380 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. 



rather narrow-oval ; outer lip faintly cross-sulcated at the edge within, and 

 very slightly sinuous above ; inner lip united to the outer one above, and 

 rather closely connected with the smooth, tortuous, and arcuate columella. 



Length, 1.43 inches; breadth, 0.75 inch; apical angle convex, diver- 

 gence about 54°. 



Four or five of the revolving bands on the body-whorl, and two of those 

 on each turn of the spire, are larger than the others, and form "rather distinct 

 nodes at the points where they cross the folds. Below these four larger 

 bands on the body-volution, there are about five or more smaller ones, which 

 diminish in size, and become more oblique on" approaching the canal ; while 

 on the obliquely flattened upper part of the whorls, there are some three or 

 four much smaller and less prominent bands or lines. 



The drawing of this species is faulty in representing the vertical ridges, 

 or costae, too narrow and too sharply defined, and in leaving out the smaller 

 of the revolving ridges, on the upper slope of the volutions. The inner lip 

 is also rejjresented too narrow above, and the outer too thin, and without the 

 very obscure sulcations within, near the margin. The figured specimen has 

 the end of the beak broken away, and the aperture narrowed a little by acci- 

 dental pressure. The columella is also not drawn prominent enough on the 

 inner side, just above the point where it is broken off below. 



Although resembling the Cretaceous species described by Dr. Stoliczka 

 from the Indian collections, this shell still differs too decidedly in specific 

 details to require a very careful comparison. In form, and even surface- 

 markings, it more nearly agrees with his Hindsia exi?nia, being, indeed, very 

 much like that shell ; but it differs materially in having its inner lip entirely 

 smooth. 



Locality and position. — Near the mouth of Heart River, on the Upper 

 Missouri ; from the Fox Hills group. 



PLEUROTOMIDvE. 



Genus TURRIS, Bolten. 



Synon.— Turns, Bolten (1798), Mus. Bolt. (ed. 2a, 1819, 87).— Fabr. (1822), Fortegn., 83.— Gray (1847), 

 Proceed. Zool. Soc, 134 (not 141).— H. and A. Adams (1853), Genera Recent. Moll., I, 

 87.— Meek and Hayden (1860), Proceed. Acad. Nat. Sci. Philad., XII, 422.— Gabb (1860), 

 Jour. Acad. Nat. Sci. Philad., IV, 37; and (1861) Synop. Moll. Cret. Form., 89; also 

 (1864) Palaeont. Cal., I, 92.— Conrad (1862), Proceed. Acad. Nat, Sci., XIV, 284.— 

 Meek (1864), Smithsonian Check-List N. Am. Cret. Fossils, 22 (not Montfort, 1810). 



