TM: TERTIARY AGE I. Eocene Pcriod.—There are living representatives of the orders and families of this period, but not of its genera or species.
II. Miocene Teriori.—Represented to-day by living genera, but all its species are extinct.
II.--2 III. Pliocene of its genera and a few of its species are represented by living forms.
IV. Pleistocene of its species are living to-day. Man appears on the globe.
V. Prehistoric abundant; animals are domesticated by him, and food-plants are cultivated.
VI. Historic record of events is preserved by the art of writing.
It will be observed that Professor Dawkins finds the earliest man in the Pleistocene, which he considers a late period of the Tertiary Age. He assents to the statement that species of the next preceding period, the Pliocene, still survive in limited numbers. Hence there is nothing essen tially impossible in the supposition that man also was then existent. To this lie replies : "Of fossil Mammalia in the Pliocene of Tuscany, only the hippopotamus is now living on earth. It is improbable that man could have been present in such a fauna. They belong to one stage of evolution, and man to another and a later." He is also of opinion that the earliest race of men—the "River-Drift Hunters," as he calls them—did not originate in Europe, and hence the most ancient remains are not to be found there. He is inclined to the view that these earliest representatives of the species invaded Europe in preglacial times along with the Other living species which then appeared. Some warm or perhaps tropical region of Central Asia was man's birthplace, and thence he migrated to the localities which later became his home.
A widely-different scheme is that proposed by the eminent French archeologist, M. Gabriel de Mortillet. He is prepared to recognize the relics of the infant arts of man at a very much earlier date than Professor Dawkins, and moreover makes a quite diverse arrangement of the later geological periods. The Tertiary he considers to have closed with the Pliocene Period, and to have been followed by the Quaternary. Many
geologists who agree with him in this consider the Quaternary Age as embracing the present time, and subdivide it into the Diluvial, which corresponds to the older Quaternary, and is characterized by the remark able aqueous phenomena attending the glacial epochs; and the Alluvial, which refers to the calmer and more gradual deposition of the river and delta strata, as we see them forming to-day. De Mortillet, however, con fines the term Quaternary to the fonner or Diluvial Period—to an epoch characterized by the appearance and retrocession of vast glaciers, approach ing the tropics from both poles and finding centres of formation in the Alps, the Andes, and other lofty mountain-chains. This period, he thinks, closed—for Western Europe at least—with some unexplained catastrophe which leaves a long hiatus in the relics of human occupa tion. From the close of this hiatus to the present day lie calls actual or present time. (See Vol. I. pp. 25, 26.) The subdivisions of this scheme M. de Mortillet obtains by naming them from particular localities—or "stations" as they are termed—where typical specimens of a special stage of industry have been discovered. He thus prepares the following plan: In the present work we shall adopt the geological system of the later strata as proposed by De Mortillet. We shall thus consider the Tertiary to embrace the Eocene, Miocene, and Pliocene, and to terminate with the latter; the terms Pleistocene, Post-Pliocene, and Diluvial will be consid ered as synonymous with Quaternary, which latter expression will gen erally be preferred; while Alluvial or Recent deposits will be reserved for expressing those which may be considered as still in process of formation. The minute subdivisions of these epochs which have been advanced by sonic archmologists need occupy our attention the less as the evidences of their correctness are by no means convincing.