PERMIAN. 423 



Carboniferous. In Arkansas the gypsum occurs in the Trinity Sands or 

 Lower Cretaceous.* 



(e) "There are frequent shore marks, ripple marks and rain drops" in 

 other formations than that of the Triassic. * 



(f) This is no reason to refer strata to a distinct horizon because in other 

 places certain strata have no fossils. But such is not the case in Texas, because 

 fossils have been found in all the strata I have called Permian to within a 

 short distance of the top, and will no doubt be found there upon proper in- 

 vestigation. 



(g) The Jurassic and Triassic of Texas are not the same as the gypsum 

 beds of Texas. The Triassic lies entirely west of the gypsums in Texas, and 

 is so understood by Marcou and White, if Dr. White concedes the fact that 

 the Pleurophorus and other Permian fossils determine the question, which he 

 has already done. The Red Beds now referred to are those that occur in 

 connection with the heavy beds of gypsum in Texas, and not the Red Beds 

 of the Triassic that I have called Dockum Beds. 



(h) The surface of the Upper Permian was deeply eroded before the Tri- 

 assic was laid down in Texas, and so were the Triassic beds deeply eroded be- 

 fore the Blanco Canyon beds were laid down; so the question of erosion does 

 not definitely show the strata to be either the one or the other. 



The entire beds of the Texas Permian are conformable, having a small dip 

 to the northwest, while the Dockum Beds (Triassic) dip to the southeast. 



To summarize the reasons for saying all the strata from the Wichita divi- 

 sion to the Dockum Beds are Permian, the following may be stated as true: 



(a) There is a continuous sedimentation from the bottom to the top. 



(d) The conglomerate of the Dockum Beds has been placed by Hayden 

 elsewhere as the line between the Permian and the Triassic. 



(b) The occurrence of Permian fossils in the strata from the bottom to 

 near the top of the Wichita, Clear Fork, and Double Mountain Beds. 



(c) The Albany Beds are characterized by a distinctively Coal Measure 

 fauna. 



(e) The Dockum Beds contain fossils of distinctively Triassic age, as deter- 

 mined by Prof. Cope. 



There will be no difficulty in understanding why the Red Beds of Texas 

 have been referred to the Triassic, if it will be kept in mind that there are 

 Triassic beds in Texas that very much resemble in general appearance the 

 Permian beds below them, although they would not be confounded with the 

 Permian where the two are seen together. Dr. Newberry thus describes the 

 beds which he correctly calls the Triassic :f 



* Arkansas Keport, Vol. 2, p. 119. 

 fMonograph, U. S. Survey, Vol. XIV, p. 13. 



