AND RECENT GRAVELS NEAR MANCHESTER. 



453 



tenth of this amount, or 20 feet. Indeed, within a less 

 distance than this, the sand dwindles down almost to no- 

 thing near St. Lnke^s, Cheetham Hill. Similar phenomena 

 are observable in many places over the tract we have ex- 

 amined; and I have reason to doubt whether in some 

 places, such as Atherton and Hindley, there is any sand 

 separating the two Boulder-clays from each other. 



This may be due in some measure to irregularity in the 

 original deposition of these beds ; but there is reason to 

 think that it is due in a still greater degree to a subse- 

 quent denudation, or removal, of strata which were once 

 deposited with more or less regularity. In confirmation 

 of this view, several instances which came under my notice 

 may be adduced, in which the Upper Till was observed to 

 lie upon an eroded surface of the sand. Out of several I 

 select two in the neighbourhood of Oldham ; but similar 

 examples were observed in a pit at Moston Hall, and in a 

 new road-cutting at Whitefield. In some other places. 



Fig. I. Section at Hey side near Oldham. 

 Length of section, 45 yards. 



B. Upper Boulder-clay, resting in a hollow denuded in the sand. 



S. The Middle Sand underlying the Till, but rising above it at the surface. 



Fig. 2. Section near Chadderton Workhouse. 



MA^^ 















'r*''K^ 



■y^ ' '^y >\ ^ 



s- • • ■ ■ 



' , / 



■ ■ Hi 1 



B. Upper Boulder-clay, on an eroded surface of the sand S. 

 The length of this section is about 50 yards, and the depth 6 yards. 



