PLIOCEN-E PEEIOD m EN^GLAKD. 499 



the gravel e reaching everj^where there to as great an elevation as c 

 does. This change seems to me to have been produced in East Anglia, 

 which is the area most remote from the ice source, either by a 

 diminution in the supply, or by the greater increase in the distance 

 of the sea which emergence produced in the shallower area to that 

 which it produced in the deeper ; so that where the ice reached the 

 sea furthest from its source, it did so by shrinking into the valleys 

 earlier than it did in the parts nearer. 



The interglacial age claimed by Mr. Skertchley for the brickearth 

 near Mildenhall and Brandon, with palaeolithic implements and mam- 

 malian remains, which occurs in the S.E. corner of Sheet 65 and 

 the N.E. corner of Sheet 51, has not yet been admitted generally by 

 geologists. 



This brickearth is underlain by the Chalky Clay with some rough 

 gravel between in places, and in some sections has this clay also over 

 it. It seems to me that this brickearth was formed by the drainage 

 issuing westwards from the inosculating valleys of the Little Ouse 

 and Waveney and from the valley of the Lark, when, though the ice 

 was wasting and had withdrawn from those valleys, a large body of 

 it still remained where this had been throughout in greatest thick- 

 ness, i. e. within the broken line of Map No. 1. 



It is to be borne in mind that, according to the inclination of the 

 land at this time, the escape of this drainage was not, as now, either 

 to the North Sea or to the Wash, but south-westwards ; and it is 

 reasonable to suppose that after the East-Anglian valleys had been 

 vacated by the ice, and this main mass of it still remained, though (so 

 to speak) in retreat, this retreat might be arrested and changed 

 into a slight advance by some temporary reinforcement from the 

 Pennine. Such a temporary advance bringing the ice against the 

 deposits of this drainage would carry Chalky- Clay moraine over 

 them. 



Inasmuch as the arboreal and other organic remains described 

 by Mr. Prestwich as present in the Hoxne bed prove that at the 

 time of its accumulation the stream which supplied the sediment for 

 it drained a surface that was occupied by arboreal vegetation, and sup- 

 ported great Mammalia, it seems to me that at this time the moraine 

 which had thus been uncovered by the shrinkage of the ice into the 

 valleys must have become clothed with such vegetation. This associa- 

 tion of arboreal vegetation with inland ice is not in accordance with 

 what obtains now in arctic latitudes ; but it may have been other- 

 wise in the comparatively low latitude of England during the Glacial 

 epoch. The observations, however, which I have to make on that 

 point, as well as on the coexistence or not of the great Mammalia 

 (most of which could not have existed without arboreal vegetation 

 to support them) with the land-ice in England, I defer to the second 

 part of this memoir. 



