RESUME OF LITERATURE. 107 



Manitou limestone. On the other hand, the horizon of the Millsap limestone is 

 certainly present at Pleasant Park, and its occurrence in this region is too fickle to 

 admit of a strong presumption based upon its presence or absence in neighboring- 

 areas." The Trias belongs to the Fountain formation or to the Fountain and 

 Wyoming combined, and the Jurassic has the characters of the Morrison formation. 



Considering next the section through Pleasant Park and comparing it with that 

 of the Pikes Peak quadrangle, a convenient point of departure is found in bed 8, 

 which, with but little doubt, belongs in the Millsap limestone. It is impossible at 

 this distance and without further information to reach a conclusion as to whether the 

 beds below this horizon are all Carboniferous, as Peale has it, or in part earlier 

 Paleozoic. The SO feet of white sandstone at the base of the section, and the other 

 sandstones above, in position and character are so like the Cambrian of the Glen 

 Erie section as to suggest to my mind that perhaps the}' are equivalent beds. 

 However, the fact that this correlation did not recommend itself to Peale, who was 

 personall}" acquainted with the sections, is an impeachment of its correctness.'' At 

 all events in the fossiliferous, calcareous stratum (bed 8), and probably in the thin 

 limestone just l^elow, we are assured, all things considered, of an equivalent of the 

 Millsap limestone and the presence of Lower Carboniferous sediments. The Triassic 

 of the Pleasant Park section probablj^ represents the Fountain formation in part and 

 in part the Wj'oming. The Jurassic cori'esponds to the Morrison formation, and 

 the massive sandstone which overlies it, "No. 1 Cretaceous," as it is called, to the 

 Dakota sandstone. The thickness of the Ked Beds is here about 1,500 feet. This is 

 aljout the average thickness of the "Wyoming formation, which was described from 

 the area of the Denver Basin, near by. But the Fountain beds also are known not 

 far off, in the northeast corner of the Pikes Peak quadrangle. Lee refers part of 

 this series to the Carboniferous and correlates it with the Fountain formation, while 

 the portion which he calls "Trias," though not accepting this as its true geologic 

 age, probably finds its equivalent in the Wyoming formation. 



Section No. 1 of Peale's report, which was taken on the south side of the South 

 Platte River, comprises about -±,000 feet of strata referred to the Triassic, Jurassic, 

 and Cretaceous. The Triassic, which here rests immediately upon the granite, 

 consists of from 1,.500 to 2,000 feet, chiefl3'of red and red and white sandstones, and 

 600 feet of white sandstones overlying them. The localitj' where this section was 

 made is probably just included in the southwestern corner of the Denver Basin. 

 There can be little doubt that the Dakota sandstone of the Denver monograph is 



oMr. A. W. Grabau has recently informed me that he has collected a Carboniferous fauna from the upper portion 

 of this limestone. It is not probable that this is an Upper Carboniferous limestone, and the conclusion seems safe tliat it 

 represents the Millsap formation. Whether the entire thickness belongs to the Millsap or the lower part represents the 

 Manitou limestone can not be ascertained. 



&Hayden, however, suggests the same thing, for he writes, remarking upon the Calciferous group- " It is possible 

 that in Pleasant Park, about 50 miles south of Denver, there are traces of this formation in the variegated sandstones 

 that lie next to the granites, as shown in the section." (Ann. Kept, for 1874, p. 41.) 



