336 M. S. Lull — Mammals and Horned Dinosaurs. 



are composed almost entirely of fresh-water shells, fragments of 

 bone, teeth, etc. 



"Along their southern and eastern border, the Ceratops beds 

 dip to the northwest, at an angle of about 16° between Buck 

 Creek and Lance Creek. One half mile east of Lance Creek, the 

 dip is 29° to the northwest. This angle of inclination rapidly 

 diminishes toward the interior, and is scarcely noticeable in the 

 vicinity of Lightning, Cow, and Doegie creeks. The fold is 

 quite abrupt as is further shown by cracks which were made in 

 the strata at the time of disturbance at right angles to their dip 

 and parallel with their strike. These fissures have been filled by 

 infiltration with materials now harder than those forming their 

 walls, and now appear in many places as projecting veins, from a 

 fraction of an inch to a foot or more in width, and from a few 

 yards to several hundred in length." 



The section was that shown by the exposure made by a 

 small tributary emptying into Buck Creek, four miles east of 

 Lance Creek and a half mile northwest of the Buck Creek 

 pens used by the cattle men for round-up purposes. This 

 watercourse has cut its way in a southeasterly direction at 

 right angles to the strike, down through the lower half of the 

 Ceratops beds, through the underlying Fox Hills sandstones, 

 and into the Ft. Pierre shales. All the strata of this entire 

 section dip to the northwest at an angle of 16°. 



The section (p. 139) is as follows : 



FEET 



Alternating sandstones, shales, and lignites, fossiliferous.. 2600 



Almost white, finegrained, massive sandstones with numer- 

 ous concretions, no fossils, about 250 



Yellowish brown, well stratified sandstones, apparently 



non-fossiliferous, about - - 150 



Hard sandstone layer. Arbitrary Fox Hills-Ceratops beds 



line _ £ 



Sandstones and shales. Shales predominant in lower por- 

 tion, toward middle the sandstones in excess, upper 50 

 feet entirely sandstones. Sandstones yellowish brown, 

 very fine-grained, firm, well stratified below but softer 

 and quite massive at top, where they contain concre- 

 tions and a Fox Hills fauna 500 



Pierre shale 



Stanton and Knoioltorts sections. — Two sections, which 

 have been described by Stanton and Knowlton (Stanton 1910, 

 p. 185), lie at the south end of the area, about 30 miles south- 

 west of the mouth of Lance Creek. Of the first one of them 

 (a) Stanton says : 



One of these lies about 2 miles east of Lance Creek nearly 

 opposite the mouth of Little Lightning Creek, and shows excel- 

 lent exposures of Pierre, Fox Hills, and the lower part of the 



