o speak of the Tertiary period as a
whole under the name of the "Age of Mammals," a title at least
as well deserved as that of "Age of Reptiles" applied to the
Mesozoic, or "Age of Molluscs" applied to the Palaeozoic epoch.

As regards the _plants_ of the Eocene, the chief point to be
noticed is, that the conditions which had already set in with
the commencement of the Upper Cretaceous, are here continued,
and still further enforced. The _Cycads_ of the Secondary period,
if they have not totally disappeared, are exceedingly rare; and
the _Conifers_, losing the predominance which they enjoyed in the
Mesozoic, are now relegated to a subordinate though well-defined
place in the terrestrial vegetation. The great majority of the
Eocene plants are referable to the groups of the Angiospermous
Exogens and the Monocotyledons; and the vegetation of the period,
upon the whole, approximates closely to that now existing upon
the earth. The plants of the European Eocene are, however, in the
main most closely allied to forms which are now characteristic
of tropical or sub-tropical regions. Thus, in the London Clay
are found numerous fruits of Palms (_Napdites_, fig. 213), along
with various other plants, most of which indicate a warm climate
as prevailing in the south of England at the commencement of the
Eocene period. In the Eocene strata of North America occur numerous
plants belonging to existing types--such as Palms, Conifers,
the Magnolia, Cinnamon, Fig. Dog-wood, Maple, Hickory, Poplar,
Plane, &c. Taken as a whole, the Eocene flora of North America
is nearly related to that of the Miocene strata of Europe, as
well as to that now existing in the American area. We conclude,
therefore, that "the forests of the American Eocene resembled
those of the European Miocene, and even of modern America" (Dana).

[Illustration: Fig. 213.--_Napadites ellipticus_, the fruit of
a fossil Palm. London Clay, Isle of Sheppey.]

As regards the _animals_ of the Eocene period, the _Protozoans_
are represented by numerous _Foraminifera_, which reach here their
maximum of development, both as regards the size of individuals and
the number of generic types. Many of the Eocene Foraminifers are of
small size; but even these not uncommonly form whole rock-masses.
Thus, the so-called "Miliolite Limestone" of the Paris basin, largely
used as a building-stone, is almost wholly composed of the shells
of a small species of _Miliola_. The most remarkable, how