70 THE PERMO-CARBONIFEROUS RED BEDS OF 



While Mr. Butters correlates the Lykins with the Rico, he notes that the 



fossils occur in regions which were separated by a land area at the time of their 



deposition. 



CONCLUSIONS. 



From the facts brought together above, several interesting conclusions 

 may be drawn. It is shown that in the Bighorn and Laramie Mountains 

 the Carboniferous limestone shades into thin red beds, just as in Kansas, 

 Oklahoma, and Texas, and that the same thing is probably true of the Black 

 Hills and at least as far south as the north line of Colorado. Probably similar 

 relations could be found from southern Kansas to the Bighorn Mountains 

 were not the beds covered by later deposits. On the west, the upper part of 

 the Red Beds, Chugwater in part and Spearfish, are generally regarded as 

 Triassic, farther toward the south there is a distinction into upper Wyoming 

 and lower Wyoming (Fountain) formations. Darton, as quoted, believes 

 the upper beds to disappear a short distance south of the Garden of the Gods 

 and the lower Wyoming (Fountain) to appear in contact with the Cretaceous 

 or Jurassic, and with this the author is in accord. With many of the observa- 

 tions of Darton, the author, from recent study, is in full agreement, but he 

 does not feel that the various beds, as the Minnekahta, Opechee, etc., 

 can be recognized so confidently in many places as Darton appears to do. 

 This is undoubtedly due in part to the author's lesser acquaintance with 

 the beds in question, but he still feels that prolonged study would not 

 render all of Darton's correlations entirely satisfactory to him, especially as 

 there is so much of terrestrial deposition, with its concomitant irregularity 

 of the beds. 



The upper Red Beds of Colorado (upper Wyoming, Lykins) are grouped 

 by Darton with the Chugwater and Spearfish, and he refers to them as partly 

 Permian and partly Triassic. The lower portion of the Colorado beds is 

 certainly Permo-Carboniferous. Butters, as shown above, has collected fos- 

 sils from these beds which Girty calls "American Permian" {fide Gecjvge) , 

 and this means practically the horizon of the Texas-Oklahoma beds. The 

 author studied the beds from Red Mountain, near Laramie, to where they 

 disappear south of Colorado Springs, with the greatest care, and, while no 

 trace of vertebrate fossils was found , the lithological similarity to the beds of 

 Texas and Oklahoma was so striking that, coupled with Butters's discovery 

 of fossils, the suggestion that these beds were laid down in a continuation of 

 the area of deposition in the south and under identical conditions is so strong 

 as to be almost conclusive. Color, texture, markings, included concretions, and 

 similar structures from one locality can be exactly matched in the other. The 

 author is convinced that the Lykins formation, at least as high as the base 

 of the pinkish, massive sandstone near its top (plate 17, fig. i), can be corre- 

 lated directly with the beds of Texas, so far as the conditions of deposition 

 and the continuity of the area of deposition goes. Whether the time of 

 deposition was exactly the same in the two areas is not certain, but the 



