350 MAN AS THE COTEMPORARY OF THE MAMMOTH 



same. In general, also, there is a diversity observable as regards the species 

 living on the western side of Norway. From this, as well as from the diflerence 

 of the testacea, which are met with in the older deposits, Lovdn has very justly 

 inferre<I that the basin of the Baltic was once connected with the Arctic ocean 

 by an arm stretching eastwardly over Lakes Ladoga and Onega to the White 

 sea, but was, on the other hand, separated by a nan-ow strip of land or isthmus 

 from the western ocean, with which it now communicates through the sound. 

 This separation must first have taken place when the glacial sea was on the 

 retreat. 1'estaceous beds are met within the region of the eastern sea at an 

 elevation of 130 feet, and these correspond in some species with the arctic char- 

 acter. But, as Loven properly remarks, the fortunes of the glacial fauna of 

 the east difl'ered from those of the same fauna in the west. The basin of the 

 Baltic \\as l)y degrees wholly separated from the polar seas, and the water, by 

 progressive freshening and depression, became more and more unsuitable for 

 arctic life ; while, at the west, the sea surrounding the southern coasts of Nor- 

 way stood constantly ki open connection with the Ai'ctic ocean, yet gradually 

 acquired during the retreat a higher temperature, so that the northern fauna was 

 driven thence, and was replaced by southern forms. This substitution did not 

 take place in the Baltic. The opening of the sound at a later period brought 

 into that basin no new species from the western sea. The Baltic basin, there- 

 fore, grew poor through the deperdition of unreplaced species; while the western 

 sea, V)y the accession of the fauna belonging to warmer waters, acquired new 

 affluence. 



Middle Europe also has had its glacial era. On both sides of the Alps, in 

 the Vosges and the Black forest, in the Pyrenees and other great mountain 

 ranges uf Europe and lesser Asia, the stone barriers and erratic blocks, the 

 rolled pebbles, the polished and grooved rocks, which speak so plainly of gla- 

 cier action, have been pointed out. 



At the time of the so-called reindeer epoch, an advance of the glaciers took 

 place for the second time, and this in consequence of a great inundation which 

 was sloW' in attaining its ultimate limits. By this incursion, most of the low- 

 lying tracts of Europe were laid under water. In Belgium, according to Dupont, 

 the flood must have reached a height of 450 feet. To this inundation are to 

 be ascribed the masses of gravelly clay, or calcareous mud, which have covered 

 a part of France and Belgium. 



The cold during this new overflow must again have become intense, but not 

 so formidable as during the great glacial era. As most caverns were submerged, 

 and men Avere forced to withdraw' into the more elevated regions, a chasm pre- 

 sents itself in the paleo-archeological documents of this period, which, from the 

 indications we possess, embraced several thousand years. Glaciers are not sud- 

 denly melted ; valleys do not soon become filled with alluvium reaching to a 

 height of some hundreds of feet on their side-walls ; tracts of country and 

 mountain chains cannot be heaved, at a jerk, as it were, into the air and raised 

 high above their previous level. Processes of this sort require time, much time ; 

 and it is only by slow degrees that a state of great refrigeration, even when its 

 causes have ceased, is transmuted into one of warmth and comfort. 



After the final retreat of the waters, the caves would again come into the 

 possession of men, and numerous and valuable proofs of human industry be 

 prepared, which have been preserved even to the present time. 



Here connnences the true reindeer era. The reindeer, as the most charac- 

 teristic representative of the northern fauna, had, beyond a doubt, inhabited, 

 with the cave-bear and mammoth, the south of France. But it is at this period 

 that it first makes its appearance in great numbers. It now spread in large 

 herds as far as the Pyrenees, leaving no grounds for supposing that it had been 

 introduced by man and kept in ancient folds. On the contrary, it lived here in 

 its wild and naturally free condition. The last mammoths were yet alive, as 



