170 [Senate 



character, not mentioned in the description of that species, are sufficient to 

 entitle this one to rank as a distinct species. 



If we may rely upon the figures and descriptions of the best European 

 authorities, our specimens have as many as eighteen or twenty more plica- 

 tions than S. cuspidaUis. 



Geological 'position and locality. In the fine-grained sandstone of the 

 age of the Chemung group, at the "Knobs," near New- Albany, Indiana. 



Spirifer carteei (n. s.)- 



Pal. N.Y. Vol. iv. 



Shell somewhat semicircular, generally more than half as long as 

 wide; extremities nearly rectangular, in young individuals 

 more salient : dorsal valve convex ; mesial fold smoothly 

 rounded, sometimes marked by a faint longitudinal depression 

 along the middle ; beak and area incurved : ventral valve the 

 more convex, most prominent a little below the beak ; mesial 

 sinus rather deep, rounded, and extending quite to the apex of 

 the beak ; area high, arcuate, longitudinally and transversely 

 striated ; foramen large, triangular ; beak obtusely angular and 

 arched : lateral slopes of the valves marked by about nineteen 

 or twenty simple rounded somewhat depressed plications on 

 each side of the mesial fold and sinus ; plications crossed by 

 concentric lines of growth. 



This species is known to me only in casts, and as impressions of the 

 exterior shell. Some of the specimens show, under a magnifier, in addition 

 to the surface markings mentioned above, faint traces of a peculiar orna- 

 mentation resembling very nearly in character that of the S. textus. 



This fossil differs from that just named, in having comparatively a 

 much smaller, less elevated, and more arcuate area : the beak is more 

 arched, and the lateral slopes of the area less angular. The impression left 

 in the matrix indicates it to have been a thinner shell than S. textus. 



Geological position and locality. In the Waverly sandstone of the age 

 of the Chemung group : Licking county, Ohio. 



