312 REPORT UNITED STATES GEOLOGICAL SURVEY. 



spire of nearly all the examples discovered wore encrusted with a 

 slightly compacted calcareous layer, which at first suggested the idea 

 that it might be the remains of a callus such as covers the spire in Lis- 

 2)odesthes White and Calyptvaphonis Conrad, hut in this case it is probably 

 a Nidlipora. The specific name is given in honor of Dr. F. V. Hayden, 

 the director of the Survey. 



Position and locality. — Strata probably equivalent with the Fort Pierre 

 Group, Cretaceous No. 4, of the Upper Missouri section ; 15 miles west 

 of Greeley, Colo., and about 6 miles south of Fort Collins. 



Anchura (Drepanocheilus)»ruh)A White. 



Plate 7, figs. 4 a and 6. 



AncJiura ruida White, 1876, Powell's Rep. Geol. Uinta Mts. p. 120. 



Shell rather small ; spire moderately elongate ; volutions about seven, 

 convex ; suture impressed ; wing moderately large, contorted, bearing at 

 its extero-posterior corner a strong falciform process, the direction of 

 which is nearly parallel with the axis of the shell ; the outer border of 

 this process is slightly convex and continuous with the outer border of 

 the body of the wing ; the extero-anterior border of the wing abruptly 

 rounded, from which, to the very short beak, the border is sinuous, 

 almost sigmoid ; posterior border of the wing deeply concave, its proxi- 

 mal half being slightly reflexed outward, as if for the passage of soft 

 parts corresponding to those that in allied genera occupy a posterior 

 canal, as the curved sinus adjacent to the columella doubtless gave pas- 

 sage to soft parts corresponding to those that in Anchura proper occu- 

 pied the anterior canal or channel of the beak ; inner lip provided with 

 a distinct and moderately broad callus, which, hi some cases at least, 

 extends beyond the distal end of the aperture across the next volution, 

 as seen by dorsal aspect of the shell ; columella very slightly produced 

 in front, and its apex flexed a little toward the dextral side of the shell. 

 Yolutions of the spire marked by many longitudinally oblique folds, 

 which extend to the suture on the proximal side of the volutions, but 

 not much beyond the middle on the distal side, and do not appear at all 

 on either the body- volution or wing. The whole surface marked by fine 

 revolving strise, which are more distinct upon the last volution than 

 elsewhere ; last volution and wing also marked by a moderately strong 

 carina, which terminates at the point of the falciform process. 



Length, 16 millimeters; breadth across the body- volution, including 

 the wing, 12 millimeters. 



This species agrees well with the subgeneric diagnosis of Meek for 

 JDrepanocheilus, and in many respects it resembles A. (D.) americana 

 Evans & Shumard sp., but it differs from that shell in its large an- 

 terior sinus, the deep sinuosity of the anterior border of the wing, and 

 the reflexion of a portion of the posterior margin of the wing. 



Position and locality. — Cretaceous strata; Upper Kanab, Southern 

 Utah. CoUected by Prof. J. W. PoweU. 



Anchura (Drepanocheilus) mudgeana (sp. nov.). 



Plate 7, figs. 3 a and 6. 



Shell of medium size for one of the genus ; spire moderately elongated ; 

 volutions about eight, convex; suture rather deep; body-volution pro- 

 portionally large ; wing proper rather small, recurved club-shaped, oc- 



