470 Systematic Paleontology 



Description. — " Subfalcate, with numerous thick obtuse nodes. This 

 is a cast in the sandstone, and the shell was probably covered with spines. 

 Length two inches." Conrad, 1841. 



"Shell obliquely subovate: volutions contiguous, about two or three, 

 very rapidly expanding from the apex; summit of the spire on a plane 

 with, or a little above, the outer volution ; aperture round. Surface marked 

 by round obtuse nodes and strong interrupted or tortuous lamellose stris." 

 Hall, 1859. 



This species in its typical form with well-marked nodes, has been found 

 only in the Oriskany formation at Warren Point. However, several 

 localities furnish specimens with irregular swellings. Such specimens are 

 doubtfully referred to tliis species. 



Diameter of shell G.-") cm.; of aperture 5 cm. 



Occurrence. — Oriskany Formation, Eidgely Member. Cumberland, 

 east side of Nicholas Mountain, Maryland ; Warren Point, Pennsylvania. 



Collection. — Maryland Geological Survey. 



[Ohern.] 



Platycer-^s gebttardi Conrad 



Plate LXXX, Figs. 2-9 



Platyceras gehhardi Conrad, 1840, Ann. Rept. N. Y. Geol. Survey, p. 206. 

 Platyceras gehhardi Hall, 1859, Nat. Hist. N. Y., Pal., vol. ill, p. 312, pi. Ivi, 



figs. 5a, &, 6, 7, 9; pi. Iv, figs. 6a, 6; p. 474, pi. cxvii, figs. 1-10, 1861. 

 Platyceras cf. gebhardi Clarke, 1900, Mem. N. Y. State Mus., No. 3, vol. Hi, 



p. 30, pi. iii, fig. 29. 

 Strophostylus gebhardi Weller, 1903, Geol. Survey N. J., Pal., vol. iii, p. 318, 



pi. xxxix, figs. 1-3. 



Descnption. — " Shell obliquely subovate or subglobose, somewhat 

 gradually expanding, and becoming ventricose in the last volution. Spire 

 composed of about four volutions, which are contiguous except the last one 

 near the aperture, the apex being nearly in the plane of the outer volution : 

 aperture expanded, campanulate, and sometimes with the lip reflexed. 

 Surface marked by fine transverse undulating striae, which are sometimes 

 distinctly bent backwards along a line near the dorso-lateral curvature of 

 the shell, or nearer to the middle of the summit, and rarely slightly 

 carinated along this line. Tn a few specimens, distinct revolving striae 

 are seen cancel lating the transverse striae." Hall, 1859. 



