Miocene period
In the Miocene period we find a great expansion of the monkeys.
These in turn enter the scene quite suddenly, and the authorities
are reduced to uncertain and contradictory conjectures as to
their origin. Some think that they develop not from the femurs,
but along an independent line from the Insectivores, or other
ancestors of the Primates. We will not linger over these early
monkeys, nor engage upon the hopeless task of tracing their
gradual ramification into the numerous families of the present
age. It is clear only that they soon divided into two main
streams, one of which spread into the monkeys of America and the
other into the monkeys of the Old World. There are important
anatomical differences between the two. The monkeys remained in
Central and Southern Europe until near the end of the Tertiary.
Gradually we perceive that the advancing cold is driving them
further south, and the monkeys of Gibraltar to-day are the
diminished remnant of the great family that had previously
wandered as far as Britain and France.
A third wave, also spreading in the Miocene, equally obscure in
its connection with the preceding, introduces the man-like apes
to the geologist. Primitive gibbons (Pliopithecus and
Pliobylobates), primitive chimpanzees (Palaeopithecus), and other
early anthropoid apes (Oreopithecus, Dryopithecus, etc.), lived
in the trees of Southern Europe in the second part of the
Tertiary Era. They are clearly disconnected individuals of a
large and flourishing family, but from the half-dozen specimens
we have yet discovered no conclusion can be drawn, except that
the family is already branching into the types of anthropoid apes
which are familiar to us.
Of man himself we have no certain and indisputable trace in the
Tertiary Era. Some remains found in Java of an ape-man
(Pithecanthropus), which we will study later, are now generally
believed, after a special investigation on the spot, to belong to
the Pleistocene period. Yet no authority on the subject doubts
that the human species was evolved in the Tertiary Era, and very
many, if not most, of the authorities believe that we have
definite proof of his presence. The early story of mankind is
gathered, not so much from the few fragments of human remains we
have, but from the stone implements which were shaped by his
primitive intelligence and remain, almost imperishable, in the
soil over which he wandered. The more primitive man was, the more
ambiguous would be the traces of his shaping of these stone
implements, and the earliest specimens are bound to be a matter
of controversy. It is claimed by many distinguished authorities
that flints slightly touched by the hand of man, or at least used
as implements by man, are found in abundance in England, France,
and Germany, and belong to the Pliocene period. Continental
authorities even refer some of them to the Miocene and the last
part of the Oligocene.
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