88 GEOLOGICAL NOTES IN THE NEIGHBOURHOOD OF ONGAR. 



far as Kelvedon Hatch, and this Httle sHpped patch alone remains 

 protected by the sides of the valley and the Boulder Clay. 



I shall return soon to the gravels of the Roding A^alley, but I 

 must first say a word or two about the high level gravels, and I will 

 first take the hills on the west which are a part of the Epping Ridge 

 and are capped with gravel at Coopersale Common and Gaynes 

 Park Wood. It has been described as Pebble Gravel by Mr. S. V. 

 Wood and the Geological Survey- and as Westleton Shingle by 

 Prof. Prestwich," who is scarcely correct in speaking of Coopersale 

 Common as a range of hills distinct from the Epping hills. It is all 

 part of one crescent-shaped ridge as I have already pointed out.* 



I noted the following section at Coopersale Common : — 



1. Clay, in places very like London Clay, but sometimes 



mottled, and always containing many small stones 

 and fragments of flint, thickness up to 4 feet. 



2. A mass of pebbles and small quartz grit and sand 



usually of a greyish colour, but sometimes mottled 

 red and grey, 5 feet. 



Bed 2 consists mainly of flint pebbles, but subangular flints and 

 pebbles of quartz of | inch or more in diameter are found without 

 difficulty. I found some small bits of white cherty stone, some 

 fragments of ironstone, and a very small red pebble, probably a 

 quartzite. I consider this gravel to be a good example of the 

 pre-glacial pebble gravel of this district, and it seems to have been 

 very little disturbed during glacial times. 



On the opposite side of the River Roding is the plateau of 

 Kelvedon Common, and it is capped in places by patches of gravel. 

 They have been described as Bagshot Pebble Beds by Mr. S. V. 

 Wood,*" and are to some extent mapped as such by the Geological 

 Survey. 



I noted the following sections : — 



Gravel Pit one furlong N. W. of Dudbrook House. Level 

 308 feet O.D. Gravel (not mapped) 5 feet or more 

 thick, not stratified, of a reddish colour or mottled 

 yellow and red ; in some places a little clayey sand. 

 Mainly flint pebbles, but there are a good many sub- 

 angular flints and a few quartz pebbles up to \ inch 

 diameter. 



2 Quart. Journ. Geol. Soc. (1868), vol. xxiv., p. 467; Whitaker's "Geology of London 

 (1889), vol. i., p. 294. 



3 Quart. Journ. Geol. Soc. (rSgo), vol. xlvi., p. 136. 



4 Essex Nat. (1890) vol. iv., p. 200; Proc. Geol. Assoc. (1891), vol. xii., p no. 



5 Quart. Journ. Geol. Soc. (1868), vol. xxiv.. p. 466. 



