3^4 



ILLUSTRATIONS OF THE 



tbi 



s 



• 



ravel, yielding eafily to the weather, al 

 lows the ftones included in it to be wafhed dowrj 

 by the torrents, and fcattered over the plains, 

 I knovi^ not if the hill of Supergue, above men- 

 tioned, is not in reality a mafs of the pudding- 

 itone which forms the border of the Alps, an^ 

 of which the materials have fufFered no tranf- 

 portation lince the time of their laft cojifolid^- 

 tjon. This at lead is certain, that Sauffure, notr 

 withftanding his accuracy, has fometimes con- 

 founded the loofe gravel on the furface witl^ 

 that which is confolidated into rock ; an inac^ 

 curacy which is to be charged, as I have elfe- 



where obferved, rather againft his fyftem than 

 bimfelf. 



345. The loofe ftones found o,n the fides of 

 hills, and the bottoms of valleys, when tra- 

 ced back to their original place, point out 

 with demonftrative evidence tbe great chan- 

 ges which have happened fince the com- 

 mencement of their journey ; and in particular 

 ferve to fhow, that many valleys which now 



deeply interfed the furface, had not begun to 

 be cut out when thefe ftones were firft detached 



r 



from their native rocks. We know, for inftance, 

 that ftones under the influence of fuch forces 

 as we are now confidering, cannot have firft de- 

 fcended from one ridge, and then afcended on 



the fide of an oppofite fidge. But the granite 



of 



