CHAPTER YI. 



THE SGI6N OF AKGIOSPERMS IN THE LATER CRETACEOUS 

 AlTD KAINOZOIC. 



It is a remarkable fact in geological chronology that 

 the culmination of the vegetable kingdom antedates that 

 of the animal. The placental mammals, the highest 

 group of the animal kingdom, are not known till the be- 

 ginning of the Eocene Tertiary. The dicotyledonous 

 Angiosperms, which correspond 

 to them in the yegetable king- 

 dom, occur far earlier — ^in the 

 beginning of the Upper Cre- 

 taceous or close of the Lower 

 Cretaceous. The reign of cy- 

 cads and pines holds through- 

 out the Lower Cretaceous, but 

 at the dose of that age there is 

 a sudden incoming of the high- 

 er plants, and a proportionate 

 decrease, more especially of the 

 cycads. 



I have already referred to the 

 angiospermous wood supposed 

 to be Devonian, but I fear to 

 rest any conclusion on this iso- 

 lated fact. Beyond this, the earliest indications of 

 plants of this class have been found in the Lower 

 Cretaceous. Many years ago Heer described and fig- 

 ni«d the leaves of a poplar (Populus primeBva) from 



Fig. 68. — Ibmiltifpriimrra, 

 lleer. Cretaceous, of 

 Greenland. One of the 

 oldest known Angio- 

 sperms. 



