478 Systematic Paleontology 



A poorly preserved specimen from the Oriskaiiy is, with grave doubt, 

 referred to this species. The general form of the shell agrees, in a 

 measure, with published descriptions and figures of this species. However, 

 the plications are not observable except faintly on the interior side of the 

 body whorl. The shell has been silicified and portions have again been 

 dissolved away and the apex is broken off, rendering exact determination 

 impossible. 



Occurrence. — ^Oriskany Fokmatiox, Eidgely Member. Knobly 

 Mountain, West Virginia. 



Collection. — Maryland Geological Survey. 



[Ohem.] 

 Platycer.\s sriRALE Hall 

 Plate LXXXV, Figs. 8, 9 



Platyceras spirale Hall, 185&, Nat. Hist. N. Y., Pal., vol. iii, p. 331, pi. Ixiii, 



figs. 4-9, 1861. 

 Platyceras spirale Meek and Worthen, 1868, Geol. Survey 111., vol. iii, p. 389, 



pi. vii, figs. 12a, &, c. 



Description. — "Shell spirally ascending: apex consisting of a single 

 minute close volution, below M'hich are one or two widely separated and 

 gradually enlarging volutions : aperture spreading, rounded or broad oval ; 

 peristome sinuate. Apex and upper part of the shell smooth, or with only 

 fine transverse striae, more or less distinctly plicated on one side below with 

 strong lamellose undulating striae." Hall, 1859. 



Length 2.25 cm. ; diameter of aperture 1.8 cm. 



Occurrence. — Helderberg Formatiox, Xew Scotland Member. 

 Corriganville. 



Collection. — U. S. National Museum. 



[Ohem.] 

 Platyceras gracile n. sp. 

 Plate LXXXV, Figs. 10-13 



Description. — Shell spirally and obliquely ascending; whorls one or 

 one and one-half; shell gracefully and spirally tapering regularly to an 

 acute apex, the summit of which lies about in the plane of the right side 

 of the aperture ; surface nuirked by irregular growth lines which often tend 

 toward irregular, low undulations; aperture slightly higher tlian wide; 



