138 J. B. Hatcher — (Jeratops Beds of Wyoming. 



The lignites occur in thin seams, never more than a few 

 inches thick, of only limited extent, and with many impuri- 

 ties. At no place in the Ceratops beds of this region have 

 workable coal beds been found. These do occur, however, in 

 the Ceratops beds of Montana. The best exposure of them 

 observed there is in Fergus county, on Dog creek, about 15 

 miles from its mouth, just above where it enters the Bad 

 Lands of the Missouri. Workable coal seams occur in Wyom- 

 ing, in the beds west of Lance creek, which overlie the 

 Ceratops beds, and will be referred to later. 



Intercalated with the sandstones, shales, and lignites, are 

 quite local deposits of limestones, clays, and marls. The latter 

 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 notice- 

 able 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 fis- 

 sures 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. 



Stratigraphical Position of the Ceratops Beds. 



The Underlying Beds. — Along their southeastern border, 

 especially between Lance and Buck creeks, are many fine ex- 

 posures of the Ceratops beds and the underlying Fox Hills. 

 Perhaps the best exposure is that made by a small tributary 

 emptying into Buck creek, about four miles east of Lance 

 creek and one-half mile northwest of the Buck creek pens 

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

 course has here 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. At this place, the bed of Buck 

 creek and the rounded hills of that region at the head of this 

 stream, embraced between the border of the Ceratops beds 

 and Fox Hills sandstones on the north and the bluffs of Mio- 

 cene clays and conglomerates on the south, are composed of 

 Ft. Pierre shales. All the strata of this entire section dip to 



