PREFACE Vll 



descriptive notes of specimens in their possession. My friends 

 Dr Nathorst of Stockholm and Dr Zeiller of Paris have gener- 

 ously responded to my requests for information on various 

 points. I wish especially to thank Dr Kidston for several 

 excellent prints of specimens in his collection and for the loan 

 of sections. I have profited by more than one examination of 

 his splendid collection at Stirling. Professor Weiss has gener- 

 ously allowed me to borrow sections from the Manchester 

 University collections, more especially several which have been 

 reproduced in the chapter devoted to the genus Lepidodendron. 

 To Professor F. W. Oliver my thanks are due for the loan 

 of sections from the collection under his charge at University 

 College. I have pleasure also in thanking Dr Scott, not only 

 for lending me sections of a Lepidodendron and for allowing 

 me to use some drawings of Miadesmia originally made by 

 Mrs Scott for reproduction in his invaluable book, Studies in 

 Fossil Botany, but for kindly undertaking the laborious task 

 of reading the proofs of this volume. It would be unfair to 

 express my gratitude to Dr Scott for many helpful suggestions 

 and criticisms, without explicitly stating that thanks to a 

 friend for reading proofs must not be interpreted as an attempt 

 to claim his support for all statements or views expressed. 

 The General Editor of the Series, Mr A. E. Shipley, has also 

 kindly read the proofs. I am under obligations also for assis- 

 tance of various kinds to Prof Thomas of Auckland, New 

 Zealand, to Mr Boodle of Kew, to Mr D. M. S. "Watson of 

 Manchester, to Mr T. G. Hill of University College, and to 

 Mr Gordon of Emmanuel College, Cambridge. I am indebted 

 to the kind offices of Miss M. C. Knowles for the photograph 

 of the specimen of Archaeopteris hibernica in the Irish National 

 Museum, Dublin, reproduced on page 561. 



