staotoh.] STROMBimE. 149 



apex of the spire; aperture narrow, oblong; outer lip in the adult 

 greatly thickened and expanded, bordered externally by a heavy ridge. 

 The posterior expansion of the outer lip is broad falciform, slightly nar- 

 rowed at the base, somewhat twisted so that it is not quite in the same 

 plane as the rest of the margin, directed backward and outward, and 

 terminating in a blunt point. About midway between this falciform 

 process and the anterior end of the canal there is a smaller subquad- 

 rate projection, directed downward and forward, in front of which 

 there is a deep, narrow sinus, followed by a third projecting lobe that 

 is broadly rounded and separated from the anterior end of the canal 

 by a well-defined notch. The tip of the canal is slightly bent inward. 

 The shell is very thin on the dorsum, which is the only portion not 

 covered in the adult by a heavy callus. Surface smooth, excepting on 

 the upper portion of the body- whorl, where it is marked by more or 

 less prominent curved transverse costae that are sometimes shortened 

 into nodes. From the front end of the last costa a rather prominent 

 subangular ridge, corresponding to the angulation of the earlier whorls, 

 passes out on the outer lip and forms the upper (posterior) border of 

 the falciform process. In the earlier stages of its growth the shell has 

 a much more simple form. 



Length of a large specimen, 41 mm ; breadth, including the expanded 

 outer lip, 39 mm ; diameter of body- whorl, exclusive of lip, 16 mm . 



This description is drawn from a large collection of well preserved 

 specimens from Huerfano park, Colorado. At several localities the 

 species is very abundant in a bed of sandstone, which I have, for that 

 reason, called the Pugnellus sandstone, as a convenient local designa- 

 tion. 



The original types of Meek's species are imperfect sandstone casts 

 from the neighborhood of Coalville, Utah, while White's types, also 

 imperfect and showing different features, came from the Arkansas 

 river above Pueblo, Colorado. Better collections recently made at both 

 these localities prove that they all belong to the species that is so 

 abundant in Huerfano park, and that it has all the characteristic fea- 

 tures of Pugnellus. 



The most nearly related form is Pugnellus manubriatus Gabb, from 

 the Chico series of California, but the resemblance is not so close as to 

 require minute comparisons. 



Locality and 'position. — At the localities mentioned in Colorado the 

 species is confined to the upper part of the Fort Benton, being most 

 abundant in the thin bed of Pugnellus sandstone, just beneath the 

 Niobrara limestone, and very rare in the ux>per part of the underlying 

 shales. At Coalville, Utah, it occurs in the sandstone of the " second 

 ridge," where it is associated with many of the same species that are 

 found with it in Colorado. It has also been found at the same horizon 

 at Bear River city, Wyoming. 



