PLEISTOCENE PERIOD 193 



over the ice- vacated lands. Spruces and junipers were 

 also northward bound, and grasses were once more carpeting 

 desolated valleys and plains. Poplars, oaks, hornbeams, 

 sycamores, and other deciduous trees were also coming up 

 from southern exile ; and old landscapes, open again to 

 sunshine, slowly recovered a long-lost wealth and beauty. 



Many vigorous species long survived in the southerly 

 latitudes to which they had been driven ; and as the warmth 

 increased they sought and found congenial conditions on 

 hill and mountain altitudes. 



Northward, too, was animal life pressing, with seals and 

 polar bears in the van, followed by mammoths, woolly 

 rhinoceroses, wolverines, musk-oxen, elk, and other hardy 

 animals. 



What, it may be asked, had become of the descendants 

 of the European Pliocene fauna when the Great Glaciation 

 was prevailing the elephants, rhinoceroses, hippopotamuses, 

 horses, deer, " sabre-toothed " cats, and other forms of 

 life ? Some species had, no doubt, died out. Some had 

 found congenial quarters in the south of Europe, others 

 had crossed to Africa. As the refrigeration increased great 

 migrations must have taken place to the latter continent ; 

 for it was easy of access, being connected at that time not 

 only with Spain across the Gibraltar Strait, but with Italy 

 also by continuous land now represented only by Malta 

 and Sicily. As genial conditions returned, the exiled species 

 sought out the haunts of their forefathers ; and straight- 

 tusked elephants (E. antiquus), rhinoceroses of a non-woolly 

 kind (R. etruscus), hippopotamuses, and other descendants 

 of the earlier fauna were to be seen well north of the Medi- 

 terranean. The species of zebra-like horses which had 

 arrived in Europe in the later Pliocene (E. stenonis'), and 

 was represented there in the early Pleistocene, seems to 

 have become extinct at the time of the Great Glaciation. 

 The later species arriving in Europe in the early part of 

 the Pleistocene, and resembling the wild horses now living 

 in Asia, was certainly again in Europe when the ice was 

 in retreat (E. caballus). The species of elephant in view 

 in the early portion of the Period, and notable for extra- 

 o 



