COI^TENTS. 



CHAPTER I. 



PA6B 



Preliminary Ideas of Geolooical Chronology and of the Classi- 

 fication OF Plants 1 



CHAPTER II. 



Vegetation of tue Lacrentian and Early Paleozoic — Questions 



AS TO Alg^ 8 



CHAPTER III. 



The Erian or Dkvonian Forests — Origin of Petroleum— The 

 AoE of Acrogens and Gymnosperms 45 



CHAPTER lY. 



The CARBONiFERotis Flora -Culmination ok the Acrooens — For- 

 mation OF Coal 110 



CHAPTER V. 



The Flora of the Early Mesozoic — Reign of Pines and Cycads . 175 



CHAPTER VI. 



The Reign of Angiosperms in the Later Cretaceous and Early 



Tertiary or Kainozoic 191 



2 



