THE TERTIARY AGE, AND ITS CHARACTERISTIC ANIMALS.
In entering upon the Tertiaries, we reach that geological age which, next to his own, has the deepest interest for man. The more striking scenes of animal life, hitherto confined chiefly to the ocean, are now on land; the extensive sheets of fresh water are filled with fishes of a comparatively modern character,—with Whitefish, Pickerel, Perch, Eels, etc.,—while the larger quadrupeds are introduced upon the continents so gradually prepared to receive them. The connection of events throughout the Tertiaries, considered as leading up to the coming of man, may be traced not only in the physical condition of the earth, and in the presence of the large terrestrial Mammalia, but also in the appearance of those groups of animals and plants which we naturally associate with the domestic and social existence of man. Cattle and Horses are first found in the middle Tertiaries; the grains, the Rosaceæ, with their variety of fruits, the tropical fruit-trees, Oranges, Bananas, etc., the shade- and cluster-trees, so important to the comfort and shelter of man, are added to the vegetable world during these epochs. The fossil vegetation of the Tertiaries is, indeed, most interesting from this point of view, showing the gradual maturing and completion of those conditions most intimately associated with human life. The earth had already its seasons, its spring and summer, its autumn and winter, its seed-time and harvest, though neither sower nor reaper was there; the forests then, as now, dropped their thick carpet of leaves upon the ground in the autumn, and in many localities they remain where they originally fell, with a layer of soil between the successive layers of leaves,—a leafy chronology, as it were, by which we read the passage of the years which divided these deposits from each other. Where the leaves have fallen singly on a clayey soil favorable for receiving such impressions, they have daguerreotyped themselves with the most wonderful accuracy, and the Oaks, Poplars, Willows, Maples, Walnuts, Gum- and Cinnamon-trees, etc., of the Tertiaries are as well known to us as are those of our own time.
It was an eventful day, not only for science, but for the world, when a Siberian fisherman chanced to observe a singular mound lying near the mouth of the River Lena, where it empties into the Arctic Ocean. During the warmer summer-weather, he noticed, that, as the snow gradually melted, this mound assumed a more distinct and prominent outline, and at length, on one side of it, where the heat of the sun was greatest, a dark body became exposed, which, when completely uncovered, proved to be that of an immense elephant, in so perfect a state of preservation that the dogs and wolves were attracted to it as by the smell of fresh meat, and came to feed upon it at night. The man knew little of the value of his discovery, but the story went abroad, and an Englishman travelling in Russia, being curious to verify it, visited the spot, and actually found the remains where they had been reported to lie, on the frozen shore of the Arctic Sea,—strange burial-place enough for an animal never known to exist out of tropical climates. Little beside the skeleton was left, though parts of the skin remained covered with hair, showing how perfect must have been the condition of the body when first exposed. The tusks had been sold by the fisherman; but Mr. Adams succeeded in recovering them; and collecting all the bones except those of one foot, which had been carried off by the wolves, he had them removed to St. Petersburg, where the skeleton now stands in the Imperial Museum. The inhabitants of Siberia seem to be familiar with this animal, which they designate by the name of Mammoth, while naturalists call [pg 340] it Elephas primigenius. The circumstance that they abound in the frozen drift of the great northern plain of Asia, and are occasionally exposed in consequence of the wearing of the large rivers traversing Siberia, has led to the superstition among the Tongouses, that the Mammoths live under ground, and die whenever, on coming to the surface, the sunlight falls upon them.
Had this been the only creature of the kind found so far from the countries to which elephants are now exclusively confined, it might have been believed that some strange accident had brought it to the spot where it was buried. But it was not long before similar remains were found in various parts of Europe,—in Russia, in Germany, in Spain, and in Italy. The latter were readily accounted for by the theory that they must be the remains of the Carthaginian elephants brought over by the armies of Hannibal, while it was suggested that the others might have been swept from India by some great flood, and stranded where they were found. It was Cuvier, entitled by his intimate acquaintance with the anatomy of living animals to an authoritative opinion in such matters, who first dared to assert that these remains belonged to no elephant of our period. He rested this belief upon structural evidence, and insisted that an Indian elephant, brought upon the waves of a flood to Siberia, would be an Indian elephant still, while all these remains differed in structure from any species existing at present. This statement aroused research in every direction, and the number of fossil Mammalia found within the next few years, and proved by comparison to be different from any living species, soon demonstrated the truth of his conclusion.
Shortly after the discovery of fossil elephants had opened this new path of investigation, some curious bones were found by some workmen in the quarries of Montmartre, near Paris, and brought to Cuvier for examination. Although few in number, and affording but very scanty data for such a decision, he at once pronounced them to be the remains of some extinct animal preceding the present geological age. Here, then, at his very door, as it were, was a settlement of that old creation in which he could pursue the inquiry, already become so important in its bearings. It was not long before other bones of the same kind were found, though nothing as yet approaching an entire skeleton. However, with such means as he had, Cuvier began a comparison with all the living Mammalia,—with the human skeleton first, with Monkeys, with the larger Carnivora and Ruminants, then with all the smaller Mammalia, then with the Pachyderms; and here, for the first time, he began to find some resemblance. He satisfied himself that the animal must have belonged to the family of Pachyderms; and he then proceeded to analyze and compare all the living species, till he had collected ample [pg 341] evidence to show that the bones in question did not correspond with any species, and could not even be referred to any genus, now in existence. At length there was discovered at Montmartre an upper jaw of the same animal,—next a lower jaw, matching the upper one, and presently a whole head with a few backbones was brought to light. These were enough, with Cuvier's vast knowledge of animal structure, to give him a key to the whole skeleton. At about the same time, in the same locality, were found other bones and teeth also, differing from those first discovered, and yet equally unlike those of any living animal. The first evidently belonged to some stout and heavy animal, the others were more slender and of lighter build. From these fragments, ample evidence to him of his results, he drew the outlines of two animals: one which he called the Palæotherium, (old animal,) a figure of which is given in the above wood-cut, and the other Anoplotherium, (animal without fangs). He presented these figures with an explanatory memoir at the Academy, and announced them as belonging to some creation preceding the present, since no such animals had ever existed in our own geological period. Such a statement was a revelation to the scientific world: some looked upon it with suspicion and distrust; others, who knew more of comparative anatomy, hailed it as introducing a new era in science; but it was not till complete specimens were actually found of animals corresponding perfectly to those figured and described by Cuvier, and proving beyond a doubt their actual existence in ancient times, that all united in wonder and admiration at the result obtained by him with such scanty means.
It would seem that the family of Pachyderms was largely represented among the early Mammalia; for, since Cuvier named these species, a number of closely allied forms have been found in deposits belonging to the same epoch. Of course, the complete specimens are rare; but the fragments of such skeletons occur in abundance, showing that these old-world Pachyderms, resembling the Tapirs more than any other living representatives of the family, were very numerous in the lower Tertiaries.
There is, however, one animal now in existence, forming one of those singular links before alluded to between the present and the past, of which I will say a few words here, though its relation is rather with a later group of Tertiary Pachyderms than with those described by Cuvier. On the coast of Florida there is an animal of very massive, clumsy build, long considered to be a Cetacean, but now recognized, by some naturalists at least, as belonging to the order of Pachyderms. In form it resembles the Cetaceans, though it has a fan-shaped tail, instead of the broad flapper of the Whales. It inhabits fresh waters or shoal waters, and is not so exclusively aquatic as the oceanic Cetaceans. Its most striking feature is the form of the lower jaw, which is bent downward, with the front teeth hanging from it. This animal is called the Manatee, or Sea-Cow. There are three species known to naturalists,—one in Tampa Bay, one in the Amazon, and one in Africa. In the Tertiary deposits of Germany there has been found an animal allied in some of its features to those described by Cuvier, [pg 342] but it has the crown of its teeth folded like the Tapir, while the lower jaw is turned down with a long tusk growing from it. This animal has been called the Dinotherium. A part of the head, showing the heavy jaws and the formidable tusk, is represented in the subjoined wood-cut.
