FEALE.] GEOLOGY PEEMO-CARBONIFEROUS STRATA. 117 



The strata exposed in the canon of the Grand will be treated of in 

 Mr. Maivine's report, to ^vhicli the reader is referred. 



Gunnison River. — Nothing was fonnd along the course of the Gunni- 

 son Elver that could be referred to the Carboniferous. 



In treating of the Carboniferous formation as exposed in our district, 

 up to this point I have made no division. I have not separated the 

 Subcarboniferous from the Coal-Measures because I had no reliable 

 data to guide me in making such a separation. I believe, however, 

 that the limestone which lies at the base of the section made on Eagle 

 Eiver represents the Subcarboniferous, although I cannot say so posi- 

 tively, and that the sandstone and shales which overlie it conformably 

 are the representatives of the Coal Measures of the eastern portion of 

 the United States. As exposed in the bluffs on the eastern side of 

 Eagle River, these sandstones and shales have black coaly-looking 

 lasers between them, while patches of black carbonaceous material are 

 of frequent occurrence in the midst of the sandstones. During their 

 dei^osition there must have been, on Eagle Eiver at least, low marshy 

 ground which probably extended around the Sawatch range. 



The beds on a creek (Map A) present the same general charact,ers as 

 those on Eagle Eiver, and belong in all probability to the same horizon, 

 although without the discovery of organic remains this cannot be posi- 

 tively asserted. The strata in their horizontal extension, as already 

 mentioned, change rapidly, so that lithological characters are very 

 uncertain tests of age. 



PERMIAN OR PERMO-CARBONIFEROUS. 



Under the head of Permian, I will describe the strata that continue 

 uninterruptedly from the top of the section given under the Carbonif- 

 erous, to the base of the Eed Beds, (Triassic?) 



I have called them Permian, from the discovery in the beds on Eagle 

 Eiver of fossils which Professor Lesquereux decided were of Permian 

 age. On Eagle Eiver, on the Grand and on Eoaring Fork the upper 

 portion of these beds is exposed, and in all these localities the beds are 

 gypsiferous. They consist of variegated strata, yellow, pink, and 

 cream-colored shales and limestone, subject to so much change that it 

 was impossible to make any continuous section. 



Dr. Hayden found a series of beds in the Black Hills which he re- 

 ferred to the Permian, as they contained fossils that had been before 

 found in Kansas and referred to the Permian. 



Below the series in Kansas is another set of beds which were also 

 referred to the Permian by Swallow and Hawn, but which have been 

 referred by Meek and Hayden* to the Upi)er Coal-Measures. Between, 

 however, is a series to which they gave the name of Permo-Carbonif- 

 erous. Professor Meek says :t " This latter distinction, however, it 

 should be remembered, is, as we have always exi^lained, even in Kansas, 

 merely an arbitrary one, not founded upon any well-defined physical or 

 paleontological break between these upper beds and the Upper Coal 

 Measures." 



On Eagle Eiver, also, as I have before said, there is no break between 

 the Carboniferous and the Permian. 



In New Mexico, Shumard claims to have found Permian strata in the 

 Guadalupe Mountains. 



* United States Geological Survey, Final Report on Nebraska, 

 t Ibid, page 130. 



