lU) CAKUUNIKKKUUS FORMATIONS AND FAUNAS OF COLORADO. 



the beds, without any attempt to determine their age. He says: "On descending 

 again later in the day we met iieavy formations of limestone dipping at nearly 

 everj' angle iuul crowning some of the high foothills. These strata are hard, 

 cherty, massive, and compact. They soon disappear with a general dip toward the 

 east. We then pass on to thick beds of conglomerate ferruginous oxides, cementing 

 rounded pebbles and water-worn bowlders." (Page 81.) The heavy limestones can 

 probablj' be safely identitied with the Ordovician and Mississippian limestones, which 

 have subsequently been named the Manitou, Fremont, and Millsap formations. The 

 conglomerates are possibly the Fountain beds. On page 81 fish remains are cited 

 from Canyon, and it seems probable that they were derived from the horizon their 

 occurrence in which has caused especial interest to attach to the Ordovician of this 

 locality. 



In 1876 S. G. Williams published a section along Oil Creek from the head of 

 Oil Creek Park to the Arkansas River. " The essential portion of this section lies 

 within the limits of the Pikes Peak quadrangle, and it is possible to identify 

 Williams's formations with some accuracy. The whitish limestone at the base of 

 his section (No. 1) is, with little doubt, the Fremont limestone. Fifty feet were 

 measured and the bottom not seen. The mottled marble above (No. 2), 15 feet thick, 

 is the ilillsap limestone of Cross. The three red sandstones overlying (Nos. .3, i, 

 and 5), which have a combined thickness of 1,140 feet, can be no other than the 

 Fountain formation. Williams says: 



"Nos. 1 and 2 are probably Carboniferous; rocks holding the same relative 

 position in the Arkansas Canj'on, and from which I have fossils, are certainly of that 

 age."* 



If my correlations with Cross's section are correct Williams is of course mis- 

 taken as to the age of his lowest bed. 



In 1892 C. D. Walcott described the geologic section at Harding's quarry, about 

 1 mile northwest of Canj^on. '' He distinguishes, describes, and names the Harding- 

 sandstone series and the Fi'emont limestone series. The former included beds l(a to 

 f); the latter, beds 2, 3, i (a-c), and apparently 5 of his section. Fossils of Ordo- 

 vician age were found in Ic and a few in lb, just below. The latter are indecisive, 

 but probably indicate the same age. Bed ic contains a large and varied fauna of 

 the Trenton type. Bed 5 consists of impure variegated limestone with interbedded 

 sandstones and argillaceous shales, and has a thickness of from 15 to 30 feet. It 

 contains a few species of fossil Brachiopoda which are correctly assigned to the Car- 

 boniferous. It thus appears that probably the whole of this section except its upper 



•lU. S. Geol. Geog. Surv. Terr., Bull., vol. 1, 2 ser., 1876. pp. 249-251. 



6Ibi(J., p. 249. 



cGeol. Soc. America. Bull., vol. 3, 1892, pp. 153-172. 



