the great masses of crystalline slates 

 placed between the protogines of the central chain of Mont 

 Blanc and the limestones at the base of its northern aspect, 

 might not pertain to the anthraciferous formation ; but no- 

 thing in the numerous localities where I have examined them, 

 enables me to answer this question in the affirmative. 



It appears to me, therefore, that it is the chain of the 

 Aiguilles Rouges which has determined the straight arrange- 

 ment of the sedimentary rocks in the Valley of Chamounix. 



This opinion appeared to me at first rather exti*aordinary ; 

 for it Avas to annul, in some degree, the geognostic import- 

 ance of the enormous protoginous chain of Mont Blanc. But 

 I am aware that on the other side of the chain of Brevent, 

 in the savage valley of the Diorza, all the beds are turned to 

 the south-east; that is to say, they rest on the chain of the 

 Aiguilles Rouges and of the Brevent. 



The chain of Fiz, rendered celebrated by the description 

 which has been given of it by M. Brongniart,t forms a part 

 of the upper crest of this lip, produced by being raised up- 

 wards. Although this inclination has been hitherto attri- 

 buted to the influence of the central chain of the Alps, yet I 

 consider it as giving support to my view of the matter. But 

 it was necessary for me to find other proofs of geological im- 

 portance in the chain of the Aiguilles Rouges, and I resolved 

 to go and seek them on the two declivities of this chain, by 

 going along it from Servoz as far as Salantin, near St Mau- 

 rice, in the Valais. 



Notwithstanding the badness of the weather, I was fortu- 

 nate enough to succeed in this expedition. I crossed places 

 so savage and so seldom explored, that, although not remote 

 from Chamounix, I could not find, among the excellent guides 



* On the Geological Age of the Anthraciferous Beds of the Department of 

 the Isere. Annalcs des Mines, 1839, t. xvi., p. 409. 

 t Description of the Neighbourhood of Paris. 



