PREFACE. 



THE second part of the Catalogue of the Cretaceous Flora 

 deals with the remains of plants from the English Lower 

 Greensand, and shows the importance of a careful study 

 of even the most unpromising fossils. Most of the 

 specimens described are merely fragments of wood, but 

 their microscopical structure proves to be so well pre- 

 served that their organisation can be clearly determined. 

 Some agree sufficiently well with corresponding structures 

 in existing plants to be referred approximately to their 

 true systematic position ; but others appear to be more 

 or less anomalous, and are not comparable with any steins 

 in the existing flora of which the histological structure 

 is known. The Catalogue, indeed, emphasises the 

 necessity for a more extended and exhaustive study of 

 the vegetative structures of the plants which are now 

 living. 



The general results of the detailed descriptions in the 

 Catalogue are summarised in the Introduction, to which 



O 9 



reference should be made especially for important 

 observations on the climate of the Lower Cretaceous 

 period. 



The dates in round brackets after authors' names refer 

 to the Bibliography at the end of the volume. 



A. SMITH WOODWARD. 



DEPARTMENT OF GEOLOGY, 

 April, 1915. 



