lxiv PROCEEDINGS OF THE GEOLOGICAL SOCIETT. [vol. lxXVl, 



Features due to Glaciation. 



It was on the low ground that the ice-sheets abandoned most of 

 their transported burden, with the result that in many parts a new 

 surface Avas built up, with new outlines and new or nearly new 

 drainage-systems. A considerable portion of the new country Avas 

 a clear gain of land at the expense of the sea ; and, in its present- 

 day encroachment, the sea in most places is only claiming its oaati 

 again. Let us examine how much of England would disappear if 

 the drifts Avere to behaA^e like their parent ice and melt out of 

 existence. I have prepared an outline-map on a small scale 

 (see folding-plate, facing p. lxxxii) in Avhich the area is approxi- 

 mately marked out ; shoAAmig also, separately, the principal extension 

 of the drift Avhere its base is above sea-leA T el. 



This map has been compiled mainly from the drift-editions of 

 the 1-inch maj)s of the Geological Survey Avhere available ; and 

 where these are lacking, from other published sources and from 

 information supplied to me by several colleagues on the Geological 

 Survey, to Avhom I desire to render my thanks. The small scale 

 of the map precludes detail, and the boundary-lines are necessarily 

 generalized, particularly those marking the inland margins of the 

 drift-sheets. In delineating the outlines of the drift beloAv sea- 

 level, I have consulted the memoirs and ' horizontal sections ' of 

 the Geological Survey, together with other literature to which 

 reference, Avhere needful, Avill be given (in footnotes). 



Turning to the map, Ave may note that the rocky coast of 

 Northumberland and Durham is broken by several embayments 

 and estuaries into which the sea would penetrate if the drifts were 

 removed, Avhile a deep drift-filled channel in the interior, connecting 

 the Eiver "Wear with the Tyne, also descends below sea-level. 1 On 

 the borders of Durham and Yorkshire the coast avouM sAving 

 inland around the present estuary of the Tees, admitting the sea 

 into a basin 10 or 15 miles Avide, with an arm running southwards 

 toAvards the Vale of York. At Whitby the buried A'alley of the 

 Esk would form a sharp inlet ; and south of Scarborough the sea 

 Avould floAv up the Yale of Pickering for about 20 miles, forming a 



1 For particulars relating to this channel, and to the drifts between Tyne 

 and Tees, see ' The Stiperficial Deposits & Pre-Glacial Valleys of the Xorth- 

 umberland & Durham Coalfield' by D. Woolacott, Q. J. G. S. vol. lxi (1905) 

 pp. 64-96 ; and ' The Scandinavian Drift of the Durham Coast & the 

 General Glaciology of South-East Durham ' by C. T. Trechmann, ibid. vol. 

 lxxi (1915) pp. 53-80 ; a]so other papers by the same authors. 



