270 NEOZOIC TIMS. [CHAP. xui. 



destruction of the older Boulder-clay, and partly from the 

 disintegration of the Chalk, only the hardest stones having 

 survived the violent processes of erosion and transport. 

 These "plateaux gravels" occupy such positions as lead 

 to the inference that they once formed a nearly con- 

 tinuous sheet over the southern Midlands. South-westward 

 they occur on the higher parts of the low ground between 

 the Chalk escarpment and the Cotteswold Hills, but are not 

 found far above a level of 600 feet, the higher parts of 

 both ranges being entirely free from this northern Drift. 

 The limits of this Drift in the Cotteswold district were 

 first described by Professor Hull, 1 and represented on a 

 map which is reproduced in fig. 8 by permission of its 

 author and the Council of the G-eological Society. It has 

 been suggested that the area covered by these gravels was 

 a land surface at the close of the Glacial epoch, and that 

 the deposit was spread over its surface by the floods and 

 torrents resulting from the melting of the masses of snow 

 "which had accumulated on this part of the land. 



In Hampshire there are gravels which occupy similar posi- 

 tions, the portions preserved showing that they originally 

 covered a wide plain or table-land which had a gentle 

 slope to the southward. The higher patches of these 

 gravels rise to a level of over 400 feet, and their lower 

 portions appear to be connected with certain marine 

 deposits or raised beaches which occur between the 

 heights of 20 and 100 feet above the present sea level. 2 

 Mr. Codrington infers that the lower gravels were deposited 

 in a shallow inlet of the sea during a period of upheaval, 

 by which the inlet was gradually narrowed into an estuary 

 ^which received the waters of rivers draining country to the 

 north, east, and south, the Isle of Wight being then con- 



1 " Quart. Journ. Geol. Soc.," vol. xi. p. 477. 



2 Codrington in " Quart. Journ. Geol. Soc.," vol. xxvi. p. 5C8. 



