The luxuriance and diversity of the Miocene flora has been employed by a German savant in identifying and classifying the Middle Tertiary or Miocene strata of Switzerland. We are indebted to Professor Heer, of Zurich, for the restoration of more than 900 species of plants, which he classified and illustrated in his “Flora Tertiaria Helvetiæ.” In order to appreciate the value of the learned Professor’s undertaking, it is only necessary to remark that, where Cuvier had to study the position and character of a bone, the botanist had to study the outline, nervation, and microscopic structure of a leaf. Like the great French naturalist, he had to construct a new science at the very outset of his great work.
Fig. 158.—Andrias Scheuchzeri.
The Miocene formations of Switzerland are called Molasse (from the French mol, soft), a term which is applied to a soft, incoherent, greenish sandstone, occupying the country between the Alps and the Jura, and they may be divided into lower, middle, and upper Miocene; the middle one is marine, the other two being fresh-water formations. The upper fresh-water Molasse is best seen at Œningen, in the Rhine valley, where, according to Sir Roderick Murchison, it ranges ten miles east and west from Berlingen, on the right bank, to Waugen and to Œningen, near Stein, on the left bank. In this formation Professor Heer enumerates twenty-one beds. No. 1, a bluish-grey marl seven feet thick, without organic remains, resting on No. 2, limestone, with fossil plants, including leaves of poplar, cinnamon, and pond-weed (Potamogeton). No. 3, bituminous rock, with Mastodon angustidens. No. 5, two or three inches thick, containing fossil Fishes. No. 9, the stone in which the skeleton of the great Salamander Andrias Scheuchzeri ([Fig. 158]) was found. Below this, other strata with Fishes, Tortoises, the great Salamander, as before, with fresh-water Mussels, and plants. In No. 16, Sir R. Murchison obtained the fossil fox of Œningen, Galacynus Œningensis (Owen). In these beds Professor Heer had, as early as 1859, determined 475 species of fossil plants, and 900 insects.
The plants of the Swiss Miocene period have been obtained from a country not one-fifth the size of Switzerland, yet such an abundance of species, which Heer reckons at 3,000, does not exist in any area of equal extent in Europe. It exceeds in variety, he considers, after making every allowance for all not having existed at the same time, and from other considerations, the Southern American forests, and rivals such tropical countries as Jamaica and Brazil. European plants occupy a secondary place, while the evergreen Oaks, Maples, Poplars, and Plane-trees, Robinias, and Taxodiums of America and the smaller Atlantic islands, occupy such an important place in the fossil flora that Unger was induced to suggest the hypothesis, that, in the Miocene period the present basin of the Atlantic was dry land—and this hypothesis has been ably advocated by Heer.
The terrestrial animals which lived in the Miocene period were Mammals, Birds, and Reptiles. Many new Mammals had appeared since the preceding period; among others, Apes, Cheiropteras (Bats), Carnivora, Marsupials, Rodents, Dogs. Among the first we find Pithecus antiquus and Mesopithecus; the Bats, Dogs, and Coati inhabited Brazil and Guiana; the Rats North America; the Genettes, the Marmots, the Squirrels, and Opossums having some affinity to the Opossums of America. Thrushes, Sparrows, Storks, Flamingoes, and Crows, represent the class Birds. Among the Reptiles appear several Snakes, Frogs, and Salamanders. The lakes and rivers were inhabited by Perches and Shad. But it is among the Mammals that we must seek for the most interesting species of animals of this period. They are both numerous and remarkable for their dimensions and peculiarities of form; but the species which appeared in the Miocene period, as in those which preceded it, are now only known by their fossil remains and bones.
The Dinotherium ([Fig. 159]), one of the most remarkable of these animals, is the largest terrestrial Mammal which has ever lived. For a long time we possessed only very imperfect portions of the skeleton of this animal, upon the evidence of which Cuvier was induced erroneously to place it among the Tapirs. The discovery of a lower jaw, nearly perfect, armed with defensive tusks descending from its lower jaw, demonstrated that this hitherto mysterious animal was the type of an altogether new and singular genus. Nevertheless, as it was known that there were some animals of the ancient world in which both jaws were armed, it was thought for some time that such was the case with the Dinotherium. But in 1836, a head, nearly entire, was found in the already celebrated beds at Eppelsheim, in the Grand Duchy of Hesse Darmstadt. In 1837 this fine fragment was carried to Paris, and exposed to public view. It was nearly a yard and a half long, and above a yard wide. The defences, it was found, were enormous, and were carried at the anterior extremity of the lower maxillary bone, and much curved inwards, as in the Morse. The molar teeth were in many respects analogous to those of the Tapir, and the great suborbital apertures, joined to the form of the nasal bone, rendered the existence of a proboscis or trunk very probable. But the most remarkable bone belonging to the Dinotherium which has yet been found is an omoplate or scapula, which by its form reminds us of that of the Mole.