"CERATOPS beds" OF WYOMING AND MONTANA 287 



relationship between the tlora of the "lower Fort Union" and the 

 "upper Fort Union;" if, however, comparison were made between the 

 "Ceratops beds" that have actually yielded dinosaurs and the typical, 

 or "upper" Fort Union, the figures would possibly be different, 

 because ir many sections such as those of the Bighorn Basin, Red 

 Lodge, Sheridan, Fish Creek, and probably along the Yellowstone, he 

 has included much more than the "Ceratops beds" in his lower Fort 

 Union. The value of the comparison with the Laramie flora is 

 impaired also by the fact that it is restricted to the 80 species of the 

 Denver Basin Laramie which is probably only a fraction of the whole 

 flora. Even with that restriction 10 species, or 12^ per cent of the 

 Laramie fiora, occur in the "lower Fort Union" and only about the 

 same percentage of " upper Fort Union" species occur in it, though 

 they are 61 in number. It is of course true that a considerable num- 

 ber of Fort Union plants are found in the "Ceratops beds," but that 

 does not necessarily prove that the latter are Eocene, nor that they 

 belong to the Fort Union formation. 



The difference between the Laramie and Fort Union floras was first 

 emphasized by Dr. J. S. Newberry, who studied and described^^ the 

 early collections of Fort Union plants which he then considered Mio- 

 cene. The Fort Union known to him, as indicated by the localities, 

 is all "upper Fort Union." His final views concerning the Fort 

 Union and Laramie floras are shown by the following extracts from I wo 

 of his latest papers, which also clearly show that the "Laramie" as 

 known to Newberry included Colorado, Mesaverde, Laramie, Denver, 

 and possibly later beds :" 



Between the foot hills of the Rocky mountains and the summit of the 

 Wasatch the older Cretaceous rocks are covered by sandstones and shales 

 which contain beds of coal so numerous and important as to give to 

 the formation the name, sometimes applied to it, of the Lignitic Forma- 

 tion. This, the true Laramie group, is distinct from the so-called 

 Laramie of the upper Missouri, named by Hayden the Fort Union 

 group, and which, in my judgment, should be considered the basal 

 member of the Tertiary. Large collections of fossil plants made by 

 Dr. Hayden and others in the country bordering the upper Missouri 



** Annals Lyceum Nat. Hist. N. Y., Vol. 9, 1868, pp. 1-76. 



" The Coals of Colorado, School of Mines Quarterly, Vol. IX, 1888, p. 329. 

 The Laramie group, its geological relations, its economic importance and 

 its fauna and flora, N. Y. Acad. Sci., Vol. IX, 1889, pp. 27, 31, 32. 



Proc. Wash. Acad. Sci., August, 1909. 



