I] INTRODUCTION 23 



may best be investigated. Geological maps show the nature 

 and distribution of the chief rock strata ; and vegetation maps 

 indicate the nature and distribution of the principal plant 

 communities. Geological memoirs describe the development 

 and structure of the strata shown on the geological maps, and 

 give lists of the fossils found in the deposits; and similarly 

 vegetation memoirs give accounts of the development and 

 structure of the plant communities, and furnish lists of the 

 species which constitute the various units of vegetation. 



The nature of the surface soil of a district may often be 

 inferred from vegetation maps (cf. p. 12), even when the existing 

 geological maps are not helpful in this regard, as is frequently 

 the case. 



Geographers too find the maps of service, as has recently 

 been testified by Professor A. J. Herbertson, who states that 

 "at last we have some modern botanical geography which is 

 really valuable to the geographer" (Herbertson, 1911: 384). 



The maps are also valuable to scientific agriculturists, who 

 find on them the limits of profitable wheat cultivation mapped 

 with very considerable accuracy (cf. pp. 204 5). 



The forester may, from the nature of the natural and semi- 

 natural woods shown on vegetation maps, obtain valuable data 

 with regard to the prospects of success of planting certain 

 indigenous or non-indigenous timber trees in any particular 

 locality ; and, to those interested in any future great scheme 

 of afforestation, the vegetation maps which have been published 

 will yield extremely valuable information (cf. p. 68). 



Vegetation maps furnish the only reliable knowledge which 

 is at present available with regard to the nature and possible 

 utilization of the " waste lands " of the country. The Board of 

 Agriculture has at its disposal an almost unlimited amount of 

 information, much of which is published in their annual Agri- 

 cultural Returns, with regard to the cultivated lands of the 

 country; but, apart from unofficial vegetation maps and 

 memoirs, there are practically no means of obtaining reliable 

 knowledge of the nature and possible utilization of the un- 

 cultivated land of any portion of the British Isles. 



Whilst, however, the geological survey of the country is 

 carried on by public funds, the vegetation survey languishes 

 under voluptary efforts. There are at present about twenty 



