Geological Society of London. S79 



both sides up to the strip of London Clay. The author accounts for 

 this distribution of the gravels by supposing that a large body of 

 water must at one time have stood at the 50-feet level, and the 

 denudation of the high terrace have been caused by the waves beat- 

 ing on the sides of the valley, and by drainage into this body of 

 water. The mid terrace he conceives may have been caused in part 

 by accumulations beneath this body of water. 



The position of the high-terrace gravel at Acton corresponded so 

 closely to that of the implement-bearing gravels of the Somme and 

 the Ouse, that the author was led to examine carefully the excava- 

 tions made in it for the construction of houses. He discovered a 

 number of implements of the drift-type, together with flakes and 

 cores, and a few roughly formed scrapers ; all these were found in 

 close contact with the London Clay, and beneath the gravel. Frag- 

 ments of fern ( Osmunda regalis) and of wood (Finns sylvestris) were 

 also found with the implements at the same level. Two implements 

 were found at Ealing Dean, 2 miles westward, on nearly the same 

 level as those of Acton, viz. 90 feet ; and these also came from the 

 bottom of the gravel. Another implement was found south of the 

 river at Battersea Eise, in the same position above the strip of 

 London Clay as at Acton, and about 60 feet above the Ordnance 

 datum. The imjDlements are of the pointed and oval types. The 

 only animal remains discovered in the high terrace consisted of a 

 tooth of ElepJias primigenius in the Acton gravel. The position of 

 this the author believes to be reliable, although he did not discover 

 it himself in situ. 



In the mid-terrace gravel a number of pits were examined be- 

 tween Shepherd's Bush and Hammersmith, and in the neighbour- 

 hood of Turnham Green, which resulted in the discovery, at the 

 latter place, of a large quantity of animal remains (noticed by Mr. 

 Busk in the following paper), all of which, like the implements of 

 the high terrace, were at the bottom of the gravel ; but no evidence 

 of human workmanship was found in the mid terrace. 



All these were found together, in the same seam of gravel, 12 

 feet beneath the surface, and all appeared to have been deposited at 

 the same time. The surface was here 25 feet above the Ordnance 

 datum, and consequently about 50 feet lower than the implements 

 of the high terrace, 1^ mile to the north. The section across the 

 valley, taken through the two places, here shows the strip of the 

 London Clay intervening between the two terraces. 



The chief points of interest which the author submitted to the 

 judgment of geologists, consisted in the presence of drift implements 

 in the high terrace, their presence in the mid terrace, and reappear- 

 ance in the existing bed of the Thames ; the great rarity or absence 

 of animal remains in the high terrace, and their abundance in the 

 mid terrace, and the occurrence of both implements and animal re- 

 mains at the bottom of the gravel in both terraces. The writer 

 concluded by adducing proofs of the great antiquity of the present 

 river-bed, which it was shown must have run in its pi'esent mean- 

 dering course in the bottom of the valley for at least 2000 years. 



