220 GEOLOGY OF THE DENVER BASIN. 



conglomerate of the latter usually contains chert pebbles with crinoid stems, 

 which may very probably have come from the erosion of the Ohio Creek 

 beds in the vicinity. The latter formation is certainly preserved only in 

 small remnants. 



Northwestern Colorado. — The Ruby beds do not seem to be present iii the 

 northwestern part of Colorado, where the Laramie coal measures are well 

 developed. But in his often-cited address Mr. Hills states his opinion 

 that the upper portion of what has been called Laramie, on the Yampa 

 River and elsewhere, will finally prove to be a distinct formation, and 

 in that ease analogous with the Arapahoe and identical with the soft, 

 yellowish sandstones occurring on the Grand River between the Ruby 

 beds and the Laramie. The only evidence adduced by Mr. Hills in favor 

 of this view is the fact that the lower part of the questionable series of strata 

 consists of normal Laramie beds, firm, even-grained sandstones, clays, and 

 coal seams of excellent quality. Such normal beds are present on the 

 Yampa in a thickness equal to their usual development elsewhere in 

 Colorado. Above them occurs a series of "soft sandy strata with some 

 shales and clays," containing beds of impure lignite, and of general different 

 physical appearance from the underlying unquestionable Laramie. The 

 Wasatch Eocene overlies this section. 



This opinion, although unsupported by definite evidence, is worthy of 

 much consideration, coming, as it does, from the geologist who is far more 

 familiar with the Laramie and its associated formations in Colorado, 

 Wyoming, and adjacent territory, than anyone else. 



The Livingston formation. Montana. The recent investigations (if Ml'. W. II. 



Weed and Dr. A. ( !. l'eale in the district covered by the Livingston and 

 Three Forks atlas sheets show that a formation directly analogous with the 

 1 tenver occurs in Montana.' 



The Livingston formation, as it has been called by Mr. Weed, occurs 

 in typical development in the Bozeman coal field, where it overlies the 

 Laramie. It had been classed with the latter previous to the investigations 



1 Geologic Atlas of the United States, Folio 1, Livingston sheet, 1894; Folio 20, Three Forks 

 sheet, by A. C. Peale, 1895. The Laramie and the overlying Livingston formation in Montana, by W. 

 II. Weed anil F. II. Knowlton: Bull. I'. S. Geol. Survey No. 105, 1893. 



