CORALLINE LIMESTONE, 327 



It is difficult to characterize a species when only the mutilated interior of the shell exists, 

 though the form of the muscular impression is in this case almost sufficient to distinguish the 

 species. 



Fig. 4 a. The interior of the ventral valve, with the dental lamins worn off. 



Fig. 4 5. An enlargement from the surface of this specimen. 



Fig. 5 a. The impression of the dorsal valve, with some portions of the shell remaining. 



Position and locality. In the Coralline limestone at Schoharie. 



{Collection of John Gebhahd junior.) 



685. 2. STROPHODONTA TEXTILIS (n. sp.). 



Pl. LXXIV. Fig. 6a-rf. 



Semioval, wider than high ; hinge line slightly extended beyond the width of the shell ; sur- 

 face marked by numerous close flat strife, which are crossed by fine concentric striae, giving the 

 surface a finely textile appearance ; hinge line crenulated. 



The specimen figured is the ventral valve, on which the shell is preserved near the base and 

 partially elsewhere, but broken away along the hinge line. The casts of the muscular im- 

 pression are also preserved. 



Fig. 6 a. The ventral valve described. 



Fig. 6 b. The hinge line enlarged, showing impressions of the crenulations. 



Fig. 6 c. A farther enlargement of a portion of the same, showing the crenulations. 



Fig. 6 d. A. portion of the surface enlarged, showing the fine concentric striae. 



Position and locality. In the Coralline limestone at Schoharie. 



(Collection of JoH^ Gebhard junior.) 



686. 10. SPIRIFER sp. 



PL. LXXIV. Figs. 7, 8a-d. 



These specimens all have the external portion of the shell exfoliated. They are closely allied 

 to S. crispus ; but two of them are of a much larger size than this species usually attains. 

 There are evidences also of four or five costae, which scarcely rise above the surface. In one of 

 them still remain some marks of concentric strife, but not sufficient to decide positively the 

 relations of the species. The specimens are all attached to the rock, and in two of them the 

 outlines are somewhat obscured by it. 



This is evidently closely allied or identical with S. crispus, and not with the species in the 

 tentaculite limestone above, which has sharper plications and more distinct concentric striae, as 

 well as longitudinal strife between them, as in iS. sidcatus of the Niagara group. 



