74 CRETACEOUS LAMELLIBRANCHIA. 



Bern arks. — From Agassiz' fig-ures alone it would be difl&cult to feel sure of the 

 identity of the English form, described by Seeley as T. hunstantonensis, with 

 T. scapha, Agassiz; but the figures of Pictet and Campiche give a much better 

 idea of the characters of the species. Seeley's figure is more accurate than 

 Lycett's, but the arrangement of the tubercles is not satisfactorily shown. 



Tijpes. — The ty})e of T. scaplui is from the Neocomian near Neuchatel. The 

 type of T. Ituiistantoneusis is in the Woodwardian Museum; it was at first stated to 

 come from the lied Chalk, but the matrix differs entirely from the Red Chalk, 

 and the specimen in all probability is from the Snettisham Ironstone nodules ^ 

 (Lower Greensand), A¥est Norfolk. 



Distribution. — Snettisham Ironstone of Sandringham Warren and Wolferton 

 Station. Snettisham Clay of Heacham and Snettisham. The recoi'ds of this 

 species from the Red Chalk of Hunstanton are probably erroneous. 



Trigonia exaltata, Lycett, 1877. 



1877. Lycett, p. 184, pi. sxxviii, fig. 2. 



Type. — In the British Museum. 



Distribution . — Lower Greensand of West Norfolk. 



TitiGuNiA RoiiiNALDiNA ? iVOrlnynij, 1844. 



1844. Trigonia Robinaldina, A. d'Orbigny. Pal. Franc. Terr. Crct., vol. iii, 



p. 139, pi. ccxcix, figs. 1, 2. 

 185U. — — — Prodr. de Pal , vol. ii, p. 78. 



1866. — — F. J. Pictet and G. Camjnche. Foss. Terr. Cret. 



Ste. Croix (Mater. Pa). Suisse, ser. 4), p. 385. 



An internal cast from the Teal by Limestone (zone of Bel. bnmsvicensis) of 

 Claxby, now in the Woodwardian Museum, probably belongs to this species. 



1 See Lamplugh, iu Whitaker a.ud Jukes-Browne, " Geol. Borders of the Wash" ('Mem. Geol. 

 Survey,' 1899), p. 16, etc. 



