stanton.] NATICID2E. 135 



The collections from Upper Kanab valley, Utah, contain 9 speci- 

 mens, two of which are figured, that are not distinguishable from rather 

 small examples of this species. The inner lip is perhaps slightly 

 straighter, the callous deposit smaller and the outer lip is some- 

 what less oblique, but in form and surface markings they agree almost 

 exactly. The principal fact that causes me to hesitate to assign them 

 to the described species is that they come from a lower horizon and 

 nearly all of their associates are different. The types and all the speci- 

 mens hitherto reported, with one exception, came from the upper por- 

 tions of the Montana formation, and from its equivalents in the south- 

 ernstates. In the Geology of the Black Hills of Dakota, Mr. Whitfield 

 states that one cast not distinguishable from this species came from a 

 much lower horizon, probably the Benton shales. 



Locality and 'position. — About 350 feet above the base of the Creta- 

 ceous section in Upper Kanab valley, Utah. 



Genus GYBODES Conrad. 



Gyrodes depressa Meek. 



PI. xxix, Figs.-ll-14. 



Gyrodes depressa Meek, 1877, U. S. Geol. Expl. 40th Parallel, vol. IV., Pt. 1, p. 159, 

 PI. 15, Figs. 1 and 1 a. 



Shell depressed subglobose, consisting of three or four rapidly in- 

 creasing whorls, the last of which is very large; spire varying from de- 

 pressed to moderately elevated and prominent ; whorls in some examples 

 distinctly truncate above, in others only slightly flattened or simply 

 rounded to the distinct, impressed suture, subangular or very narrowly 

 rounded below around the borders of the umbilicus, which is broad and 

 deep, but narrows rapidly within. Aperture ear-shaped, subangular 

 above and broadly rounded below, oblique to the axis of the shell ; outer 

 lip forming an irregular curve; inner lip nearly straight and with the 

 upper half reflexed and somewhat thickened. Surface marked by strong 

 lines of growth. 



Height of an average specimen, about 22 m,n ; the greatest breadth, 

 32 mm . In some of the more elevated examples the height and breadth 

 are nearly equal. 



This description is drawn from a large suite of well-preserved speci- 

 mens obtained in Huerfano park, Colorado, that have been compared 

 with the types and with other examples from the typical locality. The 

 types are sandstone casts, more or less distorted by pressure, so that 

 the spire is unnaturally low. In the original description the suture is 

 said to be "channeled in such a manner as to be flattened within, owing 

 to the presence of a revolving furrow just above it," but this feature is 

 accidental, the flattened channel simply representing the thickness of 

 the shell between the whorls. I have no doubt that the Colorado shells 



