510 Nolkx's of 3Iemoirs — F. W. Hai'mer — The Eadeni Glacier. 



detritus varies in different districts, in accordance with that of tlie 

 strata over whicli the ice had moved. Tlie matrix of the Boulder- 

 claj' of South Norfolk and North Suffolk, for example, has been 

 largely derived from the Kimmeridge Clay. Over this region, 

 v^hich formed in Glacial times a shallow trough running east and 

 west, corresponding with the present depression of the basins of 

 the Little Ouse and the Wavenej', as well as with the gap in the 

 Chalk escarpment between Swaffham and Newmarket, the ice 

 evidently poured in great volume, planing down the surface of the 

 Chalk and carrying its Kimmeridgian material fifty miles to the 

 east from its original source in the Fen basin. On the other hand, 

 although the Fen ice was sufficiently thick to enable it to overflow 

 the Chalk hills between Newmarket and Royston, it only travelled 

 thence to the south-east for about half that distance. In this region 

 the Boulder-clay is chalky near the escarpment, while beyond the 

 outcrop of the London Clay it is mainly composed of detritus from 

 that formation. 



Along the basin of the Ouse, where its matrix is largely Oxfordian, 

 the ice to which it was due advanced much further, to Buckingham 

 and beyond, as it also did along that of the Nene, in the direction 

 of Northampton, where Liassic debris is common. On the contrary, 

 the high land near the head waters of the Welland obstructed the 

 ice-flow, so that but little Boulder-clay seems to have found its way 

 into the area comprised in Sheet 53 of the Ordnance map. The 

 greater part of Sheet 63, however, is covered by it, and it there 

 reaches an elevation of 730 feet above the sea-level. Much of the 

 Boulder-clay of this region, in the author's opinion, was due to the 

 ice-stream of the Trent Valley, having been piled up upon the high 

 land to the east of Leicester by the pressure of ice descending from 

 the Pennines. 



It seems probable that the whole of the low-lying region between 

 the Lincolnshire Wolds and the Pennines was filled with ice during 

 the period of maximum glaciation. It is not physically possible 

 that any considerable thickness of ice could have existed on one 

 side only of the Lincolnshire ridge, which does not often exceed an 

 elevation of about 200 feet above the lower ground adjoining it. 



The author hopes to make the ultimate source of the Chalky 

 Boulder-clay ice the subject of a future paper. The prevalence of 

 Carboniferous debris in the East Anglian region seems to indicate, 

 however, that a part of it at least was of Pennine origin ; another 

 part may have been due to an overflow from the North Sea across 

 the lower part of the Chalk Wolds, and the ice may also have been 

 reinforced by the abundant precipitation to which this district was 

 subject during the Glacial period ; the moisture-bearing cyclonic 

 disturbances from the Atlantic, to which the enormous accumulation 

 of ice in the Baltic region was due, must have passed near the 

 eastern counties of England. There is no evidence to show that 

 any considerable amount of ice entered East Anglia through the 

 Wash gap during the Chalky Boulder-clay period, all the facts 

 known to the author appearing to point in an opposite direction. 



