508 University of Kansas Geological Survey. 



right valve, the posterior one being a little larger than the other, 

 and faintly emarginate at the extremity. Between these two 

 teeth there is a little larger pit, and further back a smaller one 

 for the reception of the two cardinal teeth under the beak of 

 the left valve. Each valve has one small, obtuse, anterior lat- 

 eral tooth, situated some distance in advance of the beaks, with 

 apparently very faint traces of a remote posterior lateral in one 

 or both valves. The posterior muscular impression is shallow, 

 subquadrate in form, and usually bounded in front by a faint 

 linear ridge, extending obliquely up toward the beaks. The 

 upper part of the anterior muscular impression has the same 

 form, while its prolonged portion below is slender, a little arcu- 

 ate, rather long, and directed obliquely downward toward the 

 middle of the basal margin. Just above this impression of the 

 anterior adductor, the small, oval scar of the pedal muscle is 

 seen quite detached from it." 



In the summer of 1896 I collected a large number of this 

 species from an outcrop of Fort Pierre shales in Cherry creek 

 canon, in Cheyenne county, a few miles west of Jackson ; s ranch. 

 Aviculse and Ostreae were found associated with them. The 

 horizon in which they occur is probably near the upper horizon 

 of the Fort Pierre formation. They have not been found in 

 the lower beds of the North Fork of the Smoky Hill river or on 



Butte creek. 



? Anchura sublcevis M. & H. 



Aporrhais sublcevis M. & H., 1860, Proc. Acad. Nat. Sci. Phil., xn, 178. 

 Aporrhais sublevata (misprint) M. & H., 1860, ibid., 428. 

 .' Anchura sublcevis Meek, 1864, Smiths. Check-List, N. Am. Cret. Foss., 19; 

 Meek and Hayden, 1876, U. S. Geol. Surv. Terr., vol. ix, pi. xix, ff. 3a, b. 



Description : " Shell unequally fusiform ; spire elevated ; vo- 

 lutions seven or more, convex, and separated by a rather distinct, 

 though not deep suture, last one convex above and abruptly con- 

 tracted below, with a single, small, revolving angle, which 

 passes, around to the suture, but is not visible on the succeed- 

 ing turns of the spire ; surface polished, and marked by mod- 

 erately distinct arcuate lines of growth, which are crossed by 

 rather obscure revolving lines, nearly equaling the spaces be- 

 tween on the spire, but more distant, with sometimes a few 



