22 GIRTY 



this is so, and if the resemblance of the Capitan fauna to that 

 of the Schwagerina zone warrants assigning the Capitan lime- 

 stone to that horizon, the entire Trans-Pecos Carboniferous sec- 

 tion would lie below the true Permian. 



In a preliminary paper on the Capitan fauna,' relying upon its 

 resemblance to those of the Salt Range of India, of the Carnic 

 Alps, and especially of the region about Palermo, in Sicily, faunas 

 which have been called Permian by different authorities, I called 

 that from Texas also Permian, as indeed, its discoverer, Shu- 

 mard, had done ; and, in view of its entire difference from the 

 so-called Permian of the Mississippi Valley, and upon other 

 considerations, even regarded it as upper Permian. Several 

 circumstances leave me still of the opinion that this bed may 

 be Permian. Its fauna is strikingly like that described by 

 Gemmellaro from Sicily, which Tschernyschew ascribes to the 

 Artinsk stage of the true Permian. In some respects the re- 

 semblance of the Capitan fauna to that of the Schwagerina zone 

 is also striking, but, as already remarked, there is much in the 

 Schzvagerina horizon that is not found in the Capitan fauna, 

 and much which in western Texas is found only at a much lower 

 horizon. These facts, taken in conjunction with the circum- 

 stance that the thickness of the beds comprising all four of 

 Tschernyschew's zones (for his work as the title indicates ex- 

 cludes the fauna of the Spirifer mosquensis zone) is consider- 

 ably under i,ooo feet, while the Texan series is considerably 

 over 4,000 feet, certainly lend a color of probability to the 

 hypothesis that the higher beds in Texas may be younger than 

 the Schzvagerina zone. It seems probable indeed that all four 

 of Tschernyschew's horizons are represented in the Hueco for- 

 mation, where the different faunas are not as clearly distin- 

 guishable into separate entities as in Russia, the faunas of the 

 Delaware Mountain sandstone and the Capitan limestone being 

 derived from them, but modified by evolution of surviving spe- 

 cies, the elimination of some forms and the introduction of others 

 by rhig ration. 



Another consideration is that Tschernyschew correlates the 

 Permo-Carboniferous of the Wasatch Range with the Artinsk, 



'Am. Jour. Sci., vol. 14, 1902, p. 363. 



