384 Geological Society: — 



morainic mud-bank which preceded this glacier, and was pushed by- 

 it as it advanced, and the land rose partly into the shallow sea 

 (where it covered and protected for a time the gravel which was 

 synchronously forming there), and partly onto the land; and by 

 the aid of maps he showed the islands that were overwhelmed by it. 

 He then showed, by a line on a map, the limit up to which this ice, 

 as it thickened, cut through and destroyed this first deposited mo- 

 raine and the gravel which it had covered, as well as such beds of 

 Stage II. as were formed there, all this material being pushed on to 

 add to later deposited moraine. Outside this line the gravel, for 

 the most part, remains undestroyed, its contents, particularly in 

 the uppermost layers, showing that it was fed by the approaching 

 moraine. By the level at which the junction of this gravel with 

 the moraine clay occurs he traces the position of the sea-line at this 

 time (towards the end of the formation), and finds it to rise along 

 the south-eastern edge of the clay, from 40 feet in N.E. Suffolk 

 to 160 feet in South Essex, and from that along the south-western 

 edge to upwards of 350 feet in North "Warwickshire and the parts 

 of Northamptonshire adjoining, all this agreeing with the original 

 increment of submergence in Stage II. He then showed, from evi- 

 dence afforded by the Yare and Gipping valleys, that this ice, 

 ceasing to advance in East Anglia, shrunk into the valleys of that 

 district, exposing the moraine it had previously laid down to the 

 growth of vegetation, and issued only through these valleys to the 

 sea. The Hoxne palaeolithic brick-earth he regards as the deposit 

 of a lagoon produced from the interception of the drainage of this 

 surface by the glacier-tongue thus passing through the Waveney 

 valley. The Brandon palaeolithic brick-earth he regards as connected 

 with the same state of things. 



In Stage IY. he described the plateau and cannon-shot gravels 

 of Norfolk as resulting from the washing-out of the morainic clay 

 by the melting of this ice, which, though shrunken into the valleys 

 of the East of Norfolk, still lay high and in mass in "West Norfolk ; 

 and showed that, by having regard to the different inclination of the 

 land thus traced, the position of this gravel is reconcilable in no other 

 way. The cannon-shot part of it he attributed to the torrents 

 pouring from this high-lying ice over the west side of the Wensum 

 valley ; and the plateau gravels to the deposition of other parts of the 

 same spoil carried into East Norfolk at the commencement of the 

 process and while the ice had not thawed out of the valleys, this 

 gravel afterwards, as the valley-ice thawed, being deposited in them. 

 He also traced the excavation of the trough occupied by the Bain 

 and Steeping rivers in Lincolnshire to the same cause. The finer 

 or sandy part of this material has an extensive spread in South- 

 west Norfolk, forming thick beds, and in a thinner form spreads 

 over North-west Suffolk, where it wraps the denuded edges of the 

 Hoxne and Brandon palaeolithic brick-earths. 



In Stage Y. he traced the line of gravels that overlie the Chalky 

 Clay where this clay entered the sea. This entry to the sea over 

 the Severn drainage-system took place by way of the watershed 

 between the "Welland and Avon, and by the valley of the latter. 

 Its entry into the sea over the Thames system was by way of the 



