68 



ROCKS OCCURRING AS BOULDERS IN THE UPPER- AND 

 LOWER BOULDER CLAYS. 



The boulders occurring in the Middle Sands and Gravels are as 

 much mixed as those in the Upper- and the Lower Boulder Clays, 

 and, generally, they are of the same kinds of rock in the three 

 members of any given section. 



In the boulder clays, the sand and gravel mounds, and the 

 moraines occuring in the valleys of the higher ground, there is not 

 this mingling of boulders of different kinds of rocks from various 

 directions. Usually they are only of rocks found higher up the 

 valley in which the deposit is situated. 



When gravel mounds occur at the mouth of a valley, there is 

 sometimes a mingling of boulders from opposite directions, that is, 

 from both up and down the valley, as near Whicham Hall ; but 

 this is not invariably the case. 



The vertical range through which the rocks met with in the 

 glacial deposits occur both in place and as boulders is shewn by 

 the following table : — 



