1<> CARBONIFEROUS FORMATIONS AND FAUNAS OF COLORADO. 



of the i-ase the discussion is ii irenpnil one. Kldridge's papt^r on structural features 

 nciir Denver contains an iniudenta! description of the Triassic and Inter l)ods, and an 

 account of some of tlie pctniliarities of distribution. 



.V paper ))y Cannon in 189;^ describes the geology in the vicinity' of Palmer 

 Lake, along the Front Range. He recognizes the absence of Paleozoics in this 

 vicinity, but calls attention to the prevalence of chei't bowlders, both free and in 

 t'ongk)nu'rates, containing Paleozoic types of fossils. He concludes that they repre- 

 sent exposures of certain beds that have long since been eroded. It is from an occur- 

 rence similar to those recalled b}' Cannon that the fossils described by White from a 

 conglomerate in Larimer County were obtained. During the same year appeared 

 papers by Eldridge, Farish, and McMechen, which have little bearing upon my 

 discussion, but are included in the bibliography'. This is less true of a jiaper by 

 C. D. Walcott, who describes the Paleozoic section at Can3'on, and gives lists of 

 fossils. So far as Mr. Eldridge's paper concerns us at all it embraces the same strata 

 described by Walcott, whose section is mentioned particularly in my discussion. 



In 1893 G. L. Cannon described the geology of Denver and vicinity. The olde.st 

 sedimentarj' strata considered are of course the Red Beds, which he refers to the Triassic 

 and Jurassic, but because they are possibly, in part, of Carboniferous age, this paper 

 comes pi'operty within mj- purview. The same area has been made the subject of a 

 monographic study by Emmons, Cross, and Eldridge, and I will not, therefore, give 

 Cannon's account further consideration. The itinerary in Colorado of the Fifth 

 International Geological Congress, which took place in 1891, was arranged and 

 described chieflj^ bj' S. F. Emmons and Whitman Cross, and their reports were 

 published in 1893, in the Comptes Rendus of this body. Thej' add, however, little 

 or nothing to the present discussion, and it probably will not be necessary to refer 

 to them again. 



In 1894 appeared the Pikes Peak and the Anthracite-Crested Butte folios (Nos. 

 7 and 9 of the Geologic Atlas of the United States). The Pikes Peak folio was the 

 work of Whitman Cross, who contributed to the Anthracite-Crested Butte folio 

 the description of igneous rocks, while G. H. Eldridge described the sedimentary 

 fornnations, and S. F. Emmons discussed the geologic history of the Elk Mountains. 

 These two volumes form important accessions to the literature which I am consider- 

 ing, and will receive particular discussion at a more appropriate point. 



The Geoiogj' of the Denver Basin, by Emmons, Cross, and Eldridge, in 1896, 

 deals with the area about Denver, as the title indicates, in which strata belonging to 

 the Red Beds rest directly upon the granites and metamorphics of the Front Range. 

 Though this series is referred by these authors to the Triassic, the probabilitj' that 

 part of it belongs to the Carboniferous has made it necessary to include this series 

 and all papers relating to it in mj^ discussion. To this monograph I will therefore 

 refer in the resume of geologic literature below. 



