\vanstp:ad and walthamstow, essex. 117 



Large flints, very little waterworn, from the Chalk. 



Cherty looking stone, perhaps carboniferous. 



Red very hard sandstone, and brown and grey sandstones. 



Brown quartzite boulders — common. 



Purplish-grey quartzite, somewhat glassy. 



Large quartz pebbles or boulders, one measured 3 x i| x 1 j 



inches. 

 Conglomerate or coarse grit of quartz and felspar. 

 One pebble which I think is an igneous rock. 



The Barking Side patch of gravel is one of several at about 100 

 feet level. It may well be of much the same age as the gravel at 

 Ilornchurch, which Mr. T. V. Holmes has described as overlying 

 Boulder Clay (Essex Nat. vii., pp. 1-14). Below these gravel 

 patches we find the great spread of Thames Gravel which underlies 

 the brickearth, in which mammalian remains and shells have been 

 found. One cannot depend on slight differences of altitude as a 

 conclusive test of the age of river gravels, for a river will often cut a 

 channel and then fill it up again to a greater or less extent. Thus 

 at Dartford we find a great thickness of gravel underlying the gravel 

 of Dartford Heath. A magnificent section showing this was recently 

 visited by the Geologists' Association, but as I hope that Mr. F. C. J. 

 Spurrell will soon publish a full account of it, I refrain from entering 

 on any details now. Mr. B. B. Woodward has also pointed out that 

 under certain circumstances the gravel at higher levels may be newer 

 than the gravel at lower levels in a valley.-' In the west Essex part 

 of the Thames Valley, however, I am inclined to believe that the 

 succession of the Drift formations is as follows, beginning with the 

 oldest : — 



1. The Pebbly Gravels of the Epping Ridge and Lam- 



bourne End. 



2. The Gravel of Buckhurst Hill ; a few patches of gravel 



near Loughton. 



3. The Chalky Boulder-Clay. 



4. The Gravel of Hornchurch overlying the Chalky Boulder- 



Clay and the gravels at about 100 feet O.D, of Rom- 

 ford and Barking Side. 



5. The great sheet of gravel at Barking, Ilford, and Wal- 



thamstow, which is for the most part below 50 feet 

 O.D. 



6. The brickearth of Ilford, with mammalian remains, etc." 



2 Proc. Geol. Assoc. 1889-90, vol. xi., p. 386. 



3 See on this question T. V. Holmes, 1893, Essex Nat., vol. vii. ?. i. 



