OL1GOCENE PERIOD 153 



Germany ; and tree-ferns, ebony, olive, jujube, dragon trees, 

 and big-leaved arums were luxuriating in scenes where to- 

 day they would perish with cold. 



In North America the heat must have declined, as palms 

 were being driven from many of their old haunts, and 

 hardier growths, such as conifers, grasses, and deciduous 

 trees, were spreading over the forsaken sites. 



