Ch. XVI.] 



FOSSIL SHELLS OF THE LOXDON CLAY. 



293 



and other mountain-chains now forming the backbones of great con- 

 tinents, were raised from the deep ; nay, even before a part of the con- 

 stituent rock masses now entering into the central ridges of these 

 chains had been deposited in the sea. 



The marine shells of the London clay confirm the inference deriva- 

 ble from the plants and reptiles in favor of a high temperature. Thus 

 many species of Conus and Voluta occur, a large Cyprcea, C. ovifor- 

 mis, a very large Rostellaria (fig. 252), a species of Cancellaria, six 

 species of Nautilus (fig. 254), besides other Cephalopoda of extinct 

 genera, one of the most remarkable of which is the Belosepia * (fig. 

 255). Among many characteristic bivalve shells are Leda amyg- 

 daloides (fig. 256) and Cryptodon angulatum (fig. 257), and among 

 the Radiata a star-fish called Astropecten (fig. 258). 



Fig. 250. 



FOSSIL SHELLS OF THE LONDON CLAY. 

 Fig. 251. Fig. 252. 



Voluta nodosa. Sow. Phorus extensus, 

 Highgate. Sow. Highgate. 



Fig. 253. 



NauUlus centralis, Sow. Highgate. 

 Fig. 254. 



Rostellaria ampla, Brander. £ of nat size ; 

 also found in the Barton clay. 



Fig. 255. 



Aturia zicsac, Brown and Edwards. 

 Syn. Nautilus ziczac, Sow. 

 London clay. Sheppey. 



Belosepia sepioidea. De Blainv. 

 London Clay. Sheppey. 



* For description of Eocene Cephalopoda, see Monograph by F. E. Edwards, 

 Palaeontograph. Soc, 1849. 



