452 MR. E. HULL ON THE DRIFT-DEPOSITS 



Stockport, Poynton, Wilmslow, Prestbury, Macclesfield, 

 Crewe, &c. 

 4. Lower Boulder-clay, or Till. Monton, Salford, Manchester, 

 Heaton Norris, &c. 



It would be mere repetition were I to attempt to describe 

 these subdivisions of the Drift ; and I shall therefore not 

 dwell at any length on the stratigraphical character of 

 these beds^ further than to make one or two observations. 



The Upper and Lower Boulder-clays are in all re- 

 spects similar. Of the stones and boulders which they 

 contain, at least two-thirds exhibit marks of glaciation; 

 and there can be no question that they are both subglacial 

 deposits. 



Both subdivisions are also laminated or rudely stratified. 

 On this point Professor Ramsay and myself became con- 

 vinced after a careful examination of many sections,, some 

 near Manchester, others along the estuary of the Mersey. 



On the other hand, the Middle Sand and Gravel (No. 3) 

 is altogether distinct in this latter respect from the Boulder- 

 clays both above and below it. The pebbles it contains 

 are always water-worn and rounded ; and I am persuaded 

 that during its deposition very different physical conditions 

 must have pervaded this part of England from those which 

 obtained the ascendancy during the periods of the Upper 

 and Lower Till. I now pass on to notice certain facts 

 regarding the arrangement of the several members in this 

 district. 



Denudation of the Middle Sand. — In confirmation of 

 the views just stated, I may here draw special attention 

 to the evidence afforded of a very extensive denudation of 

 the sand previously to the deposition of the Upper Boulder- 

 clay. The thickness of the sand undergoes the most rapid 

 changes. In some places, as at Kersal Moor for instance, 

 it attains a thickness probably not under 200 feet; and 

 within a distance of not more than 4 miles (that is, at 

 Newton Heath and Openshaw) the thickness is just one- 



