Mabyland Geological Survey 459 



behind the periphery but very prominent upon the body; body spirals 

 rather low. broad, flattened fillets which override the costals in undi- 

 minished vigor, separated upon the posterior portion of the whorls by 

 interspirals of approximately equal width but becoming more rounded, 

 more elevated, and less distant anteriorly; sutures impressed but rather 

 indistinct; aperture rather wide, arcuate; outer lip broadly rounded, 

 apparently subvaricose; inner lip oblique, non-plicate; pillar flattened; 

 canal short, broad, recurved. 



Dimensions (slightly imperfect individual). — Altitude 32.5 mm., maxi- 

 mum diameter 25 mm. 



This species suggests in general contour P. subdensatus Conrad. It is 

 at once separable, however, by the nodose axial sculpture upon the spire 

 and the coarser spiral sculpture. 



Occurrence. — Monmouth Formation. Brightseat, Prince George's 

 County. 



Collection. — Maryland Geological Survey. 



Pyrifusus monmouthensis n. sp. 

 Plate XVI, Figs. 5, 6 



Description. — Shell compressed dorso-ventrally, broadly lenticular in 

 outline, the maximum diameter falling near the median horizontal ; spire 

 scalariform, multispiral, the exact number of whorls not known but prob- 

 ably about six ; whorls very sharply constricted at the fasciole, the poster- 

 ior portion closely appressed against the preceding volution, the anterior 

 portion nearly horizontal; sides of the whorls not far from vertical, the 

 ultima flattened and obliquely tapering at the base ; axial sculpture of 

 narrow, pinched costa?, subequal in size and spacing upon the spire, evan- 

 escent at the fasciole and upon the base and the final half turn of the 

 ultima ; appressed portion of whorl finely nodulated but not in close har- 

 mony with the axials ; spiral sculpture restricted to the sides of the whorls 

 on the spire, and a few faint lira at the base of the body, those of the spire 

 approximately seven in number, least feeble near the fasciole, those on the 

 body perhaps ten in all ; suture lines distinct, impressed, minutely crenu- 



