450 CROSS AND HOWE — RED BEDS OF SOUTHWESTERN COLORADO 



and only exposed locally " (12, page 215). This last qualification is but 

 a general saving clause, for he nowhere refers to observed Triassic or 

 Jurassic beds and in fact remarks in another place that " without 

 the appearance of either Triassic or Jurassic we find the Cretaceous 

 sandstones belonging to No. 1 [Dakota] resting immediately upon the 

 red Carboniferous sandstone. No transitory formations whatever are in 

 sight between the two," etcetera (12, page 222). 



The reference of the San Juan Red beds to the Upper Carboniferous 

 was due to the discovery by Endlich in 1873 of fossils in the reddish, 

 limestone-bearing section of the Arkansas valley and Sangre de Cristo 

 range. Indeed, he provisionally correlates the San Juan strata with 

 this formation — his " Arkansas sandstone " (12, page 240). On the 

 Hayden map Endlich represents the " Upper Dakota " as resting on the 

 " Upper Carboniferous." In this division of the section it is plain that 

 the Jurassic Gunnison group (La Plata and McElmo formations) is 

 included in the " Upper Dakota," and that the " Upper Carboniferous " 

 consists of the Red beds. 



In 1875 W. H. Holmes examined the country west of Endlich's terri- 

 tory of the previous year, and the Hayden map shows two formations 

 namely, u Lower Dakota " and " Trias," interpolated between " Upper 

 Carboniferous " and " Upper Dakota." The sections studied by these 

 two geologists are, however, practically the same and the overlaps indi- 

 cated by the Hayden map simply show the method of adjustment 

 adopted in compilation. The Red beds are referred to the Trias by 

 Holmes in his report (23) without special discussion of the question. 

 Except in the zone bordering Endlich's field, no area examined by 

 Holmes and actually occupied by Red beds is colored as " Upper Car- 

 boniferous " on the Hayden map. 



The Red beds near Ouray were hastily examined by A. C. Peale in 

 1875. In his report he refers to them as above the Carboniferous and 

 says that " above them is the Dakota sandstone " (35, page 41). He, 

 however, recognized the Jurassic (or McElmo beds) as present beneath 

 the Dakota on the north side of Dallas creek, beyond a fault, and the 

 final map, in the Hayden atlas, represents Trias, Jura, and " Lower 

 Dakota " as present at Ouray. The strata now under discussion un- 

 doubtedly comprised the Triassic section of Peale. 



An important contribution to knowledge of the San Juan Red beds 

 was made by R. C. Hills in 1880 (20) and 1882 (21) in the discovery of 

 vertebrate, invertebrate, and plant remains in the San Miguel valley. 

 The locality of this discovery is about 1? miles below the present site of 

 Telluride. The vertebrate remains consisted principally of teeth belong- 

 ing to a belodont crocodile, and one specimen represented a ganoid fish 



