Manchester Memoirs, Vol. Ixii. (1918), No. 11. 5 



The evidence from the sections quoted above, and from numer- 

 ous others, proves that there is great variability in the Glacial deposits 

 of the Manchester district. In places these deposits consist mainly 

 of thick clays or equally thick sands, but the clays may contain 

 lenticular sandy bands, and the sands lenticular clay bands. 



It is very desirable to consider the vertical sequence of the Drift 

 deposit in the Manchester area with reference to the classifications 

 proposed for them, in view of the important theoretical and practical 

 deductions which have been drawn from their supposed arrange- 

 ment. 



Classification of the Glacial Deposits 



The first of these classifications was proposed by Binney in a 

 paper which he read to this Society in 1848. In this paper he gave 

 the vertical succession as being — 



*(4) River gravels. 



(3) Glacial sands. 



(2) Boulder-clay. 



(1) Gravel -bed. 



He himself, in referring to his classification, says : " Probably 

 the deposits mentioned above will not always be found in the perfect 

 order there laid down ; no doubt some of them may be found wanting 

 at places ; especially the Glacial sands and the gravel-bed, which have 

 often been removed." In the many sections now available the 

 gravel -bed is absent nearly as often as it is present, so that it does 

 not seem desirable to regard it as a definite stratum. 



The second classification was proposed by Hull in 1863 and was 

 by no means tentative, as Binney's was. It is as follows : — 



(3) Upper Boulder-clay. 



(2) Middle sands and gravels. 



(1) Lower Boulder-clay. 



This tri-partite division of the Drift was extended by Hull and 

 De Ranee to the Glacial deposits of Southern Lancashire generally, 

 from the sea to the Pennines, and was adopted for the purposes of 

 the Geological Survey. 



In his paper Hull says that the sands are very variable in thick- 

 ness, and that sometimes the Upper Boulder-clay may be seen coming 

 down on to the Lower Boulder-clay. This he attributes partly to 

 variation in deposition but mainly to erosion. As an example of 

 variation in thickness, he describes the Drift as being over 200 feet at 

 Kersall Moor, while four miles away, at Newton Heath and Openshaw, 

 it is only 20 feet. 



The Upper Boulder-clay, he says, occupies the districts, near 

 Manchester, of Hyde, Denton, Newton, Failsworth, Oldham, and the 



1 These beds are numbered by Binney in the reverse order, the uppermost 

 being numbered (1). 



