NORTH AMERICA AND THEIR VERTEBRATE FAUNA. 51 



STRATIGRAPHY OF THE RED BEDS IN OKLAHOMA. 



North of the breaks of the Big Wichita the surface of the country is 

 rolhng and grass-covered, and there is very httle exposure of the rocks or clays, 

 but it is evident that the same formations exposed farther south are continued. 

 Cummins found Wichita fossils {Cricotus, Edaphosanrus, and Dimetrodon) 

 near where the road leading from old Fort Augur to Fort Sill crosses Deep 

 Red River. This is his Indian Territory locality. The author found frag- 

 ments of Edaphosaurus spines near Emerson and fragments of Eryops and 

 Dimetrodon near Randlett, on the south side of Deep Red Run or River. 

 This last locality is several miles east of where Cummins got his fossils. 

 The surface of the breaks at the last locality shows mostly a deep -red clay, 

 with irregular patches of conglomerate (carrying the bones) and irregular 

 sandstone lenses, with much coarse concretionary material. The top layer 

 is 2 to 3 feet of shaly white sandstone. Both the fossils and the character 

 of the beds would tend to confirm Cummins's conclusion that these beds 

 are of Wichita age. Williston, traversing the same region somewhat farther 

 north, found a few fi;agments of bones (Diplocaulus, etc.) in isolated patches. 



These localities are well within the area marked by Gould '^ as "red beds 

 of uncertain relationship," surrounding the Wichita Mountains, and we 

 may be certain that the Wichita and Clear Fork extend at least as far north 

 as the fossils have been found, and probably include most of the area marked 

 as uncertain on Gould's map. Immediately surrounding the mountains the 

 land is more rolling and unbroken, and exposures are scarce. The exact 

 age of the sediments near the mountains remains undemonstrated, but 

 Gould describes them in terms that might well be applied to the Wichita 

 or Clear Fork formation in Texas : ^ 



"Lawton Area. — One of the areas referred to includes the country surrounding 

 the Wichita Mountains on all sides, occupying practically all of Comanche and 

 Kiowa Counties, besides eastern Greer, southern Washita, and southwestern Caddo 

 Counties. The deposits of the Greer formation surround the Wichita Mountains 

 at a distance of from 20 to 30 miles, on all sides except on the south. It is between 

 these Greer outcrops and the mountains that the rocks referred to occur. They 

 consist chiefly of red clay shales, with a few ledges of sandstone and dolomite, and 

 in that regard correspond to the Woodward. Like the Woodward, also, these 

 beds appear to underUe the Greer. Until the correlation of the rocks with the Texas 

 beds south of the Red River has been worked out, however, the exact relation of 

 the red beds of this area must remain a matter of doubt." 



Between the beds surrounding the mountains, which are so evidently 

 of Clear Fork and Wichita age, and the Enid of Oklahoma, which carries 

 the same fossils, the Greer and the Woodward are exposed in a long strip 

 running northwest-southeast. The Greer has been correlated with the 

 Double Mountain formation, and the Woodward with the upper part of 



» Gould, Map, U. S. Geological Survey, Water Supply and Irrigation Paper No. 148. 

 b Gould, Ibid., p. 73. 



