2 86 PLANT LIFE. 



beginning of the Cretaceous or Chalk period. Instead of 

 Cryptogams and extraordinary Conifers, one finds a 

 whole series of well-developed Dicotyledons and Mono- 

 cotyledons. These in leaf and stem closely resemble 

 modern plants, and must have formed an essentially 

 modern-looking flora. The Pine, Oak, Maple, Alder, 

 Willow, Poplar, and even such shrubs as the Sweet Gale, 

 are found in deposits of the Chalk period. There is some 

 ground, too, for supposing that the complex inter- 

 dependence of the plant and animal world with which 

 we are now familiar was even then fully established. All 

 the great groups of insects were in existence. Fossil 

 butterflies are found in the same strata as certain 

 Willows ; and, at the present time, the caterpillars of 

 the same genera find their food upon the descendants 

 of these Willows. 



After the Cretaceous period it is possible to distinguish 

 representatives of modern floras. Dicotyledons and 

 Monocotyledons had not only attained their supreme 

 position, but they forthwith began to multiply, and 

 developed into migrating floras, which drove one 

 another all over the world, until the conditions of the 

 present day were produced. 



The Eocene flora of Europe contained forms which 

 are closely allied to the tropical plants of India, and to 

 the extraordinary vegetation of Australia. 



In the Miocene period, the flora changes from tropical 

 to subtropical, with many "' American ^^ types. Before 

 the end of this epoch " Atlantic'' and ''Mediterranean''' 

 plants had made their appearance, and these became 

 dominant in the " Pliocene " period, and have remained 

 the most important European plants until the present 

 day. Before continuing the history of vegetation 

 through the Great Ice Age, it is important to note what 



