No. 109,] 



EhYNCHONELLA FITCHAifA. 



PaL N.Y, Vol, iii, pi. 103, f. 1, 



Shell longitudinally oval or ovate : dorsal valve convex ; beak 

 slightly incurved ; cardinal margin excavated on each side of 

 the beak for the reception of the broad dental laminse of the 

 other valve : ventral valve depressed-'convex, most elevated in 

 the umbonial region, flattened towards the lateral margins and 

 depressed in front, forming a faint broad and undefined sinus. 

 Surface ornamented by about seventy-five angular plications, 

 which, occasionally bifurcate. 



This species differs from the last, wbicii it nearly approaxjhes in general 

 form, in being more distinctly sinuate, and in having sharper and less nu- 

 merous plications, while the beak is more pointed and less incurved. 



Geological position and locality. Oriskany sandstone, Carlisle { N.Y.). 



EhYNCHONELLA MULTISTRIATA. 



Pal. N.Y. Vol. iii, pL 102, f. 5 ( 3 on plate); and pi. 106, f. 3. 



Shell subcircular, transversely suboval-depressed : ventral valve 

 depressed-convex, most elevated in the umbonial region, flat- 

 tened, towards the lateral margins and slightly depressed in 

 tront, forming a broad, very shallow, undefined sinus ; dorsal 

 valve unknown. Surface marked by numerous fine regular bi- 

 furcating strise, which are well defined nearly to the apex of 

 the beak. 



This species may be distinguished from the foregoing by its transversely 

 oval form, and more numerous as well as much finer strias or plications. 



Geological position and locality. Oriskany sandstone, Helderberg 

 mountains. 



