S. S. Lull — Mammals and Horned Dinosaurs. 339 



examined here belong to the Fox Hills. The higher unques- 

 tioned Lance formation was not studied at this place." 



Knowlton (1911, p. 372), however, says of the section under 

 consideration : 



" The section made on the south side of the Cheyenne River at 

 the mouth of Lan.ce Creek shows a thickness of 405 feet of Fox 

 Hills above the Pierre, but the highest point in the section at 

 which marine Fox Hills invertebrates were found is over 100 

 feet below the top. It further appears from this section that the 

 upper four members, aggregating 115 feet in thickness, contain 

 carbonaceous and lignitic shales as well as fragments of dinosaur 

 bone and brackish-water invertebrates, certain of which are the 

 same as those found in, and there said to indicate the Laramie 

 age of, the 400 feet of beds already mentioned as reported by 

 Stanton and Knowlton above the typical marine Fox Hills. To 

 the writer [Knowlton] it seems altogether more probable that the 

 four upper members of this section belong to the Lance forma- 

 tion and not to the Fox Hills. . . If this portion of the section 

 is placed in the Lance formation, where it certainly appears to 

 belong, the thickness of the Fox Hills in the section is reduced to 

 285 feet, or but little more than half of the maximum thickness 

 assigned to beds of this age in the Converse County region. 

 While this evidence may not be considered conclusive, it must at 

 least be admitted that it strongly suggests the possibility that 

 even here, as in the areas already discussed in the Dakotas and 

 Montana, the Fox Hills is of variable thickness, due to the 

 erosion of the upper portions before the deposition of the Lance 

 formation." 



Doneghy's section, 1911^. — Mr. Doneghy's section, prepared 

 in the summer of 1914, begins in very nearly the same place 

 where Stanton's section (b) and that of Hatcher in 1893 were 

 taken, that is, in the canyon of Buck Creek near the mouth of 

 the draw mentioned by Hatcher and a short distance north of 

 the Buck Creek pens. While it was occasionally necessary to 

 depart to the right or left of a straight line in order to follow 

 the exposures, the general trend of the section was N. 80° W. 

 It was continued up the slope across the successive outcrops until 

 the summit of the divide between Lance and Buck creeks was 

 reached. Thence west to Lance Creek the general slope of the 

 land surface, which is about 10°, approximately coincides with 

 the dip, so that practically nothing further can be learned. 

 Mr. Doneghy did not go west of Lance Creek. This section is 

 more detailed than any of the others and hence is hard to com- 

 pare with them. Our supposition was that the lignite beds 

 were necessarily Lance, so that the horizon " * " about 200 

 feet above the bottom of the section was taken as the possible 

 line of demarcation between the Fox Hills and the Ceratops 



