VI 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 being unnecessarj' 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 

 4, 12, 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. 



