Ch. XVI.] 



SHELLS OF THE BARTON CLAY. 



287 



Fig. 226. 



rest on white sands, used for making glass, and constituting the up- 

 per member of the Barton series, A. 4, p. 281, next to be mentioned. 

 Wliite sands and Barton clay, A. 4 (Table, p. 281). — In one of the 

 upper sandy beds of this formation, Dr. Wright found Chama 

 squamosa in great plenty. The same sands contain impressions of 

 many marine shells (especially in Whitecliff Bay) common to the up- 

 per Bagshot sands afterwards to be described. The underlying Bar- 

 ton clay has yielded about 252 marine shells, more 

 than half of them, according to Mr. Prestwich, pecu- 

 liar ; and only about one in twenty being common to 

 the London clay proper, a much older Eocene group 

 (see p. 291), with which the Barton clay was formerly 

 confounded. About one-third of the Barton clay 

 shells agree specifically with those of the calcaire 

 grossier of the Paris basin. * It is nearly a century 

 since Brander published, in 1766, an account of the Chama squamosa. 

 organic remains collected from these Barton and Hord- 

 well Cliffs, and his excellent figures of the shells then deposited in the 

 British Museum are justly admired by conchologists for their accuracy. 



SHELLS OF THE BARTON CLAY, HANTS. 



Certain foraminifera called Nummulities begin, when we study the 

 tertiary formations in a descending order, to mako their first appear- 



ing. 227. 



Fig. 22S. 



Fig. 229. 



Fig. 230. 



Mitra scabra. Yoluta ambigua. Typhis pungens. 



Voluta athJeta. Barton 

 and Bracklesham. 



Fia 231. 



Fig. 232. 



*i. 



Fig. 234. 



Terebellum fusi- Terebellum so- Cardita sulcata, 

 forme. Barton pita, Brandner, 

 and Brackles- Lam. 



nam. Seraphs convo- 



lution, Monti 



Crassatella sulcata* 



* Quart. Geol. Journ., vol. xiii. p. 134. London 1857. 



