^02 General Botany 



of many types of angiosperms. The rocks of the Upper Creta- 

 ceous contain an abundance of fossils of broad-leafed plants such 

 as oak, willow, beech, maple, tulip, sassafras, and palm. The 

 sudden appearance of so great a diversity of forms shows that 

 as a group they must have diverged from the other fossil groups 

 a long time previously. Thus far very few of the pre-Cretaceous 

 ancestors of the angiosperms have been discovered. 



The Tertiary vegetation. During the Tertiary the forests were 

 dominated by angiosperms and conifers, much like the forests 

 of today. It was during the Tertiary that there came a gradual 

 lowering of temperature on the earth and the differentiation of 

 distinct torrid, temperate, and frigid zones, replacing the pre- 

 vious uniformly mild temperatures of the Cretaceous. This 

 lowering of temperatures culminated in the Glacial period, which 

 closed the Tertiary. 



REFERENCE 



Seward, A. C. Fossil Plants (4 vols.). G. P. Putnam's Sons, New York; 1917. 



