A CONTKIBUTIOX TO THE LoWER DeVOXIAN FaUXAS OF MARYLAND 29 



Occurrence. — Oriskaxy Formation, Eidgely Member. Devil's Back- 

 bone, Hancock, Kuobly Mountain near Cumberland. 



Collections. — Maryland Geological Survey, Maryland Academy of 

 Sciences. 



Genus PLATYCERAS Conrad 



Platyceras nodosum Conrad 



Plate LXXIX, Figs. 13, 14 



Platyceras nodosum Conrad, 1841, Ann. Rept. Pal. N. Y., p. 56. 



Platyceras nodosum Hall, 1859, Nat. Hist. N. Y., Pal., vol. ill, p. 473, pi. cxv, 



figs. 1-6; pi. cxvi, figs. 1-4, 1861. 

 Platyceras nodosum Clarke, 1900, Mem. N. Y. State Mus., No. 3, vol. in, p. 31. 



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 lamel- 

 lose strise." Hall, 1859. 



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

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

 localities furnish specimens with irregular swellings. Such specimens are 

 doubtfully referred to this species. 



Diameter of shell 6.5 cm.; of aperture 5 cm. 



Occurrence. — Oriskany Formation, Eidgely Member. Cumberland, 

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



Collection. — Maryland Geological Survey. 



Platyceras gebhardi Conrad 



Plate LXXX, Figs. 2-9 



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

 Platyceras gebfiardi Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 312, pi. Ivi, 



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

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



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

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



pi. xxxix, figs. 1-3. 



