A. C. Peale — Application of the Term Laramie. 55 



Lignitic, embracing all deposits of brackish water origin ; 3d, 

 Upper Lignitic, including all beds of purely fresh-water origin. 

 In my opinion, the first division would include all beds to the 

 summit of the true Cretaceous ; the Middle Lignitic embraces 

 my Transition Series, or, if the} T are not admitted by geologists, 

 I would insist upon their Lower Tertiary age. The Upper 

 Lignitic, or fresh-water deposits, are of unquestioned Tertiary 

 age".. This makes it clear that Hayden did not intend to 

 include in the Laramie all the beds he had previously referred 

 to the Lignitic, not even his "Great Lignitic" — (Fort Union) 

 being so included. The term Laramie was used by him and 

 by all the geologists of his survey to include the beds resting 

 immediately and conformably upon the Fox Hills. It was so 

 used in the Reports of the Survey and in the Atlas of Colorado, 

 as also by King and his colleagues in their reports and Atlas. 



That Cross and Eldridge separated from the upper part of 

 the Laramie formation, as colored in the Atlas of Colorado, 

 the Denver and Arapahoe formations which were found 

 unconformably resting upon the Laramie, and which they 

 divided into an Upper and Lower division, in no way invali- 

 dated its existence ; nor do mistakes in correlation in other 

 localities of beds with the undoubted Laramie according to the 

 original definition along the Front Range in Colorado, whether 

 made by members of the Hayden Survey in southern and 

 western Colorado, by King and his successors in Wyoming, or 

 by the Canadian geologists who call the Fort Union beds 

 Upper and Lower Laramie, destroy the validity of the term. 

 It would matter little if no Laramie were found in central 

 Wyoming below the great unconformity, where it may have 

 been removed by erosion, or that we find that we have to 

 extend the Fort Union downward and find it sometimes resting 

 unconformably upon Fort Pierre Cretaceous without Laramie 

 or even without Fox Hills beds beneath it. That we find in 

 Colorado, Wyoming and Montana a series of beds to which 

 local names have been given, such as Livingston, Denver, 

 Arapahoe, Black Buttes beds, Evanston beds and Carbon beds, 

 all of which lie above the great unconformity and below the 

 Fort Union, and which cannot be correlated with either the 

 Laramie or the Fort Union, is a good and sufficient reason to 

 include them under the term Shoshone proposed by Mr. Cross. 



It may be questioned whether the Black Buttes beds (Aga- 

 thamus beds) should be included in Cross's Shoshone, but at 

 the present time the preponderance of evidence apparently 

 warrants such a reference. If the unconformity at the base of 

 these beds noted by Meek and Bannister in 1872 and Powell in 

 1876* should be fully demonstrated, the beds certainly could 



* Geology of the Uinta Mountains, 1876, p. 72. 



