INVERTEBRATE PALAEONTOLOGY. 



385 



volutions broken away. They arei most prominent around the middle of the 

 volutions, and llnis sometimes assume rather the appearance of n row of little 

 nodes. 



i know of no described species more nearly approaching this than some 

 of those figured by Deshayes from the Paris Basin Tertiary ; hut these all 

 differ too decidedly to require critical comparison. Possibly 1 should write 

 the name of this species Tunis (Surcula) ?ninor,&s the posterior sinus of the 

 outer lip is not a slit, as in the more typical forms of the genus, but a rather 

 wide, rounded sinuosity ; though the lines of growth as represented by our 

 figures, particularly figures 9, a, and H, c, do not curve enough to give an 

 exact idea of the depth of the sinus of the lip. 



Locality and position. — Evans and Shumard's specimens of this species 

 came from Moreau and Grand Rivers, Dakota; apparently from the Fox 

 mils group of the Upper Missouri Cretaceous series. Those studied and 

 figured by us came from the Yellowstone River, Montana. 150 miles from 

 its mouth, from beds containing a blending of the fossils of the Fox Hills 

 and Fort Pierre groups. 



Turris (S ii re u la)? con tortus, M. & H. 



Plate 31, rigs. 7, «, b. c. 



Fusus contortus, Meek and 'Ravelin 1 1856), Proceed. Acad. Nat. Sei. Philad., VIII, 0.">. 

 Pleurotomaria contorta, Meek" and Hayden (1860), ib., XII, l-.">. 



Tttrrix conturtus, Meek and Hayden (1804), ib., 422. — Meek (1864), Smithsonian Cheek-List N. Am. ('ret. 

 Fossils, 22. 



fig- 49. Shell rather short-fusiform ; spire turreted, moder- 



ately elevated, but not quite equaling the length of the 

 aperture and canal; volutions five and a half to six, dis- 

 tinctly concave above, and convex around the middle, 

 where they are each ornamented by about eleven 

 oblique, rlexuous, elongated nodes, or costa?, equaling 

 the sinuosities between ; last turn prominent around 

 OHtortW! - the middle, ami tapering obliquely into the rather short. 



A dorsal view, to show x ' 



the curves of the lines of nearly straight, canal below; suture distinct; aperture 



growth, not correctly rep- , , i i ,, 



resented in the figures on nariw-subobovate, angular above, most convex on the 

 P late :J1 - outer side, and tapering into the canal below : outer lip 



broadly prominent in outline along the middle, somewhat contracted below, 

 and again curving backward into the broadly rounded, rather deep, sinus 



19 H 



