CHAPTEE XVIII. 



PLEISTOCENE DEPOSITS. 



THE long series of palaeozoic, mesozoic, and cainozoic strata being 

 completed to the crag of our eastern coast, the distribution of land 

 and sea where now are the British Isles was in some considerable 

 degree sketched out. By early systems of movement the chains of 

 the Highlands, and the south of Scotland; of Donegal, and the 

 mountains of Mourne and Wicklow; the ridges of the north of 

 England; the insulated groups of Charnwood and Malvern, and 

 the elevated tracts of Wales, had been raised and settled into hills 

 before the mesozoic age. 



At a later time the mesozoic and great part of the cainozoic 

 strata were pressed upward, and something like the main features 

 of the oolitic and chalk ranges traced out as we now see them. 

 Not exactly indeed ; for the breadth of the oolites was then much 

 greater to the west, so as to occupy, with crests equal to or 

 surpassing the summit of Cleeve, what is now the Vale of Glou- 

 cester, and the chalk extended so much beyond the White Horse 

 Hill and Marlborough Downs as to have furnished abundant heaps 

 of unbroken and unchanged flints to the extremity of what is now 

 the Vale of Evenlode. The regions mentioned were raised out of 

 the sea, and placed above its level, and subjected to meteoric waste ; 

 and against some of the surfaces of this old land, where it passed 

 under the sea, the crag and other strata were formed on lines of 

 ancient coast, and at sea-levels not greatly differing from those now 

 observed. 



One might think that since the date of the deposition of crag, 

 on the eastern coast of ' old England,' parallel to what is now the 

 East-Anglian shore, the levels of land and sea had been little 

 disturbed, beyond the 20 or 30 feet rise of the limited crag beds 

 and more extended shell beaches into dry land. Yet it is generally 



