James Geikie

“ We can picture to ourselves the old race of hunters, with the contemporaneous steppe fauna, gradually passing east and northeast, while the forests continued to encroach upon and overspread the fertile lands of central Europe. It is possible that Neolithic man may here and there have come into contact with his Paleolithic predecessor, but of this we have no evidence. All we certainly know is that the latter vanished from central Europe with the steppe fauna, and that when Neolithic man made his earliest appearance a forest fauna was in possession of the land. ”

“ When we remember that an arctic-alpine flora formerly flourished on the low grounds of central Europe, it seems extremely probable that the tundra epoch must fall within the glacial period. But the glacial period embraced a complex series of geographical and climatic changes, and it is necessary, therefore, to come somewhat closer to the question. Among the most conspicuous deposits of the Ice age are moraines of all kinds and fluvio-glacial gravels, while the löss, as we have seen, is the most prominent accumulation of the tundra and steppe epochs. ”

“ Doubtless most of the snow which covered the plains of our continent in winter melted and disappeared in summer, just as is the case in the tundras and steppes of our own day. The carcasses of animals that may have perished in blizzards would thus most frequently become uncovered in spring, to be devoured by hyenas, wolves, and bears, and the disarticulated skeletons might often be bleached and weatherworn before they were finally buried in loss. Nor was it only in plains and open valleys that sudden death may have overtaken large numbers of animals at a time. ”

“ It is, in short, quite possible now to draw maps of Europe which shall give a fairly accurate presentment of the aspect presented by our continent in glacial times. On maps of a sufficiently large scale we can delineate not only the great inland ice of the north and northwest, but the snow fields and numerous glaciers of the Alps and other mountainous tracts, together with the areas covered by fluvio-glacial deposits. ”

“ Should they chance to become well covered with snow in winter, then, when warmth returns and the snow gradually melts away, plants quickly spring up, and the heaps become fixed and cease to drift. It is obvious that not infrequently land shells, and often enough the remains of mammals, must be entombed in such wind-blown materials.
In winter, however, it is snow more commonly than dust that drifts before the wind. The great snowstorms of the subarctic steppes are quite as terrible as those of the tundras. No life can withstand the fury of the blizzards, and many are the disasters on record. ”

“ It is certain, however, that gravel, grit, and sand would not be the only materials carried forward by those rivers. As they reached the low-lying tracts their rate of flow would gradually diminish, and finer-grained materials—fine silt and loam—would eventually be deposited. When we consider the great volumes of water descending to the low grounds, we can not, indeed, escape from the conclusion that many wide areas in the plains during a glacial epoch must have been inundated, and in those slack waters and temporary lakes the finer-grained fluvio-glacial sediments would tend to accumulate. ”

“ Our knowledge of the former distribution of the arctic lemmings is no doubt not so full as it will yet be, but already we have ascertained that these creatures ranged as far south as central France and the base of the Alps, in Switzerland, and as far west as Somerset, in England. Besides the arctic fox, many other northern forms were congeners of the lemmings in middle and western Europe, such as mountain hare, muskox, reindeer, glutton, voles of various kinds, ermine, weasel, wolf, common fox, and the now extinct mammoth and woolly rhinoceros. ”

“ It will be remembered that during the first glacial epoch a great Baltic glacier existed, and an arctic fauna lived in the North Sea. That epoch was succeeded by the first interglacial stage, when the southern part of the North Sea became dry land, and England was occupied by an abundant mammalian fauna—comprising hippopotamus, elephants, rhinoceros, horse, bison, boar, many kinds of deer, and a number of carnivores, including bears, hyena, saber-toothed tiger, wolf, fox, etc. The contemporaneous flora was temperate, resembling very much that which now exists in southeast England. ”

“ Among the organic remains yielded by the löss are some that indicate arctic conditions, while others are strongly suggestive of a steppe climate, and yet others tell us of forest lands. It is impossible that all the creatures referred to could have lived side by side in the same region, and annual migrations will not wholly explain their appearance in the same deposit. The evidence leads to the conclusion that the accumulation of the löss must represent a long period of time daring which climatic changes took place. ”

“ The banded lemming, as a rule, has left its remains most abundantly in hilly and upland tracts, while those of the Obi lemming are met with more frequently in low-lying areas—a distribution quite in keeping with that which obtains at present in the tundras. That these arctic animals were not mere passing or occasional visitors is shown by the fact that young and full-grown individuals occur together in hundreds at various places and are associated with the remains of other characteristic arctic animals which breed in the same regions. ”

“ If perfectly preserved carcasses are rare, such is not the case with skeletal remains. In many places throughout Siberia the bones of various mammals occur in enormous quantities, huddled together, as it were, in very limited spots. It seems impossible to account for such hecatombs on any other supposition than that they are the silent records of great blizzards and snowtorms. Even in our own time herds of wild reindeer, with their young, are overcome by snowstorms in the tundras, while in North America great flocks of sheep and cattle frequently perish in the same way. ”

“ The strong hiatus that separates the Old Stone and the New Stone epochs in western and northwestern Europe has not yet been bridged over in middle and southern Europe. When last we see Paleolithic man he is hunting the reindeer and the mammoth in the Danubian steppes. His Neolithic successor seems not to have appeared in middle Europe before steppe conditions had passed away and a forest flora and fauna had become dominant. ”

“ Lastly, in winter, storms of snow and dust are common.
We may now take a similar brief glance at the steppe lands of Europe and Asia. The regions included under this head show considerable variety. Some steppes are mere desert wastes while others are fertile tracts capable of high cultivation. Many are low plains, others are elevated plateaus, the former having a subarctic, the latter a subtropical climate; and between low and high steppes many gradations are met with. All are more or less characterized by an extreme range of temperature. ”

“ In winter, if little snow has fallen, the unprotected ground is similarly scoured by the tempests, dust, sand, and even small stone being carried forward. Thus both in summer and winter sand and dust storms play an important role, and loose materials are piled up to great depths in valleys, and in the ravines, fissures, and crevices of the rocky hills. ”

“ Man, as I have already mentioned, lived in middle Europe in tundra times, and we have abundant evidence of his presence there throughout the succeeding steppe epoch. Again and again his relics and remains have been met with at all levels in the loss throughout central Europe. Thus in the valleys of the Danube and some of its tributaries they have been discovered in undisturbed löss at depths of from 20 to nearly 100 feet from the surface. ”

“ The climate of Europe generally became temperate, and immense forests overspread wide regions. It was during the approach of these conditions, as we have seen, that Paleolithic man seems finally to have vanished and the Neolithic races to have made their earliest appearance in Europe. The British Islands at this time formed part of the continent and the Baltic existed as a great fresh-water lake. The lower buried forests of our peat bogs are among the conspicuous remains of this stage. ”

“ But even in those wooded regions the seasons are strongly contrasted. In general, we may say the steppe lands in summer are practically rainless. The ground is thus parched and burnt up, so that sand and dust rise with every wind, and as the open plains are often swept by summer burans, vast quantities of loose materials are transported from place to place, and here and there accumulate in hollows and depressions, or come to rest in the lee of sheltering rocks and hills. ”

“ The climate became more genial, and so once more favored the growth of forests, which in many places began to overspread the now dry peat bogs, beneath which the trees of the earlier forest epoch lay entombed. Eventually, however, colder and more humid conditions returned, and small glaciers appeared in a few places among the loftiest heights of the Scottish Highlands. The position of the moraines of these glaciers indicates a height of 3,500 feet for the snow line. ”

“ It is not necessary to suppose that all the relics and remains of the mammoth and its congeners in Siberia are evidence of the destructive effect of blizzards. The animals doubtless met their death under many different circumstances. Sometimes they would appear to have been bogged in swampy holes and morasses. I have referred to the peculiar ice formations of the arctic coast lands. These are sheets of ice of unknown thickness, preserved under more or less thick accumulations of earthy and loamy materials. ”

“ The terminal moraines of these glaciers have been mapped out, and the general conditions of the epoch have been so well ascertained that the position of the snow line at the time has been determined. It is believed to have been upon an average some 4,000 feet lower than now. While the valleys of the Alps were thus gorged with ice and the basin of the Baltic was occupied by an immense mer de glace, it is not probable that the higher parts of our islands could have escaped glaciation. We can hardly doubt that snow fields and glaciers must also have existed here. ”

“ Turning to the abundant animal remains, we find that these represent no fewer than 49 species, viz, 30 mammals, 15 birds, 3 amphibians, and 1 fish. All the most characteristic tundra forms—the banded lemming and its peculiar associates—are now absent, and in their place we find a true steppe fauna. Amongst the new arrivals are red suslik, pika, and true hamster, and associated with these are such constant visitors of the steppes as manul cat, wild horse, dzeggetai, and various birds. ”

“ The banded lemming is an especially characteristic form, since it is confined to the maritime tracts of Eurasia and the adjacent islands, and the corresponding areas of North America, and is never met with in the forest zone. The Obi lemming has a similar distribution, but ranges somewhat farther south, and not quite so far north, as the banded lemming. The arctic fox is another characteristic member of the tundra fauna, having a high northern range. ”

“ With the approach of spring vegetation rapidly develops, becoming rank and luxuriant, but with the heat of summer it quickly fades and withers away. Severe frost, and frequently heavy snowstorms, characterize the winter. In such areas as are more or less wooded the climate is somewhat less continental, the summers being relatively less dry and the winters not so cold. ”

“ Among the animal remains are those of mam- moth, woolly rhinoceros, musk ox, reindeer, elk, horse, lion, glutton, bear, wolf, arctic fox, common fox, and hyena. Nor is it only in the loss that we have human relics associated with the tundra and steppe faunas. ”

“ Scattered through this earth are abundant remains of arctic lemming, arctic fox, mountain hare, reindeer, glutton, and a number of other forms which are constant summer visitors to the tundras. The banded lemming is the most plentifully represented species, and next to it in abundance comes the alpine hare. In close association with this tundra fauna occur flint implements, and awls, chisels, harpoons, and needles of bone and horn. ”

“ Third, we have the presence of certain remarkable ridges of gravel and sand which appear to have been formed in tunnels under the ice, and of enormous sheets of similar materials which have been spread out by the waters escaping from the terminal front of the inland ice of northern Europe, while in all the great valleys leading down from the Alps and other glaciated mountains we see broad terraces of alluvial detritus which have been deposited by torrential streams and rivers. ”