42 



LAEAMIE FLORA OF THE DENVER BASIN. 



Fort Union was regarded by Hayden as of the 

 same age as the Laramie, if not, indeed, in- 

 cluded in it. 



As is well known, Hayden originally consid- 

 ered all of his Laramie (Laramie and Fort 

 Union) as of Tertiary age, but his latest con- 

 clusion was that the whole mass was of a transi- 

 tional character—that is, it formed beds of pas- 

 sage between the Cretaceous and Tertiary. 

 Newberry 3e in commenting on this conclusion 

 said: "It is easy to see that this result was 

 inevitable, after he had united an Upper Cre- 

 taceous with a Tertiary formation under one 

 name." 



Clarence King, however, did not accept 

 Hayden 's reference of the Fort Union to the 

 Laramie. When preparing the final volume 

 on the systematic geology of the vicinity of 

 the fortieth parallel, he had before him 

 Lesquereux's "Tertiary flora," above quoted, 

 and after admitting that he had never visited 

 the locality and could not therefore . " speak 

 with any definiteness, " he added (p. 353) : 



I consider it worth while to point out here a noticeable 

 ambiguity in its evidence. Cope, in his introduction to 

 his volume on the Cretaceous, cites dinosaurs as coming 

 from the Fort Union, from which he refers the fauna to 

 the Mesozoic series. On the other hand, the character- 

 istic plant life of the country differs entirely from that 

 described by Lesquereux in Volume II, Tertiary flora. 

 It is noticeable that he nowhere describes in that volume 

 any of the plants from the classic Fort Union locality, 

 a series which has been studied by Newberry and which 

 contains not only a general resemblance but some actual 

 species identical with the Miocene of Greenland and 

 northern Europe. * * * Until fresh evidences of 

 the stratigraphical relations, and a full discussion of the 

 fauna of the whole series of rocks at Fort Union is fully 

 made, a definite correlation is impossible, and at present 

 writing the entire difference between the plants at Fort 

 Union and anything in Colorado or Wyoming that is of 

 value at all suggests that they can not be related to any 

 of the southern groups. I apprehend that the plant 

 horizon at Fort Union will be found to be nothing but a 

 northward extension of the White River Miocene. 



King's reference of the Fort Union to the 

 White River has not of course been sustained, 

 but otherwise his suggestions have proved to 

 be wonderfully near the truth. 



C. A. White did much to merge the Fort 

 Union in the Laramie. In fact, in what was 



* Newberry, J. S., The Laramie group: New York Acad. Sci. Trans., 

 vol. 9, p. 3, 1889 (reprint). 



perhaps his last utterance s7 on the subject 



he said : 



The localities at which Laramie strata were first studied 

 by geologists were often distant from one another, and 

 they were not then recognized as constituting one great 

 formation. * * * These deposits consequently re- 

 ceived a different name in each district. They thus have 

 received such names as Fort Union group, Judith River 

 group, Lignitic group, and Bitter Creek series. The term 

 Lignitic soon came to be applied to the strata of several 

 districts which are now included in the Laramie. 



It was not possible, according to White, to 

 distinguish between Fort Union and Laramie 

 by the invertebrates, and this view was 

 generally entertained by paleontologists for 

 many years thereafter. 



The influence of what are now known to have 

 been the erroneous views of Hayden, White, 

 and others is well shown in Ward's elaborate 

 paper "Synopsis of the flora of the Laramie 

 group," 38 in which he included in the Laramie 

 not only the Fort Union but also beds now 

 known to belong to the Montana, Arapahoe, 

 Denver, Lance, and other formations. It 

 should not be presumed, however, that he failed 

 to note that there were striking differences be- 

 tween the typical Laramie flora and that of the 

 Fort Union, but he was misled by the opinion 

 of the time that all the formations he included - 

 formed an unbroken sedimentary sequence. 

 His investigation was undertaken primarily to 

 ascertain the bearing of the plants on the ques- 

 tion of the age of the Laramie, but naturally it 

 failed in reaching definite results. In this pa- 

 per Ward described many new forms from a 

 great many localities and horizons, though so 

 many were from the Fort Union that New- 

 berry, 39 in commenting on it, said: "But" his 

 monograph as a whole is simply an important 

 contribution to what was before known of the 

 Fort Union flora." 



It is undoubtedly to J. S. Newberry that most 

 credit is due for keeping alive and insisting 

 upon the distinctness of the Fort Union from 

 the Laramie. From the beginning of his 

 studies of the material collected by Hayden in 



8 ' White, C. A., Correlation papers— Cretaceous: U. S. Geol. Survey 

 Bull. 82, p. 147, 1891. 



88 Ward, L. F., U. S. Geol. Survey Sixth Ann. Rept., pp. 399-557, 

 pis. 31-65, 1886. , 



8 » Newberry, J. S., The Laramie group: New York Acad. Sci. Trans., 

 vol. 9, p. i, 1889 (reprint). 



