40 THE EVOLUTION OF PLANTS 



When we get down to the Lower Cretaceous 

 (of which our Lower Greensand is an example) 

 we find ourselves at the beginning of the Angio- 

 spermous history. Then* remains are very rare 

 in most beds of this age, but at two places, one 

 in Portugal and the other in the State of Virginia, 

 they are found in considerable numbers. They 

 resemble various living plants, such as Poplars, 

 Willows, Fig-trees, and Laurels; Monocotyledons 

 are also present. In the beds just below, Angio- 

 sperms are altogether absent, so we seem to 

 have got back here to their first appearance, 

 and, indeed, there are no older trustworthy 

 records of this class of plants in any part of 

 the world. 



This apparently sudden appearance of quite 

 well-developed Flowering Plants is still, perhaps, 

 the greatest difficulty in the record of evolution. 

 The Angiospenns must have had a previous 

 history of some kind, and must, we may assume, 

 have been derived from some older group of 

 plants. Can we form any idea what group this 

 was? This is the question which the work 

 of the last few years has done something 

 towards answering, and we will go on in the 

 next chapter to explain what has been discovered 

 about it. 



In order to make the subject as plain as pos- 

 sible, it will be necessary first to go a little more 



