42 ANCIENT PLANTS 



of the mountain chains in Europe which are standing- 

 to the present day. In the many plant -containing 

 deposits of this age, we find specimens indicating that 

 the flora was very similar to the plants now living, and 

 that flowering plants held the dominant position in the 

 forests, as they do to-day. In fact, from the point of 

 view of plant evolution, it is almost an arbitrary and 

 unnecessary distinction to separate the Tertiary epoch 

 from the present, because the main features of the 

 vegetation are so similar. There are, however, such 

 important differences in the distribution of the plants 

 of the Tertiary and those of the present times, that 

 the distinction is advisable; but it must always be re- 

 membered that it is not comparable with the wide 

 differences between the other epochs. 



Among the plants now living we find representa- 

 tives of most, though not of all, of the great groups of 

 plants which have flourished in the past, though in the 

 course of time all the species have altered and those of 

 the earliest earth periods have become extinct. The 

 relative importance of the different groups changes 

 greatly in the various periods, and as we proceed 

 through the ages of time we see the dominant place 

 in the plant world held successively by increasingly 

 advanced types, while the plants which dominated earlier 

 epochs dwindle and take a subordinate position. For 

 example, the great trees of the Carboniferous period 

 belonged to the Lycopod family, which to-day are 

 represented by small herbs creeping along the ground. 

 The Cycad-like plants of the Mesozoic, which grew in 

 such luxuriance and in such variety, are now restricted 

 to a small number of types scattered over the world in 

 isolated localities. 



During all the periods of which we have any know- 

 ledge there existed a rich and luxuriant vegetation 

 composed of trees, large ferns, and small herbs of 

 various kinds, but the members of this vegetation have 

 changed fundamentally with the changing earth, and 



