512 University of Kansas Geological Survey. 



A fragment of a specimen belonging to this species was col- 

 lected from the upper Fort Pierre shales of Devil's Canon, in 

 Cheyenne county. It was found associated with Baculites ovatus, 

 which occur free in the shales. 



? Heteroceras cochleatum M. & H. Plate cvn, fig. 2. 



Turrilites (Helicoceras) cochleatus M. & H., 1858, Proc. Acad. Nat. Sci. 



Phil., x, 55. 

 Helicoceras cochleatum Meek, 1864, Smiths. Check-List, N. Am. Cret. 



Fobs., 25. 

 ? Heteroceras cochleatum Meek, 1876, U. S. Geol. Surv\, vol. ix, pp. 477, 



478, 479, pi. xxn, ff. 2a, b. 



Description: "Shell sinistral, very thin, and composed of 

 rounded nearly or quite contiguous whorls, which gradually 

 increase in size from the smaller to the larger extremity ; um- 

 bilicus slightly wider than the largest whorl ; surface orna- 

 mented by numerous rather regular bifurcating annular costse, 

 which first pass obliquely backward and outward from the um- 

 bilicus above, then curve so as to cross the ventral or outer side 

 obliquely downward and forward ; but on reaching the under 

 side, they curve backward as they reach the umbilicus. There 

 are also two rows of irregular obscure, flattened, or depressed 

 oval nodes, one of which rows passes arouad nearly over the 

 siphuncle, which is located near the middle of the outer side of 

 the whorls, while the other is placed less than one-fifth the cir- 

 cumference of the whorl lower. 



"The septa are distant, and divided into complex lobes and 

 sinuses, which are a little unsymmetrical in their subordinate 

 details, but of about the same size and general form on oppo- 

 site sides of the siphuncle. The siphonal lobe is comparatively 

 small, and ornamented at the extremity by four small branches, 

 the two terminal of which are a little larger than the others, 

 slightly dissimilar, and each provided with five or six un- 

 equal, sharp digitations ; the other two branches are not ex- 

 actly opposite, differ slightly in form, and are each armed 

 with from three to five or six unequal, sharp digitations ; 

 the other two branches are not exactly opposite, differ slightly 

 in form, and are each armed with from three to five or six 



