392 DESCBIPTIONS OF NEW SPECIES OF FOSSILS, 



rounded folds, which are about equal to the spaces between them ; crossed by revolving 

 bands, wider than the spaces between them, and distinctly defined upon the longitudinal 

 folds and in the spaces. Aperture narrow, oblique, obtusely angular behind, gradually 

 contracting in front into a narrow canal ; outer lip thick ; columella broad ; a distinct 

 spiral groove or constriction marking the junction of the canal with the inflated part of 

 the last volution. Spiral angle, 52. Breadth, .1 inch. 



This shell presents all the external characters of Fusus, but the imperfection of the 

 columella renders it impossible to determine fully its character. The impressed or 

 constricted line at the base of the last volution passes around, parallel with the 

 revolving lines, into the aperture, and may have produced a fold upon the inner lip, 

 which might be a sufficient reason for removing it from this genus. The suture is a 

 narrow constricted line, impressed nearly at right angles to the direction of the spire, 

 and the depressions between the longitudinal folds are terminated abruptly above, 

 before reaching the suture, by an irregular ridge caused by the extension and thicken- 

 ing of the upper extremities of the folds. 



Locality and Position. Sage Creek. Upper part of division No. 4 of Section. 



FUSUS 1 TENUILINEATA, U. Sp. 

 PLATE III. FIG. 8, a- c, and fig. 9, a - c. 



Shell elongate-terete ; volutions (number unknown) slightly convex in the middle, 

 last one flattened, or sometimes slightly concave above the middle; aperture sub- 

 rhombic, terminating in an acute angle behind, and narrowing in front into a canal ; 

 surface marked by very fine, undulating, closely arranged revolving lines, which are 

 stronger immediately below the suture ; suture plain, linear. Spiral angle about 25 ; 

 breadth, .37 inch. 



The only specimen in our collection is a fragment consisting of about two and a half 

 volutions, the last one too imperfect to admit of the determination of the form of the 

 aperture. Another fragment, fig. 9, #, &, is from the collection of Dr. Evans, now in 

 the possession of Dr. Shumard in St. Louis. The aperture in this one is nearly entire, 

 and, where partially exfoliated, shows in some places a thickening of the shell, with 

 impressions of crenulations, as if the growth had been interrupted at intervals. It is 

 with much doubt that this shell is referred to the genus Fusus. 



Locality and Position. Sage Creek. Upper part of division No. 4 of Section. 



