No. 109.] 55 



longations of the hinge crenulatioiis ; foramen very narrow, not 

 closed. Surface marked by somewhat faint radiating strise, which 

 bifurcate regularly about two or three times at uniform distances 

 from the beak. 



This species is remarkable for the large size to which it sometimes at- 

 tains ; a few individuals having been found measuring from 3^ to 4 inches 

 in breadth, and from 3 to 3g inches in length : being perhaps the largest 

 brachiopod known in the rocks of this State. 



Geological position and locality. In the Oriskany sandstone, Albany 

 and Schoharie counties. 



StROPHOMENA ( StROPHODONTA) LINCKLiENI ( n. S.). 



Pal. N.Y. Vol.iii, pi. 93, f.2&3; pi. 94, f.2. 



Shell subsemicircular, more than three-fourths as long as broad ; 

 lateral margins usually contracted near the extremities of the 

 hinge-line : ventral valve convex in the central region and 

 towards the front, somewhat flattened laterally : dorsal valve 

 concave, deflected round the front and sides ; hinge-line crenu- 

 lated, nearly or quite equal to the greatest width of the shell. 

 Surface marked by fine, closely arranged radiating striae, crossed 

 by obscure concentric lines of growth : interior granulose, and 

 more or less striate ; visceral impre'ssions strongly marked. 



Both internal and external casts of the dorsal valve of this species are 

 quite abundant ; but no specimens of the ventral valve have yet been re- 

 cognized. Consequently its form and character can only be inferred from 

 those of the opposite valve. 



Geological position and locality. Oriskany sandstone, Albany and 

 Schoharie counties. 



Strophomena depressa, var. ventricosa. 



Pal. N.Y. Vol.iii, pi. 94, f.3. 



Shell transversely oblong, subsemicircular ; length and breadth 

 sometimes nearly equal ; front often straight in the middle, and 

 parallel to the hinge-line : ventral valve extremely ventricose, 



