Notices of Memoirs — Deep Borings in Kent. 511 



down the bore. Anyway it proves nothing. As regards the character 

 of the beds, however, I think that a reasonable conclusion may be 

 inferred from the specimens. 



In my published account certain beds are referred, with some doubt, 

 to the Lower Greensand. The reference is wrong and the doubt right, 

 for the top five feet, of the 49 credited to Lower Greensand, really 

 belong to the base of the Gault, and the bottom thirteen feet to the 

 Wealden, as I believe. The Lower Greensand is left, therefore, with 

 only 31 feet of clayey sand. It is curious that specimens from 

 the bottom part (838 to 848 feet) are exactly like the corresponding 

 specimens from the bottom part of the Lower Greensand in the 

 Chatham boring (932 to 943 feet), the two sets having about the same 

 vertical extent (10 or 11 feet). 



These specimens remind one of the division known as the Sandgate 

 Beds, and I am inclined to think that this division alone occurs at 

 Dover, the Folkestone Beds above and the Hythe Beds below having 

 thinned out, although both those divisions are thicker than the 

 Sandgate Beds at the outcrop. 



The clayey beds beneath have been proved to a thickness of some 80 

 feet, the boring ending at about 930 feet. In my paper I spoke of 

 chalky matter occurring in them, but in this I was wrong. The white 

 specks in the small specimens first seen certainly looked calcareous, but 

 the examination of better specimens has shown that they are anything 

 but that. Indeed, the prevailing character is the absence of any 

 effervescence when the clays are treated with hydrochloric acid ; in 

 many cases peculiarly fine-grained whitish beds simply absorb the acid, 

 without any effervescent action. 



On comparing the specimens with other clays, they were found to be 

 unlike any of the marine Cretaceous and Jurassic clays, and it seemed 

 to me that their affinities lay rather with the Wealden series, and 

 probably with the lower, or Hastings division, than with the Weald 

 Clay. 



I have only lately been able to test this by the help of a set of 

 specimens that Mr. G. Maw has been kind enough to send me. On ex- 

 amining them I found that three specimens of Weald Clay, from Surrey, 

 effervesced readily, which is perhaps not surprising as they came in two 

 cases from close to Horsham stone, and in the other from near a Paludina- 

 bed. Nine specimens from a more distant district, Dorsetshire, did not 

 effervesce ; but one can hardly give the exact position of these in the 

 Wealden Series. Ten specimens from the Ashdown Series, the lowest 

 division of the Hastings Beds, not only, in some cases, resembled Dover 

 specimens in character (I speak from memory, not having had the two 

 sets side by side), but in every case refused to notice the presence of 

 hydrochloric acid. 



Should this classification be right, it serves to strengthen very much 

 the conclusion, in my paper, that Dover is on all grounds a good site 

 for a deep trial- boring, 1 for it looks as if the bottom part of the great 

 Wealden Series came there within 600 feet of the surface in the low 

 ground, the boring being described on a site 280 feet above the sea. 

 1 Quart. Journ. Geol. Soc. 1886, vol. xlii. p. 44. 



