1866.] WHITAKER — lOWEE LONDON TEETIAEIES. 411 



and it is remarkable that this denudation is quite even, the thin bed 

 of purple sand or sandstone nearly always occurring at the junction. 

 In West Kent, on the other hand, tite denudation has been uneven, 

 and the Oldhaven Beds rest on various parts of the underlying 

 series. 



I have not seen this bed for some way westward from Shottenden 

 and Boughton-under-Blean, and near Sittingbourne the junction of 

 the Oldhaven and the Woolwich Beds is more irregular. At Upnor, 

 however, there is some sand, whitish at top and purplish below, 

 dividing the shell-beds (4) from the sands (2) ; and this, I have no 

 doubt, is the same as the like bed at the top of 2, near Canterbury. 

 It occurs also near Cobham (Section 8, PI. XXII.), and is very likely 

 represented near Woolwich by the " layer of hard concretionary 

 limestone" which sometimes underlies the shell-bed*, and by the 

 clay with calcareous concretions in the same position at Loam Pit 

 HiU, Lewisham. 



(4) The most easterly place at which the well-known Woolwich 

 clay with Cyrence, Melcmice, and other cstuarine shells has been seen 

 is Sittingbourne, where, however, there is no clear section of it. 

 These clays, which are of a dark colour, laminated, with the shells 

 in the lines of bedding, mostly stiff, but sometimes sandy, thicken 

 westward and are well shown at the great Upnor section, where 

 they are about 6 feet thick, and partly without shells. Hence to 

 London they are generally rather thicker, but near Abbey Wood are 

 sometimes cut off altogether by the Oldhaven beds (see section 7, 

 PL XXII.) They reach their greatest thickness just south of Chisel- 

 hurst, where more than 20 feet of them was shown in the cutting 

 on the London, Chatham, and Dover Railway. West of London this 

 bed soon thins out again. In the neighbourhood of Woolwich the 

 sand below sometimes contains like shells, and may be a distinct bed, 

 coming in between those numbered 2 and the clay shell-bed; 

 though, on the other hand, it may be simply 2 in another condi- 

 tion. Perhaps, too, there is sometimes another and higher set of clay 

 shell-beds, divided from 4 by sand or clay t ; but this is a matter 

 of detail, here of no importance, and in the list of fossils any upper 

 set of shell-beds is included under No. 4. 



(5) At Sittingbourne there is, next below the Oldhaven Beds, a 

 light- coloured sand with Cyrence, Melanice, Ostrece, &c., which must 

 thin out eastward, as it occurs nowhere in the Canterbury district ; 

 whilst westward it is thicker, as may be seen at Upnor. Further 

 west, however, it has suffered more from denudation, and is some- 

 times quite cut off by the pebble-beds of the Oldhaven Series. 



In the neighbourhood of Lewisham the top part of the Woolwich 

 Beds consists of mary feet of alternations of sand and clay, the 



* Prestwich, Quart. Journ. Geol. Soc. vol. x. p. 103. 



t At the cliff-section on the Prench coast westward of Dieppe there are two 

 masses of the clay shell-heds, separated by clay ; and the cliff at Newhaven, in 

 Sussex, shows a great thickness of the same divided into two by unfossiliferous 

 sand and clay. 



