part -4] ELEPBAS-ANTlQVVS BED OF CLACTOX-OJf-SEA. 607 



to a very considerable depth. That is to say. that after Boyne 

 times the river was rejuvenated, and its fall became relatively very 

 much more rapid than it had been before. 



The Taplow Terrace group of deposits covers a considerable 

 period of time, and includes quite notable changes in the river 

 itself, in the river-deposits, and in the fauna. The earlier Taplow 

 deposits seem much nearer to the later Boyne deposits than they 

 are to the later deposits of the Taplow stage. I sometimes wonder 

 ■ whether we have not rather overlooked one of the essential condi- 

 tions of river-terraces. If one stands on the flood-plain of a river, 

 one is always told to look across to the other flood-plain on the 

 opposite side, and to note the corresponding terrace on each side ; 

 but it is at least equally important to look in imagination through 

 the water, and to note the difference in level between the contem- 

 porary deposits of the river-bed and the Hood-plain. 



At Stoke Newington the river-bank of Taplow times abuts 

 against the Boyne Terrace, at a level of about 100 feet O.D. 

 At Grays, the Boyne Terrace still maintains much the same level, 

 but the Taplow Terrace has dropped nearly 50 feet. At Shoebury- 

 ness the Corbicula Beds of the Taplow Terrace are found below 

 the level of low tide. This relatively rapid fall of the Taplow 

 Terrace gives us the key to the position of the Clacton bed. 



One should consider the relative dating of these Taplow deposits 

 a little more closely, as they must come into comparison with the 

 Clacton bed. The basement-gravel at Stoke Newington yields 

 contemporary implements of the Late Chellean stage : that is to 

 say, it was the river-bed at the time when much of the Boyne 

 Terrace deposits were laid down on the Hood-plain. The higher 

 portion of the Stoke Newington deposits yields a well characterized 

 Mousterian industry and fauna, as first shown by the late 

 Worthington G. Smith. 



The Grays deposits are divided pakeontologically into two groups, 

 although it is noteworthy that both occur at the same level, so the 

 active period of river-erosion had then been arrested. The earlier 

 group (Little Thurrock) consists of the classical Corbicula and 

 Hippopotamus Beds ; while the basement-gravel of the later group 

 (West Thurrock) yields an abundant proto-Mousterian industry, 

 characterized by the familiar ' tortoise-cores ' and Levallois flakes, 

 and is closely succeeded in the overlying beds by the Eleplias- 

 prlmlf/eiilus fauna. 



Following upon the above-mentioned suggestion of arrested 

 erosion at Grays, which would scarcely be conclusive in itself, we 

 have irrefragable evidence at Clacton, supported by contributory 

 evidences elsewhere, 1 of a reversal of the movement, and of the 

 invasion of the area by estuarine conditions. 



From the above outline of the facts, one may, I think, feel 

 justified in narrowing down the correlation between the river- 



1 See the Eeport on the Mnllusca by Mr. A. S. Kcnnard & Mr. B. B. Wood- 

 ward, appended to the present paper, p. 633. 



