FORMATIONS OF THE FRONT RANGE 421 



the Minnekahta limestones of the Black hills. The overlying red, sandy 

 shales, with gypsum, are very like the Spearfish formation of the region 

 north.* The pinkish sandstone at the top, underlying the Morrison, is 

 the same as the top member at other localities north. 



Peale* and Marvinef have described some features of the Red Bed 

 exposures on South Platte river, at the mouth of the canyon. The 

 basal beds lying on the granite consist of coarse, white and red, mottled 

 sandstones, overlain by finer grained red sandstones, in all 1,500 to 2,000 

 feet thick, capped by 600 feet of white sandstone corresponding to the 

 " creamy sandstone 1 ' of Eldridge (Tensleep sandstone). This member 

 has reddish bands 4 to 6 feet thick, separating the white portions into 

 bands 20 to 30 feet thick, in part conglomeratic. The upper Wyoming 

 division is not well exposed, but it is reported to contain a layer of com- 

 pact, red limestone near its base and thin limestones and limy shales 

 higher up. 



A similar section was given for Willow creek by Doctor Peale, and 

 Eldridge J has given some details regarding the succession of limestones 

 in the upper Wyoming beds in that vicinity. There are four thin layers 

 of white limestone, one lying immediately on the " creamy sandstones ' 

 and the others 30, 60, and 70 feet above. 



For Perry park (formerly Pleasant park), on Beaver creek, there are 

 sections by Doctor Peale § and Mr AV. T. Lee.|| Doctor Peale's section 

 of the Red beds, etcetera, at Pleasant (Perry) park, Colorado, is as follows : 



Feet 

 Thin limestones (at base of Morrison, probably) 



Gypsum 81 



Slopes with few outcrops of thin limestone beds, four in all, averaging 4 feet 



thick (probably in red shales) 401 



Mottled yellow and red sandstones, very light colored above, mottled red- 

 dish below, .... .. _ AA 



Massive red sandstones 



Slope apparently underlain by red sandstones J 



Coarse white sandstone, loosely cemented in upper part, has bands of red 



sandstone varying from 1 to 3 feet thick 80 



Small outcrop of limestone, with chert pebbles and fossils (Terebratula and 



Spiriferina) overlain by purplish sandstone and gray sandstone 6 



Irregular bed of limestone, with pebbles of greenish chert and limestone. . . 3 

 Red calcareous sandstone, very hard, and with cross-bedding layers 1 inch 

 thick — 3 



* Seventh Ann. Rept. U. S. Geo], and Geog. Survey of the Territories for 1873, by F. V. Hayden, 

 p. 195. 



+ Ibid., pi. opposite p. 93. 



X Geology of the Denver Basin. Monograph U. S. Geol. Survey, vol. xxvii, 189G. 



2 Seventh Ann. Rept, U. S. Geol. and Geog. Survey of the Territories for 1873, by F. V. Hayden, 

 pp. 197-199, pi. 2. 



|| Am. Geologist, vol. 29, 1902. pp. 97-98. 



