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. In similar latitudes on the continent the same mammalian fauna flourished, while the flora was temperate, but suggestive of less strongly contrasted summers and winters than the present. A kind of insular climate, in short, seems to have characterized north Germany.
To this genial interglacial epoch succeeded the second and most extreme of all the glacial epochs. An enormous mer de glace then extended over all northern and northwestern Europe, from the British area in the west to the Urals in the east, and from Lapland in the north to the mountains of middle Europe in the south. (See Map B.)
When these extreme conditions eventually passed away, the second interglacial epoch supervened, characterised, as the earlier one had been, by a genial temperate climate, by the presence in England and the continent of the great pachyderms and their congeners, and by the appearance of Paleolithic man.
This second interglacial epoch was in its turn succeeded by a third advance of the Scandinavian "inland ice," which once more coalesced with the mer de glace of the British area. It did not, however, flow so far as its predecessor. Nevertheless, it reached the Valdai Hills in the east, the valley of the Elbe in the south, and covered all Scotland, the north of England, and the major portion of Ireland. This ice flow was most probably contemporaneous with the third advance of the great glaciers of the Alps. (See Map C.)
It is noteworthy that the löss in north Germany nowhere overlies the morainic accumulations of the third glacial epoch. It does, however, cover the marginal area of the ground formerly invaded by the second and greatest mer de glace. This clearly shows that the löss of north Germany must belong, in part at least, to the second interglacial epoch. The fact that it everywhere avoids the regions over which the third great ice sheet prevailed, does not, however, prove that tundra and steppe conditions did not supervene at a later date in middle Europe. The evidence supplied by the alpine lands, and the great valleys that drain those lands, is quite conclusive of the contrary. There is no doubt whatever that the Paleolithic reindeer hunters followed the chase in middle Europe long after the third great Scandinavian mer de glace had retired from the plains of north Germany. The geographical distribution of the wind-blown loss shows that steppe conditions were restricted to a broad belt of land in middle Europe.
