RESUME UPPER CARBONIFEROUS AND RED BEDS 441 



The Chugwater formation (upper Wyoming Red beds) is only 140 feet 

 thick at the Garden of the Gods, and it appears to thin out and disap- 

 pear a few miles southward, bringing the Fountain formation into con- 

 tact 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 probabl} 7 represents part of the later Carboniferous, 

 the Permian, Triassic, and all of the Jurassic periods. Soutli of the 

 Arkansas river some of the Chugwater beds probabl} 7 appear again, 

 although at present their identity is not established. The Badito for- 

 mation 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 Foun- 

 tain 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 Bed series (Fountain-lower 

 Wyoming). These beds overlie or merge into the basal limestone series 

 on the eastern slopes 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 

 southeastern Colorado can not be classified with certainty from the 

 present evidence. On the Purgatoire river and Muddy creek the prin- 

 cipal body of Red beds is separated from the Morrison formation by 

 gypsum or gypsiferous shales strongly suggestive of the Chugwater for- 

 mation (upper Wyoming), and it is immediately under this gypsum, in 

 the Purgatoire canyon, that I found the shoulder bone of a supposed 

 Bolodont. Mr Willis T. Lee has traced the Red beds farther southward 

 into northeastern 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 represent the dis- 

 tinctive top sandstone of the Chugwater formation in northern Colorado 

 and southern Wyoming. It is prominent in the Two Butte uplift, con- 

 stituting 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 examined the Red beds in 

 Kansas, and feel that a comparison of published statements with my 

 observations in the regions north and west would not aid in the corre- 

 lation. 



SUNDANCE FORMATION 



The Jurassic appears to exist only in the northwestern portion of the 

 region to which this report relates, apparently owing to non-deposition 

 in other portions of the region. In the Bighorn mountains and Black 



