SITRFACE-DEPOSITS OF THE EALIXG DISTRICT. 199 



(already referred to) is shown near Freeland E-oad, about half a 

 mile to the west ; a section there shows the floor running nearly up 

 to the surface and sloping to the west ; it evidently represents a 

 depression in the lower beds which has been filled with brick-earth. 

 The banks of gravel exposed even lulien the brick-earths were being 

 deposited (and which, in many cases, may have been broken up and 

 disturbed by floods) afforded many secure sites upon which these 

 ancient people lived. 



With regard to the lower surfaces, it appears that, though subject 

 to similar changes, they were never entirely destroyed. The 

 unabraded implements and flakes, as sharp as these Crefiield-Road 

 specimens, which I have found at lower levels, say at 8, 10, and 12 

 feet all over the district, render it probable that they too have 

 remained on the spots where they were left by the men who used 

 them, but were covered, first with a stratum of sand, and afterwards 

 with gravel. 



The waste and slipping of the surface of the London-Clay hills in 

 this district to lower levels, even under the present temperate 

 condition of things, is so marked, that it must have been a very 

 important factor, even after the waters had retreated from it. This 

 action may be seen actively in progress on the slopes of Horsington 

 Hill, which is exposed to the elements in all directions *. 



I regret that I have never found any bones or shells in the upper 

 terrace. I have, however, a small collection of both from the mid- 

 terrace deposits near the boundary of Brentford with Ealing. The 

 shells belong to the same species as have previously been recorded 

 by Messrs. Trimmer, Morris, and Belt. The bones are : — 



Cuboid of Hipjjopotamus, slightly rolled, determined by Mr. E. 



T. Newton, of the Geological Survey. 



Metatarsus of Bos primiqenius or J5. ^ -r- n i j i^ • i 

 7- -r i/ unrolled, determined 



Bovine teeth, probably B. lonrjifrons . i ^^^^ ^^^ j^^^ ^^^^^ 

 Remains of Cervus capreolus J 



A large number of other bones were found, including part of the 

 jaw (probably) of Rhinoceros ; but they are too fragmentary and 

 too much roUed to be determined with certainty. 



Discussion. 



Prof. T. M'^K. Hughes asked the author whether it was possible 

 that the series of flakes could have been swept into hollows or col- 

 lected in any way from the surface. Their state of preserv^ation was 

 different from that of the implements from the gravels and loams, 

 and suggested more recent exposure to atmospheric action. 



Prof. W. Boyd-Dawkins said that the discovery of floors of human 

 occupation in the river-gravels of the Thames Yalley was of con- 



* According to Sir Andrew Ramsay and ]\Ir. Whitaker, the escarpments of 

 the Cretaceous deposits of the North and South Downs have mainly been 

 formed by the same subaerial denudation. If this be so, then the same agents 

 must have produced an enormously greater effect on the soft Eocene beds and 

 alluvium in N.W. Middlesex. 



