stanton.] PLEUROTOMID.E, ACTvEONID^E. 161 



PLEUROTOMID^l. 

 Genus PLEUKOTOMA Lamarck. 



Pleurotoma? hitzi Meek. 

 PI. xxxiv, Fig. 4. 



Turris (Surcnla) f hitzi Meek, U. S. Geol. Sur. Terr., vol. ix, p. 386, Fig. 50 in text. 

 Compare Fusus shumardi (H. &. M.) Whitfield, 1880, Geol. Black Hills of Dakota, p. 

 424, PI. 12, Figs. 7 and 8. 



" Shell elongate- conical (or fusiform), thin; spire much produced and 

 turreted; volutions about seven, distinctly convex, or subangular 

 around the middle, and flattened or concave with an outward slope 

 above the angle, and convex below; last one not larger than the regu- 

 lar enlargement of the others from the apex, each provided with about 

 thirteen prominences or little obscure vertical folds, which on the angle 

 of the last turn assume rather more the character of obscure nodes ; 

 entire surface marked by raised, revolving lines; aperture trigonoid- 

 oval, being biangular above and abruptly contracted below; beak, if 

 any existed, unknown. 



"Length (exclusive of the beak), about 2 inches; breadth, 0.90 inch; 

 slopes of spire somewhat convex, and diverging at an angle of about 

 36°." 



The only example of this species known to me is the imperfect type 

 specimen, which does not show either the generic or the specific char- 

 acters very well. 



The small fossil described by Whitfield (loc. cit.) and referred by him 

 to Fusus shumardi has fully as close resemblance to the earlier whorls 

 of this species as it has to Fusus shumardi, and the fact that it comes 

 from the Fort Benton group, the same horizon from which Turris hitzi 

 was obtained, while Fusus shumardi came from a higher horizon, makes 

 its identification with the former species more probable. 



Locality and position. — On the Missouri river opposite Fort Shea, 

 where it is associated with fossils of the Colorado formation. 



ACT^EONID^E. 

 Genus ACTION Montfort. 

 Action propinquus n. sp. 

 PI. xxxiv, Figs. 5-8. 



Shell small, slender ovate, with six convex volutions ; spire moder- 

 ately elevated, acute; suture impressed or slightly channeled. Sur- 

 face marked by fine, punctate, revolving lines, of which there are about 

 six visible on each whorl of the spire and about twenty on the body 

 whorl. The aperture is narrow, acute behind and narrowly rounded 

 in front. There is one prominent fold on the columella. 

 Bull. 106 11 



