108 CARBONIFKROUS FORMATIONS AND FATNAS OF COLORADO. 



tlic biLsiil meuiber of I'ciile's Cretaceous (bed 7). Beneath this, in Peale's section, is 

 a space estimated at 600 feet, a portion of which only is equivalent to the Morrison 

 formation, as the latter has an average thickness of but 200 feet. The remainder 

 and major portion of Peale's Jurassic, and his Triassic, having a maximum aggregate 

 thickness of 3,100 feet, must be included in the Wj'oming formation. The lieavy 

 bed of Avhite sandstone (No. 14) forming the top of Peale's Triassic is probabl}' the 

 "ci'eamy sandstone" which constitutes the upper member of the lower Wyoming. 

 The Wyoming formation is referred to the Trias in the Denver Basin monograph, . 

 but, as alread}' pointed out, in view of the great variation in thickness of the lower 

 member, especiallj^ if the Fountain formation does occur as near as at Perry 

 Park, it seems pi'obable that the heavier sections of the Wyoming may include 

 at their base portions of a distinct series, most likely the Fountain beds. This 

 has been suggested also by Emmons, one of the joint authors of the Denver Basin 

 monograph. 



The beds here at the base of the section resemble those in Pleasant Park 

 similarlj^ situated. The latter, I suspect, may prove to be Cambi'ian, and the 

 resemblance noted suggests the possibility that the base of the section here also may 

 be of Cambrian age. The Millsap limestone, if the name may still be applied at 

 Pleasant Park, had there thinned to complete insignificance, and if absent altogether 

 the Red Beds of the Fountain formation would rest immediatelj^ upon the basal 

 sandstones. It seems more probable, however, that the whole earl}' Paleozoic 

 section is here missing. 



In a recenth' published paper W. T. Lee" describes the areal geologj!" of the 

 Castle Rock region. Except for the Red Beds, the only Paleozoics described occur 

 in Perrj' Park. No detailed section is given and the characters of the geologic 

 sequence described ma}' be condensed as follows: The onl}' Cambrian outcrop occurs 

 6 miles south of the area mapped, near Deadmans Creek. It is a deep-red quartzite 

 25 feet thick and corresponds in character and stratigraphic position with a similar 

 quartzite in Manitou Park referred to the Cambrian in the Pikes Peak folio. Above 

 the red quartzite appears a series of cherty limestone layers interstratified with 

 red clay. Some obscure brachiopods, identified as Dalmanella testudinaria, indicate 

 that the age of this bed is Ordovician. 



The Carboniferous is thus described: 



"At the base of the formation occur 40 feet of coarse-grained, crumbling sand- 

 stone, conglomeratic in places and mottled in varying shades of red and gray. 

 Above this sandstone is a series, 10 to 15 feet thick, of deep red to white cherty 

 limestone in laj^ers, alternating with red shale. Near the top of this series is the 

 fossiliferous seam. Above is a series of several hundred feet of coarse-grained 



aAm. Geol., vol. 29, 1902, pp. 96-109. 



