1] 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 voluntary efforts. There are at present about twenty 
