PERMIAN VERTEBRATE FOSSILS IN TEXAS 745 



south of Kiowa Peak in Stonewall County, Texas {Second Ann. 

 Rept. Tex. Geol. Sur. No. 15, p. 406). This would be about the base 

 of the Double Mountain Division. 



DISTRIBUTION 



Of the eight genera of Stegocephalia only four, Trimerorhachis , 

 Zalrachys, Eryops and Cricotus, have been found in the Wichita. 

 The first three, together with Diplocaulus, Dissorhopus, Acheloma, 

 and Anisodexis, are found also in the Clear Fork, Cricotus alone 

 being absent from the latter beds. In all cases, however, the species 

 occurring in the two divisions are different. 



Of the Cotylosauria, Diadectes, Empedias, Pariotichus, and 

 Pantylus are common to both divisions, but only a single species, 

 Diadectes phaseolinus, occurs in both. In all other cases the genera 

 are represented by distinct species. Chilonyx and Bolosaurus are 

 confined to the Wichita, while Bolbodon, Isodectes, Hypopnous and 

 Lahidosaurus appear only in the Clear Fork. 



The Chelydosauria are found only in the Clear Fork. 



The distribution of the Pelycosauria is equally distinctive. While 

 three species of Dimetrodon and two of Naosaurus extend through 

 both divisions, we have as characteristic genera of the Wichita, 

 Cleopsydrops, Ctenosaurus, Theropleura, Metamosaurus, Paleosaurus 

 and Emholophorus and of the Clear Fork Edaphosaurus only. 



It is therefore evident that the divisions of Wichita and Clear 

 Fork which were proposed at first on purely stratigraphic grounds 

 are fully warranted and upheld by the fossils found in them. And it 

 will be found when the invertebrate forms collected from these 

 divisions on the Colorado shall have been studied that this separa- 

 tion is equally warranted there. 



