480 Systematic Paleontology 



Genus PSEUDOMELANI A Pictet and Campiche 

 [Mat. Pal. Suisse, ser. vi, 1862, p. 266] 



Type. — Chemnitzitt normaniana d'Orbigny. 



Shell rather heavy, elongate-conic ; whorls quite numerous, flattened, 

 the sides of the spire converging evenly toward the apex and little or not 

 at all interrupted at the suture lines; external sculpture not developed; 

 sutures not channelled; body whorl smoothly rounded at the base; aper- 

 ture rather small, lobate, peristome discontinuous, angulated behind, 

 evenly rounded in front; outer lip thin, smooth; inner lip concave, rein- 

 forced but not plicate ; umbilicus imperforate. 



Pseudomelania is one of the most typical of Mesozoic genera. It was 

 initiated in the Trias and has been found at almost every horizon in the 

 entire Mesozoic, but apparently did not survive its close. The genus has 

 not been reported in any considerable numbers from this country, although 

 it is very abundant abroad. It is probable that a number of the species 

 referred to Eulima would find their true affinities with this genus. 



Pseudomelania monmouthensis n. sp. 

 Plate XVI, Fig. 10 



Description. — Shell of moderate size for the genus, thin, highly polished, 

 elongate-conic in outline; whorls probably eight or ten in all, flattened 

 laterally, decreasing very slowly in size and converging at an angle of 

 ± 15° ; sutural channels concealed by a thin glaze which is frequently 

 broken away; body whorl obscurely carinated at the periphery, obliquely 

 constricted at the base; aperture obliquely lobate, angulated behind, 

 rounded in front, the labral convexity a little higher than the labial con- 

 cavity ; columella feebly reinforced ; parietal wall free from glaze. 



Dimensions. — Altitude ± 10 mm., maximum diameter 2.8 mm. 



The type is unique, but at least it is sufficient to definitely establish the 

 presence of this genus in the Upper Cretaceous deposits of Maryland. 



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

 County. 



Collection. — Maryland Geological Survey. 



Etymology: i//ei'5?js, false; Melania. a genus of gastropods. 



