Thus the oldest and lowest of the Tertiary rocks—which are themselves collectively the most recently formed—is the "Eocene," and the succeeding "Miocene," "Pliocene," and "Quaternary," are given in their due order; the latter formations bringing us to the soils and surface accumulations of our own day. The "Ice Age," or "Glacial Epoch," we may also note, occurred during the Post-Pliocene period, as shown above.
Turning now to the past history of the elephants, we find the first chapter of that biography to open in the "Miocene" age. The earlier or "Eocene" period contains no elephant fossils, and it may have been that in this Eocene age, which beheld the first beginnings of nearly all the existing quadruped races, the evolution of the elephant stock from its ancestry was taking place. Leaving for the present the consideration of the probable root of the elephantine tree, we thus discover in the Miocene period the first beginnings of elephant existence. In this period the mastodons roamed over Europe and India, while in this age also the dinotheriums, with their great lower tusks, made their first appearance on the stage of time. As the geological series progressed, and as the Pliocene age succeeded the Miocene times, we discover the elephants in increasing numbers. The Miocene, with its relatively few elephantine forms, contrasts forcibly with the increase of those animals in the succeeding age. Europe and India harbor its Pliocene elephants, as we have seen; while both Europe and America in this latter age possessed the mastodons. The Post-Pliocene period, however, dawns in turn, to find the mastodons still existent in North America, but unknown in Europe; while the mammoth now appears as a representative form, along with survivals of the European elephants of the Pliocene time. The "pygmy elephants" of Malta also belong to the Post-Pliocene age.
Thus we discover that a distinct succession of types of elephantine forms has taken place on the earth's surface, beginning with elephants which, like the dinotherium and mastodon, differ from existent species, and ending with elephants which, like the mammoth or the European elephants of the Pliocene, more or less closely resembled the quadruped giants of to-day. It becomes interesting further to trace out the later history of the race before the bearings of these facts on the origin of the elephant race are discussed. The mammoth, for example, certainly survived the "ice-age," to the irruption of which was probably due the extinction of the other elephantine forms. We know of this survival because its remains occur in "recent" or "post-glacial" deposits. We are also certain that early man must have beheld the mammoth as a living, breathing reality, for its remains have been found associated with the rude implements of early men, and a rough portrait of the great red-haired elephant has been discovered, scratched on one of its tusks a rude but unquestionable tribute of early art to the science of zoology. Its woolly hair, protecting it against