36 A Contribution to the Lower Devonian Faunas of Maryland 



A'olution : aperture expanded, campanulate, and sometimes slightly re- 

 flexed. Surface marked by longitudinal plications, which are more or less 

 strongly developed, and are crossed by fine closely arranged lamellose 

 strife, which are often crowded into wrinkles upon the middle and lower 

 part of the shell." Hall, 1859. 



A poorly preserved specimen from the Oriskany 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 Formation, Eidgely Member. Knobly 

 Mountain, West Virginia. 



Collection. — ]\Iaryland Geological Survey. 



Platyceras spirals Hall 

 Plate LXXXV, Figs. 8, 9 



Platyceras spirale Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 331, pi. Ixiii, 



figs. 4-9, 1861. 

 Platyceras spirale Meek and Wortlien, 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 which 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 strise, more or less distinctly plicated on one side below 

 with strong lamellose undulating stria." Hall, 1859. 



Length 3.25 cm.; diameter of aperture, 1.8 cm. 



Occurrence. — Helderberg Formation, New Scotland Member. 

 Corriganville. 



Collection. — U. S. National Museum. 



