PREFACE 



IN the Preface to Volume III I expressed my thanks for help 

 given to me by many friends in the course of the preparation 

 of the subject-matter of Volumes III and IV, but Dr Scott has 

 again earned my gratitude by Very willingly and to very good 

 purpose continuing the tedious task of reading the proofs. It is 

 also a pleasure to acknowledge the help received from the Staff 

 of the University Press. 



Since the publication of Volume III Paleobotany has been 

 deprived of the services of three senior investigators, Professor 

 C..E. Bertrand of Lille, Monsieur Grand'Eury, and Mr Clement 

 Eeid, men whose researches along different lines of inquiry have 

 played a prominent part in the progress of the science during 

 the last few decades. By the death of Miss Ruth Holden, a 

 graduate of Harvard University and a Fellow of Newnham 

 College, Cambridge, Palaeobotany has lost an unusually gifted 

 and promising worker : though a citizen of a country which was 

 then neutral her strong sense of duty led her to lay aside, 

 temporarily as we hoped, botanical research for work with a 

 British Medical Unit in Russia where she died in April of last 

 year. Miss Holden's last contribution to Paleobotany (' On the 

 Anatomy of two Palaeozoic stems from India ' ; Annals of Botany, 

 vol. XXXI. p. 315, 1917) was published too late to be considered 

 in Volume III. 



If it is possible to carry out my intention of supplementing 

 the descriptive treatment of plants, which forms the basis of 

 Volumes I-IV, by a general review of the Floras of the Past the 

 results will be published as an independent work more intelhgible, 

 I hope, to the general reader than the text-book which, with a 

 certain sense of relief, is now brought to a conclusion. 



A. C. SEWARD. 



Botany School, Cambridge, 

 May, 1918. 



