HISTORICAL REVIEW OF THE LARAMIE PROBLEM. 



11 



One fruitful source of difference of opinion has been in 

 the misunderstanding in regard to the different horizons 

 of coal strata of the West. That there are important coal 

 beds in rocks of well-defined Cretaceous age can not be 

 disputed, and I have long since yielded that point. 

 What we wish to show more clearly is that there exists in 

 the West a distinct series of strata which we have called 

 the Lignite group, and that it is entirely separate, paleon- 

 tologically and geologically, from a great group of strata in 

 the lower Cretaceous, and perhaps extending down into 

 the Jurassic, which contains a great number of thick and 

 valuable beds of coal. It is not necessary to discuss the 

 question whether the term Lignitic shall be applied to the 

 coal of either or both groups. I have used the term 

 Lignitic for the upper group without reference to the 

 quality of its fuel, simply to distinguish it from the other 

 great groups of older date, the ages of which are not 

 questioned. 



From the above statement it is clear that 

 Hayden was entirely willing to admit the exist- 

 ence of coal in the Cretaceous of the Rocky 

 Mountain region, and from .this it of course 

 followed that the term "Lignitic" was not ap- 

 plicable to all the coal-bearing strata; in fact, 

 he distinctly stated that the term was to be 

 applied only to the upper coal-bearing series. 

 He still argued, however, for the connection of 

 the coal-bearing beds of the Laramie Plains 

 and Colorado with the vast group to the 

 northwest. 



The same report contained a long paper by 

 A. C. Peak on the geology of. portions of 

 Colorado,, in which he presented a series of 

 tables illustrating the progress of opinion 

 regarding the "Lignitic group." He dis- 

 cussed the different opinions at length and 

 reached the following conclusions: 



1. The lignite-bearing beds east of the mountains in 

 Colorado are the equivalent of the Fort Union group of 

 the upper Missouri and are Eocene Tertiary; also, that the 

 lower part of the group, at least at the locality 200 miles 

 east of the mountains, is the equivalent of a part of the 

 lignitic strata of Wyoming. 



2. The Judith River beds have their equivalent along 

 the eastern edge of the mountains below the Lignite or 

 Fort Union group and also in Wyoming and are Cretaceous, 

 although of a higher horizon than the coal-bearing strata 

 of Coalville and Bear River, Utah. They Jorm either the 

 upper part of the Fox Hills group (No. 5) or a group to be 

 called No. 6. 



Also in this report for 1873 Lesquereux had 

 an extensive paper under the title "On the 

 Tertiary flora of the North American Lignitic, 

 considered as evidence of the age of the for- 

 mation." He again took up the objections that 

 had been urged against his interpretation and 



answered each in detail as the evidence appeared 

 to him. His opinion remained unchanged. 



The historical review of opinion which pre- 

 ceded the introduction of the term Laramie has 

 now been presented in sufficient detail to make 

 clear the necessity for a convenient, usable, 

 common appellation. Those who had ap- 

 proached the subject from a study of the 

 northern areas — that is, of the upper Missouri 

 River region and contiguous territory — were 

 naturally impressed with the strength of the 

 argument for the Tertiary age of the lignite- 

 bearing beds, while those who had first become 

 familiar with the more southern areas were 

 quite as strongly of the opinion that the beds 

 they studied were of Cretaceous age. Sub- 

 sequent study has shown that both these views 

 contained a measure of truth. 



As A. C. Peale was at that time actively en- 

 gaged in geologic work in the Rocky Mountain 

 area, his recollection of the conditions then 

 current, as set forth in a recent article, 40 is of 

 interest : 



As a member of the Hayden Geological Survey at the 

 time the term "Laramie" was first proposed and used by 

 both the Hayden and King organizations, and as one of 

 those who first used it, a statement of my recollection 

 may be of some interest here. Just at the time the work 

 of the Exploration of the Fortieth Parallel, under Clarence 

 King, was approaching completion, and their geologic 

 maps were being colored, the work of the United States 

 'Geological and Geographical Survey of the Territories had 

 also reached the stage when it became necessary to color 

 the maps of Colorado, upon which field work was begun 

 in 1873 and finished in 1876. As two of the maps of the 

 former organization adjoined the work of the Hayden 

 Survey along the northern line of Colorado, it was deemed 

 desirable that there should be some correlation, in terms 

 at least, where the work joined. There was substantial 

 agreement as to most of the formations, about the only 

 difference being as to the age of the beds resting con- 

 formably upon the Fox Hills Cretaceous of Hayden as 

 exposed along the line of the Union Pacific Railway and 

 to the westward of the foothills of the Front Range of 

 Colorado, where they were usually designated by Hayden 

 and the members of his Survey as the Lignitic beds of 

 eastern Colorado or the lignitic coal group of the eastern 

 slope. These beds were considered by King to be of 

 Cretaceous age, while Hayden was inclined to consider 

 them as belonging to the Tertiary. At this time Clarence 

 King wrote to Dr. Hayden asking him to propose a name 

 for these debatable beds — debatable only as to age, for 

 both agreed as to their stratigraphic position. In reply to 

 this letter Hayden suggested the name Laramie, which 

 was accepted by King, as indicated by him on page 331 



<o Peale, A. C, On the application of the term Laramie: Am. Jour. 

 Sci., 4th ser., vol. 27, p. 45, July, 1909. 



