Only one representative of the great Drift fauna, the musk-ox, has been able to preserve its life to the present day on the larger remnants of its former vast home, such as Greenland and Grinnell Land.
The Tunguse Schumachow had been more fortunate as early as 1799. During his boating expeditions along the coast, on the look-out for mammoth-tusks, he observed one day, between blocks of ice, a shapeless block which was not at all like the masses of driftwood that are generally found there. In the following year the block had melted a little, but it was only at the end of the third summer that the whole side and one of the tusks of a mammoth appeared plainly out of the ice; the animal, however, still remained sunk in the ice-masses. At last, towards the end of the fifth year, the ice between the ground and the mammoth melted more quickly than the rest, the base began to slope, and the enormous mass, impelled by its own weight, glided down on to the sand of the coast. Here Adams found the carcase in 1806, or as much as the dogs and wild animals had left of it. The whole skeleton, with a portion of the flesh, skin, and hair, has since formed one of the chief ornaments of the collection in the Academy at St. Petersburg. According to Von Toll, who personally visited the site of Bojavski’s discovery, the following profile presented itself there: first the tundra stratum; then an alternation of thin strata of loam and ice; under these a peat-like layer of grass, leaves, and other vegetation, that had been washed together; then a fine layer of sand, with remains of Salix, etc., and finally stone-ice. At another place, in Gulf Anabar, in 73° north latitude, Von Toll also found the ground-moraine under a fossil ice-bed, which appears to prove his theory of a Drift region of inland ice, of which the stone-ice beds of New Siberia and Eschscholtz Bay are remains.
Of these strata the frozen loam deposits over the stone-ice, containing the willow and the alder, are doubtless Interglacial. Some of the remains of the alder are in such wonderful preservation that there are still leaves and whole clusters of catkins on the branches.
The land-mass to which the present New Siberian Islands belong was only dismembered at the end of the Interglacial Period, when colder sea-currents procured an entrance, and the accumulation of snow-masses diminished simultaneously with the sinking of the land, whereas the cold increased. The flora died off, says Von Toll, and the animal world was deprived of the possibility of roaming freely over vast areas. Only one representative of the great Drift fauna, the musk-ox, has been able to preserve its life to the present day on the larger remnants of its former vast home, such as Greenland and Grinnell Land.
Remains of the Ice Age
As we have said, the geological and climatic conditions in all regions of the earth affected by the Glacial Period were closely similar to those just described. In other places the Drift stone-ice has long disappeared, but the ground-moraines of the former inland ice-masses, and the surface-moraines (terminal and lateral) of the former gigantic glaciers, constitute its unobliterated traces. On the moraines of the earlier Glacial Period we find the strata of the Interglacial Period deposited, and on the later moraines of the second (last) Glacial Period lie the remains of the post-Glacial Period, in the course of which a continual increase in the yearly temperature—probably only a few degrees of the thermometer—caused the glaciers to melt and retreat, and opened the way for the return of plants and animals to what had been deserts of snow and ice. The place formerly occupied by the Interglacial and Glacial fauna is then taken by the post-Glacial fauna, which proves considerably different.
A number of the most characteristic species of the former sections of the Drift Period are already absent in the earliest post-Glacial deposits; the fauna approaches nearer and nearer in its composition to that of the present day. The inland ice-masses and gigantic glaciers began to melt away, and gradually retired to the present limits of the glaciation that forms the remains of the Glacial Period of the Drift. The animal forms of the beginning of the post-Glacial Period are still living, and the plants characterising this final stage of the Drift Period are still growing on the borders of the ice at the present day. In the post-Glacial Period a few Northern forms—such as the reindeer, lemming, ringed lemming, glutton, zizel, whistling hare, and jumping mouse—still retained for a time their habitats in Central Europe. Part of the Drift fauna—as the horse, wild ass, saiga antelope, and Asiatic porcupine—concentrated again in the Asiatic steppes, from which they had formerly won their territory of the Drift Period; the specific Glacial forms—the reindeer and his above-mentioned companions—followed the retreating ice-masses into the Far North, and even into Polar regions. Another part—the specially Alpine forms, such as the ibex, chamois, marmot, and Alpine hare—migrated with the Alpine glaciers into the high valleys of the Alps, where they could continue the life they had led in the lowlands during the Glacial Period. The mammoth, woolly-haired rhinoceros, and cave-bear are extinct.
The present-day mammalian fauna of Europe and North Asia accordingly bears a comparatively young character; during the Drift, and especially in consequence of the Glacial Period, it underwent the most considerable transformations.
Coming of Man upon the Scene
It is in the middle of this great drama of a gigantic animal world struggling and fighting for its existence with the superior powers of Nature, during the Interglacial period of the Drift, that man suddenly appears upon the scene in Europe like a deus ex machina.