222 drift deposits of manchester 



On the Composition of the Till. 



The phenomena presented by the different 

 beds of gravel and sand forming deposits Nos. 1, 

 2, and 4, are so like the eifects we now observe 

 being produced on the beaches, strands, and water- 

 courses, at the present time, that we can have 

 no doubt as to the manner in which they were 

 formed, any more than of the origin of the shingle 

 beds and sand banks of our coasts. The pebbles 

 contained in them are rounded, and have nearly 

 all lost their angles by attrition, and none of 

 them, to my knowledge, have been met with 

 having their surfaces scored with strice. These 

 deposits are, in point of fact, nothing more than 

 raised beaches and old sand-banks, cut through 

 by currents of water, which formed the valleys 

 before and during the time of their elevation. 

 The Till however is a deposit very different in its 

 characters to any that we now see being formed ; 

 for while its clay and its finely laminated beds of 

 silt would seem to show that it was deposited in 

 still water, the great and small blocks of stone 

 scattered throughout its mass pell-mell, would lead 

 us to believe that violent currents had been in 

 action at the same time that the clay and silt were 



