412 GEOLOGY OF NORTHWESTERN TEXAS. 



In regard to the difficulty of identifying the Permian formation in the 

 United States Prof. Endlich, in his report on the geology of the Wind River 

 Range, in 1877, says: "The determination of the strata has been made with 

 great difficulty, owing to the lack of characteristic fossils in the formation. 

 At that locality the beds of Permian are composed of yellow and red sand- 

 stones and shales, with some dolomite, resting directly upon the hard blue lime- 

 stone of the Carboniferous, and are overlaid by the Red Beds of the Mesozoic 

 Group. The formation is conformable with both the Carboniferous below and 

 the Mesozoic above. The inclination is nearly east and west, and in many 

 places has both anticlinal and synchlinal folds. There is great uniformity of 

 thickness and lithologicai character." 



In a section made by St. John of the Pierris Mountain he gives two fos- 

 sils, Lingula and Pleurophorus, which he says are similar to the Pleurophorus 

 found in the lower Missouri regions, and probably identifies that horizon with 

 the one further to the east. 



Capt. C. E. Dutton, in a report on the Physical Geology of the Grand 

 Canyon District, in 1882, page 64, says: "After the Carboniferous, came the 

 Permian Age, in which were laid down from eight hundred to fifteen hun- 

 dred feet of sandy shales. The stratification was wonderfully even and 

 everywhere horizontal. The Permian beds are often ripple marked, and 

 betray many evidences that they accumulated in shallow waters." 



He also says that the same state of affairs continued through the Trias, 

 which lies immediately upon the Permian. Again, on page 9, he speaks of 

 the Permian lying immediately below a band of pale sandstone of very coarse 

 texture, often becoming a conglomerate. This is the same conglomerate that 

 Major J. W. Powell calls the Shinarump, and which Mr. C. D. Walcott 

 places as the divisional line between the Permian and Triassic. 



I have already adopted this horizon as the line between the Permian and 

 Trias in this part of Texas. 



In studying the fossils of the Permian of Texas I have not attempted to 

 correlate them with the fossils found in the Permian in Europe, nor do I 

 think it necessary to have them so in order that the beds in Texas should be 

 placed in that division. It is a well known fact that some fossils that are 

 characteristic of a division in Europe are not found in the same division in 

 America, but are found in other divisions, and become characteristic of the 

 formation where found. 



Take for instance the Fusilina cylindrica, Fischer, which in Europe is found 

 nowhere except in the Sub-Carboniferous, while in America it is not found 

 in any place except in the Coal Measures, and the attempt to correlate strata 

 in America with that of Europe by the fossils alone has led to some grave 

 mistakes. 



