M, Renoir on the Traces of Ancient Glacien. 83 



moving downwards, do not fail to maintain their existence for 

 many years, and that at levels sufficiently low to permit us to 

 see a vigorous vegetation going on at their sides on declivities 

 of the same elevation as themselves. If, then, the upper por- 

 tions of our glaciers were once melted, no others would be 

 formed where they are now so extensive. Of this we have a 

 proof in the ridges visited by MM. Studer and Agassiz, on 

 which, notwithstanding their height being so favourable for 

 such an occurrence, no permanent glacier is forming, nor will 

 any other ever exist. 



The slow but continual diminution of portions enclosed in 

 the manner formerly mentioned, is shewn very evidently by 

 the height of the polished and striated walls which rise above 

 them. The slipping from a higher to a lower situation is ren- 

 dered still more obvious by the moraines left behind. The 

 magnitude of these moraines diminishes rapidly from the most 

 ancient, which are immense, and most remote from the foot of 

 the glaciers, to those recently formed, which are very small. 

 Taken altogether, they form a scale for measuring the pro- 

 gress, of destruction which the ice has undergone, and for 

 comparing their ancient mass with the little which now re- 

 mains to us. In our opinion, the diminution of glaciers is 

 evident, and their complete disappearance at a period more or 

 less remote is unquestionable. 



Since masses of ice, at a certain epoch, could be perma- 

 nently formed even to the very foot of mountains, and since 

 now they can no longer reproduce themselves in a permanent 

 manner even at their summit, we perceive to what a degree 

 the temperature of the earth's surface must have been elevated 

 from the time of their first melting to the present ; a conside- 

 ration which comes in support of the system which we have 

 presented in the note alluded to. 



We have stated that communications received from men of 

 science engaged in recent expeditions, seem to confirm the 

 reasons adduced for believing in the existence of a universal 

 ice, at a period immediately preceding that of tlie human spe- 

 cies. In fact, these communications seem at once to shew how 

 very slight w as the chance of erratic blocks being conveyed 

 by floating icebergs from the northern regions during the pro- 

 gress of a great debacle ; since M. C. Martens, member of the 

 Northern Scientific Commission, says, that in two voyages (to 



