268 



Cardiola retrostriata. von Buch. (Fig. 190.) {Glyp- 

 tocardia speciosa. Hall: Pal. N. Y., Vol. V., Pt. I., p. 426, 

 Pis. LXX, LXXX.) 



Distinguishing Characters. — Small size, nearly circular out- 

 line: oblique truncation from beak to posterior extremity: 



Fig. 100. Cardiola retrostriata. From the Genesee slate, enlarged to four diameters 

 (from Hall I. 



broad, fiat, rounded plications, with very narrow inter- 

 spaces; arching lamellose concentric stria?. 



Found in the lower gray Naples shales and Goniatite layer, 

 at Sections 1 to 4 (common): also in the Strophalosia bed, 

 on the Lake Shore ( one fragment of a large specimen ). 



Gems CYPRICARDINIA. Hall. 



[Ety. : Resembling the genus Ci/print rfJia.] 

 (1859 : Pal. N. Y., Vol. III., text, p. 266.) 



Shells with unequal valves, the right valve more convex. 

 Outline varying from obovate to trapezoidal, with a short 

 rounded anterior end and a wider obliquely truncate poste- 

 rior end. Sub-anterior incurved beaks; straight or arcuate 

 cardinal line, which arises from the beak ; external ligament ; 

 one long lateral tooth; concentric lamellose undulations and 

 finer stria-, and in some specimens radiating stria 3 , charac- 

 terize this genus. 



Cypricardinia indenta. (Conrad.) (Fig. 191.) (Pal. 

 X. V.. Vol. V.. Pt. I., p. 485, PI. LXXIX.) 



Distinguishing I 'haracters. — Slightly sinuate basal margin ; 

 straight cardinal line; distinct cincture on right valve, less 



