ISOCARDIA. 



151 



Remarks. — This species occurs in the Chalk Rock, but is not common. All the 

 specimens seen are casts, but one shows a fragment of shell. 



Type. — The type is stated by Romer to have come from the Pliiner-kalk of 

 Strehlen (Dresden), but Geinitz says that he has never found the species at that 

 locality. 



Distribution. — Chalk Rock of Dover, Cuckhamsley, Aston Rownnt, Princes 

 Risborough, Thickthorn Hill (Bledlow), and Luton railway cutting. 



Family— ISOCARDIIDiE, Gray. 



Genus — Isocardia, Lamarck, 1799. 

 ('Mem. Soc. Hist. Nat. Paris,' p. 86.) 



Isocardia similis, Sowerl>y, 182G. Text-fig. 25. 



182G. Isocardia similis, J. de C. Sowerby. Min. Conch., vol. vi, p. 27, pi. dxvi, 



fig. 1. 



— A. d'Orbigny. Prodr. de Pal., vol. ii, p. 163. 

 J. Morris. Cat, Brit. Foss., ed. 2, p. 204. 



— F. J. Pictet and G. Campiche. Foss. Terr. Cret. Ste. 



Croix (Mater. Pal. Suisse, ser. 4), 

 p. 240. 



— F. StoliczJca. Palseont. Indica, Cret. Fauna S. India, 

 vol. iii, pp. 188, 194. 



1850. 

 1854. 

 1865. 



1870. 





~\ 



Pui. 25. — Isocardia similis, Sowerby. Lower Oreensand, near Santlgate. Right valve, and anterior view. 

 British Museum (Nat. Hist.). The Type. Natural sizr. 



