This geographical configuration in pleistocene times may perhaps account for the distribution of the palæolithic implements in the river gravels. The Seine and the Somme debouch into the same valley as the rivers of the south of England, and the Straits of Dover mark the position of a low watershed leading into the valley of the German Ocean, on the sides of which, in the eastern counties, river-bed implements are so numerous. These are of the same type in northern France, Sussex, Hampshire, Kent, and as far north as the Wash; and were therefore used by the same race of men. The difference between them and those of the cave-dwellers in the south and west, may be due to their possessors occupying different hunting grounds. Each tribe of American Indians at the present time has its own territory for hunting, which is jealously guarded against encroachment, and in which the articles peculiar to the tribe are being accumulated in the refuse-heaps, while other sets are being accumulated in other districts. If we suppose that the palæolithic savages divided up their hunting grounds in this manner, the difference which exists between the implements of the river-beds and caves may be readily explained, as well as their being found for the most part in different areas.
The pleistocene climate in the area north of the Alps and Pyrenees will be treated in the [eleventh] chapter, after the examination of the cave-fauna of southern Europe.
CHAPTER X.
THE FAUNA OF THE CAVES OF SOUTHERN EUROPE AND THE EVIDENCE AS TO THE MEDITERRANEAN COAST-LINE IN THE PLEISTOCENE AGE.
Changes of Level in the Mediterranean area in Meiocene and Pleiocene Ages.—Bone-caves of Southern Europe.—Of Gibraltar.—Of Provence and Mentone.—Of Sicily.—Of Malta.—Range of Pigmy Hippopotamus.—Fossil Mammalia in Algeria.—Living Species common to Europe and Africa.—Evidence of Soundings.—The Glaciers of Lebanon.—Of Anatolia.—Of Atlas.—Glaciers probably produced by elevation above the Sea.—Mediterranean Coast-line comparatively modern.
In the preceding chapter we have seen that north-western Europe was elevated, during the pleistocene age, to an extent of at least 600 feet above its present level; so that Ireland was united to Britain, and Britain was joined to the mainland of Europe, proof of this elevation being dependent upon the soundings on one hand, and the distribution of the fossil mammalia on the other. Such a change must necessarily have affected the whole physical conditions of the area, since the substitution of a mass of land for a stretch of sea, and the higher altitude of the land, would tend to produce climatal extremes of considerable severity. It is indeed no wonder that during this time of continental elevation, the hills of Wales, Yorkshire, Derbyshire, Cumbria, and Scotland should be crowned with glaciers, or that there should have been a migration to and fro of animals, comparable to that which is now going on in Siberia and the northern portions of North America. The condition of southern Europe at that time has a most important bearing on any conclusion which may be drawn as to the pleistocene climate in France, Germany, or Britain. For if it be proved that the Mediterranean Sea was then smaller than it is now, the greater land-surface would increase both the heat of the summer and the cold of the winter in central and north-western Europe.
Changes of Level in Mediterranean area in Meiocene and Pleiocene Ages.
The geological evidence that the Mediterranean region has been subjected to oscillations of level during the tertiary period, is clear and decisive. Prof. Gaudry[241] has proved, in his work on the fossil remains found at Pikermi, that the plains of Marathon, now so restricted, must have extended in the meiocene age far south into the Mediterranean, so as to afford pasture to the enormous troops of hipparions and herds of antelopes, the mastodons and large edentata, revealed by his enterprise. The rocky area of Attica, as now constituted, could not have supported such a large and varied group of animals, nor could the broken hills and limestone plateaux have been inhabited by hipparions and antelopes, if their habits at all resembled those of their descendants living at the present time. It may, therefore, reasonably be concluded that Greece, in those times, was prolonged southwards, and united to the islands of the Archipelago by a stretch of land. If Africa were then as now the head-quarters of the antelopes, it is very probable that one of the lines by which they passed over into Europe, and spread over France and Germany, was in this direction. Nevertheless, it must be admitted that the changes of level, which have taken place since the meiocene age in those regions, are so complicated as to render it almost impossible to restore the meiocene geography.
In the succeeding, or the pleiocene age, the presence of the African hippopotamus in Italy, France, and Germany, can only be accounted for by a more direct connection with the African mainland than is offered by a route through Asia Minor. It would seem, therefore, that the Mediterranean Sea could not then have formed the same barrier to the northern migration of the animals which it does now. In many regions, however, the present land was then sunk beneath the sea, and marine strata, of pleiocene age, were accumulated in the Val d’Arno, Sicily, and southern France.