In the Pliocene, though the facies of the mammalian fauna of Europe becomes more modern, and a few modern species occur, the climate becomes colder, and in consequence the apes disappear, so that the chances of finding fossil men are lessened rather than increased in so far as the temperate regions are concerned. In Italy, however, Capellini has described a skull, an implement, and a notched bone supposed to have come from Pliocene beds. To this it may be objected that the skull—which I examined in 1883 in the museum at Florence—and the implement are of recent type, and probably mixed with the Pliocene stuff by some slip of the ground. As the writer has elsewhere pointed out,[205] similar and apparently fatal objections apply to the skull and implements alleged to have been found in Pliocene gravels in California. Dawkins further informs us that in the Italian Pliocene beds supposed to hold remains of man, of twenty-one mammalia whose bones occur, all are extinct species, except possibly one, a hippopotamus. This, of course, renders very unlikely in a geological point of view the occurrence of human remains in these beds.
[205] "Fossil Men," 1880.
In the Pleistocene deposits of Europe—and this applies also to America—we for the first time find a predominance of recent species of land animals. Here, therefore, we may look with some hope for remains of man and his works, and here, in the later Pleistocene, or the early Modern, they are actually found. When we speak, however, of Pleistocene man, there arise some questions as to the classification of the deposits, which it seems to the writer Dawkins and other British geologists have not answered in accordance with geological facts, and a misunderstanding as to which may lead to serious error. They have extended the term Pleistocene over that Post-glacial period in which we find remains of man, and thus have split the "Anthropic" period into two; and they proceed to divide the latter part of it into the Pre-historic and Historic periods, whereas the name Pleistocene should not be extended to the Post-glacial age. The close of the Glacial period, introducing great physical and climatal changes, some new species of mammalia and man himself, should be regarded as the end of the Pleistocene, and the introduction of what some French geologists have called the Anthropic period, which I have elsewhere divided into Palanthropic, corresponding to the so-called Palæolithic age, and Neanthropic, corresponding to the later stone and metal ages.[206] These may be termed respectively the earlier and later stages of the Modern period as distinguished from the Pleistocene Tertiary.
[206] "Modern Science in Bible Lands."
In point of logical arrangement, and especially of geological classification, the division into historic and pre-historic periods is decidedly objectionable. Even in Europe the historic age of the south is altogether a different thing from that of the north, and to speak of the pre-historic period in Greece and in Britain or Norway as indicating the same portion of time is altogether illusory. Hence a large portion of the discussion of this subject has to be properly called "the overlap of history." Further, the mere accident of the presence or absence of historical documents cannot constitute a geological period comparable with such periods as the Pleistocene and Pliocene, and the assumption of such a criterion of time merely confuses our ideas. On the one hand, while the whole Tertiary or Kainozoic, up to the present day, is one great geological period, characterized by a continuous though gradually changing fauna and series of physical conditions, and there is consequently no good basis for setting apart, as some geologists do, a Quaternary as distinct from the Tertiary period; on the other hand, there is a distinct physical break between the Pliocene and the Modern in the great Glacial age. This, in its Arctic climate and enormous submergence of the land, though it did not exterminate the fauna of the northern hemisphere, greatly reduced it, and at the close of this age some new forms came in. For this reason the division between the Pleistocene and Anthropic ages should be made at the beginning of the Post-glacial age. The natural division would thus be:—
I. Pleistocene, including—
(a) Early Pleistocene, or first continental period. Land very extensive, moderate climate. This passes into the preceding Pliocene.
(b) Later Pleistocene, or glacial, including Dawkins' "Mid Pleistocene." In this there was a great prevalence of cold and glacial conditions, and a great submergence of the northern land.
II. Anthropic, or period of man and modern mammals, including—
(a) Palanthropic, Post-glacial, or second continental period, in which the land was again very extensive, and Palæocosmic man was contemporary with some great mammals, as the mammoth, now extinct, and the area of land in the northern hemisphere was greater than at present. This includes a later cold period, not equal in intensity to that of the Glacial period proper, and was terminated by a great and very general subsidence, accompanied by the disappearance of Palæocosmic man and some large mammalia, and which may be identical with the historical deluge.