﻿S. V. Wood, J un.~~ American and British Surface- Geology. 549 



appears to me now to throw a clear light on this case. This cutting 

 was made through the north side of the Yare Valley, and in it the 

 chalky clay was exposed with the Middle Glacial sand containing 

 its shell-bed under it on the uj)per part of the valley side ; but lower 

 down the whole of the clay had been ploughed out, and the sand 

 was all twisted up with the Lower Glacial (Bure Valley) sand, on 

 which, after the first excavation of the valley, it had been deposited. 

 In the valley below the chalky clay may still be seen in section 

 resting on the glaciated chalk floor of the valley, and it is clear that 

 we have here an illustration of what glacier-ice produces when moving 

 over clays and sands, viz. their destruction in part and the twisting 

 of the rest with the soft beds on which they repose.^ A similar 

 feature of ice plough was afforded (some years ago when the cutting 

 had been fresh scarped on one side) by the railway cutting at the 

 East Suffolk Railway Junction, Ipswich, in the Gipping Valley. If 

 such features were exhibited generally over the plateaux through 

 which these valleys are cut, we might explain them merely by a 

 general advance of the ice ; but there has been no such ploughing 

 over the plateaux, as the numerous inland pit sections over them and 

 the continuous sections of them which the cliffs north and south of 

 Lowestoft afford, show in the case of the Yare Valley most clearly. 

 Thus the succession of events in East Anglia was, first the deposit 

 by marine agency over a floor formed of Chalk, Lower Tertiaries, 

 and Crag, of the Lower Glacial series in considerable thickness ; 

 next the excavation of the valley -troughs (whether subaerially or 

 subaqueously may be here left out of consideration), into which, as 

 shown by Mr. Harmer and myself, the Middle Glacial sand was 

 bedded and covered by the chalky clay ; and then, while the chalky 

 clay was still in progress, these deposits were elevated into land, so 

 as to form the coast belt which I have described. This belt was 

 pressed on its western side by the great body of ice which, having 

 passed over Lincolnshire, occupied the fen, and from whose mass the 

 tongue-like glaciers passing through some of these valleys to the sea 

 went off and formed the means by which the land-ice escaped ; and 

 these by their ploughing produced that subsequent denudation of 

 those valleys, and gave rise as they receded to those deposits of 

 morainic clay which we find in them, resting upon glaciated chalk, 

 which were so long puzzles to me. In the case of the smaller 

 valleys as well, as in those lateral to the few main ones through 

 which the glacier tongues passed, the patches of chalky clay which 

 occur in their bottoms appear to have been produced by the drifting 

 into them of floe-ice freighted with sheets of the morainic material. 

 The action of this inland-ice upon the western parts of Norfolk and 

 Suffolk may also be traced in the abrupt termination in these parts 

 of the counties of the Lower and Middle Glacial, as though both had 



' Where this cutting was carried through, sand had rested on sand, viz. the 

 Middle Glacial on the Bure Valley beds ; but a pit about a quarter of a mile west, 

 of old date, showed the Middle Glacial sand resting on the Contorted Drift, which 

 in that neighbourhood is uncontorted. The valley plough referred to in the text 

 had here contorted the two together, and so given rise to this exceptional feature. 



