NORTH AMERICA AND THEIR VERTEBRATE FAUNA. 6$ 



"The upper and lower Wyoming are very distinct from each other from the 

 Garden of the Gods north to the State Hne, as recognized by the geologists of the 

 Hay den survey and clearly set forth in the Denver monograph, where the terms 

 'lower Wyoming' and 'upper Wyoming' were introduced. The upper Wyoming 

 consists mainly of fine-grained sediments extending from the 'creamy sandstone,' 

 which I believe to be the equivalent of the Tensleep, to the base of the Morrison 

 formation. It consists mainly of bright-red shales, always with a thin limestone 

 layer or series toward its base, and from Platte Canyon northward with a massive 

 pinkish sandstone at its top. The included limestone is believed to represent the 

 Minnekahta horizon of the Black Hills and other regions, indicating a short but 

 widespread interval of limestone deposition at this epoch in the West. The few fos- 

 sils found in this limestone unfortunately do not settle its age, but there appears to 

 be but little doubt that its representative in the Black Hills is Permian. The over- 

 lying red shales, with gypsum, in northern Colorado may be Permian or Triassic, 

 for the fossils in the limestones which occur near the top of the extension of this 

 series into the Bighorn uplift do not indicate whether the beds are Paleozoic or 

 Mesozoic. 



"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 nondeposition of the Chugwater beds or to their removal by erosion in pre- 

 Morrison times. As it is, the hiatus probabU- represents part of the later Carbon- 

 iferous, 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 

 Wyoming) 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 (Pennsyl- 

 vanian) 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 forma- 

 tion bj' gypsum or gypsiferous shales, strongly suggestive of the Chugwater (upper 

 Wyoming) formation. It was immediately under this gypsum in Purgatory 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 gj'psiferous hori- 

 zon gives place to a massive sandstone, termed the Exeter sandstone, constituting 

 the summit of the Red Beds, a member which may represent the distinctive top 

 sandstone of the Chugwater formation in northern Colorado and in southern Wyo- 

 ming. The sandstone is prominent in the Two Buttes uplift, constituting the sum- 

 mit 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 feci that a comparison 

 of the published statements with my observations in the region north and west 

 should aid in the correlation" (beginning p. 162). 



