82 CARBONIFEROUS FORMATIONS AND FAUNAS OF COLORADO. 



The most suitable standard sections with which to compare this of Peale's are 

 those described in the Leadville monograph and in the Tenmile folio. There can be 

 little doubt that in the Lower Carl)oniferou.s of Peale's section the Leadville lime- 

 stone is included, and probably something more. He seems to have assigned to the 

 Lower Carboniferous beds 40 to 72 of his detailed section No. 18. His Upper Car- 

 boniferous is probably the Weber grits of the Tenmile folio. The Weber shale of 

 that folio I suspect to be equivalent to the upper part of his Lower and the lower 

 part of his Upper Carboniferous. His Permian appears to correspond in the main 

 to the Maroon formation of the folio, but it is possible that with it is included a 

 part of the Wyoming sandstone, which in the main answers to his Triassic. This 

 formation — i. e., the Permian — is in part described as being pink and containing 

 gypsum, characters rathei' suggestive of the beds which in other sections he calls 

 Permian and Triassic, and also of the Wj'oming sandstone; but it is singular that 

 none of the formations in either the Leadville monograph or the Tenmile folio is 

 described as being gypsiferous, nor is this character mentioned in the original detailed 

 sections from which the generalized one is supposed to be derived. 



Just as the lower part of Peale's composite section for the Park Range is based 

 mainly upon section No. 18 of 1873, the upper part is based upon section No. 9. In 

 the latter all the higher beds up to 52 which he refers to the Triassic are "Permian." 

 The Triassic, here 1,.500 feet thick, probably represents the Wyoming formation, and 

 the beds below, ehieflj^ because of the abundance of limestone strata, would more 

 naturally belong in the Maroon formation. If this is so, and if the upper part of 

 the composite section is based upon this, or, consistently, upon several detailed 

 sections, then the "Permian" of the general section would answer to the Maroon 

 formation of the Tenmile folio without containing any of the Wyoming. Peale 

 seeks to correlate the Permian beds of the Park Range with those in the Elk Moun- 

 tains for which the same designation is emploj'ed. To this there would be no objec- 

 tion, as both probabljr represent the upper portion of the Maroon formation without 

 extending up into the Wyoming sandstone. He also, however, assigns both these 

 groups to the Permian of the Eagle River section. This does not seem to me 

 altogether probable, as I svispect that the upper portion of the Eagle River Permian 

 belongs to the Wjj^oming sandstone. 



The relation to that of the Dolores River region of this Park Range section is 

 open to two interpretations. In the one case the Coal Measures and Permian of the 

 latter represent the Coal Measures and lower portion of the Permian in the former. 

 In the other case onlj' the Coal Measures division of the Park Range beds represents 

 the Coal Measures and lower Permian in the Dolores River region, the Permian of 

 the former being wanting in the latter. The Park Range "Triassic" would in any 

 case answer to the upper part of his "Permian" combined with the lower part of his 

 "Triassic" of the Dolores River section. 



