has been amply
sufficient to give simply the outlines of the other periods. In order to
fix more clearly the sequence of life, we will give an outline showing
the periods we have reviewed, and also the subdivisions of the Cenozoic
time, which we are now to examine with more care.

OUTLINE.

LIFE. Archaean Time. The Beginning: Includes the long lapse of time when
the globe could not support life, but towards its close faint traces of
life, both animal and vegetable appeared.

Paleozoic Time. The Period of Old Life Forms: Forests of flowerless
trees; but pines grew in the coal measures. Animal life largely
invertebrate; but amphibians and reptiles among the vertebrate appear at
the close.

Mesozoic Time. The Period of Middle Life Forms: Flowering trees
increasing in number and importance. Deciduous trees make their
appearance. Animal life largely reptilian. The class Mammalia
represented by marsupials.

Cenozoic Time. Tertiary, or Age of Mammals: Eocene, Miocene, Pliocene.
Quarternary, or Age of Man: Glacial or Pleistocene, Recent.

At the close of the Mesozoic time, great elevations of land took place
in both America and Europe, especially in the northern portions.<21>
This could not fail to have a great effect on life, both animal and
vegetable.

During the Eocene, or first division of the Tertiary Age, we have simply
to note the steady progress of life. There were forests of species of
oaks, poplars, maples, hickories, and other common trees, and others
now found only in tropical regions. Palm trees were growing in the upper
Missouri region of the United States. And England was decidedly a
land of Palms, as no less than thirteen species are known to have been
growing there. Cypresses, yews, and pines graced the scene.<22> Our
special interest centers, however, in the mammals of this epoch.

Illustration of The Paleotherium.--------

In the preceding epoch marsupials only were represented. But in beds
of the middle and closing portions of the Eocene period we meet with a
sudden increase of Mammalian life. Whale-like animals were especially
abundant in the seas; and on our Western plains were animals like the
tapirs of India, and rhinoceros-like animals as large as elephants<23>
but having no trunks, and diminutive little animals not larger than
foxes, from which have come our horses. Europe also had a varied
Mammalian fauna. There were numerous hog-like animals. Animals, like the
tapirs of tropical As