328 



PALiEONTOLOGY OF NEW-YOEK. 



Fig. 7. The dorsal valve of a specimen, showing evidences of five plications on each side of the 



mesial sinus. 

 Fig. S «, b, c. A very convex dorsal valve, where the evidences of plications are more obscure, 



though the surface still preserves marks of concentric strias. 

 Fig. 8 d. A smaller specimen having the angle partially covered by the stone. 



Position and locality. In the Coralline limestone at Schoharie. 



(^Collection of JonN Gebhard junior.) 



623. 6. SPIRIFER CRISPUS. 



PL. LXXIV. Fig.da-h. 

 Beference page 262, pi. 54, fig. 4. 

 After examining numerous specimens of this shell, I am unable to find any distinctive features 

 by which to separate it from the Niagara specimens. In those represented, the outer surface is 

 more or less exfoliated, and the plications are but faintly visible. This character, in specimens 

 from the Niagara shale, is very variable ; some of the specimens showing distinct plications, 

 while others are almost entirely smooth. In one specimen from the Coralline limestone, a 

 broken and depressed portion of the shell shows concentric striae undistinguishable from those 

 of the Niagara shale. Even the exfoliated specimens preserve evidences of these concentric 

 strice, and are quite undistmguishable from similarly exfoliated specimens from the Niagara 

 group. From all these circumstances, I can have no hesitation in referring the specimens from 

 the Niagara and the Coralline limestone to the same species. 



Fig. 9 a-k. Different views of several specimens of this shell, showing very clearly its identity 

 in form with those figured on PL 54, the latter having the plications more strongly 

 developed. 



Position and locality. In the Coralline limestone at Schoharie. 



{Collection of John Gebhard junior.) 



687. 58. ATRYPA NUCLEOLATA {n. sp.). 



Pl. LXXIV. Pig. 10 o- m. 

 Compare ^trypa nitida, page 268, plate 25, fig. 1, of this volume. 

 Shell round oval or oval ovoid ; beak of the dorsal valve often much extended, and incurved 

 over the ventral valve; surface concentrically striated; front of the shell indented, the in- 

 dentation connected with a depression or groove down the centre of the dorsal valve, and 

 sometimes a similar one on the lower half of the ventral valve. 



This species approaches very closely the Jl. nitida of the Niagara group, but is less elon- 

 gated, and the indentation in front and the groove down the centre of the dorsal valve are 

 more conspicuous in the species from the Coralline limestone. There are sometimes, however, 



