It would carry me too far, were I to attempt to give anything more than the most cursory sketch of the animals of the Tertiary age; and, indeed, they are so well known, and have been so fully represented in text-books, that I fear some of my readers may think even now that I have dwelt too long upon them. Monkeys were unquestionably introduced upon earth before the close of the Tertiaries; some bones have been found in Southern France, and also on Mount Pentelicus in Greece, in the later Tertiary deposits; but these remains have not yet been collected in sufficient number to establish much more than the fact of their presence in the animal creation at that time. I do not offer any opinion respecting the fossil human bones so much discussed recently, because the evidence is at present too scanty to admit of any decisive judgment concerning them. It becomes, however, daily more probable that facts will force us sooner or later to admit that the creation of man lies far beyond any period yet assigned to it, and that a succession of human races, as of animals, have followed one another upon the earth. It may be the inestimable privilege of our young naturalists to solve [pg 346] this great problem, but the older men of our generation must be content to renounce this hope; we may have some prophetic vision of its fulfilment, we may look from afar into the land of promise, but we shall not enter in and possess it.
The other great types of the Animal Kingdom are very fully represented in the Tertiaries, and in their general appearance they approach much more closely those of the present creation than of any previous epochs. Professor Heer has collected and described the Tertiary Insects in great number and variety; and the Butterflies, Bugs, Flies, Grasshoppers, Dragon-Flies, Beetles, etc., described in his volumes, would hardly be distinguished from our own, except by a practised entomologist. Among Crustacea, the Shrimp-like forms of the earlier geological epochs have become much less conspicuous, while Crabs and Lobsters are now the prominent representatives of the class. Among Mollusks, the Chambered Shells, hitherto so numerous, have become, as they now are, very few in comparison with the naked Cephalopods. The Nautili, however, resemble those now living in the Pacific Ocean; and some fragments of the Paper-Nautilus have been found, showing that this delicate shell was already in existence. There is one very peculiar type of this class, belonging to the Tertiaries, which should not be passed by unnoticed. It partakes of the character both of the Cretaceous Belemnites and of the living Cuttle-Fish, and is known as the Spirulirostra. Another very characteristic group among the Tertiary Shells is that of the Nummulites, formerly placed by naturalists in immediate proximity with the Ammonites, on account of their internal partitions. This is now admitted to have been an error; their position is not yet fully determined, but they certainly stand very low in the scale, and have no affinity whatever with the Cephalopods. The subjoined wood-cut represents one of these Shells, so numerous in the Tertiaries that large masses of rock consist of their remains. The Univalve Shells or Gasteropods of the Tertiaries embraced all the families now living, including land and fresh-water Shells as well as the marine representatives of the type. Some of the latter, as, for instance, the Cerithium, are accumulated in vast numbers. The limestone quarries out of which Paris is chiefly built consist wholly of these Shells. The fresh-water basins were filled with Helices, one of which is represented in the following [pg 347] wood-cut, with Planorbis, Limnæus and other Shells resembling those now so common in all our lakes and rivers, and differing from the living ones only by slight specific characters. The Bivalves also have the same resemblance to the present ones, including fresh-water Mussels as well as the marine Clams and Oysters. Among Radiates, the higher Echini (Sea-Urchins) have become numerous, while the other Echinoderms of all families abound. Corals include, for the first time, the more highly organized Madrepores.
In the Tertiaries we see the dawn of the present condition of things, not only in the character of the animals and plants, but in the height of the mountains and in the distribution of land and sea.
Let us give a glance at the continents whose growth we have been following, and see what these more recent geological epochs have done for their completion. In Europe they have filled the basin in Central France, and converted all that region into dry land: they have filled also the channel between France and Spain; they have united Central Russia with the rest of Europe by the completion of Poland, and have greatly enlarged Austria and Turkey; they have completed the promontories of Italy and Greece, and have converted the inland sea at the foot of the Jura into the plain of Switzerland. But this fruitful period in the progress of the world, when the character of organic life was higher and the physical features of the earth more varied than ever before, was not without its storms and convulsions. The Pyrenees, the Apennines, the Alps, and with them the whole range of the Caucasus and Himalayas, were raised either immediately after the Cretaceous epoch, or in the course of the Tertiaries. Indeed, with this most significant passage in her history, Europe acquired all her essential characters. There remained, it is true, much to be done in what is called by geologists "modern times." The work of the artist is not yet finished when his statue is blocked out and the grand outline of his conception stands complete; and there still remained, after the earth was rescued from the water, after her framework of mountains was erected, after her soil was clothed with field and forest, processes by which her valleys were to be made more fruitful, her gulfs to be filled with the rich detritus poured into them by the rivers, her whole surface to be rendered more habitable for the higher races who were to possess it.