PTERTA. 03 



Bemarlcx. — In England this species has, up to the present time, been definitely 

 recognised in the Adlnocamux, qnadratus zone only. 



The specimen figured by Romer is relatively higher than most of tlie EiigHsh 

 examples, but in other characters tliere is close agreement. 



Pferia scminuda (Dames) ' resembles Pteria tennicostatd, l)ut appears to differ 

 in the ribs on the left valve being of more nearly uniform size, and in tlie presence 

 of distinct ornamentation on the right valve. 



Type. — The type is stated by Romer to have come from the Lower Chalk of 

 Lindner Berg, near Hanover, but according to Dr. J. Bohm the horizon is really 

 the quadratns Chalk. 



Distribution. — Zone of Jdinocamax quadrntn.-i of West Harnham, near Salisbury, 

 and Sewerby (Yorkshire). Upper Chalk (? A. quadratics zone) of Coddenham 

 (Suffolk), Wells (Norfolk), and Ruston Parva (Yorkshire). 



Sub-ijcints — PsEUDOPTER.\, F. B. Meel; 1873. 



(' 6tli Ann. Eep. U.S. Geol. Survey of the Territories,' p. 489; Meek, ' Invert. Cret. and Tert. Poss. 

 U. Missouri ' (Eep. U.S. Geol. Survey, vol. ix, 1876), p. 29.) 



PtEBIA (PSEUD0PTER.\.) SUBDEPRESSA {d'Orhijilij), 1350. Plate IX, fig. hi, b. 



1845. AvicuLA DEPEESSA, E. Forbes. Quart. Journ. Geol. Soo., vol. i, p. 247, pi. iii, 



fig. 7 (uou A. depressa, Miinster, 1841). 

 1850. — SUBDEPBESSA, A. (VOrhujny. Prodr. de Pal., vol. ii, p. 119. 



1854. — DEPRESSA, /. Morris. Cat. Brit. Foss., ed. 2, p. 163. 



1855. — suBDEPEESSA, G. Cotteau. MoU. Foss. de I'Yonne, p. 104. 



1869. — — F.J. Pidet and G. Campiche. Foss. Terr. Crct. Ste. 



Croix (Mati'r. Pal. Suisse, ser. 5), 

 p. 70. 

 1871. — — F. Stoliczka. Palseont. ludica, Cret. Fauna S. ludia, 



vol. iii, p. 398. 

 Remarks. — This species is very imperfectly known at present. It resembles 

 P. Jialdonensis from the L^pper Greensand of Haldon (see below) but is easily dis- 

 tinguished by the strong concentric ridges ; it also appears to be relatively louger 

 and less convex. 



Type. — In the Museum of the Geological Society (No. 2050). 

 Distnbutiou. — Lower Greensand (Crackers) of Atherfield. Recorded by Topley 

 from the Atherfield Clay of Peasmarsh and Shalford. 



' • Zeitschr. d. deutseh. geol. Gesellseh.,' vol. xxvi (1874), p. 765, pi. xxi, fig. 3 ; Notling, ' Die Fauua 

 d. baltisch. Ccuomau.' (Palseout. Abliaudl., vol. ii, 1885), p. 21, pi. iii, figs. 7, 8. 



