THE PLAINS PROVINCE 109 



'"The Chugwater formation (upper Wyoming Red Beds) is only 140 feet 

 thick at the Garden of the Gods and appears to thin out and disappear a few 

 miles south, bringing the Fountain formation into contact with the Morrison, 

 a relation due either to non-deposition of the Chugwater beds or to their removal 

 by erosion in pre-Morrison times. As it is, the hiatus probably represents part 

 of the later Carboniferous, the Permian, the Triassic, and all of the Jurassic periods. 

 South of the Arkansas River some of the Chugwater beds probably appear again, 

 although at present their identity is not established. 



'"The Badito formation of Hills appears to be simply the Fountain formation 

 of Cross and Gilbert. The Sangre de Cristo formation to which Hills refers in 

 the Walsenburg folio appears to represent a great development of Fountain (or 

 lower \Yyoming) deposits. It is stated that remains of an upper Carboniferous 

 fauna and flora occur in this formation, which is added evidence as to the age 

 of the lower Red Beds (Fountain-lower Wyoming) series. These beds overlie or 

 merge into the basal limestone series on the eastern slope of the Sangre de Cristo 

 (Culebra) Range, in which Mr. Willis T. Lee has discovered an extensive upper 

 Carboniferous (Pennsylvanian) fauna. 



'"The red beds revealed in the canyons of the southeastern Colorado can 

 not be classified with certainty from the present evidence. On Purgatory River 

 and Muddy Creek the principal body of red beds is separated from the Morrison 

 formation by gypsum or gypsiferous shales, strongly suggestive of the Chugwater 

 (upper Wyoming) formation. It was immediately under this gypsum in Purga- 

 tory Canyon that I found the shoulder bone of a supposed belodont. Mr. Willis 

 T. Lee has traced the Red Beds farther south into northeast New Mexico, where 

 the gypsiferous horizon gives place to a massive sandstone, termed the Exeter 

 sandstone, constituting the summit of the Red Beds, a member which may repre- 

 sent the distinctive top sandstone of the Chugwater formation in northern 

 Colorado and in southern Wyoming. The sandstone is prominent in the Two 

 Buttes uplift, constituting the summit of the Red Beds, and is underlain by red 

 shales, which contain a thin bed of limestone, noted by Mr. Gilbert, strikingly 

 like the Minnekahta horizon. I have not made observations on the Red Beds 

 in Kansas and do not feel that a comparison of the published statements with 

 my observations in the region north and west should aid in the correlation.' 



"Girty 1 regards the Fountain formation as Pennsylvanian. Henderson 8 re- 

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

 David White, 3 from the evidence of fossil plants, would place it in Pottsville 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 underlying the Carbon- 

 iferous limestone in southeastern Wyoming and of the Permian and overlying 

 Red Beds of Kansas. 4 The Red Beds of this region he considers 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 



1 Girty, U. S. Geological Survey, Professional Paper No. 71, pp. 369-370. 

 5 Henderson, Jour. Geol., vol. 16, pp. 491-492, 1908. 



1 White, David, U. S. Geological Survey, Professional Paper No. ^l, p. 370. 

 4 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. 



