514 University of Kansas Geological Survey. 



? Hetet'oceras angulatum M. & H. Plate cviii, fig. 2. 



Helicoceras angulatum M. & H., 1860, Proc. Acad. Nat. Sci. Phil., xn, p. 176. 

 ? Heteroceras angulatum Meek, 1876, U. S. Geo'l. Surv. Terr., vol. ix, p. 485, 

 pi. xxi, ff. 3a, b, c; 1864, Smiths. Check List N. Am. Cret. Foss., 25. 



Description: "Of this shell we have a single non-septate 

 fragment, t-\yo and seventy-eight hundredths inches in length, 

 with a diameter of one and fifty -hundredths inches at the large 

 end, and one and thirty-seven hundredths inches at the smaller 

 extremity. It is rounded or subcylindrical, and makes a broad, 

 (dextral?) curved spiral, in such a manner that, if continued,, 

 around, the volutions would be disconnected and encircle an 

 umbilical cavity apparently more than three times their own 

 breadth. The surface is ornamented by distinct angular costse,- 

 which pass around the whorls obliquely, where they sometimes 

 bifurcate. I have not yet seen the septa of this species, but its 

 large size and very broad curve will distinguish it from any other 

 known species of this type in these rocks, excepting the last (H. 

 cochleatum) , from which it differs in having angular instead of 

 rounded costse and in being coiled in the opposite direction. 

 Its angular cost^e will equally distinguish it from any of the 

 others, even should they be found attaining as large a size, and 

 in such short fragments as not to show the exact nature of the 

 curve. Like the last, it is only referred provisionally to this 

 genus upon the supposition that it belongs to the deflected part 

 of the body of the shell." 



The specimen in the University collection is a small, non- 

 septate fragment, having a length of about fifty mm., its cir- 

 cumference, at the larger end, being thirty-three mm. and at 

 the smaller end, twenty-six mm. The specimen was collected 

 by Mr. George Cooper from Wallace county, probably from the 

 Fort Pierre shales on the North Fork of the Smoky Hill river, 

 near Mc All aster. 



