^O COLORADO COLLEGE STUDIES. 



these shales resembles that which prevails in most of the 

 terranes of the Salt Fork division below, more than that of 

 the Kiger terranes above the Dog Creek. The dolomite 

 varies from light-gray to dark-gray, and clay-impregnated 

 portions may partake of the red color of the including 

 shales. In lithological character, it varies from solid stone 

 which serves a fair purpose as a building-stone for the 

 rougher uses, to that which is so contaminated with clay as 

 to be soft and worthless. It is often cellular or cancellated. 

 A dark and cellular variety occurs at the top of a remnantal 

 mound of the Dog Creek at the highest point of the range of 

 lofty tables that forms the eastern front-line of the Gypsum 

 hills southwest of Medicine Lodge, this mound being the 

 most easterly outlier of the Dog Creek formation in Kansas. 

 The thickness and stratigraphic relations of the Dog 

 Creek formation are well displayed south of Lake City on 

 Do£f creek, from which the formation is named, and on Lit- 

 tie Bear creek, and thence westward in Barber and Coman- 

 che counties and the southeastern part of Clark county, 

 on various branches of the Medicine Lodge river, Salt fork, 

 and Cimarron river. In Oklahoma, it is seen on the bluffs 

 of the latter river in the immediate vicinity of the Great 

 Salt plain. 



THE RED BLUFF BEDS. 



While the rocks of the Kiger bear certain general 

 resemblances to those of the Salt Fork division, they yet 

 present in the main a different aspect. This prevailing 

 difference is especially due to the thick body of bright- red 

 rocks that constitutes at once the second member of the 

 Kiger division and the major part of the Kiger sedimenta- 

 tion, viz., the Red Bluff beds. 



This formation consists of seme 175 or 200 feet of li^ht- 

 red sandstones and shales. Its thickness is not fully shown 

 in the valley of the Medicine Lodge river, having there 

 been reduced by pre-Cheyenne and later erosion, but is 



