PREFACE. 



The object of tliis work is to give, in a connected 

 form, a summary of the development of the vegetable 

 kingdom in geological time. 



To the geologist and botanist the subject is one of 

 importance with reference to their special pursuits, and 

 one on which it has not been easy to find any conveni- 

 ent manual of information. It is hoped that its treat- 

 ment in the present volume will also be found suffi- 

 ciently simple and popular to be attractive to the 

 general reader. 



In a work of so limited dimensions, detailed descrip- 

 tions cannot be given, except occasionally by way of 

 illustration ; but references to authorities will be made 

 in foot-notes, and certain details, which may be useful to 

 collectors and students, will be placed in notes appended 

 to the chapters, so as not to encumber the text. 



The illustrations of this work are for the most part 

 original ; but some of them have previously appeared 

 in special papers of the author. 



J. W. D. 



February, 1888. 



•^'T^t^ 



