194 



Fisher — Ages of the " TraiV and "Wmy." 



I have no hesitation in saying that the deposit in question at 

 Hford and Grays is this trail. At Ilford it consists chiefly of gravel 

 and London clay confusedly mixed. The accompanying sketch, copied 

 from one made on the spot, gives a rough idea of the manner of its 

 occurrence. Now we have both these materials in the neighbour- 

 hood of Ilford, in the gravel of the Thames valley, and in the Lon- 

 don clay of the higher grounds. 





Section of about eight feet of the upper part of Uphall Brick-field at Ilford, Essex. 



a. Warp. 



b. c. Trail. 6 is clayey gravel ; c, London Clay, with a few gravel pebbles. 



d. Yellowish light-coloured stratified sand, belonging to the Brick-earth series, 



but disturbed by the deposition of the trail. 



e. A pebbly band, in ■which a tooth of Mephas antiquus (in my possession) was 



found at /. 

 (The head of Elephas primigenius, in the British Museum, was found in a lower 

 band.) 



At Grays, on the other hand, the trail is thinner, and altogether 

 a less important member of the section. The cause of this appears 

 to be that the locality is on sloping ground. The materials of the 

 trail are there chiefly of Thanet sand derived from the hill side 

 above. It contains gravel also, but in subordinate quantities. 



I do not believe that any argument as to the age of the Brick- 

 earth can be founded upon this deposit, except — what would be self- 

 evident without it — that it is older than the latest denudation of 

 the surface. 



Mr. Wood, jun., in his paper on the Thames valley, looks upon 

 this trail in the Uphall pit at Ilford as a layer of the Thames valley 

 gravel, in situ, overlying the Brick-earth, and has thence concluded 

 that the Ilford Brick-earth is older than that of Grays. Mr. Daw- 

 kins, however, appeared to consider the two Brick-earths of the 

 same age. Their age relative to each other, or to the Thames gravel, 

 is not affected by the gravelly capping of the Uphall pit on the sup- 

 position of its being trail. 



