OF SOME DEEP BOEINGS IN KENT. 



199 



The Dovee Convict- Peison Boeing. 



Since the reading of my paper the Dover boring has been carried 

 a few feet deeper, and has been abandoned from want of success in 

 finding water. I have visited the site, in company with Major 

 Beamish, E.E., who had charge of the prison- works, and secured a 

 number of good specimens of the bottom-clays. 



The few small specimens previously to hand seemed of rather 

 doubtful character, partly by reason of the attempted personation 

 therein of fossils. The abundant material since to hand, however, 

 disposes of any doubt as to the bond fide character of the earlier 

 specimens, which is satisfactory. 



The new specimens themselves may hardly have been thought 

 satisfactory by my colleagues, Mr. G. Sharman and Mr. E. T. 

 Newton, who carefully examined them ; for, after washing and 

 sifting pieces of many of these, they arrived at a negative result. 

 They could find no sign of fossils, save for a solitary specimen of 

 a Botalia. Whether this was really in place in the bottom-clays, 

 or had been carried down into them by the boring- tool, is a question 

 not worth debating. 



As we can get no information from fossils, we must turn to the 

 oft-abused lithological character of the specimens for guidance, and 

 in this case, I think, with some result. Before taking up this subject, 

 however, some corrections may be made in the classification of the 

 beds in my former paper. 



In the first place, there can be little doubt that the three beds, of 

 a total thickness of five feet, doubtfully classed as the top of the 

 Lower Greensand are really the clayey greensand and nodule-bed 

 that form the base of the Gaulfc. 



In the second place, the lowest bed bracketed with the Lower 

 Greensand, though with doubt, is shown by specimens to belong 

 instead to the underlying series. 



The taking away of these 18 feet of beds from the Lower Green- 

 sand leaves that formation with a thickness of 31 feet only, and it 

 will be of some interest to make out what divisions of that formation 

 are present. At the outcrop, some miles to the S.W., we have four 

 divisions : — the Atherfield Clay, at the bottom, nearly 50 feet thick, 

 much in excess of the usual thickness in Kent ; the Hythe Beds, 

 about 60 feet ; the Sandgate Beds, here reaching a thickness of about 

 80 feet, though usually much less ; and the Folkestone Beds, 90 feet 

 thick, at the top. 



Beginning with the lowest of these, here, as at Chatham, there is 

 no sign of the marine Atherfield Clay. The two borings also agree 

 in the absence of anything like the sandy calcareous mass of the 

 Hythe Beds. When examining specimens from the lower part of 

 the Dover Lower Greensand, it struck me that I had seen something 

 of the same sort amongst the Chatham specimens, and on turning to 

 these it was found that the two sets exactly agreed in character, as 

 far as regards the bottom eleven feet or so ; for, on putting the 

 specimens side by side, it was impossible in some cases to see the 



