74 EVOLUTION OF THE EARTH 



struggles there rises a greater InteHIgence, seen in nearly all 

 of the mammal stocks, but particularly in one, the monkey- 

 ape-man line. Brute-man appears on the scene with the intro- 

 duction of the last glacial climate, a most trying time for all 

 things endowed with life, and finally there results the domi- 

 ' nance of reasoning man over all of his brute associates. 



The Cenozoic era was a time of especially marked geo- 

 graphic alteration, as is especially well seen in the evolution 

 and spread of the elephant stock or Proboscidea. These 

 animals arose in Africa early in the era, but there was no 

 means by which they could spread into other continents, because 

 Africa remained isolated. At about the middle of the Ceno- 

 zoic, the Alps were rising and these crustal alterations also 

 gave birth to a land-bridge across the Mediterranean connect- 

 ing Europe and Africa. Across this bridge the long-faced 

 elephants, now all gone, spread first into Europe and thence 

 Into Asia. A little later much of Asia began to rise, and the 

 culmination Is seen in the grandest of all mountains, the present 

 Himalayas. These alterations permitted the elephant stock 

 to spread across Asia and the Nome bridge into Alaska and 

 wider North America, and they had no sooner arrived there 

 than they were on their way across the newly arisen Panama 

 bridge, thence to spread all the way south Into distant Argen- 

 tina. North America was then peopled with many kinds of 

 camels and horses, and they, along with many other animals, 

 migrated Into South America. Wanderlust was upon the 

 world, and from South America there migrated into our coun- 

 try great sloths, a claw of one of which was found by Thomas 

 Jefferson In Virginia, and described as that of a huge lion. 

 The great Democrat may be excused for his error, since in 

 those days fossil sloths were unknown In North America; 

 rather should he be praised, for he Is the only president who 

 has described a fossil, other than live ones ! 



Times of volcanic activity. In all that has been said we 



