Reports and Proceedings. 2S3 



plosions ; but, with these exceptions, no earthquake had attended the 

 eruptions or the formation of the island. 



3. " Note on the Junction of the Thanet Sand and the Chalk, and 

 of the Sandgate Beds and Kentish Eag." ^ By T. M'Kenny Hughes, 

 Esq., B.A., F.G.S. 



At the bottom of the Thanet Sand there is always a bed of green- 

 coated flints in a green and rust-brown clayey sand, which the 

 author is of opinion was derived from the decomposition of the 

 chalk by the percolation of carbonated water, after the deposition of 

 the Thanet Sand, as none of the flints are water- worn, and only 

 chalk fossils have been found in the bed. 



At the base of the Sandgate beds, and resting on rubbly Kentish 

 Eag, there is generally a bed of green sand ; it may be seen in the 

 quarries, near Maidstone, where it occupies furrows of the nature of 

 pipes. Mr. Hughes endeavoured to show that this bed has been 

 derived from the decomposition of the Eag after the deposition 

 of the brick-earth, and that the rubbly limestone below it is the 

 same in process of decomposition. He remarked, in conclusion, that 

 conformabilities or unconformabilities of beds must not be inferred 

 from an examination of the line of junction only, as that may have 

 been very much modified after the deposition of the newer formation. 



4. " On the Lower London Tertiaries of Kent." By "W. Whitaker, 

 Esq., B.A., F.G.S. 



This paper gave the general results of the Geological Survey 

 work in the Tertiary district of Kent, chiefly by the author, who 

 expressed liis agreement with Mr. Prestwich's paper, except in a 

 few matters of mere detail. 



Eive different members of the Thanet Beds were distinguished, 

 the only constant one being the " base-bed," the possible formation 

 of which, after the deposition of the sands, etc. above, worked out 

 ia detail by Mr. Hughes, had occirrred also to the author. It was 

 shown that the fine Thanet Sand of West Kent was replaced east- 

 ward by beds of fossiliferous sandy marl and sand, which came on 

 in succession above it. 



Of the overlying Woolwich Beds, only the lower part is present 

 in the eastern part of the county, the middle (the estuarine shell- 

 beds) and upper parts being limited to the western and central 

 districts. 



The sands of East Kent, which Mr. Prestwich had somewhat 

 doubtfully classed with the basement-bed of the London Clay and 

 the pebble-beds of West Kent, part of which had been classed with 

 the Woolwich series and part with the basement-bed, the author had 

 been led to look upon as a distinct division, to which, he gave the 

 name " Oldhaven Beds," and which are separable alike from the 

 London Clay above and from the Woolwich Beds below. 



The basement-bed of the London Clay, in the limited sense in 

 which it is imderstood by the author, changes its structure according 

 to that of the underlying beds. 



The author corrected some mistakes that had been made in a 

 1 See also Mr. G, Dowker's paper on this subject at p. 210. 



