FOSSILS OF THE CLINTON GROUP. 549 



Huffman's Quarry. When the shell itself has been entirely removed 

 the space remaining vacant in the umbilical region is larger in this 

 species than in the case of B. exiguus. But when the shell is preserved, 

 the last whorl closes the umbilical region, leaving only a very shallow 

 depression there. The specific term is intended to recall this feature of a 

 closed, covered, umbilical region. Along the median line or back of the 

 shell there never is a distinct carina, avery indistinct median elevation 

 may be found towards the aperture of larger individuals, but this has 

 never been observed to be as strong as in the case of B. exigtius. The 

 largest diameter of the shell is 17 mm. and it must have had about the 

 same width at the aperture. 



BeUei'ophon {Bucania) trilobatus, Sowerby. 



(Plate 27, Figs. 33a, b.) 



Conrad's Bucania trilobata is at least generically related to the 

 Bellerophon trilobatus of Sowerby. If therefore it be not identical it re 

 quires at least a new name. A form of this general character was found 

 in the Beavertown marl at Huffman's Quarry. Prof. E. W. Claypole has 

 found more typical specimens in the top of the Clinton, near MifHin- 

 town, Juniata county, Pennsylvania. 



In these specimens the shell Was preserved here and there in a frag- 

 mentary way. The surface was smooth ; no trace of a carina nor of a slit- 

 band was present. 



Cyrtoiites Youngi, Foerste. 



(Plate 31, Figs, 7, la.) 



The shell is very much compressed laterally, the sides meeting under 

 very acute angles forming a sharp keel. The surface of the shell is or- 

 namented by fine not very distinct striae, visible under a lense, bending 

 backwards toward the keel. The specimen is 6.8 mm. long, and the 

 aperture is 1 mm. wide. The type was found at Hanover, Indiana. 



Pleurotomaria inexpectans, Hall and Whitfield. 



But little can be added to the description of this species, published 

 in the Paleontology of Ohio, Vol. II. The species is not at all infrequent 

 at Todd's Fork, near Wilmington. In one good specimen six transverse 

 striae occurred in a distance of 2 mm. Longitudinal striae are scarcely 

 visible, being best seen below the median ridge of the last volution. This 

 median ridge is a longitudinal or revolving striation which passes along the 

 middle of the upper part of each volution, gradually increasing in size 

 towards the mouth. It is present in all .specimens examined recently, 

 and, while never sharp, becomes broad and high enough to form at least 

 a low ridge. The slit does not form a groove bounded by distinct raised 

 ridges or striae as in most Pleurotomaritz, but forms an obtuse ridge there 



