1862.] WHITAKER LONDON BASIN. 267 



So that the Thanet Sand is absent, as is also the case further 

 northward. 



At Castlebear Hill, near" Ealing, and at the Hanwell Lunatic 

 Asylum, the Woolwich and Reading Beds were found directly above 

 the Chalk * ; and the Thanet Sand does not occur anywhere further 

 to the west. 



The Woolwich and Reading Beds seem to have their greatest thick- 

 ness near London, but do not vary much in this respect eastward of 

 Hungerford (not taking into account any northerly thinning). 



With regard to the beds S.E. and E. of London, I do not agree 

 with Mr. Prestwich in classing the thick pebble-bed of Blackheath 

 &c., with the basement-bed of the London Clay : I take it rather to 

 be the top part of the Woolwich and Reading Beds. In the neigh- 

 bourhood in question the former really consists of a clayey pebble- 

 bed, from a few inches to rather more than three feet in thickness. 

 It may be seen at Loam-pit Hill (Lewisham), in the cutting on the 

 London and Brighton Railway south of the New Cross Station, in 

 that (on the Croydon and Epsom Railway) S.W. of West Croydon 

 Station, in that (on the Mid-Kent Railway) east of Beckenham, and 

 in a brickyard about half-way between the Bromley and Bickley 

 Stations. At the eastern end of the long cutting at Bickley, I saw 

 it (in November 1860) overlaiu by London Clay, and overlying a 

 sandy pebble-bed, like that of Blackheath, which is here the top bed 

 of the Woolwich and Reading Series. In the clayey *' basement-bed " 

 the pebbles were, as usual, without any orderly arrangement ; whilst 

 those of the underlying bed were arranged in lines of false bedding 

 (with a westerly dip of 10° to 20°) through the whole length of the 

 section (about 400 yards). The sides of this cutting have since been 

 covered up. 



I am also inclined to think that in a more eastern part of Kent 

 Mr. Prestwich has again been too generous to the basement-bed of 

 the London Clay. In the neighbourhood of Heme Bay he includes 

 in it a bed of sand underlying the true London Clay, but which, for 

 my part, I would rather class with the Woolwich and Reading Beds. 

 At the southern end of the large cutting on the Sheerness Branch 

 Railway, about a mile and a quarter north of Sittingbourne, I saw, 

 in December 1860, the following section (quite clear, and of some 

 length) : — 



London Clay, partly of a greenish colour ; no pebbles at the base, 

 and nothing like the usual basement-bed to be seen. 



Light- coloured sand ; at the base a bed of shells, in a bad state of 

 preservation about 6 feet. 



Brown clayey sand, with obscure casts of shells {Cyrena cuneiformis? 

 and C. cordata ?) and a few flint-pebbles about 1 foot. 



White and light-coloured sand, with beds of shells, very perfect, but 

 very easily broken (Cyrena cuneiformis, C. cordata, Ostrea, Me- 

 lania inquinata, Cerithium), of which there was to be seen 



about 8 feet. 

 * Quart. Joum. Greol. Soc. vol. x. p. 94. 



