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



rally known that other moraines exist besides those which, at 

 the present day, skirt the edges of the glaciers. Messrs Venetz 

 and Charpentier were the first to introduce these to notice, and 

 they have observed them chiefly in the lower valleys of the 

 Alps. One point regarding these remains still to be discussed ; 

 it is the connexion which it has been endeavoured to esta- 

 blish between these erratic blocks, and the glaciers which formed 

 the nucleus or matrix, so to speak, of the great moraines, the 

 traces of which are still found upon the northern shores of the 

 Lake of Geneva. It is to this point I now intend to request 

 your attention. 



Thejiicts, at aU events, which have been observed by Messrs 

 Venetz and Charpentier * have been gained for science ; and it 

 is also important to proclaim their extreme accuracy, for upon 

 this naturally depends the validity of whatever conclusions may 

 be legitimately deduced from them. 



At distances, more or less considerable, from the existing 

 glaciers, we find, at different elevations, moraines which are 

 perfectly similar to those which still encircle the glaciers. They 

 ai'e equally concentric, and form walls which follow the sinuo- 

 sities of the sides of the valleys. Every where many stages of 

 them may be discovered, the most elevated of which may be 

 found some hundreds of feet above the bottom of the upper val- 

 leys of the Alps, where glaciers now no longer exist. In de- 

 scending into the loiaer valleys, we still encounter them, at the 

 successive elevations of twelve and fifteen hundred feet, and 

 even at eighteen hundred feet ; there are also some, which are 

 quite distinct, at a height of two thousand feet above the bed 

 of the Rhone, in the neighbourhood of Saint-Maurice in the 

 Valais. They may be followed even to the margin of the Lake 

 of Geneva. Some very elevated ones exist above Vevey, and in 

 the environs of Lausanne, which correspond with those on the 

 southern side of the lake. 



If these moraines are not generally noticed, this is owing to 

 the fact, that they are much more elevated than are any of the 

 common routes, and that those occurring in the lower districts 

 have generally been much disturbed by descending torrents. 



It is not at all a difficult matter to distinguish these ancient 



" See this Journal, vol. xxi. p. 210, and vol. xxi'. p. 2^. 



I 



