348 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. 



and its folds or costse stronger and swelling out into more distinct nodes, 

 while the substance of the shell is rather thinner. 



The outer lip and canal of our specimen are imperfect; but the lines 

 of growth show that the margin of the first did not differ materially in its 

 outline from that of the last-described species, though its canal appears to 

 have been rather straighter. 



Locality and position. — Grand River; upper part of the Fort Pierre 

 group, or formation No. 4 of the Cretaceous series of the Northwestern 

 Territories. 



Pyi-ifusus N <• [» i (i nc 1 1 a) in ter textus, M. & H. (sp.). 

 Plate 19, figs. 14, a, b. 



Fusus intertextus, Meek ami Hayden (1857), Proceed. Acad. Nat. Sci. Philad., IX, 139. 

 Pt/rifusus intertextus, Meek (1664), Smithsonian Check-List N. Am. Cretaceous Fossils, 22. 



Shell fusiform, rather thick; spire conical, apparently about two-thirds 

 the length of aperture and canal; volutions about five and a half, concave 

 above, and convex around the middle, where they are each ornamented by 

 thirteen or fourteen regular, short folds, or vertically-elongated nodes, about 

 as broad as the spaces between; body-whorl tapering rather gradually into 

 the canal; suture not very strongly defined; surface marked by distinct lines 

 of growth, crossed by rather strong, elevated, revolving lines, usually a little 

 less than the intervening depressions ; aperture narrow-obovate, rather acutely 

 angular above, and narrowing gradually below; inner lip closely anchylosed 

 to the columella, which is slightly arcuate along the middle, and straight, or 

 nearly so, below. 



Length, about 187 inches; breadth, 0.86 inch. Apical angle convex; 

 divergence, 50°. 



This species is somewhat similar to P. Newberryi, but may be distin- 

 guished by its more elongated form, narrower body-volution, and more 

 elevated spire. Its revolving lines are also stronger, more distant, and differ 

 in showing a slight disposition to form small subnodose prominences at the 

 points where they are crossed by the lines of growth. 



From the last, it differs in having about two volutions less, and the 

 upper part of the spire is not near so slender. The nodes, or folds, are also 

 much less prominent, and its revolving lines -stronger and more distant, 

 especially near the middle of the whorls. It is also a more solid shell. 



