PEEMIAN. 491 



lithologic character in the mountain province are much more notable and render correlations 

 less certain. * * * UntU many districts have been reexamined with care, it will be prema- 

 ture to attempt direct correlation of the Dolores and Cutler formations as such with the 

 elements of sections in central and northern Colorado; but there are various facts beartog on 

 the distribution of Triassic and Carboniferous Red Beds which may be briefly presented: 



Turning to the lower part of the Red Beds, evidence has recently been presented by the 

 late W. C. Knight showing that in the Laramie Basra of southern Wyoming the Triassic strata 

 of Hayden and King should be referred in part at least to the Carboniferous system and probably 

 to the Permian series. Knight gives a section of 1,578 feet of Red Beds which rest on granite. 

 A little below the middle of this section a fossiliferous sandstone was found, the fauna resembling 

 "to a marked degree the fossils of the Kansas and Nebraska Permian." Only one thin lime- 

 stone was noted in the section, but Knight made the significant observation "that the strata 

 of the lower portion of the Red Beds are identical with the strata of limestones to the northward, 

 the difference in the lithological characteristics being due to the varied physical conditions 

 during sedimentation." 



These limestones also contain in their upper portion a fauna resembling that of the Kansas 

 "Permian," but Knight remarks that Coal Measure fossils have not as yet been collected from 

 the lower beds. 



Since Knight could find no stratigraphic or fossil evidence for subdividing the Red Bed 

 section of the Laramie Plains, he refers it as a whole to the Permian and compares it particularly 

 with the Permian of Kansas and Oklahoma. * * * 



Accepting the views expressed by Knight concerning the fauna of Red Beds of the Laramie 

 Plains, it is clear that the section above his lowest fossil-bearing horizon is younger than the 

 Rico formation [Pennsylvanian] but may correspond as a whole or in part to the Cutler forma- 

 tion. * * * The unfossiliferoys portion whose reference to the Permian is still open to 

 possible doubt is 850 feet in thickness, and it does not appear that the section was complete, 

 up to the Jurassic beds. There is, therefore, ample room for a Triassic formation in the Red 

 Beds of the Laramie Plains." * * * 



In the vicinity of the Triassic horizon observed by Hills [on Grand and Eagle Rivers, Colo- 

 Tado] the upper Paleozoic section is of very different character from that near Laramie, but its 

 upper portion was assigned to the Permian by Peale on the basis of a few plants considered by 

 Lesquereux as of that age. The strata so referred are gjrpsiferous shales of various colors, 

 yellow, pink, and creamy, with some limestone, and are not to be correlated either with the 

 Laramie Permian or the Cutler beds on present evidence. These gjrpsiferous beds are overlain 

 by the Red Beds of Peale, assigned to the Triassic, and seemingly this division must include the 

 bone beds of HUls, since the succeeding formation is apparently the normal fresh water Jura. 



* * * The well-known Red Bed section of the Front Range foothUls in Colorado was 

 assigned to the Trias upon no definite evidence, by geologists of the Hayden Survey. * * * 



In the Denver monograph Emmons and Eldridge named the entire Red Bed section of 

 that district the Wyoming formation, distinguishing within it the lower and upper divisions, 

 on purely lithologic grounds. The Lower Wyoming embraces beds like the Fountain in litho- 

 logic character and, in addition, the quartzose Creamy sandstone. Both Emmons and Darton 

 liave recognized the resemblance of the red arkose strata of the Lower Wyoming to the Foun- 

 tain beds; but the suggestion of the latter that the Fountain and Lower Wyoming are quite 

 ■equivalent is to my mind less natural than to consider the Lower Wyoming a group embracing 

 the Fountain beds and the lithologically distinct "Creamy sandstone," which Darton thinks 

 is equivalent with the Tensleep sandstone of the Bighorn Mountains, Wyoming, and which in 

 any case deserves a special name. 



The Upper Wyoming of the Denver region embraces the remainder of the Red Bed sec- 

 tion, and it is referred to the Trias by Emmons and Eldridge. Darton, however, in his valu- 



"At Red Mountain, south of Laramie City, characteristic Upper Triassic vertebrates occur in the uppermost 

 "'Red Beds." See WiUiston, S. ^X., Jour. Geology, vol. 13, 1905, p. 339.— B. W. 



