of Colorado and New Mexico. 529 



the Denver are worked up this percentage will undoubtedly be 

 considerably increased. 



As already mentioned, Lesquereux noted the evident affin- 

 ity of the flora here called the Raton flora with that of the 

 "Lignitic" or "Eo-lignitic" of Mississippi. These beds are now 

 known as the Wilcox formation, which extends from Western 

 Georgia through Alabama, Mississippi, Louisiana, and well into 

 Texas. It rests conformably on the marine Eocene Midway 

 formation, and has at various points intercalated beds of marine 

 Eocene invertebrates, hence there can be no doubt as to its age. 

 The flora of the Wilcox formation comprises, as at present 

 standing in the books, about 65 species, but Mr. E. W. Berry 

 has recently secured large additional collections and has pre- 

 pared a monograph in which he has enumerated about 170 

 species, many, however, from the upper portion of the forma- 

 tion. Over 30 species of plants are common between the Raton 

 and Wilcox formations and the conclusion is reached that the 

 Raton formation is to be correlated with the Wilcox and is also 

 Eocene in age. 



As it has been shown that there is an intimate relation between 

 the Raton and Denver formations, it naturally follows that if 

 the former is Eocene, as now demonstrated, the latter is also to 

 be so regarded. This, however, is simply a confirmation of 

 the original contention of Cross,* when he described and named 

 the Denver formation in 1889, and in his latest published utter- 

 ance he again insists on this view. In the latter paper he saysf : 

 "I desire now to urge their reference [the Shoshone group] to 

 the Eocene. The Denver beds were originally referred by me 

 to the Eocene, but the great weight attached to the Mesozoic 

 affinities of the vertebrate fauna by paleontologists led to a 

 tentative acquiescence in the assignment of the Arapahoe and 

 Denver formations to Cretaceous in the Denver monograph." 

 All the direct and collateral observations recently made within 

 this area have confirmed this reference to the Eocene. 



The wider application of the results here recorded to the 

 stratigraphic position of certain ceratopsian dinosaurs as reported 

 from many other localities, is obvious, since if the Denver is 

 Eocene and is older than the Lance formation, as it is now 

 believed to be, it naturally follows that the latter is the more 

 certainly Tertiary. 



Summary. 



(1) The coal-bearing section of the Raton Mesa region of 

 Colorado and New Mexico was at first (1867 to about 1883) 

 considered to be of Tertiary age, bat later (1883-1905) it came 



* The Denver Tertiary Formation, this Journal (3), vol. xxxvii, pp. 

 261-282, 1889. 



f Proc. Wash. Acad. Sci., vol. xi, p. 42, 1909. 



