RECENT ADVANCES IN GEOLOGY. 451 
In the flora of the Great Lignite Basin of Nebraska, which 
is referred to the Miocene age, Hayden has detected the oak, 
the tulip or poplar, the elm and walnut, and a true fan- 
palm, with a leaf-spread of twelve feet ;—all, however, of 
extinct species. These forms he regards as characteristic of 
a sub-tropical climate, such as now prevails in the Gulf 
States. The fan-palm (Sabal Campbellii) is the representa- 
tive of the Sabal major of the European Tertiaries, and the 
Sabal palmetto of our Southern States. 
The Cinnamonium, an unquestioned tropical type, while 
not thus far detected in the Missouri Basin, has been found 
by Lesquereaux in the Cretaceous (?) beds of Bellingham 
Bay, on our Northwestern coast; in the Eocene of the 
Lower Mississippi, and in the lignite beds of Vermont. 
Professor Newberry, in a review of the flora of the Cre- 
taceous and Tertiary Ages of North America, thus re- 
marks : 
"We have, therefore, negative evidence, though it may 
be reversed at an early day by further observations, that the 
climate of the interior of our continent, during the Tertiary 
Age, was somewhat warmer than during the Cretaceous 
Period; and that during both the same relative differences 
of climate prevailed between the western and central por- 
tions that exist at the present day." 
The Drift Epoch was ushered in by a marked change in 
physical influences, by which the whole flora of the extreme 
northern hemisphere was so far affected that certain forms 
were blotted out of existence, while other forms were forced 
to seek, by migration, a more congenial climate, and accom- 
modate themselves to altered conditions. In the higher 
regions we find a predominating growth of mosses and saxi- 
frages, and at the southern limits of the Drift a buried 
vegetation of an Alpine character. 
f we examine the faune of the two epochs— particularly 
the land animals which we may suppose to be peculiarly 
susceptible to atmospherie changes— we shall find that there 
