120 CARBONIFEKOUS FORMATIONS AND KAUNAS OF COLORADO. 



Foiiiitaiii fonimtioii on ihc oustcrii .slope of the Kocky Mountains is meagei- and 

 coiitiadiftoiy, and it is still a tiuestion whether it should be classed as Permian or 

 Triassic.-' 



It would thus appear that the earlier Paleozoic is entirely unrepresented in this 

 quadrangle, even the Harding and MilLsap formations I'ecognized in the Puehlo quad- 

 rangle having disappeared. A change of tint similar to that noted by Hills as 

 occurring in the Badito formation has been desci'ibed in many local sections of the 

 red-colored beds of Colorado. The uj^per strata are often spoken of as brick red 

 and the lower ones as being brownish red or maroon colored. Hills compares the 

 lower part of his Badito formation with the Arkansas sandstone, thus suggesting a 

 correlation with the Maroon formation and its equivalents in other parts of Colorado, 

 while the upper, bright-red portion may represent the Lenado beds, the "Wyoming 

 formation in the Tenmile district, etc. Upon this hypothesis the Badito formation 

 would contain the dividing line between the Wj^oming and Fountain formations, and 

 include about 100 feet of each series, the one above, the other below. This may be 

 the case, and could be explained in its relation to the conditions existing in the Pueblo 

 and Pikes Peak folios by considering the uucomformities which preceded the Fountain 

 formation, the WA'oming formation(?), and the Morrison formation. But in view 

 of the great thickness of the Fountain beds in the Pueblo quadrangle immediately 

 north and of the apparent absence there and in the Pikes Peak quadrangle of the 

 Wyoming formation it seems as if the color change in this case were being misinter- 

 preted and as if the Badito formation represented the Maroon and Fountain horizon. 



The Spanish Peaks quadrangle adjoins the Walsenburg quadrangle on the south. 

 In its northwest corner this quadrangle should include, according to the Haj^den 

 atlas, an area of Carboniferous rock, probably part of Endlich's Arkansas sandstone; 

 but the facts brought out in this folio show the Haj'den mapping to have been 

 incorrect. The oldest strata recognized in the Spanish Peaks folio is the Morrison 

 formation, there being no Archean or Paleozoic in this area. 



In his report upon the San Luis district " Endlich described the geologic suc- 

 cession along the Front Range from a point somewhat south of Colorado Springs to 

 the thirtj^-eighth parallel.'' South of Canyon an overlap of younger deposits con- 

 ceals the beds of the Juratrias, which reappear, however, north of the limit above 

 referred to. The northern area at least has been the subject of other reports, espe- 

 cially that of Cross upon the Pikes Peak quadrangle and Gilbert upon the Pueblo 

 quadrangle; fortunate!}', since it seems impossible to make much out of Endlich's 

 account. In this northern and more extensive area he gives three sections, to which, 

 as usual with this author, measurements of thickness are lacking, and from these it 

 would appear that he missed all of the admitted Paleozoics along this tract, though 



aU. S. Geol. Geog. Surv. Terr., [Seventh] Ann. Eept., for 1873, 1874, pp. 275-361. 

 b Pages 312 to 316 and 328 to 329 of his report. 



