Deep Channel of Drift in the Valley of the Cam. 121 



a Southern Drift derived from the Lower Greensand of the Wealden 

 area, and from the Chalk and Tertiary strata formerly extending 

 partly over it. 



8. That during the Diestian period the Weald was probably partly 

 or wholly submerged, and that between this and the insetting of the 

 Glacial period, the Wealden area and the Boulonnais underwent 

 upheaval resulting in the formation of an anticlinal range from 

 2000 to 3000 feet high. 



9. That from the slopes of this range the materials of the Southern 

 Drift were derived, and spread over what is now the south side of 

 the Thames basin. 



10. That this denudation commenced at the time of the Red Crag, 

 and went on uninterruptedly through successive geological stages. 



11. That consequently, though the Southern Drift preceded the 

 Westleton shingle, the two must at one time have proceeded syn- 

 chronously. 



12. That the valley-system of the Wealden area dates from 

 Pliocene times, — the initial direction of the transverse valleys from 

 Preglacial times, — and of the longitudinal valleys from Glacial times. 



13. That the Thames basin results from the elevation of the 

 Weald and the flexures of the Chalk and Oolites of the Midland 

 counties, and dates from a period subsequent to the Westleton Beds. 



14. That the genesis of the Lower Thames similarly dates from 

 early Pleistocene times, whilst its connexion with its upper tribu- 

 taries and the Isis, which possibly flowed previously north-eastward, 

 took place at a rather later period. 



March 12.— J. W. Hulke, Esq., F.R.S., Vice-President, 

 in the Chair. 



The following communications were read : — 



1. " On a Deep Channel of Drift in the Valley of the Cam, 

 Essex." By W. Whitaker, Esq., B.A., F.R.S., F.G.S. 



In Scotland and in northern England long and deep channels filled 

 with Drift have been noticed, but not in southern England. 



For some years one deep well-section has been known which 

 showed a most unexpected thickness of Glacial Drift in the higher 

 part of the valley of the Cam, where that Drift occurs mostly on the 

 higher grounds and is of no very great thickness. Lately, further 

 evidence has come to hand, showing that the occurrence in question 

 is not confined to one spot, but extends for some miles. The beds 

 found are for the most part loamy or clayey. 



At the head of the valley various wells at Quendon and Sickling 

 show irregularities in the thickness of the Drift, the Chalk coming 

 to or near the surface in some places, whilst it is nearly 100 feet 

 below it in others. 



Further north, at Newport, we have the greatest thickness of 

 Drift hitherto recorded in the South of England, and then without 

 reaching the base. At one spot a well reached Chalk at 75 feet ; 



