PALAEONTOLOGY OF NEW-YORK. 
Rhynchonella multistilata. 
Plate CII. Fig. 3 ; and Plate CYI. Fig. 3. 
Rhynchonella multistriata : Hall, Regents’Report for 1856, p.85; Palaeozoic Fossils, 1857, p.45. 
Shell depressed suborbicular. Yentral valve depressed convex, most ele¬ 
vated in the urnbonial region, flattened towards the lateral margins 
and depressed in front, forming a broad shallow undefined sinus. 
Dorsal valve unknown. 
Surface marked by numerous fine regular bifurcating striae, which are 
well defined nearly to the apex of the beak. 
This species is more finely striated than the preceding, and is more nearly circular 
in form, the length and breadth being about equal; while in the casts of that one, 
the width is greater than the length. 
Plate cii, fig. 3. View of the dorsal talve. 
Plate cvi, fig. 3. An imperfect dorsal valve of a younger specimen. 
Geological position and locality. In the Oriskany sandstone : Helderberg moun¬ 
tains. 
Rhynchonella pleiopleura. 
Plate CII. Fig. 3«-c & 4a- c. 
Atrypa pleiopleura : Conrad, Annual Report on the Paleontology of New-York, p.55. 
Rhynchonella pleiopleura : Hall, Regents’ Report for 1856, p.86; Paleozoic Fossils, 1857, p. 46. 
Shell transversely oval. Dorsal valve the larger, somewhat gibbous, 
having a round undefined mesial fold : beak incurved; cardinal border 
excavated in deep fossets on each side of the beak, for the reception 
of the dental lamellae of the opposite valve. Yentral valve nearly flat, 
most elevated near the beak, having a somewhat deep broad rounded 
sinus near the front margin, which is prolonged into a rounded or 
subtriangular projection. 
Surface ornamented b} r from sixty-four to seventy subangular bifurcating 
striae or plications. 
