The terraces of gravel deposited by existing rivers and the deposits in caverns in the limestone regions of Western Europe—the so-called "Pleistocene" strata—contain, besides the flint weapons of man and rare specimens of his bones, the remains of animals which are either identical with those living at the present day (though many of them are not living now in Europe) or of animals very closely similar to living species. Thus we find the bones of horses like the wild horse of Mongolia, of the great bull (the Urus of Cæsar), of the bison, of deer and goats, of the Siberian big-nosed antelope, of the musk-ox (now living within the Arctic circle), of the wild boar, of the hippopotamus (like that of the Nile), and of lions, hyenas, bears, and wolves. The most noteworthy of the animals like to, but not identical with, any living species are the mammoth, which is very close to the Indian elephant, but has a hairy coat; the hairy rhinoceros, like, but not quite the same as, the African square-mouthed rhinoceros; and the great Irish deer, which is like a giant fallow-deer. These three animals are really extinct kinds or species, but are not very far from living kinds. In fact, the most recent geological deposits do not contain any animals so peculiar, when compared with living animals, as to necessitate a wide separation of the fossil animal from living "congeners" by the naturalist who classifies animals and tries to exhibit their degrees of likeness and relationship to one another by the names he adopts for them. The mammoth is a distinct "species" of elephant. It requires, it is true, a "specific" or "second" name of its own; but it belongs to the genus elephant. Hence we call it Elephas primigenius, whilst the living Indian elephant is Elephas Indicus. The reader is referred to the preceding chapter for further notes about elephants.
The strata next below the Pleistocene gravels and cave deposits are ascribed to the "Pliocene age"—older than these are the "Miocene" and the "Eocene," and then you come to the Chalk, a good white landmark separating newer from older strata.
We know now in great detail the skeletons and jaws of some hundreds of kinds of extinct animals of very different groups found in the Eocene, the Miocene, the Pliocene, and the Pleistocene layers of clays, sands, and gravels of this part of the world. Nothing very strange or unlike what is now living is found in the Pleistocene—the latest deposits—but when we go further back strange creatures are discovered, becoming stranger and less like living things as we pass through Pliocene to Miocene, and on—downwards in layers, backwards in time—to the Eocene.
Though the past history of the Mediterranean sea shows that it was formerly not so extensive as it is now, and that there were junctions between Europe and Africa across its waters, yet the deeper parts of that sea are very ancient, and some of the islands have long been isolated. In Malta the remains of extraordinary species of minute elephants have been found, one no larger than a small donkey, and in the island of Cyprus an English lady, Miss Dorothea Bate, has discovered the bones of a pigmy hippopotamus (like that still living in Liberia) no larger than a sheep. Miss Bate some three years ago heard of the existence of a bone-containing deposit of Pleistocene age in limestone caverns and fissures in the island of Majorca, and with the true enthusiasm of an explorer determined to carry on some "digging" there and see what might turn up. In the following spring she was there, and obtained a number of bones, jaws, and portions of skulls, which appeared at first sight to be those of a small goat. Its size may be gathered from the fact that its skull is six inches long. These and the bones of a few small finches were all that rewarded her pains. The bones of fossil goats (of living species) are found in caves at Gibraltar and in Spain; so at first the result seemed disappointing. But on carefully clearing out the specimens and examining them in London, Miss Bate found that the supposed goat bones obtained by her in Majorca were really those of a new and most extraordinary animal, to which (in a paper published in the "Geological Magazine" in September, 1910) she has given the name "Myotragus balearicus."
Fig. 16.—Side-view of the skull and lower jaw of a goat. inc. i. The three lower incisor teeth of the left side. can. i. The little canine teeth grouped with them. p. The toothless front part of the upper jaw. m. s. Upper molars or "grinders." m. i. Lower molars or grinders. Compare this and the following figures with Fig. 10, showing the more complete "dentition" of the pig.
Fig. 17.—Horizontal view of the teeth in the lower and upper jaw of the goat. In front of the lower jaw the group of three incisors (inc. i.) and one canine is seen, whilst the toothless bony plate (p.) of the upper jaw, against which they work, is seen in the right-hand half of the figure. The molars, "grinders," or cheek-teeth are numbered 1 to 6 in each jaw.
Fig. 18.—Side view of the skull of a typical "rodent" mammal, the Coypu rat (Myocastor coypus) from South America. inc. s. Upper incisor. inc. i. Lower incisor. m. s., m. i. Upper and lower molars, grinders or cheek-teeth.