536 A. C. VEATCH 
ness are wholly composed of these leaves in a good state of preservation, and so 
perfect are they that they could not have been transported any great distance.* 
The extreme western portion of the area described by Hayden in the 
above as occupied by the Tertiary—that is, the region in the imme- 
diate vicinity of St. Mary’s station—is underlain by Lower Laramie 
strata, but along the railroad the beds are almost entirely covered 
by Quaternary débris. The beds actually studied by Hayden in this 
area, and upon which he based his opinion, are certainly wholly 
Upper Laramie. ; 
In summarizing his results in a letter written from the field to the 
commissioner of the General Land Office, Hayden shows that he had 
already begun to suspect that his decision that all coal-bearing beds 
in this region are Tertiary is not well founded. In the same letter he 
announces his unqualified belief that the Tertiary beds—that is, 
those yielding the plants at Carbon, Medicine Bow stage station, and 
Rock Creek—are unquestionably conformable with the Cretaceous. 
He says: 
We have taken the position also that the coal-bearing beds of the Laramie 
Plains are of Tertiary age, although some marine fossils are found in strata con- 
nected with the coal. There may be some thin seams of impure coal in the upper 
Cretaceous beds... . . I can find no want of conformity between the Tertiary 
and Cretaceous beds, and indeed so gradually and imperceptibly do the Creta- 
ceous beds pass up into the Tertiary that I have not been able to determine the 
line of separation.? 
In a review of the same subject before the American Philosophical 
Society on February 19, 1869, Hayden clearly shows that he regards 
the Carbon locality as not only the most important locality in the 
Laramie Plains, but as the connecting link between the great Lig- 
nitic group of the Missouri River (which he then, because of the flora, 
regarded as Miocene) and the coal-bearing deposits of Wyoming. 
He says, in summarizing his geological observations at this time: 
The Cretaceous formations occupy the country for 60 miles from Laramie 
City to Lake Como. Genuine Jurassic beds . . . . are here exposed for a short 
1[Second Annual Report, U. S. Geological Survey of the Territories] Annual 
Report, Commissioner of the General Land Office for 1868, 1868, p. 249; Proceedings 
of the American Philosophical Society, Vol. XI (1869), p. 37- 
2 Annual Report, Commissioner of the General Land Office, for 1868, 1868, 
p- 253; First, Second, and Third’ Annual Reports, U. S. Geological Survey of the 
Territories (1873), p. 100. 
