NORTH AMERICA AND THEIR VERTEBRATE FAUNA. 55 



formation of this member, the Whitehorse, and in a number of localities 150 and 

 17s feet were recorded. Exposures are common along the top of the Gypsum Hills 

 from Canadian County to the Kansas line and beyond. 



"Whitehorse Sandstone Member. — The Whitehorse sandstone was also described 

 (under the name of Red Bluff sandstone) by Professor Cragin, in his first paper, 

 as follows : 



"This fonnation consists of some 175 or 200 feet of light red sandstones and shales. 



* * * Viewed as a whole it is very irregularly stratified, being in some cases considerably 

 inclined, in others curved, and this oblique and irregular bedding, being on a much larger 

 scale than that of the ordinary cross-beddings, at first glance gi\'es the impression of dips, 

 anticlines, synclines, etc., that have been ]iroduccd by lateral ])rcssure; the dips, however, 

 being in various directions. * * * The Red Bluff Beds exhibit the most intense coloration 

 of any of the rocks of the series. When the outcrops are wet with recent rains their vividness 

 of color is still greater, and the contrasts of their almost vcnnilion redness with other colors 

 of the landscape are most striking. Spots and streaks of bluish or greenish gray sometimes 

 occur in these rocks, lout not to nearly so great an extent as in the lower beds. The sand- 

 stones of the Red Bluffs are generally too friable for building stone, but in some instances 

 selected portions have proved hard enough for such use, and arc fairly durable." 



"In Oklahoma the Whitehorse member often weathers into conspicuous buttes 

 and mesas. For instance, in eastern Woodward and western Woods Counties a row 

 of these buttes, which rise 100 to 200 feet above the surrounding country, extends 

 from the vicinity of Whitehorse Springs, whence the name, southwest across the 

 Cimarron, to the high divides beyond. To some of these buttes characteristic 

 names have been given, as Lone Butte, Potato Hill, Watersign Hill, Wild Cat Butte, 

 and the like. The noted Red Hill between Watonga and Geary, in southern Blaine 

 County, is composed chiefly of the Whitehorse formation. South of South Canadian 

 River this sandstone thickens, and on weathering often forms conspicuous bluffs, 

 such as the famous Caddo County Buttes, southwest of Bridgeport. The White- 

 horse sandstone is exposed along the Washita from near Chikasha, Indian Territory, 

 westward, and in the vicinity of Anadarko it forms bold bluffs both north and .south 

 of the river, and extends as far west as Mountain View. Ledges which probably 

 belong to the same general horizon outcrop north of the Wichita Moimtains in the 

 vicinity of Hobart and Harrison, and it is not impossible that further studies may 

 demonstrate that the .same beds extend under the upper gypsums across Greer 

 County. 



"Day Creek Dolomite. — Resting upon the upper part of the Whitehorse sand- 

 stone in Kansas and Oklahoma is a conspicuous ledge of hard white dolomite, 

 first described by Professor Cragin from exposures in southern Kansas, as follows : 



"Upon the latest of the Red Bluff rests a persistent stratum of dolomite, varying in 

 thickness from less than a foot to 5 feet or more. * * * It is a true dolomite, containing 

 with the carbonate of lime an equal or even greater percentage of carbonate of magnesia. 



* * * Though not of great thickness, it is an important member of the upper Pcmiian of 

 southern Kansas and northern Oklahoma, owing to its persistence, which makes it a con- 

 venient horizon of reference. * * * The stone is nearly white in fresh fracture, weathering 

 gray, and often has streaked and gnarly grain rcsemljling that of fossil wood. * * * Its 

 cherty hardness and fracture are not due to the presence of silica, as one is tempted to infer, 

 but are characters belonging to it as a dolomite. It is a durable building stone." 



"In his second paper on the Permian rocks, in describing a typical Oklahoma 

 locality, Professor Cragin says: 



"The brow of the Red Hills near Watonga, Oklahoma, is capped with the Day Creek 

 dolomite, which here presents itself a compact stratum of gra3^ somewhat pinkish or reddish 

 tinged, cherty, hard rock, little different from the typical ledge that skirts the flanks of 

 Mount Lookout, in Clark County, Kansas. The stratum here has a thickness of 3 feet." 



