R. S. Tarr — The Permian of Texas. 



Art. II. — The Permian of Texas ; by "Ralph S. Tare. 



From the time of the publications of Marcou and Shnmard on 

 the Geology of the Southwest to the present, the existence of 

 Permian in Texas has been reported by various observers. 

 Many have doubted its existence, but Prof. C. A. White* has 

 brought forward conclusive evidence on this point and it is 

 not now doubted that a large part of Texas is occupied by 

 Permian beds. Much remains to be done in this region before 

 the distribution of these strata through space and time is thor- 

 oughly understood. In the first and second annual reports of 

 the Texas Geological Survey, Mr. W. F. Cummins has added 

 many facts of interest to our knowledge of the Permian of 

 Texas, which he estimates to have a thickness of fully five 

 thousand feet. 



A detailed study of the Carboniferous beds beneath the 

 Permian, both in the eastern and western side of the basin, 

 and a reconnoissance trip across the Permian deposits are the 

 basis for the following remarks upon the Permian, the excuse 

 for their publication being the limited information on hand in 

 regard to this formation. 



The Permian of Texas occupies a broad, gentle syncline in 

 the Carboniferous, the western arm being a part of the Rocky 

 Mountain uplift. Its present boundaries, and consequently 

 its former extension, have not been ascertained. Many hundred 

 square miles are covered by these strata in the sub-humid and 

 arid belt of central Texas, the Pecos River forming, approxi- 

 mately the western boundary, while on the east the strata do 

 not extend much farther than Abilene. 



In lithologic character the strata are distinctive and, except 

 near the contact, not to be confounded with the Carboniferous. 

 They are chiefly beds of clay, sandstone and conglomerate, 

 strikingly red in color. Limestone beds also occur, these 

 usually being a pale gray, quite characteristic, though often 

 stained on the surface by the red clay from the red beds. In 

 addition to these strata there are beds of gypsum and of salt, 

 and in the center of the district all the water is rendered unpal- 

 atable by the presence of these salts. Most of the beds are 

 unfossiliferous, but Dr. White has described thirty-two species 

 of invertebrate fossils from the Texas Permian, and Prof. 

 Cope fifty-seven species of vertebrates. It is upon this basis 

 that the beds have been referred to the Permian. 



It is the object of this paper to indicate the sequence of 

 events which have led to deposition of the Permian beds in 



* Am. Nat., xxiii, p. 109, Feb., 1889. 



