he halcyon days of the
Tertiary Era. Among the bony fishes, all our modern and familiar types
appear.

The amphibia and reptiles also pass into their modern types, after a
period of generous expansion. Primitive frogs and toads make their first
appearance in the Tertiary, and the remains are found in European beds
of four-foot-long salamanders. More than fifty species of Tertiary
turtles are known, and many of them were of enormous size. One carapace
that has been found in a Tertiary bed measures twelve feet in length,
eight feet in width, and seven feet in height to the top of the back.
The living turtle must have been nearly twenty feet long. Marine
reptiles, of a snake-like structure, ran to fifteen feet in length.
Crocodiles and alligators swarmed in the rivers of Europe until the
chilly Pliocene bade them depart to Africa.

In a word, it was the seven years of plenty for the whole living world,
and the expansive development gave birth to the modern types, which were
to be selected from the crowd in the subsequent seven years of famine.
We must be content to follow the evolution of the higher types of
organisms. I will therefore first describe the advance of the Tertiary
vegetation, the luxuriance of which was the first condition of the great
expansion of animal life; then we will glance at the grand army of
the insects which followed the development of the flowers, and at the
accompanying expansion and ramification of the birds. The long and
interesting story of the mammals must be told in a separate chapter,
and a further chapter must be devoted to the appearance of the human
species.

We saw that the Angiosperms, or flowering plants, appeared at the
beginning of the Cretaceous period, and were richly developed before the
Tertiary Era opened. We saw also that their precise origin is unknown.
They suddenly invade a part of North America where there were conditions
for preserving some traces of them, but we have as yet no remains
of their early forms or clue to their place of development. We may
conjecture that their ancestors had been living in some elevated inland
region during the warmth of the Jurassic period.

As it is now known that many of the cycad-like Mesozoic plants bore
flowers--as the modern botanist scarcely hesitates to call them--the
gap between the Gymnosperms and Angiosperms is very much lessened. There
are, however, structural differences which forbid us to regard any of
these flowering cycad