32 THE PERMO-CARBONIFEROUS RED BEDS OF 



Wichita conglomerate.* It is traceable in the breaks of the small creeks 

 which form the main exposures in the region. North of the Big Wichita 

 River this layer is very persistent, and forms a good reference horizon (see 

 plate 8, fig. 2). Above it are 100 to 200 feet or more of red clays, sandstones 

 and conglomerates, carrying typical Clear Fork vertebrates. (Here are the 

 Cacops beds of WiUiston, Lysorophus beds, etc.) On the north side of the 

 Big Wichita, the beds above the Wichita conglomerate appear as prominent 

 bluffs capped with a heavy conglomerate or sandstone. West of Haskell 

 the land is level and the rocks are concealed by a considerable thickness of 

 surface soil, but at Sagerton, some 12 miles southwest of Haskell, the bluflf 

 shows at its foot cleaner clays, with little conglomerate and a much more 

 regular and even stratification; at this place appear also the first layers of 

 satin spar which are so characteristic of all the Permo-Carboniferous beds 

 above the Clear Fork. The gypsum which occurs in the Clear Fork Beds 

 is in local patches, and far from abundant. Evidently there was a serious 

 change in the conditions of sedimentation between the Clear Fork and 

 Double Mountain time. All along the line drawn by Cummins separating 

 the formations, the difference between the beds may be recognized within 

 a mile or more by the characters described. 



OCCURRENCE OF FOSSIL VERTEBRATES. 



Vertebrate fossils are not found through all of the Wichita formation, 

 but have been collected from the whole thickness of the Clear Fork. If a 

 line be drawn south from the Big Wichita River, a little east of HoUiday in 

 Wichita County, east of Archer in Archer County, and continuing for an 

 undetermined, but not great, distance south of the latter place, it will mark 

 the east line of the occurrence of vertebrate fossils in the Wichita.'' A con- 

 siderable thickness of deposits only to be reckoned as belonging to the 

 Wichita lies below the beds mentioned. 



Fossils occur in the Clear Fork to its upper limit, for Cummins reports 

 finding bones on Paint Creek, a few miles south of Haskell. North of Haskell 

 vertebrates have been found for only a few miles west of the road from 

 Seymour to Vernon. 



Any attempt to describe the beds in which the vertebrate fossils occur 

 is fraught with the greatest difficulty, as they are in the highest degree dis- 

 continuous; only the fossil hunter, whose success may depend on following 

 a single layer, can realize the impossibility of tracing any one of the layers 

 of sandstone, clay, or conglomerate for more than a very short distance. 

 Perhaps the best general idea of the beds may be gained by realizing that 

 the limestones outcrop with a strike a little east of north, and a gentle 

 westerly dip; though they can not be traced continuously for more than a 

 mile or so, they indicate the general lie of the beds, which are in general 



» Case, Bull. Amer. Mus. Nat. Hist., vol. xxiii, p. 662, 1907. 



^A recent letter to the author from Dr. C. L. Baker of the University of Texas reports the discovery 

 of a small skull of Cardiocephalus from Halsell in central western Clay County. 



