LARAMIE FLORA OF THE DENVER BASIN. 



vertebrates and invertebrates, had been found 

 somewhat conflicting, though it favored the 

 Tertiary side. It was the fossil plants, of 

 which great numbers were found, that proved 

 of most value in influencing opinion. The 

 material, especially that obtained by Hayden 

 while on the Rajmolds expedition of 1859-60, 

 was studied by the well-known paleobotanist 

 J. S. Newberry. Although Newberry's report 

 was evidently prepared and submitted as early 

 as 1867, it was not published until 1S69, when 

 it appeared as an appendix to Hayden's ac- 

 count of the geology.'' Newberry argued 

 strongly for the Tertiary (Miocene) age of the 

 "Fort Union or Great Lignite series." The 

 preliminary paper in which the Fort Union 

 plants were first described by Newberry was 

 published in 1868,'" though the final publica- 

 tion in which they were fully described and 

 adequately illustrated was not published until 

 1898.=" 



The fossil plants obtained by Hayden in 

 Colorado and Wyoming in 1867 and 1868 were 

 studied by Leo Lesquereux, and his preliminary 

 report on them was printed in the form of a 

 letter to Hayden.-' They included plants from 

 the Laramie Plains, Wyoming, the Denver 

 Basin of Colorado, and the Raton Mountains 

 of southern Colorado and northern New 

 Mexico. Lesquereux regarded the plants from 

 all these localities as of Miocene age, a con- 

 clusion which of course confirmed Hayden in 

 his opinion held at that date (1869) that all 

 the coal of the West was of Tertiary age. 



Up to this time there had apparently been 

 practical unanimity as to the Tertiary age of 

 the lignite series, "the only varying evidence 

 being found in what Dr. Leidy considered the 

 Wealden type of the Judith River vertebrates." 

 The first dissenting voice to this general current 

 belief appears to have been raised by John L. 

 Le Conte, who had accompanied an expedition 

 for the' survey of an extension of the Union 



•» Hayden, F. V^., Geological report of the exploration of the Yellow- 

 stone and Missouri rivers, under the direction of Capt. W. F. Raynolds, 

 in 1859-flO, 1869. Newberry's "Report on the Cretaceous and Ter- 

 tiary plants" occupies pp. 145-174. 



» Newberry, J. S., Notes on the later extinct floras of North ,\merica, 

 with descriptions of some new species of fossil plants from the Cre- 

 taceous and Tertiary strata: New York Lyceum Nat. Hist, .\niials. 

 vol. 9, pp. 1-76, 1888. 



'•• Newberry, J. S., The later e.\tinct floras of North America (a post- 

 humous work, edited by Arthur Hollick): U. S. Geol. Survey Mon. 

 35, 1898. 



•' Am. Jour. Sci., 2d ser., vol. 45, pp. 205-208, 1868; reprinted in V. S, 

 Geol. Survey Terr. Third Ann. Rept., pp. 195-197, 1873. 



Pacific Railroad from Smoky Hill River, Kans., 

 to the Rio Grande. The first announcement 

 is an extract from a letter dated Fort Craig, 

 N. Mex., October 3, 1867, published in the 

 American Journal of Science for January, 

 1868." In this letter he stated that he had 

 been enabled to make an examination and 

 determine tlie age of a bed of anthracite near 

 Old Placer Mountain, 25 miles southwest of 

 Santa Fe, N. Mex.-^ The data upon which the 

 Cretaceous age was predicated were not given 

 at this time but were set forth in his full 

 report ^* published later in 1868. At a num- 

 ber of localities, but notably in the canyon of 

 Purgatoire River and near Trinidad, he found 

 undoubted CVctaceous invertebrates associated 

 with the coal, and in the higher beds he col- 

 lected plants which Lesquereux pronounced of 

 Tertiary age. Although Le Conte's paper 

 bears date of February, 1868, it evidently was 

 not published on that date, for in the paper he 

 speaks of having seen Hayden's article on 

 "Lignite deposits of the West" in the March 

 number of the American Journal of Science for 

 that year. In fact, he devotes several pages 

 (pp. 65-68) to disproving Hayden's contention 

 that all the coal of the West was of Tertiary 

 age. In addition to studying the rocks of the 

 Raton-Trinidad area, Le Conte made a journey 

 from Trinidad to Denver, noting the coal near 

 Colorado City and in the Denver Basin at 

 Marshall, Golden, and other places. All this 

 coal he considered to be of Cretaceous age, in 

 spite of the evidence for Tertiary age adduced 

 by Haj'den and Lesquereux. 



Without unduly anticipating it may be 

 pointed out that subsequent study in the 

 Raton-Trinidad area has shown that both Le 

 Conte and Lesquereux were right — that is, 

 the beds which yielded the Inoceramus are now 

 known to be separated by marked uncon- 

 formity from those above which supplied most 

 of the plants studied by Lesquereux. (See pp. 

 18-19.) 



" Cretaceous coal in New Mexico: Am. Jour. Sci., 2d ser., vol. 45, p. 

 136, 1868. 



» Two years later F. V. Hayden visited this region and reported that 

 the coal beds were above Cretaceotis rocks containing Ostrea congesta, 0. 

 larva, Iiwceramus, etc. The anthracite he explained as being due to 

 the presence of an enormous dike. (See Preliminary field report of 

 the United States geological survey of Colorado and New Mexico [U.S. 

 Geol. Survey. Terr. Third Ann. Rept.], pp. 66-OS, 1S89.) 



>* Le Conte, J. L., Notes nn the geology of the survey for the extension 

 of the Union Pacific Railway from the Smoky Hill River, Kans., to the 

 Rio Grande, pp. l-n7, 1868. 



