222 THE DEVONIAN AND CARBONIFEROUS. [bull.80. 



garding these correlations. In the first paper he reported the corre- 

 lation of " Subcarboniferous, Carboniferous, and t Permian " by the 

 fossils examined, but he thinks " there are no true Permian strata in 

 Colorado, Utah, Wyoming, or Idaho, but may be farther west." In 

 the second paper he accepted the evidence of the fossils (" Bakewellia^ 

 etc.) reported by Mr. Walcott from the red beds above the Aubrey 

 limestone as proving them to be "correlatives of the Permian of 

 Europe." " It does not follow that the periods were strictly coeval in 

 the two continents." 



Mr. Gilbert, in the Philosophical Society, 1 stated that " the contact 

 of these beds is frequently, and perhaps generally, unconformable in 

 the vicinity of the locality where the fossils are found, but there was 

 no such break separating them from the Trias beds above." And Mr. 

 J. W. Powell, discussing the same paper, remarked that "the strati- 

 graphic evidence, as well as the fossils, confirmed the correlation of the 

 beds as Permian from the Great Basin of Uinta and Arizona." The 

 fossils found were substantially the same as those found by Mr. King. 



In 1880 Mr. E. T. Cox 2 reported that the rocks about Tucson contain 

 fossils of Devonian, Subcarboniferous, and Coal Measure species. The 

 rocks are semicrystalline, coarse grained, and easily decomposed. 



The most exhaustive study of the Paleozoic formations of the Great 

 Basin province of the west was made by Mr. Arnold Hague in the 

 Eureka district, an abstract of the report upon which was published 

 in 1883. 3 



All the identification of fossils for this report were made by Mr. 

 Charles D. Walcott, who prepared a report in 1882 to go with Mr. 

 Hague's report, but subsequently enlarged it, adding results of his 

 study of new collections and of the sections themselves, and pub- 

 lished the final results as an exhaustive memoir in 1884. 4 



This Eureka section, Nevada, as reported by Mr. Hague, is 30,000 

 feet thick, made up of 7,700 feet Cambrian, 5,000 feet of Silurian, 8,000 

 feet of Devonian, and 9,300 feet of Carboniferous. 



The nomenclature and classification adopted for the Upper Paleozoic 

 is as follows : 



Feet. 

 f Upper Coal Measures (limestone) ...» 500 



Carboniferous { 



{ 



> Weber Conglomerate 2,000 



Lower Coal Measures (limestone) 3,800 



Diamond Peak quartzite 3,000 



Devonian.... 5 White Pine shale , 2,000 



I Nevada limestone 6,000 



Silurian Lone Mountain limestone, etc -. , 1,800 



1 "Permian-Carboniferous overlap in the west, "(abstract), by G. K. Gilbert. Washington Pbil. Soc. 

 Bull., vol.3, pp. 105-106. 

 *Cox, E. T. : The Geology of Southern Arizona. Am. Nat.,vol. 14, 1880, pp. 541, 542. 



3 Abstract of Report on the Geology of the Eureka District, by Arnold Hague. 3d Ann. Kept, of 

 the U. S. Geol. Survey for 1881-'82, 1883, by J. W. Powell, Director, pp. 241-288. 



4 Monographs of the U. S. Geol. Survey, vol. 8, 1884. Paleontology of the Eureka District, by Charley 

 Doolittle Walcott, pp. 1-298, Pis. I-XXIV. 



