THE FOSSIL RECORD 21 



As it is impossible to cover the whole ground, 

 only the higher groups of plants are considered; 

 for this part of the Vegetable Kingdom the fossil 

 record is always available and always important. 

 The questions which will be considered are: 



The Evolution of the true Flowering Plants or 

 Angiosperms (Chapter II and III). 



The Evolution of the Seed-plants generally 

 (Chapter IV). 



The Evolution of the great groups of the 

 higher Cryptogams, i. e. of those Spore- 

 plants which share with the Seed-plants 

 the possession of a vascular system (wood 

 and bast) (Chapters V to VII). 



A table of geological strata is given for refer- 

 ence, in which the relative thickness of the 

 various formations (down to the Cambrian) as 

 they occur in Britain is roughly indicated on 

 a scale of about 1 inch to 20,000 feet. A few 

 words of explanation may be added, as regards 

 those formations to which we shall have to refer 

 in the following pages. 



The Tertiary formations represent, geologi- 

 cally speaking, the modern period of the record. 

 So far as plants are concerned, no really great 

 change occurred during Tertiary times that 

 is to say, the same classes of plants which now 

 constitute the Flora of the world flourished 



