STRATA IN THB NEIGHBOURHOOD OF LONDON. H^ 



he has found, in a s^^iliceous state, specimens of stromhus 

 pes pelicani, and a species of cucuUcea, nearly resembling 

 tiiose which are met with in the Black-down whetstone pits. 

 ' Patches of plastic clay are frequently found over the and frequently 

 chalk : some of these are yellow, and employed for the com- ['fr's day, of°*' 

 mon sorts of pottery ; but Others are white, or grayish white, different 

 and are used for finer purposes. The toarser clay is very 

 frequently met with, nor are the finer kinds of very rare 

 •ccurrence. In the Isle of Wight two species of plastic 

 white clay are worked for the purpose of making tobacco- 

 pipes. A similar clay, which is used for making gallipots, 

 is dog from the banks of the Medway. A fine light ash- 

 coloured, nearly white clay, which is employed in pottery- 

 vrorks, is also dug at Cheam near Epsom in Surry. 



The upper ovjlinty chalk, which is the next older stratnm, Upperor flinty 

 is extremely thick, forming stupendous cliffs upwards of thick stratum, 

 six hundred and fifty feet high, on the south-eastern coasts 

 of the island. It extends nearly through almost all that part 

 of the island, which lies south of a line supposed to be drawn 

 from Dorchester in the County of Dorset to Flamborough- 

 head in Yorkshire. 



In this stratum there is a great quantity of ftin^:, chiefly The flinfm 

 in irregularly formed nodules, disposed in layers, which pre- ^^^^^^^^ layers. 

 serve a parallelism with each other and with continuous seams 

 of flint, sometimes not exceeding half an inch in thickness. 

 The chalk contains a fine sand, which may be separated^by 

 washing*. 



The fossils of this stratum are for the most part peculiar Fossils of this 



to it ; very few of them being found in any other. They also stratum chiefly 

 ' J r » ./.i-i peculiar to it. 



appear to agree very closely with those species found in the Closely allied 



chalk of France, by Messrs. De France, Cuvier, and Brong- ^ "*^°^^ ^^ 



niart. The number of fossils noticed by these gentlemen 



amounts to fifty ; but they have yet only particularised a part 



of them. These are here compared with what appear to be 



the correspondent fossils in the English part of this btratum ; 



and some others are also painted out, which these gentlemen 



have not yet mentioned as being found in the neighbour* 



hood of Paris. 



* The chalk In the neighbourhood of Paris contains, according to Nfr. 

 Bouillon La Grange, magnesia 0*11, and Sil^x 0*19^ 



I 2 I« 



