and Fossil Remains near London, S41 



Does it not seem that the first appearance, or creation, of land-anhnals 

 was on the dry land of this stratum, and that they were overwhelmed 

 in these spots, by that sea which deposited the present superincum- 

 bent strata of gravel \ 



STRATA INTERPOSED BETWEEN THE CLAY AND THE CHALIC 



It is almost impossible to speak with precision of the subjacent 

 strata, which are situated between the clay and the chalk, since very 

 considerable variations occur as to their thickness, and indeed as to 

 the form in which their constituent parts are disposed ; and since 

 there exist but few sections, at least in the neighbourhood of the 

 metropolis, which present a view of the strata composing this for-^ 

 mation. They are included in the following account by Mr. Farey : 

 " A sand stratum, of very variable thickness, next succeeds, and lays 

 " immediately upon the chalk, in most instances, as between Green- 

 " wich and Woolwich, on the banks of the Thames ; which has 

 " often been called the Blackheath sand : it frequently has a bed of 

 " cherty sandstone in it, called the grey-weathers."* 



Gn the upper, part of a mound at New Charlton some traces 

 of the lowest part of the blue clay appear, covered by not more 

 than a foot of vegetable earth. This layer of clay does not seem 

 to exceed two feet in thickness, which, indeed, it possesses only on 

 the top of some of those mounds, which occur so frequently as to 

 render the surface in this district very irregular. In this clay, oysters 

 of different forms are found : some approaching to the recent species, 

 and others longer and somewhat vaulted ; but they are in general 

 so tender as to render it very difficult to obtain a tolerable specimen. 

 With these also occur numerous Cerithla^ Turritella and Cytherea^, 

 Lam. all of which are in a similar state with the oysters, and appear. 



• Report on DerbyshirCj &c. vol, I. p. 111. 



