82 M. Renoir on the Traces of Ancient Glaciers. 



left by the receding ice between these mountains and the mo- 

 raine-like deposits. 



From what has been said, it will be seen that we regard the 

 glaciers now existing in the fractures and elevated valleys of our 

 mountain-chains as being the remains of generally distributed 

 ice. AVe mentioned last year the reasons which induce us to 

 believe that these remains would disappear during our era. To 

 these proofs we think it proper to add the following reflection : 

 M. Studer has affirmed, in his Notice regarding some Pheno- 

 mena of the Diluvian Epoch, that, having ascended with M. 

 Agassiz the crest of the Riffel, which is 500 feet above the 

 upper part of the glacier of Gornerin, — a height which the 

 glacier can never be supposed to have reached' since the com- 

 mencement of the present epoch, — they saw the surfaces of 

 rocks polished like a mirror, and covered with furrows and 

 striae nearly horizontal, and of a nature entirely similar to those 

 in contact with the glacier itself. 



This glacier, therefore, has formerly occupied this extreme 

 height. But the upper portion, being less massive, and ex- 

 posed throughout its whole surface to the combined actions of 

 the sun and currents of Avarm air, has disappeared. The ad- 

 ditions made to it by the colds of winter could not compensate 

 for its loss in the summer. The portion still remains which 

 is enclosed within the walls of the rent or small valley, and 

 this melts more slowly, because not exposed to the action of 

 the agents mentioned but at its surface only, the other faces 

 being protected from the warm winds by the rocks which li- 

 mit and support them. This nucleus, whose mass cannot be 

 below the temperature of zero, congeals, every summer night, 

 the water produced by rains or the melting of the ice during 

 the day by the heat of the sunr The snow which falls during 

 the winter is partly retained there throughout the spring, and 

 even summer, by alternate freezing and melting, which, by 

 transforming what remains of the snow into new ice and at- 

 taching it to the old, thus repairs a part of the loss which the 

 mass sustains every year by meteoric actions. ^ 



A proof that it is the property of the nucleus of a glacier 

 never to have a temperature below zero, and which retards 

 its destruction, is, that this nucleus, in all glaciers, descends 

 much below what is called the line of perpetual snow ; and that 

 the same xnasses, melting all the time, although slowly, and 



