EECAPITULATION OF PALEOZOIC FORMATIONS. 185 



of the same Permian fo&sils, although these are scai'ce and not well preserved." 

 Darton does not state more specificalh' the species found at Morrison, nor have the 

 fossils themselves come to hand. He obtained from the same horizon at Lj'ons, 

 farther north, however, a hand specimen containing more or less indistinct impres- 

 sions of a gasteropod and a pelecj'pod. The former is very small and has the general 

 appearance of a JVatica or Naticopsis, but may be something quite different. The 

 pelec5'pod is also small, oblong, and transverse, having somewhat the shape of a 

 small Pleurophorus, but in this case also the generic position is indeterminable. 

 Taken by itself this fauna is altogether negative as to the question under considera- 

 tion, while a comparison with the fauna of the Minnekahta limestone of the Black 

 Hills is almost equally inconclusive. It would be unsafe to say that neither of the 

 species from Colorado occurs in the Black Hills, but the gasteropod has not j^et been 

 found there, and though I should be unwilling to state definitely that the pelecypod 

 is different from some ill-preserved forms among the Black Hills fossils, I believe 

 that it is not the same. For the present, therefore, it will probably be best to regard 

 the j^aleontological evidence as nil. Reduced to a proposition of identification of 

 horizon b^- means of tracing lithologic chai-acter and stratigraphic position, the 

 correlation may be accepted with caution. 



The area south of that examined by Marvine was the subject of Peale's report 

 for 1873. Peale gives no general description of the Red Beds and attempts no 

 classitication, save by calling the lower portion Triassic, with a Jurassic series over- 

 lying. The Triassic beds, which are in a general way the equivalent of' the typical 

 Wyoming formation, especiallj' with the upper portion of the thicker and all of the 

 thinner sections, consist mainly of red, pink, and white sandstones, and are repre- 

 sented upon the Hayden atlas as continuous from the South Platte, where Peale's 

 district begins, to Perry Park. Between Perrj"^ Park and Colorado Springs they are 

 concealed b}' overlap of later sediments, while in the vicinit}' -of Colorado Springs 

 and in Manitou Park areas of greater or less extent are represented. The Triassic 

 beds appear to be for the most part in direct contact with the Archean, but at Perry 

 Park, Manitou Park, and Colorado Springs areas of Carboniferous and in some 

 cases Silurian strata are represented as undei'lying them. While the Triassic appar- 

 ently consists mainl}^ of sandstones, the Jurassic comprises for the most part lime- 

 stones and shales, and probably is the equivalent more or less precisel}^ of the 

 Morrison formation. 



The Hayden atlas represents Upper Carboniferous sediments as intervening 

 between the granite and Triassic in Perr}^ Park. As I have already shown, the lime- 

 stone described by both Peale and Lee as lying near the base of the sedimentary 

 series in Periy Park carries Mississippian fossils and is to be correlated with the 

 Millsap limestone. The sandstone beneath it I think may possibly be Cambrian. It 



