CHAPTER XVIII. SUCCESSION OF VEGETABLE LIFE. 395 



CHAPTER XVIII. — Succession of Vegetable Life (Cont'd). 



Plants of the Tertiary — Plants of the Quaternary — 

 The Defective Record. 



Plants of the Tertiary. From the flora of the Cretaceous 

 to that of the Tertiary, the transition is one of easy gradations. 

 The plants of the lower Eocene closely resemble those of the 

 upper Cretaceous, but as time progresses the older forms grad- 

 ually disappear, to be replaced by modern ones, until the majority 

 of the genera, and even a large proportion of the species, are 

 identical with those found at the present time. The flora at the 

 same time becomes exceedingly rich and varied. 



This is the age of the highest development of mammalian 

 animals : it is also the age when the higher forms of vegetable 

 life reach their culmination ; for not only were all the types, and 

 nearly all the species now existing represented, but there were 

 many more which perished in the vicissitudes of the great ice 

 age which followed. 



If we could behold before us the living flora of the Tertiary, 

 Ave might be surprised at its luxuriance in species, we might 

 wonder that in our own latitude are many plants, such as the 

 Magnolia, Bald Cypress, Pecan and Sweet-gum, that now grow 

 farther south, but we should recognize our own Oaks, Walnuts, 

 Elms, Lindens, Roses and hundreds of other well known forms. 

 The forests and glades would wear a familiar look. At least we 

 should observe no greater differences between this and the flora 

 of our own time, than we may find by comparing those of similar 

 climates in different parts of the world now. In fact, we have, 

 in the present flora of Australia, a fragment of the early Tertiarv 

 flora preserved, with scarcely a change to the present time. This 

 is due partly to the exemption of that continent from the extreme 

 vicisitudes of climate which, during the Quaternary, so greatlv 

 modified the floras of more northerly regions, and partly to its 

 insular condition, which prevented the intermingling of other 

 floras, and thus rendered less ardent the struggle for existence 



