608 



FOSSIL PLANTS OF THE TERTIARY STRATA. 



the Till of the Clyde. The London clay contains numerous fruits be- 

 longing to many hundred species of plants. The first tertiary land of 

 which we have knowledge, seems to have been richly clothed with 

 plants. The strata are, generally speaking, rich in fossils. _ The stems 

 and leaves appear to be those of Dicotyledons, little differing from the 



plants of the present day (figs. 821-825). In the brown coal of this 

 series, the structure of the wood is evident, and distinctly exogenous 



Figs. 821-825. Structure of ordinary Dicotyledonous stems, to illustrate the appearances pre- 

 sented by some tertiary fossil woods. 



Fig. 821. Portion of a Dicotyledonous (Exogenous) stem cut transversely. Xatural size. 

 Fig. 822. Section of the same magnified, to show the occurrence of large porous vessels. Tlie 



issue. 



Fig. 824. Leaf of an unknown fossil Elm of the middle Tertiary epoch. 

 Fig. 825. Leaf of Comptonia acutiloba, an Amentaceous plant of the si 



same epoch. 



