241 



"'S 



•> 



^p^' 



Fig. 152. Avicidopecten pr'n 

 (from Hall). 



A Uu'ge left valve, much extended posteriorly 



Found in the Encrinal limestone, at Section 5 (rare) ; in 

 the shale down to and in the Trilobite beds, at Sections (3, 7, 

 8, and on the Lake Shore (rare) ; also in the shale below the 

 Trilobite beds, in Averv's Creek. 



AvicuLOPECTEX EXACUTrs. Hall. (Fig. 1,5.3.) (Pal.N.Y., 

 Vol, V,, Pt, I„ p. 8, PI, III.) 



IHstingiushing Characters. — Beak more acute than in the 

 preceding species : proportionally larger wing; concave ])os- 

 terior margin: sharp alternating rays, with broad concave 

 interspaces, extending into the ear and wing. 



Fig. 153. Avicnlopecten exacutus. Right and left valves, from Hamburg. Erie Co., 

 N. Y.: the figure of the left valve does not show the concentric lamellae, and the beak is 

 represented as too acute (from Hall). 



