66 THE PERMO-CARBONIFEROUS RED BEDS OF 



Girty* regards the Fountain formation as Pennsylvanian. Henderson,'' 

 regarded the lower part as Mississippian and the upper as Pennsylvanian, 

 and David White," from the evidence of fossil plants, wotdd place it in 

 Potts ville time. 



In Professional Paper 53, United States Geological Survey, Darton speaks 

 of the Red Beds of Colorado. He says that in southern Colorado the Red 

 Beds lie on an irregular surface of granite, except in certain embayments, as 

 the ones at Manitou and Canyon City, where lower Paleozoic rocks intervene. 

 The Red Beds have been found to be an extension of the Red Beds under- 

 lying the Carboniferous limestone in southeastern Wyoming and of the Per- 

 mian and overlying Red Beds of Kansas."^ The Red Beds of this region he 

 considers as divisible into three parts: (i) the Fountain or lower Wyoming 

 (the lowest), consisting of coarse red grits which he found to represent the 

 upper Carboniferous limestone of Wyoming; (2) the Tensleep sandstone, 

 traced as far south as the Manitou embayment; (3) the gypsiferous red shale 

 and sandstone of the Chugwater, which represents the Red Beds of the Black 

 Hills and Wyoming. The lower part of the Chugwater he considers as Per- 

 mian, the upper part as Triassic or Permian. 



Lee ^ has described the Red Beds of southeastern Colorado and north- 

 eastern New Mexico. He found in southeastern Colorado a great thickness 

 of red beds lying beneath a shale formation which he regards as Morrison in 

 age. These beds extend as far south as the valley of the Canadian River in 

 New Mexico, showing in the walls of the various canyons. The Red Beds, 

 which he regards as of Permian or Permo-Carboniferous age, consist of many 

 feet of red sandstone and shale lying unconformably beneath the Morrison 

 shales. It is certain that in the Canadian Valley, from Tucumcari to the 

 Conchas Canyon, the Red Beds are of Triassic age (plate 11 and plate 12, 

 figs. I and 2) ; this is shown by the contained fossils, phytosaurs and Unio, 

 collected by the author. In the same beds Darton found the remains of a 

 phytosaur on the Purgatory River in southeastern Colorado. The red beds 

 as described by Lee terminate above the heavy beds of gypsum and gyp- 

 siferous clay, but near Folsom, New Mexico, he found a heavy red sandstone, 

 the Exeter, lying unconformably upon the Red Beds. It is very probable 

 that this sandstone extends farther south than is mentioned by Lee, as a 

 heavy red sandstone equivalent to the Exeter in position is seen as far south 

 as the north wall of the Canadian Valley near Montoya, New Mexico. Con- 

 sidering the evidence of the fossils discovered, it seems probable that the red 

 beds described by Lee are Triassic in age. 



» Girty, U. S. Geological Survey, Professional Paper 71, pp. 369, 370. 



I" Henderson, Jour. Geol., vol., 16, pp. 491,492, 1908. 



" White, U. S. Geological Survey, Professional Paper 71, p. 370. 



'' The Red Beds of Kansas have since been shown to be continuous, in part at least, with the Permian 

 limestones and not to overlie them. — E. C. Case. 



■ Lee, Jour. Geol., vol. ix, p. 393, 1901 ; Ibid., vol. x, p. 36, 1902; Jour. Geography, vol. i, p. 35, 1902 ; 

 Ibid., vol. II, p. 62, 1903. 



