RESUME OP LITERATURE. 119 



tion. Gilbert refers the whole to the Juratrias. Onl}" so far as anj' part of these 

 strata belong to the series which farther north has been called the Wyoming forma- 

 tion do I believe this reference to be a correct one. The Fountain formation I have 

 little doubt is Carboniferous. Of course, without fossils, opinions as to its age are 

 largely matters of conjecture. 



The Fountain formation is, according to Gilbert, conformably overlain by the 

 Morrison formation; but Cross has shown the existence above the Fountain of an 

 important erosion interval. 



These Paleozoics. which Gilbert refers to the Harding and Millsap formations, 

 form, by their outcrojj, part of an area which is represented under the Lower 

 Carboniferous color in the Hayden atlas. Endlich described these beds as grayish 

 limestone and shale, from which it would appear that he missed the Harding beds. 



The Walsenburg quadrangle is a 30-minute quadrangle whose northwest corner 

 is formed by the intersection of the thirt}' -eighth parallel north latitude and the one 

 hundred and fifth meridian. It lies immediately south of the Pueblo quadrangle and 

 its northern l)order is not far south of the town of Pueblo, Colo. The geology of 

 this quadrangle has been described and the formations mapped in the folio atlas of 

 the same name. 



According to the Hayden atlas, this quadrangle should contain a small area of 

 Carboniferous in its southwestern corner (Arkan.sas sandstone), but this area proves 

 to be occupied by Eocene ( ?) and Upper Cretaceous rocks. 



The northwestern corner includes part of the southern end of the Wet Moun- 

 tains, or of the Greenhorn Mountains, the area in which Endlich described Juratrias 

 rocks as mentioned above. 



The oldest sedimentary formations recognized by Hills in this quadrangle are the 

 Badito and the Morrison formations, of which the former is referred questioningly 

 to the Carboniferous, and the latter to the Juratrias. Of the Badito, Hills says: 



"The upper half of this formation consists of brick-red sandstone, about 100 

 feet in thickness, generally massive or thick bedded, but sometimes shaly on the 

 weathered surface. It apparently corresponds to part of the Fountain formation, 

 but to what portion of it is uncertain. The lower half consists of about the same 

 thickness of very coarse conglomerate of a brownish-red color. * * * No organic 

 remains by which the age of these beds could be satisfactorily determined have been 

 found within the limits of the quadrangle. In the Sangre de Cristo Range, to the 

 westward, the stratigraphic section corresponds very nearly with that at the southern 

 extremity of the Greenhorn Mountains, except in respect to the thickness of the 

 conglomerate. Below the Cretaceous beds and the Morrison formation there is in 

 each case about the same thickness of capping red sandstone, but the coarse con- 

 glomerate and sandstone on which it rests attam in the Sangre de Cristo a thickness 

 of several thousand feet. In that locality the beds have ati'orded remains of an 

 Upper Carboniferous fauna and iiora. The evidence of a similar character from the 



