14 GIRTY 



the fact that the horizon of some of the beds corresponds to one 

 in the East whose fauna is for the most part scanty and is as 

 yet practically unknown (Pottsville). On the other hand, a 

 number of the Western faunas are quite distinct and altogether 

 unknown in the East. Reciprocally, the familiar upper Penn- 

 sylvanian faunas of Kansas and Nebraska have not been found 

 in a facies at all characteristic in the Western region. 



Within the past 2 or 3 years I have given much preliminary 

 study to the faunas of the Trans-Pecos region of Texas and 

 New Mexico, where is found the longest section of Pennsyl- 

 vanian rocks in the West of which I have personal knowledge, 

 aggregating in all over 6,000 feet. The upper portion of this 

 section constitutes what I have called the Guadalupian series. 

 The upper division of the Guadalupian consists of the Capitan 

 limestone, some 1,800 feet thick, and the lower is the Dela- 

 ware Mountain sandstone, with a thickness somewhat greater. 

 Beneath the Guadalupian series occurs the Hueco formation, or 

 Hueconian, comprising upwards of 2,000 feet of limestone. 

 The faunas of these formations are quite different from those of 

 the Eastern States. Very few species can be definitely identi- 

 fied as common to both areas, and these are chiefly such as 

 enjoy a world-wide distribution. Through the West, however, 

 these faunas will probably prove to have extended widely. 

 Their general character is shown in some preliminary lists in a 

 report upon this region, by G. B. Richardson, recently issued as 

 a bulletin of the Texas Geological vSurvey.^ The Hueco forma- 

 tion, which is in the main a limestone, will perhaps prove to be 

 the same as the Aubrey formation of northern Arizona, which 

 consists of sandstone and limestone in alternation, and I am ten- 

 tatively correlating these formations with the Weber quartzite of 

 Utah. The Delaware division, comprising chiefly sandstones 

 in the Guadalupe Mountains, with a few calcareous beds, but 

 very variable in the character and proportions of its constituents, 

 can possibly be correlated with the Permian of Walcott's Grand 

 Canyon section and with the " Permo-Carboniferous " of the 

 Wasatch Mountains. However, if there is some doubt about 

 the correspondence of the Arizona beds, there is still more in 



lUniv. Texas Min. Suiv.. Bull. No. 9, Nov. 1904, pp. 32 et seq. 



