UNCLE IN ENGLAND. 17 



duced by rivers and torrents, to which the name 

 of alluvium is given. 



" Diluvial gravel is highly interesting," he 

 said, " not only as it assists in explaining the 

 causes of the present state of the globe, but as 

 it even indicates the direction of the great cur- 

 rents of the deluge. For instance when, within 

 a few miles of the neighbouring town of Glou- 

 cester, we see rounded pebbles derived from 

 rocks, which are found only in the mountains of 

 the north-west of the island, we may be sure 

 that a branch of that current must have rushed 

 to the southward. It has, therefore, been a 

 favourite object of some geologists to trace these 

 travelled fragments to their native masses ; and 

 to discover the apertures in the mountain bar- 

 riers through which they had been swept. 



" When the intervening country is nearly flat, 

 there is no difficulty in ascribing the removal of 

 the debris to the currents of which we have been 

 speaking. But it is frequently found in situa- 

 tions that are separated by deep vallies from the 

 parent hills from which it appears to have been 

 torn. For instance, fragments of the primitive 

 rocks that compose the Alps are found scattered 

 on the sides of the Jura mountains, though, 

 between those two ranges, the valley that con- 

 tains the lake of Geneva is interposed. On the 

 low hills, near Bath, we find the flints belong- 

 ing to the chalk formation, though several deep 



C 3 



