82 Professor Favre's Geological Researches 



Rouges, which had already twice frustrated our efforts. We 

 soon arrived at the Col de Berard, an elevated passage of 

 2463 metres, by barometer, and which is not without danger, 

 as a glacier covered with snow had to be crossed. From the 

 summit of the col, we follow the ridge looking southwards. 

 Along this ridge it is very difficult to advance. "We require, 

 indeed, to walk on large fragments of rock which are easily 

 displaced. We move on, however, with a kind of enthusiasm. 

 Couttet shared in my zeal. We soon arrive at a first 

 aiguille placed on the ridge we are following. It is com- 

 posed of crystalline slate, and contains a bank of saccaroidal 

 limestone. From this point, we see the upper part of the 

 Aiguille Eouge, and the beds of slate and limestone on its 

 summit. We now see no obstacle to prevent us reaching it, 

 and our joy is great. We must descend from this aiguille, 

 and pass near a small lake surrounded with snow and rocks ; 

 a lake which certainly had never before been visited by man. 

 At last we arrive at the last acclivity of the peak of the 

 great aiguille ; we walk on the slates and limestones. I had 

 reason, therefore, to attach importance to these horizontal 

 beds, which I had seen through my glass fi-om the top of Gliere. 

 The first thing to be done is to reconnoitre the locality and 

 take a glance at all the rocks : for this purpose we must 

 reach the summit. There are two ways to it ; one follows 

 the side of the aiguille as far as the southern reverse, and by 

 that it appeared to us that we could ascend. But to reach 

 it, it is necessary to walk on a cornice of a foot broad, with 

 an immense precipice on the one side, and an overhanging 

 rock on the other, which perhaps will completely close up the 

 passage. We try another way ; it also is quite impracticable, 

 opening on to a kind of bridge, one or two feet broad, and 

 terminated by a rock six or eight feet high, which from its 

 form would be aifficult to scale, even were it otherwise acces- 

 sible than by the narrow passage which leads to it. I was, 

 therefore, compelled, to my great regret, to abandon the idea 

 of reaching the highest point of this chain. I calculated, 

 however, that I was within 16 metres of the summit, that is 

 to say, nearly the height of the peak of the other Aiguilles 

 Rouges. I am certain that this estimate of 16 metres, then, 

 cannot be any considerable erroi-, for both Couttet and my- 



