SUCCESSION I2f THE TRENT BASIN, 443 



Quartzose Sand is distributed, the elevated districts which it covers, 

 and the persistency with which the current-bedding retains its direc- 

 tion, all point to a period of submergence during which ice-action 

 had partially, if not wholly, ceased. 



The lithological similarities presented by these two Boulder-clays 

 render it almost impossible to distinguish the one from the other, 

 except where they are associated with the intermediate arenaceous 

 deposits. Of course the general correctness of the classification will 

 not be affected by the occasional uncertainty as to whether a parti- 

 cular deposit of Boulder-clay is older or newer than the sand. 



An idea often finds expression that the presence of any particular 

 rock in a given section is entirely due to chance, and that the whole 

 Pleistocene system is really a confused assemblage of clays, sands, 

 or gravels, charged with rock-debris, brought indiscriminately from 

 all directions. This idea probably arises from the supposition that 

 the erratics were carried by coast-ice and icebergs, which, drifting 

 about under the action of varying currents, carried their burdens to 

 great distances, and scattered them upon the sea-bottom, or thrust 

 them upon the coast-lines. Now in the Pleistocene deposits of the 

 Trent basin such jumbling never occurs without good and evident 

 reasons. In fact the lithological character of each deposit, and the 

 disturbances to which it has been subjected, are each of the utmost 

 importance in giving us a clue to its age, and point to the action 

 of an agency much less fitful than ocean-currents. I do not deny 

 that icebergs and coast-ice have transported boulders to great dis- 

 tances, but regard glacier-ice as the chief agent in determining the 

 distribution and lithological character of Boulder-clays. 



In addition to the glaciers which spread over the Trent basin from 

 the Pennine axis, there is every probability that a united Scotch 

 and Cumbrian ice-stream, after passing over Lancashire and Cheshire, 

 entered the westerly portion of the area. The proofs that this 

 occurred in Newer Pleistocene times seem complete, but, owing to 

 the scarcity of Older Pleistocene Boulder-clays in Staffordshire, the 

 evidence is less conclusive for the epoch we are now dealing with 

 than could be wished. 



1. Early Pennine Boulder-clay, 



The Early Pennine Boulder-clay does not appear to have been so 

 largely developed as some of the later beds, an inference supported 

 by the frequent, but by no means general, absence of pebbles of 

 Pennine rock from the sand of the next stage. 



South of Leicester, at Oadby, a brick-yard near the racecourse 

 shows reddish morainic Boulder-clay with quartz pebbles and 

 numerous Coal-measure erratics passing up into brick-earth and 

 sand, the former containing bands of strong clay and occasional 

 masses of morainic Boulder-clay. 



In the valley of the Wreak, between Syston and Melton Mowbray, 

 the Early Pennine Boulder-clay seems well developed. The only 

 good section occurs at Thrussington. 



To do justice to the Older Pleistocene deposits of this valley, it 



