638 REVIEWS. 
and fiora of the Tertiary deposits of this country, when compared 
with those of the Ol orld, reach back one epoch into the past. 
We have already obliterated the chasm between the Permian and 
the Carboniferous era, and shown that there is a well-marked in- 
osculation of organic forms—those of supposed Permian affinities 
passing down into well-known Carboniferous strata, and admitted 
Carboniferous types passing up into the Permian. We believe that 
the careful study of these transition beds is destined to obliterate 
the chasm between the Cretaceous and Tertiary periods, and that 
there is a passing down into the Cretaceous period of Tertiary forms, 
and an extending upward into the Tertiary of those of Cretaceous 
affinities. It appears also, that every distinct fauna or flora of a 
period ought to contain within itself the evidence of its own age 
or time of existence, with certain prophetic features which reach 
forward to the epoch about to follow. If thereis a strict unifor- 
mity in all the operations of nature when taken in the aggregate, 
as I believe there is, then this is simply in accordance with the law 
of progress which in the case of the physical changes wrought out 
in the geological history of the world has operated so slowly that 
infinite ages have been required to produce any perceptible change. 
The position .that I have taken, in all my studies in the West, is 
on the great extended movements which I have regarded as gene- 
ral, uniform and slow, and the results of which have given to the 
ti 
marine. It was no fault of the fossils themselves that they were 
mistaken in this instance.” ete 
Prof. Hayden’s remarks on the relation of the Quaternary period 
to the Tertiary are of much interest : — 
. “As we have previously remarked, we believe that the Quater- 
nary period, although more difficult to study, will be found to be 
scarcely second in importance to any of the previous great epochs 
in geology. A careful study of these modern deposits will un- 
doubtedly show consecutive links by which it was united to the 
Tertiary period, in the same manner as the Cretaceous and Tertiary 
are connected in the case of the great Tertiary lake now indicated 
y the deposits on White and Niobrara Rivers, in Nebraska, m 
which the waters continued to cover a greater or less area through 
most of the Quaternary period, at least, as is shown by the thick 
