540 A. C. VEATCH 
group without reference to the quality of the fuel simply to distinguish it from the 
other great group of older age, the age of which is not questioned... . . It is well 
known that I have held with some tenacity the opininon that the coal formations 
of the West are of Tertiary age; and I still regard the Lignitic group proper as 
transitional or lower Eocene. 
The name “‘ Laramie beds” is used in the first of the above quota- 
tions in a simple geographic sense, but it clearly indicates what to 
Hayden was a most natural term. In the Hayden report for 1873, 
published in 1874, Marvine, in discussing the exposures in the vicinity 
of Denver and Golden, Colo., used the geographic name “Colorado 
Lignitic group,”! with the suggestion “that the extended explora- 
tions of Hayden and others would seem to prove almost conclusively 
that the Colorado Lignitic group is the direct southern stratigraphical 
equivalent of the Fort Union group of the upper Missouri.” But 
he adds the precautionary statement : “ When all the facts are known, 
they may develop some new ideas as to geological transitions.” The 
Colorado beds in the above clause from Hayden’s History of the 
Lignitic Group are clearly the same as the “Colorado Lignitic group” 
of Marvine, and there was thus at this time two natural names for the 
Lignitic group as developed in Wyoming and Colorado—the Colorado 
group and the Laramie group. When Hayden and King agreed to 
use the term ‘Colorado group” as an appropriate name for the com- 
bined Fort Benton, Niobrara, and Pierre,? the term ‘“‘ Laramie group”’ 
was left as the natural and appropriate designation. 
In “Notes on the Lignitic Group of Eastern Colorado and Por- 
tions of Wyoming,” which appears to have been the last paper written 
by Hayden on this subject before the adoption of Laramie, he states 
that 
throughout the Lignitic proper, that is the portion occurring above the Fox Hills 
group, I have never found any true nonconformity. That there may be in some 
places an interrupted sequence in the beds is quite possible... . . That there 
have been many oscillations of the surface, that it has been alternately above and 
below water many times, may be inferred from the numerous coal-beds. In the 
aggregate, there could hardly have been any marked interruption in the sequence 
of the deposition, even up to the summits of the highest Tertiary, though between 
t Seventh Annual Report, U. S. Geological and Geographical Survey of the Terri- 
tories for 1873, 1874, p. 107. 
2 Report of the Geological Exploration of the Fortieth Parallel, Vol. I (1878), p. 298. 
