188 PALEONTOLOGY OF NEW JERSEY. 
Order SCUTIBRANCHIATA. 
Suborder PODOPHTHALMA. 
PLEUROTOMARIIDA. 
Genus PLEUROTOMARIA De France. 
PLEUROTOMARIA BRITTONI, n. sp. 
Plate xxi, Figs. 7-9. 
Shell below a medium size, broadly conical in form, rising from a 
flattened base; the apical angle being about 80°. Volutions four, or from 
four to five in number, slighty scaliform in character; the outer face being 
flattened or very slightly convex, nearly in the direction of the spire, the 
upper surface of any individual volution being a very little larger than the 
basal edge of the next above it, and very slightly rounded on the angle; 
suture lines distinct in the casts. Base flattened or scarcely convex for 
two-thirds the width from the outer edge, which is moderately sharp, and 
then rapidly rounding into the moderately sized umbilicus. Aperture ob- 
liquely quadrangular, the inner basal or umbilical angle rounded. Slit of 
the outer lip not definitely ascertained in any of the specimens, which are 
all internal casts, but as nearly as can be ascertained has been narrow and 
placed at the outer basal angle, and not extending backward for more 
than one-third of the outer volution. Surface features unknown. 
The casts of this species bear considerable resemblance, in miniature, 
to those of Pleurotrema solariformis herein described from the Middle Marls 
at Timber Creek, New Jersey, but the slit in the aperture has been contin- 
uous (i. e., not composed of a series of oval perforations), and placed in the 
lower angle of the volution instead of midway between that point and the 
upper edge, as in that one. It is also more highly conical in form. 
Formation and locality: In Green Marls at the base of the Upper Marl 
Bed, at Farmingdale, New Jersey. Collected by Dr. Britton. 
