568 The American Naturalist. [June, 
together for the first time a fairly complete list of all the upper Creta- 
ceous species the existence of which had generally been ignored in the 
discussion of the question. These as well as the Eocene species of all 
parts of the world were directly compared with the Laramie species. 
The very careful analysis of this table which I made showed that the 
Laramie flora occupies an intermediate place between that of the upper 
Cretaceous (above the Dakota group and Cenomanian) and that of the 
Eocene. The only conclusion I drew, if conclusion it can be called, 
was that the whole discussion was a war of words, often unworthy of 
the talent that had been expended upon it.”  ' 
__ ProF. J. J. STEVENSON said : “I should like to say a word or two 
about the section that Dr. Newberry has put on the board. The 
‘statement that the Colorado group cannot be differentiated in Colorado 
is not altogether correct. It is true that in a considerable area beyond 
the Arkansas range it is a very difficult thing indeed to differentiate 
the Colorado group; but along the plain in front of the Rocky 
Mountains in Colorado and New Mexico there is not the slightest diffi- 
culty in recognizing the Fort Brenton as a mass of black shale; the 
Niobrara above that, gray to blue limestones separated by black shale , 
then the Fort Pierre, drab to yellow sandy shales, containing nodules 
of limestone and iron ore, while above that and quite easily separable 
from it we find in northern and central Colorado the Fox Hills group. 
This is the Cretaceous along the waters of the South Platte, where the 
Fox Hills group is characterized all the way, from the bottom to the 
top, by a nodose fucoid, falymenites major, which was at one time a 
very interesting topic of discussion. The Fox Hills group in central 
Colorado is upwards of one thousand feet thick, consisting mostly of 
sandstones, some of them calcareous and rich in Fox Hills fossils, with 
some beds of coal, which have been opened in the neighborhood of 
Greely. At Cañon City, Colorado, the Fox Hills group is only about 
250 feet thick, that being the vertical extent of the Halymenites. In 
that interval are the important coal beds and numerous sandstones or 
shales containing plants which doubtless answer to those of the plant 
bed which I found on one occasion near Evans, on the South Platte, 
but which I could never find again. Further southward, near Trini- 
dad, Colorado, the Fox Hills is only 8o feet thick, that being the ver- 
tical range of the Halymenites. In that field, however, the Fox Hills 
has been included in the Laramie ; but the Laramie group above the 
great coal-bearing series is easily separable from the Ha/ymenttes sand- 
stone. Southward, in New Mexico, the Halymenites or Fox Hills 
sandstone entirely disappears. 
