404 CRETACEOUS LAMELLIBRANCHIA. 



rounded forms (like Sowerby's sinuata) are older individuals of the same type, and 

 sometimes attain a height of 8 or 9 inches. 



A small, oval, very inequilateral form, with a rounded carina, was named Exogyra 

 laevigata by Sowerby (1829), and was stated to have come from the Irish Green- 

 sand. An examination of the type shows clearly that it was not obtained from 

 that deposit, but from the Hythe Beds ; the form of the shell and the character of 

 the matrix agree perfectly with other examples which have been found in the 

 Hythe Beds (figs. 208, 209). 



The examples from the Lower Greensand of Upware, which were referred by 

 W. Keeping to Exogyra Coition!, probably belong to this species, but the specimens 

 seem to me too few and not sufficiently perfect to enable the identification to be 

 made with certainty. 



In England Sowerby's name (sinuata) has been generally used for this species, 

 but Defrance's name (Gouloni) has been adopted by foreign writers; the former is 

 used here since, although Defrance's name has priority, the description was 

 scarcely sufficient for identification and was not accompanied by either a figure 

 or a reference to a figure. 



Types. — Gryphma Gouloni, Defrance, from the neighbourhood of Neuchatel. 

 G. sinuata, Sowerby, from the Hythe Beds of Ashford, and E. laevigata from the 

 Hythe Beds, in the British Museum. G. aquila, Brongniart, from the Upper Aptian 

 of the Perte du Rhone. Q. sinuata, Phillips, from the Speeton Clay, in the York 

 Museum. Exogyra subsinuata, Leymerie, from the Neocomian of the Aube. 



Distribution. — Atherfield Beds of Atherfield, Compton Bay and Sevenoaks. 

 Ferruginous Sands of Atherfield and Shanklin. Hythe Beds of Hythe, Lympne 

 and Maidstone. Folkestone Beds of Folkestone. Ma mm ill at us bed of Okeford 

 Fitzpaine (Dorset). Speeton Clay (zones of Belemnites lateralis, B. jaculum and B. 

 brunsvicensis) of Speeton. Claxby Ironstone (zone of B. lateralis) of Donnington. 

 Tealby Limestone (zone of B. brunsvicensis) of Claxby. 



Exogyra tuberculifera, Koch and Bunker, 1837. Plate LXI, figs. 7 — 11. 



1835. Exogyra spiralis, F. A. Riimer. Verstein. nord-deutsch. Oolith.-geb. p. 65 



(partim), (lion E. spiralis, Goldfuss). 

 1837. tuberculifeka, F. C. L. Koch ami W. Bunker. Nord-deutsch 



Oolith.-geb., p. 54, pi. vi, fig. 8. 

 ? 1839. subplicata, F. A. Romer. Verstein. uord-deutsch. Oolith.-geb., 



Nachtrag., p. 25, pi. xviii, fig. 17. 



1841. Romer. Die Verstein. d. nord-deutsch. Kreidegeb., 



p. 47. 

 tuberculifera, Ri'iiner. Ibid., p. 48. 



1842. subpi.icata, A. leymerie. Mem. Soc. geol. de Prance, ser. 2, 



vol. v, p. 18, pi. xi. figs. 4 — 6. 



