234 DRIFT DEPOSITS OK MANCHESTER, ETC. 



vation of the land, and consequent shoaling of the 

 sea, the icebergs would cease to enter the latter, 

 but strong currents of water, probably produced by 

 the dissolving of neighbouring glaciers and other 

 causes, brought down the beds of sand and gravel 

 (No. 2,) and covered up the Till. On the land 

 continuing to rise, these sand banks would be 

 more exposed to the action of the currents, owing 

 to the waters becoming shallower, and then the 

 valleys and undulations now seen in this neigh- 

 bourhood would be formed by currents cutting 

 through Nos. 2, 3, and 4, and removing portions 

 of those deposits, so as to form the gravels and 

 sands No. 1. Similar effects, on a small scale, 

 may now be seen taking place in the sand banks 

 of our present coast, on the recession of the tide, 

 where numerous little valleys are excavated, and 

 slight deposits of gravel deposited on their sides 

 and at their extremities. No doubt the action of 

 the streams of water at present flowing in the 

 valleys may have, in some measure, assisted to 

 excavate them ; but by far the greater part of 

 the erosion has been done when this part of the 

 country was under the sea. 



