EESUME OF LITERATURE. 103 



these strata with the "Primordial" of the Black Hills, and tried to correlate them. 

 Hayden's Carbonifei'ous, a series of calcareous, areno-calcareous, and arenaceous 

 beds said to occur on both sides of the Rocky Mountain Divide, probably includes 

 the fossiliferous strata alreadj^ mentioned. His Permian color, I think, must have 

 been introduced on general principles without, it may be, his having any definite 

 beds in mind, and certainly without any definite evidence of their Permian age. 

 Regarding this same area, Haj^den writes in 1868 :'^' 



"At the head of Pole Creek on the eastern margin and in the Laramie Plains 

 west, the Carboniferous rocks are mostly of a red arenaceous character, with a few 

 lavers 2 to 10 feet in thickness of whitish or yellowish limestone. From these 

 limestones I collected Producttis prattenianxis, Athyris suhtilita, and other well- 

 known Carboniferous forms. Above these red beds which contain intercalated beds 

 of limestone is a considerable thickness of purely red arenaceous beds, but in studying 

 all these rocks with some care from Pole Creek nearly to Pikes Peak, I could not 

 separate the red beds from the Carboniferous b}' any break in continuity, and I was 

 rather inclined to the opinion that inasmuch as a large portion of the gypsiferous or 

 variegated beds could be shown to be Carboniferous they might possibly all be 

 included in that period." 



In 1869 Haj'den* made an extended and apparently a hasty trip chiefly along 

 the eastern edges of the Rocky Mountains from Chej^enne, Wyo., as far south as 

 central New Mexico. His observations deal in large measure with the eastern 

 margin of the Front Range, but as they appear to be inaccurate in many particulars, and 

 have been duplicated by the more detailed work of later geologists, I have made no 

 serious attempt to compare or to harmonize them with known facts or present S3'stems 

 of classification. Hayden recognized the general absence of Paleozoic outcrops along' 

 the Front Range, and refers the Red Beds to the Triassic, with the reservation that 

 they may in part be Jurassic.'' But he is b}^ no means consistent in maintaining this 

 opinion, even in the course of the single paper under consideration, for, after citing 

 a limestone with an undeniable Carboniferous fauna from the line of the Union 

 Pacific Railroad just north of Granite Canyon,"* he says that near Park station are 

 some dull-purplish sandstones and pudding stones "which are probably of Carbon- 

 iferous age,"" while to the same period he assigns a considerable thickness of lime- 

 stone observed on Boxelder Creek in association with red Triassic sandstones.-^ 

 The last two localities are in Colorado, but the first is in Wyoming. On the other 

 hand, on page 126, the statement occurs: 



"I do not know of anji- portion of the West where there is so much variety 

 displayed in the geology as within a space of 10 iniles square around Colorado City. 

 Nearly all the elements of geological study revealed in the Rocky Mountains are 



aAm. Jour, Sci. (2), vol. 45, 1868, p. 324. 



6See U. S. Geol. Geog. Surv. Terr., First, Second, and Third Ann. Eepts., 1873, Tliird Ann. Kept., pp. 103-251. 



olbid., p. 113. tilbid., p. 111. elbid., p. 118. /Ibid., p. 120. 



