368 HISTORICAL GEOLOGY. 



Life-System. 



General Character. This era is called Cenozoic be- 

 cause modern life in its main features commences here. 

 We are therefore prepared to find that, among plants and 

 lower animals, the general similarity to present forms is 

 so great that the difference would hardly be recognized 

 by the popular eye. We must touch yery lightly on these 

 lower forms. 



Plants. We have already seen that in the Cretaceous 

 many familiar genera of forest-trees were introduced. In 

 fact, so far as trees are concerned, the Cenozoic might be 

 said to commence in the Cretaceous. In the Tertiary 

 nearly all the genera are the same as now, although the 

 species are mostly different. The genera are the same as 

 now, lut not in the same localities. On the contrary, the 

 same genera grew much farther north than now. The 

 vegetation indicated a much warmer temperature than 

 now. In Eocene times, palms and other tropical plants 

 grew all over Europe, and the mean temperature seems to 

 have been 75 to 80. In Miocene times, evergreens, like 

 those now about the shores of the Mediterranean, nour- 

 ished even to Lapland and Spitzbergen. The mean tem- 

 perature of Europe was 16 to 20 higher than now. 



In America, during the Eocene, palms and figs and 

 evergreens, in Dakota, show a temperature there about 

 that of Florida now. In Miocene times, Sequoias very 

 like the Big tree and the Redwood of California, and 

 taxodiums, and magnolias almost, if not quite, identical 

 with the cypress of the Southern swamps and the Mag- 

 nolia grandiflora of Southern forests were abundant in 

 Greenland. The temperature of Greenland was then at 

 least 30 higher than now. It is easy to see that polar 

 ice could not have existed, and Arctic expeditions would 

 have been an easy matter, if man had lived at that time. 

 We give some figures of Tertiary plants (Figs. 327-332). 



