12 



LARAMIE FLORA OP THE DENVER BASIN. 



of the volume on systematic geology, 41 where he says: 

 "During the slow gathering of the evidence which shall 

 finally turn the scale I proposed to Dr. Hayden that we 

 adopt a common name for the group and that each should 

 refer it to whatever age his data directed. Accordingly, 

 it was amicably agreed between us that this series should 

 receive the group name of Laramie and that it should 

 be held to include that series of beds which conformably 

 overlies the Fox Hills." 



It may be of interest to point out that, so 

 far as now known, the word Laramie used as 

 a geologic formational term first appeared in 

 an author's proof of geologic map No. II of the 

 Fortieth Parallel Survey, by Clarence King 

 and S. F. Emmons. This map was dated 

 November 15, 1875, and was noticed in the 

 American Journal of Science for February, 

 1876, but in - neither place was there any 

 definition of the term. The first printed 

 description of the Laramie was apparently 

 that given by Arnold Hague a in volume 2 of 

 the final reports of the Fortieth Parallel Survey, 

 in which he presented a very small and rela- 

 tively unimportant section that claims dis- 

 tinction only on the ground that it was the 

 first section ever published of the Laramie. 

 It was measured on the Denver Pacific Rail- 

 road 5 or 6 miles west of Carr station and about 

 18 miles southeast of Cheyenne, Wyo. Peale a 

 stated that "this section, if any should be so 

 considered, would be the typical Laramie 

 section." 



Hayden first used the term Laramie in an 

 article published in 1877. 44 In this article he 

 followed the coloring on King's map above 

 mentioned,' which he undoubtedly had before 

 him at the time. 



King and the members of his Survey frankly 

 and, as he says, "cheerfully" adopted the 

 classification and nomenclature of the Upper 

 Cretaceous section as defined by Hayden. 

 After describing the Cretaceous rocks of their 

 area up to and including the Fox Hills, King 

 said: 45 



Here, with those who follow Hayden, the Cretaceous 

 series comes to an end. Conformably over this (Fox Hill) 

 lies the group which Hayden and I have agreed to call the 

 Laramie, which is his Lignitic group and is considered by 

 hi™ as a transition member, between Cretaceous and 



« XI. S. Geol. Expl. 40th Par. Kept., vol. 1, 1878. 



« Idem, vol. 2, pp. 60, 61, 1877. 



« Am. Jour. Soi., 4th ser., vol. 27, p. 49, 1909. 



« Notes on some artesian borings along the line of the Union Pacific 

 Railroad in Wyoming Territory: U. S. Geol. and Geog. Survey Terr. 

 Bull., vol. 3, pp. 181-185, April 5, 1877. 



« IT. S. Geol. Expl. 40th Par. Eept., vol. 1, p. 348, 1878. 



Tertiary. There is no difference between us as to the 

 conformity of the Laramie group with the underlying 

 Fox Hill. It is simply a question of determination of age 

 upon which we differ. 



King was in error, however, in stating that 

 the Laramie was the equivalent of Hayden's 

 Fort Union "group," or indeed that it included 

 all of the so-called Lignitic, and it was un- 

 doubtedly the assumption by subsequent 

 writers that this was so that led to much of 

 the discussion and difference of opinion that 

 speedily arose. Hayden's last published word 

 on this point 48 occurs in the letter transmitting 

 Lesquereux's "Tertiary flora" to the Secre- 

 tary of the Interior and is as follows: 



If objection is made to the use of the term "Lignitic" 

 group, I would say that in this work it is restricted to a 

 series of coal-bearing strata lying above the Fox Hills 

 group, or Upper Cretaceous, and these are embraced in 

 the divisions Laramie and Fort Union groups. It is well 

 known that there are in various parts of the West, espe- 

 cially along the fortieth parallel and soiithwestward, very 

 thick beds of coal in the various divisions of the Cre- 

 taceous, extending down even into the upper Jurassic. 

 Had this not been the case, the more general term Lignitic 

 would not have been retained by the Survey in preference 

 to any other. 



On the succeeding page of this letter he 

 summed up his conclusion in the following 

 words : 



The facts as we understand them at the present time 

 would seem to warrant this general division, viz, a marine 

 series, Cretaceous; gradually passing up into a brackish- 

 water series, Laramie; gradually passing up into a purely 

 fresh-water series, Wasatch. It is also probable that the 

 brackish-water beds on the upper Missouri must be corre- 

 lated with the Laramie, and that the Wasatch group as 

 now defined and the Fort Union group are identical as a 

 whole, or in part at least. 



The Laramie was by that time fairly 

 launched, and the literature devoted to it be- 

 came increasingly voluminous and scattered. 

 It is not possible nor perhaps desirable in the 

 present connection to follow all the intricate 

 ramifications of the discussion, and only an 

 outline of the salient features will be attempted. 

 The two points that attracted most attention 

 were the areal distribution of the Laramie and 

 of course its age. As so frequently happens 

 in discussions of this kind, the pendulum when 

 once started was permitted to swing too far, 

 with the .result that beds were included in the 

 Laramie that subsequent study has proved 

 have little or no intimate connection with 



<• U. S. Geol. Survey Terr. Rept., vol. 7, p. iv, 1878. 



