DRIFT-STAG i:S OF THE DARENT VALLEY. 16'i 



for the search being limited to the surface*. These implements were, 

 however, always found in close association with those drift-beds, 

 and confined to the area over which they spread. These are never met • 

 with in the intervening valleys, except an occasional derived speci- 

 men in the newer drifts. Besides this, the colour and incrustation 

 of the specimens show that the}' have been embedded in a surface- 

 drift, wliich,with others, has suffered denudation, and it is probable 

 that a large number of the specimens have been brought to the 

 surface on which they are now found in course of working the land. 



With respect to the Limpsfield gravel, it certainly wanted some of 

 the characters of a river-drift, but ice and snow may have had a 

 good deal to do with its lodgment. It is evident also that it has 

 been derived from the Tertiary outliers on the adjacent Chalk 

 escarpment 300 to 400 feet above Limpsfield Common, whence the 

 fall would be exceptionally rapid. At the same time, the Limps- 

 field gravel assumes much more the character of a river-gravel as it 

 descends the valley, in consequence of receiving tributary streams 

 and acquiring greater water-power and deeper waters. 



Respecting the brick-earth and the Chevening gravel, the Author 

 pointed out that the disturbed condition of the former could be best 

 explained by floating ice, and of the latter by a covering of ice and 

 snow. That there should be an absence of striated surfaces and 

 scratched stones was no more than might be expected, considering 

 the want of hard rocks. Other evidence would, however, be found 

 in the paper, which, from its length, he had found it necessary to 

 omit in reading. There was certainly an appearance of stride on 

 some of the implements and older flints, but whether that arose 

 from ice-action or from the rubbing and knocking about they . 

 received in the old drift-streams he would not at present like to 

 pronounce. 



The formation of the Chalk escarpment presented great difficulties. 

 In the North of England, where the great ice-sheet passed over high 

 hills, the escarpments would no doubt suffer defacement, but here 

 the character of the ice-action would be different. The Author did 

 not suppose that the great northern ice-sheet extended over this 

 area. A southern central ice-area may then have existed in the 

 Wealden highlands, and the ice and snow in these valleys have been 

 local. The height of the glacial period preceded the Limpsfield 

 gravel, and the "W. and E. and the S. and N. directions of the flows 

 were the result of different physiographical conditions at different 

 periods. 



The Author then expressed his obligations to the three gentlemen 

 who had so greatly assisted him by their researches in the field, the 

 results of which were to be seen in the large collection of Elint 

 Implements exhibited. 



* I have now seen the fine specimen mentioned on p. 133. It is (> inches 

 long by 3f in. wide, very flat and round-pointed, and shows no wear. It 

 more resembles one of the large St. Acheul types. It was found on the top of 

 the soil last thrown out of the hole. 



