Wood — 071 the East Essex Gravels. 405 



been excessive and repeated. Denudations, rivalling that wliicli I 

 have, in. these papers, endeavoured to establish, and contemporaneous 

 with it, have, I beheve, taken place in other parts of England ; of 

 v^hich the greatest effects are exhibited by the region of the Isles of 

 Wight and Purbeck, of Somersetshire, and of the combined district 

 of South-east Yorkshire and North Lincolnshire. In the latter 

 instance there is, I think, evidence to show this ; but in the other 

 cases the evidence is defective for want of a starting point of Upper 

 Drifts nearer than that crowning the brow of the Than^es valley. 

 What is wanted in the case of the Isle of Wight area is a starting 

 point Upper Drift resting on the Upper Bagshot series of Hamp- 

 shii'e ; and, notwithstanding the general denudation of the Upper 

 Drift south of the Thames, it is not unlikely that patches of this 

 formation may remain on the great Tertiary tracts of the south of 

 England. Very small patches of it frequently occur in the east of 

 Engjand in the midst of wide tracts of the denuded inferior beds, 

 frequently from having been let down by faults; and I am not with- 

 out hope, therefore, that, if the attention of geologists resident in 

 the neighbourhood of the great Bagshot tracts of Chobham and 

 Erimley, and that of the New Forest, were, directed to this object, 

 some trace of the Upper Drift might be discovered there. 



No confirmation of the supposed occurrence in the Thames gravel 

 of the flint implement found in Gray's Inn Lane, and described by 

 Mr. J. Evans,' has yet been obtained ; and the extensive and freely 

 worked sheets of the Thames and East Essex gravels have failed to 

 yield what has occurred in such abundance in the gravels of the 

 Somme, Seine, Little Ouse, and Lark valleys, and in those of the 

 Avon at Salisbiiry, of Hampshire, Biddenham, etc. I would not 

 hazard a conjecture whether or not man dwelt in Britain during the 

 Thames and East Essex gravel period ; but certainly the absence 

 of his remains in that gravel does accord with the far higher 

 antiquity assigned to it here over those in which his remains 

 have occurred. From the delineation I have given of the outHnes 

 of land and sea during the Thames gravel period, it will be seen 

 that I regard the Chalk country, out of which the valley of the 

 Somme and of that at Salisbury was formed, as undergoing denu- 

 dation by the sea at this time ; and that it was not until this 

 denuded Chalk was elevated, that the valley of the Somme, the 

 Avon, and of the Weald, were cut out of it. In this state of 

 things the gravels of the Somme, Seine, and Avon, would come 

 more into corelation with those described under the symbol, x5, 

 etc., or else of those of the Wealden Greensand terrace (a;6), and, 

 taking all things known of them into consideration, I think nearest 

 with the latter (ic6). It is true that in the former Cijrena flmninalis 

 occurs, which does not seem to have been detected in the latter; 

 but as this shell has retreated in a south-easterly direction to- 

 wards the Nile, in the interval between then and now, its presence 

 in France, and its absence in this country, during the period marked 

 by series x 6, may not be inconsistent. The gravels of Bedford and 

 1 Aiclijeologia, vol. xxxviii., 1860. 



