18S CARHdNll'KKOUS KOK.MATIONS AND KAUNAS (»K COLOKADO. 



Sli'vonsoii citos tlic rollowiii";' soction t'l'oni I'cdvcr Crcolv a l'(>\v miles iiortlKnist 

 ol' C'iuiyoii: 



Sciiioii 1)11 Beaver Greek. 



1. SandstoiH', Mcift, l)l(i(i(l-i'eil, .■^liiily aliovf, (■oiigidimTatt^ l)flo\v , 1(10 



2. Gypsum .' 100 



.'). Sandstone, soft, mostly decp-rpd, with layers of ^ray, somewhat miea- 

 eeous, shows much cross bedding and is entirely unaltered. It is con- 

 glomerate throughout, liut especially so at the base, where for several 

 hundred feet it contains pebbles as large as a hen's egg and com- 

 pletely agatized. The coarseness of the uiaterial diminishes regu- 

 larly to the top, where it is comparatively fine in grain. Estimated 

 thickness 2, 500 



The locality of this section is within or just outside the area of the Pikes Peak 

 quadrangle, and the strata which Stevenson refers to the Triassic probably belong- 

 in the Fountain and Morrison formations. The thickness of the lower .series, 2,500 

 feet, which is onlj^ estimated, is much greater than Cross cites for the Fountain beds, 

 and it is possible that in it ai-e included some of the Wyoming series, which is sup- 

 posed to intervene between the Fountain and the Morrison east of the quadrangle. 

 At the same time Gilbert allows the Fountain formation a thickness of 2,100 feet in 

 the Pueblo quadrangle near by. 



South of Canj'on the Red Beds and Paleozoics are again concealed for a short 

 distance, but reappear on the eastern side of the Wet Mountains southwest of Pueblo 

 in an area which is represented in the Hayden atlas under the Lower Carboniferous 

 and Triassic colors. A portion of this area is included within the Pueblo quadrangle, 

 where the beds designated as Lower Carboniferous and Triassic on the Haj^den maps 

 are called by Gilbert the Millsap limestone and the Fountain formation, these names 

 being, of course, borrowed from the Pikes Peak quadrangle, which lies northwest of 

 the Pueblo quadrangle and corners with it. As I have already suggested, the upper 

 half at least of Gilbert's Millsap is without much doubt the equivalent of the original 

 Millsap, but because there is a considerable thickness of the Ordovician Fremont 

 limestone at Canyon it seems possible that the lower portion maj' be older. 



Gilbert refers the Fountain formation to the Juratrias period and describes it as 

 consisting of coarse, deep-red sandstone containing a considerable admixture of claj'. 

 In the upper half of the series are man}' beds of red and chocolate-brown shale, in 

 the lower part are conglomerates. The lowest bed seen is a coarse conglomerate 

 containing pebbles and bowlders of gneiss, schist, and granite similar to those of the 

 adjacent Archean. The thickness near Beulah is 2,100 feet. The top of the series 

 is not there seen, but the missing beds are probably thin. The Fountain formation 

 here, as farther north, and like the Wyoming formation of the Denver Basin, is 

 succeeded by the Morrison formation. 



