410 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mai\ 21, 



of a pale-grey sand, often of a yellowish or greenish tint, much 

 false-bedded and rather coarse, whilst the underlying sand of the 

 Thanet Beds is fine and not false-bedded. Eastwards, however, 

 the sand of the former gets fine and loses its false- bedding, for 

 which reasons, and from the absence of the pebbly bottom bed, it is 

 almost impossible to divide the two ; indeed no one would think of 

 doing so from an examination of that district alone ; it is only be- 

 cause they are sharply separated on the west that one is forced to 

 try to divide them in the far east. 



The " Corbula-bed " of the coast west of the E^culvers and of 

 the Eichborough section is near the bottom of this division. It is 

 this Corbula-bed which has yielded the fossils (except some teeth of 

 Lamnce) that have been found in the Woolwich Beds in the eastern 

 part of Xent, and nearly aU. of which are sihcified. They are 

 marine, except a specimen of Cyrena cuneiformis, which Mr. Dowker 

 found at "Woodnesborough, near Sandwich. 



2 a is a, bed of flint-pebbles in greenish loam, which overlies the 

 bettom-bed just west of St. Mary's Cray and at Loam Pit HiU, 

 Levrisham. 



2 6 is a mottled clay (green, red, &:c.), sometimes like the plastic 

 clays of the west, as in the railwa^'-cutting at Eltham, and some- 

 times sandy, as on the hills near Cobham. In the latter district I 

 have seen beneath it (in a lane-section) a light -green sand (Section 

 8, PL XXII.), which may belong to 2, bu^ on the other hand, may 

 be the bottom-bed. 



It will be seen that 2, 2 a, and 2 b all occur in the same position ; 

 that is to say, they each fill up the space between the bottom -bed (1) 

 and the estuarine sheU-beds (4) [not taking into account the thin 

 bed (3)] ; and as we cannot be sure that we ever see any two of 

 them together, it is therefore not unlikely that they simply replace 

 one another ; but as I cannot be sure of it, I have thought it better 

 to give each a separate index-mark. 



2 h thickens under London into the mass of mottled plastic clays 

 and sands which have been found beneath the shell-beds in many 

 weUs* (Section 4, PI. XXII.), and further west joins the other like 

 mass which comes on above the shell-beds. 



(3) This bed, though very thin, often indeed no more than three 

 inches thick, is of some importance theoretically, as from its con- 

 stancy it shows the amount of denudation which the Woolwich Beds 

 of East Kent had suffered before the deposition of the Oldhaven 

 Beds. In that part of the county it is a pale purple-grey sand, 

 often hardened into smaU lumps of sandstone, which, as Mr. Prest- 

 wich has noticed, sometimes show traces of the holes of boring 

 mollusksf. In the neighbourhood of Canterbury the Oldhaven 

 Series comes on at once above this bed ; and therefore either none of 

 the higher parts of the Woolwich Series ever existed here, or they 

 have been worn away before the deposition of the Oldhaven Beds ; 



* See Prestwich in Quart. Joum. Geol. Soc. vol. x. pp. 142, 143; 148-150. 

 t Quart. Journ. Geol. Soc. vol. x. p. 110, 



