Calaveras skull.]

But according to Professor Josiah Whitney there is reason for supposing
that man existed in California at a still more remote period. He holds
that the famous skull discovered in 1866, in the gold-bearing gravels of
Calaveras county, belongs to the Pliocene age.[10] If this be so, it
seems to suggest an antiquity not less than twice as great as that just
mentioned. The question as to the antiquity of the Calaveras skull is
still hotly disputed among the foremost palaeontologists, but as one
reads the arguments one cannot help feeling that theoretical
difficulties have put the objectors into a somewhat inhospitable
attitude toward the evidence so ably presented by Professor Whitney. It
has been too hastily assumed that, from the point of view of evolution,
the existence of Pliocene man is improbable. Upon general
considerations, however, we have strong reason for believing that human
beings must have inhabited some portions of the earth throughout the
whole duration of the Pliocene period, and it need not surprise us if
their remains are presently discovered in more places than one.[11]

[Footnote 10: J. D. Whitney, "The Auriferous Gravels of the
Sierra Nevada", _Memoirs of the Museum of Comparative Zooelogy
at Harvard College_, Cambridge, 1880, vol. vi.]

[Footnote 11: In an essay published in 1882 on "Europe before
the Arrival of Man" (_Excursions of an Evolutionist_, pp.
1-40), I argued that if we are to find traces of the "missing
link," or primordial stock of primates from which man has been
derived, we must undoubtedly look for it in the Miocene (p.
36). I am pleased at finding the same opinion lately expressed
by one of the highest living authorities. The case is thus
stated by Alfred Russel Wallace: "The evidence we now possess
of the exact nature of the resemblance of man to the various
species of anthropoid apes, shows us that he has little special
affinity for any one rather than another species, while he
differs from them all in several important characters in which
they agree with each other. The conclusion to be drawn from
these facts is, that his points of affinity connect him with
the whole group, while his special peculiarities equally
separate him from the whole group, and that he must, therefore,
have div