376 M. Agassiz on Glaciers, Moraines, and Erratic Blocks. 



the Jara, since the epoch of the transport of these alpine rocks, 

 or, in other words, that the polished surfaces have not been 

 dislocated or disturbed since the transport of the blocks. But 

 as these surfaces form a large part of the northern bank of the 

 lakes of Neuchatel and Bienne, they prove, so far as they are 

 concerned, that the Swiss lakes had previously existed ; and 

 the continuity of the moraines, upon the opposite banks of the 

 Lake of Geneva, proves that this basin likewise was anterior to 

 the transport, since it has preceded the formation of the moraines, 

 as we shall very soon see. 



In considering the intimate connection between the different 

 facts which we have just been describing, it is manifest that 

 every explication which does not account nt the same time for 

 the polish of the surface of the soil, for the superposition and 

 the rounded form of the pebbles, for the sand reposing imme- 

 diately upon the polished surfaces, and also for the angular 

 form of the great superficial blocks, is an explication which is 

 quite inadmissible as accounting for the erratic blocks of the 

 Jara ; and these objections forcibly apply to all the hypo- 

 theses respecting the transport of blocks with which I am ac- 

 quainted. 



I shall now proceed to that explanation of the phenomena 

 Avhich I consider the most plausible ; and which is the result of 

 my own views, together with those of M. Schimper, upon the 

 subject. In glancing at many general questions which are 

 connected with the explanation, I have no intention of expa- 

 tiating upon them. I wish simply to demonstrate that the 

 subject now before us has a relation to the most interesting and 

 important geological inquiries. 



The study of fossils has for some time led to very unex- 

 pected results, especially since it has assumed a physiological 

 character ; that is to" say, since it has been recognised, that a 

 progressive development exists in the whole range of those 

 organized beings which have formerly peopled the earth ; and 

 since epochs of renewal have been recognised throughout the 

 whole. Those individuals who have admitted this progression 

 ought not now to entertain any fears in prosecuting these con- 

 sequences to their legitimate limits ; and the idea of a uniform 

 and constant diminution of the earth's temperature, such as is 



