-10 A Contribution to the Lower Devonian Faunas of Maryland 



Description. — " Globose : whorls somewhat scaliform, or flattened 

 above; lower part of eolumella prominent: labrum reflected; width and 

 length of aperture nearly equal," Conrad, 18-i2. 



'' Shell globose or depressed globose and often obliquely ovoid, varying 

 in form. Spire moderately elevated, consisting of three or four volutions, 

 the last of which is extremely ventricose ; volutions flattened upon the 

 upper side; aperture circular or subovate; columellar lip reflexed. Sur- 

 face marked by fine closely arranged stria? parallel to the lines of growth." 

 Hall, 1859. 



Length of maximum form T cm. ; diameter 9 cm. 



This species is very common in the Oriskany of Maryland. Some forms 

 of Platyceras gehhardi bear a strong resemblance to this form, but the 

 latter always has an elevated spire which, with the prominence of the lower 

 part of the columella, serves to distinguish the species. 



Occurrence. — Oriskany ForMxItion, Eidgely Member. Cumberland, 

 Hancock, east side Nicholas jMountain, Maryland; Warren Point, Penn- 

 sylvania ; Knobly Mountain, West Virginia. 



Collections. — Maryland Geological Survey, U. S. N'ational ^Museum. 



DiAPITOROSTOMA DEPRESSUM (Hall) 



Plate LXXXVI, Figs. 11, 12 



Platyostoma depressa Hall, 1859, Nat. Hist. N. Y., Pal., vol. ill, p. 301, pi. Iv, 

 figs. 4a, 4&. 



Description. — " Shell depressed globose. Spire short, little elevated 

 above the body of the shell : volutions three or four, a little depressed at the 

 suture and regularly curving on the top and sides; aperture round or 

 transversely suboval. Surface somewhat lamellose-striate." Hall, 1859. 



This species as found in Maryland is poorly preserved. Only about 

 a half-dozen individuals have come under the notice of the writer, most 

 of them being in the U. S. National Museum and having been identified 

 by Schuchert. 



Occurrence. — Oriskany Formation, Eidgely Member. South end 

 of Nicholas Mountain (?). Helderberg Formation, New Scotland 

 Member. Corriganville. 



Collections. — Maryland Geological Survey, U. S. National ]\[useum. 



