v1 PREFACE 
one-inch maps as had been anticipated, owing to the fact that 
the six-inch maps of the moorlands of the district, with the 
exception of those in the West Riding of Yorkshire, are not 
contoured. 
With regard to the nomenclature of plant communities, the 
terms plant formation and plant association are used in 
accordance with resolutions passed unanimously by the British 
Vegetation Committee, and presented to the International 
Congress of Botanists held at Brussels in 1910. They are 
used in the same sense throughout Tansley’s Types of British 
Vegetation. 
The names of plants are, as a rule, the same as those given 
in the tenth, the latest edition of The London Catalogue of 
British Plants (London, 1908). This being so, the author- 
citation is omitted, as beg unnecessary in a work of this 
character: synonyms, however, are added in special cases. The 
sequence adopted is that of Engler’s system which, in several 
European countries and in the United States of America, is 
rapidly superseding that of Bentham and Hooker. 
I wish to thank Mr J. Ramsbottom, B.A., of the British 
Museum (Natural History), for kindly reading the proof-sheets, 
the Royal Geographical Society for use of the blocks of figures 
412,15, 22, 24 and 25, and Mr A. Wilson, F.L.S. for use of the © 
blocks of figures 19, 30 and 31. 
C. E. M. 
CAMBRIDGE, 
December 1912. 
