30 COLORADO COLLEGE STUDIES. 



westward beyond Cave creek, and to a limit not observed 

 by the writer, but stated by Prof. St. John to be at "Cotton- 

 wood creek". On the Cimarron river it forms the brow 

 of the bluffs along the south side of the river at the bridge 

 of the Panhandle branch of the A. T. t!e S. F. railway and 

 extends thence to the southeastern part of Clark count}-, 

 Kansas. At Ashland, in the latter county, clay-charged 

 gypsum, probably representing this or the Sliimer hori- 

 zon, was pierced in a well at a depth of about 125 feet 

 by Dr. W. J. Workman. The outcrop of the Medicine 

 Lodge gypsum on the Cimarron river has not been ex- 

 plored by the writer below West creek m the western edge 

 of Woods county, Oklahoma; but according to Mr. H. C. 

 Chapman, Editor of the Okeene Eagle, it gradually recedes 

 from the river south of the Glass mountains, passing the 

 head of Salt creek in Blaine county, where it is tunneled 

 into a remarkable park-like system of natural bridges, and 

 thence extends southeastward to Darlington (a few miles 

 from El Reno), on the North Canadian. On the latter 

 stream the greater portion of the outcrop of this gypsum 

 is doubtless east of the crossing of the Panhandle line, but 

 a few miles southeast of Beaver City there is a bed of gyp- 

 sum which may belong to either of the Cave Creek hori- 

 zons or to a higher one. A section of this bed on lower 

 Clear creek presents a lenticular outline, and the weathered 

 rocks at the foot of the bluff contain salmon-colored nodules 

 in a whitish ground-mass, like plums in a pudding, a 

 feature which is only a phase of the mottled or semi-crys- 

 talline character seen in the Medicine Lodge gypsum on 

 the Cimarron and elsewhere. 



The principal stratum of gypsum described and illus- 

 trated in their Red River Report by Capt. Marcy and Dr. 

 Shumard as occurring on the Canadian and on the forks of 

 the Red river, can scarcely be other than the Medicine 

 Lodge gypsum. 



North of the river of its name, the Medicine Lodge 



