BIBLIOGRAPHY. 1 5 



what as in the Hayden atlas. Tilden also describes the ore deposits at Red Cliff, and 

 gives the geologic sequence occurring there. This will be mentioned separately 

 below. 



In 188S Emmons published a preliminary note on Aspen, in which the section in 

 that vicinity is described and compared with the Leadville section. As the statement 

 of fact is little different from that in the Aspen monograph, by Spurr, I shall not give 

 this paper special I'eference in the resum^. Kedzie briefly describes the ore deposits 

 and geology of the Red Mountain mining district of Ouray, and Siver and Brunton 

 those of Aspen. Brunton's is an able paper, with iigures of models showing topogra- 

 phy, and a carefully considered section iu which the same formations as those at Lead- 

 ville appear. The Weber formation is referred to the Middle Carboniferous, and the 

 upper beds of the Carboniferous are not considered. Lakes discusses the geology 

 of Colorado ore deposits in a paper which was published in the same form in two 

 places. So far as concerns mj^ subject this paper was too general and elementary, as 

 to both geology and paleontology, to require especial consideration. 



Again, in 1889 the geology and mineral deposits of Aspen were treated by Hen- 

 rich in a carefully prepared paper, published in the Transactions of the American 

 Institute of Mining Engineers. Henrich compared his section with that of Emmons 

 at Leadville, and that of Lakes, published in 1887, and called attention to several 

 errors made by the latter. His section closed with the Weber shales, so called. 

 White described the geology and physiography of the eastern portion of the Uinta 

 Mountains in a paper whose geologic bearing is rather structural than historical. 

 Eldridge described the geologic sequence in the vicinity of Denver from the Archean 

 up. The lowest sedimentaries are, of course, the Red Beds, whose characters are 

 given and whose age is discussed. 



In 1890 Newberry published some notes upon the geology of the Aspen mining- 

 district. The divisions recognized by him are the Cambrian quartzite, the Silurian 

 quartzite and limestone, the Lower Carboniferous dolomite, the Lower Carboniferous 

 blue limestone, the Middle Carboniferous shale and shaly limestone, the Middle Car- 

 boniferous limestone, and the Jura-Triassic sandstones. The equivalence of this 

 section with that adopted by Spurr in his Aspen monograph is too obvious to need 

 special discussion. Apparently' Newberry's two Middle Carboniferous formations 

 are the same as the Weber formation, while the Juratrias, of which there are said to 

 be many hundred feet, comprises the Maroon formation and the bright- red sandstone, 

 noted by Spurr in the Lenado Canyon. Emmons's paper on orographic movements 

 in the Rocky Mountains is important to the subject in hand because of its bearing 

 upon the disposition of land and water in Colorado during Carboniferous time and 

 the relation of the Carboniferous faunas and sediments at different points in this 

 State. This subject will be considered at a later place. The same author describes, 

 in McFarlane's Railroad Gruide, the Carboniferous of Coloi'ado. but from the nature 



