EUROPE BEFORE THE ARRIVAL OF MAN. 731 



amount of evidence which seems to prove that man existed in California at an 

 equally remote date. Now it is perfectly clear that the human race must have 

 been in existence for a very long time before it could have become so widely dis- 

 persed over the earth as to occupy countries so distant from each other as Cali- 

 fornia and Portugal. For the first appearance of man on the earth we must, 

 therefore, go far back in the Pliocene period at any rate; and if we are to find 

 traces of the "missing link," or primordial stock of primates from which man 

 has been derived, we must undoubtedly look for it in the Miocene. 



Of the three stages of the Tertiary period here passed in review, we have 

 seen that the Eocene was characterized by the entire absence of genera and 

 species of mammals identical with those now living ; in the Miocene there were 

 genera, but no species, identical with those now living; in the Pliocene there 

 was at least one species in Europe that has survived to the present day. When 

 we come to the Pleistocene age, we find a majority of the species identical with 

 such as still exist. But in regard to this Pleistocene fauna there are some curious 

 circumstances, which show that the climate of Europe had begun to be subject 

 to vicissitudes such as it had not known in the earlier Tertiary epochs. Among 

 the Pleistocene mammals of Europe we find such as are characteristic of warm 

 climates, — as the lion, leopard, hysena, elephant, rhinoceros, and hippopotamus; 

 and along with ijiese we find such as characterize sub-arctic climates, — as the 

 musk-sheep, reindeer, glutton, arctic fox, ibex, and chamois; and yet again we 

 find such denizens of the temperate zone as the bison, horse, deer, wild boar, 

 brown and grizzly bears, wolf, and rabbit, to which may be added the mammoth 

 and woolly rhinoceros. 



Now, as Mr. James Geikie has ably shown, this singular juxtaposition of 

 northern, southern, and temperate forms points directly to great vicissitudes of 

 climate. It is quite clear that when the reindeer came down as far as southern 

 France, the climate must have been very different from what it was when the 

 hippopotamus bathed in the Thames. We know otherwise from purely geologic 

 evidence, that the Pleistocene climate was very extraordinary. Hitherto, dur- 

 ing the Tertiary period, the temperature of Europe seems to have been steadily 

 but slowly decreasing, from the Eocene epoch, when it was subtropical, to the 

 end of the Pliocene, when it was temperate, though warmer than at present. 

 But in the Pleistocene epoch there were at least four or five, and probably several 

 more, extreme changes from a warm to a cold climate, and back again. This 

 period, or the greater part of it, has been known as the " Glacial Epoch " or the 

 "Great Ice Age"; but recent researches have shown that over Britain and cen- 

 tral Europe there were several glacial epochs, alternating with warm inter-glacial 

 periods of long duration. When the cold was at its maximum, the whole area of 

 Finland, Scandinavia, and Scotland, with the North and Baltic Seas, was buried 

 under a stupendous sheet of ice, varying from looo to 2000 feet in thickness; and 

 this ice-sheet sent off glaciers as far east as Moscow and as far south as Dresden, 

 while the Alps, the Pyrenees, and the mountains of Auvergne became centres of 

 glaciation, inferior, indeed, to the great northern ice-sheet, but still immense in 



