534 A. C. VEATCH 
to Cheyenne along the east base of the mountains. In this investi- 
gation he recognized in the Laramie Plains Cretaceous beds up to 
and including the Fox Hills,t and found that “at Rock Creek, about 
4o miles west of the big Laramie River, the lignite beds overlap? 
the Cretaceous.’ He collected from these lignite beds “‘in the 
Laramie Plains . . . . two species of plants, a Populus anda Plat- 
anus, specifically identical with those found on the upper Missouri.’’4 
This collection of plants was studied by Lesquereux’ and listed as 
from ‘‘Rock Creek, Laramie Plains.” As knowledge of the flora 
progressed, Lesquereux-referred this collection to the same horizon 
as the Carbon plant-beds,°® and in the light of present knowledge 
there can be no reasonable doubt that they came from the same 
formation. After his field-work of 1867, Hayden announced the 
doctrine, entirely natural from his knowledge of and experience with 
the coal-bearing beds in the Dakotas, eastern Montana, and north- 
eastern Wyoming, that all the coal-bearing beds of the Rocky Moun- 
tain region are younger than the Fox Hills. He thus included certain 
Upper Montana coal-bearing beds which in the region of Rock Creek 
directly underlie the Upper Laramie strata containing the plants 
referred to above. 
In 1868 Hayden, continuing the “Survey of the Territories,” 
extended his investigations of the Laramie Plains. He proceeded 
from Fort Sanders along the Overland Stage Road as far as Pass 
Creek, and then turned north to Fort Steele. Returning to Fort 
Sanders, he proceeded to examine the geology along the line of the 
Union Pacific Railroad from Fort Sanders westward.’ In his account 
1 Final Report, Geological Survey of Nebraska (1872), p- 55: 
2 From the usage of the word ‘“‘overlap” through Hayden’s writings, it is believed 
that he used the word as a synonym of “overlie,” and not in its present technical geologic 
sense. 
3 American Journal of Science, Second Series, Vol. XLV (1868), p. 205. 
4 Ibid., p. 204; see also p. 101; and Final Report, Geological Survey of Nebraska 
(1872), p. 55: : 
5 American Journal of Science, Second Series, Vol. XLV (1868), p. 205; [Third 
Annual] Preliminary Field Report, U. S. Geological Survey of Colorado and New 
Mexico (1869), pp. 95, 96. 
6 Fifth Annual Report, U.S. Geological Survey of Montana for 1871, 1872, p. 306. 
7[Second Annual Report, U. S. Geological Survey of the Territories, embracing 
Wyoming] Report of the Commissioner of the General Land Office for 1868, 1868, pp- 
