ORISKANY FAUNA OF BECRAFT MOUNTAIN 53 



finely radiate surface. Indeed the exterior appears at first view to be 

 almost smooth and shows numerous concentric growth-lines, but fine 

 striae are invariably present, so fine and numerous as to produce a 

 striated effect without a very clear definition of individual lines. The 

 aspect of the species is sufficiently peculiar to distinguish it readily 

 from other forms. 



Stropheodonta lincklaeni was described from the Oriskany 

 sandstone of Albany and Schoharie counties. The species is not com- 

 mon at Becraft mountain. 



Leptostrophia magnifica Hall 



Plate 7, fig. 36 



1859. Slrophodonta magnifica Hall, Paleontology of New York. 3 : 414, 

 pi. 93, fig. 4; 94, fig. 2a--d ; 95, fig. 8 



1892. Leptostrophia magnifica Clarke, op. cit. p. 413 



A few specimens which apparently represent this Oriskany species 

 have been observed, though none of these attain the normal propor- 

 tions ; yet they are large, perplane shells, surpassing the dimensions 

 of Lept. becki and conforming in external and internal features 

 with Lept. magnifica, to which they are provisionally referred. 



Leptostrophia oriskania, sp. nov. 



Plate 7, flg. 29-35 



1892. Leptostrophia cf. ~becki, and L. perplana Clarke, op. cit. p. 413 

 The most abundant fossil in these rocks is a species of Lepto- 

 strophia of uniformly small size and somewhat variable in the 

 aspect of the exterior. In the work above cited I was disposed to 

 regard some specimens of this, in which the concentric corrugations of 

 the surface are most pronounced, as representing the Helderbergian 

 species Lept. becki, though their uniformly smaller size was 

 recognized ; others, having the surface almost or wholly devoid of cor- 

 rugations, were referred to the middle Devonic species L . perplana 

 Conrad. On a review of the material it has become evident that all 

 have features common to both of those inentioned and represent but 

 a single species. It might be looked on as a small variety of Lept. 



