26 Proceedings of the Royal Physical Society. 
It is true that the habitats and life-histories of individual species of plants 
and animals are becoming more closely studied, and have recently become a 
valuable feature of our text-books. Our real field naturalists have also 
discarded the county method for others in which natural boundaries, such as 
watersheds, are used, especially in their relations to river basins or to climate, 
but the advance of ecology demands that we should aspire to a still more 
intimate and inclusive knowledge of distribution in regard to life association. 
Alike in plant ecology and entomology, as examples of ecological studies, 
we want to know the sum of plant and insect associations on each as nearly 
natural habitat as can still be found, with their ecological relations both 
biological and physical. We want to grasp and to be able to describe, before 
it is too late, the present range of such habitats and their probable extension 
in the past. The value of the results that would accrue from a study of the 
chalk grassland, taken in conjunction with its entomology and malacology, 
must be perfectly clear to any field naturalist, and the same may be said in 
regard to our southern natural beech forests. The plant and animal associa- 
tions of each of these habitats are almost completely natural and strongly 
interwoven and self-supporting, but to a marked degree independent of the 
surrounding associations as regards their species. The same applies to the 
coastal sand dunes, though differences in geographical relation, and the 
migratory coastal nature of the formation, have resulted in variations in the 
types of plant and animal association in the north, south-east and west. The 
fens and the reed-belt are also famous for the close restrictions of their species, 
while the northern and southern heaths and the moorland have wider 
developments of associated floras and faunas. 
How then may we map out the country for the purposes of the ecologist ? 
The divisions given in the 7ypes of British Vegetation (2) form an excellent 
beginning so far as the plant basis is concerned, but the writer is prejudiced 
in favour of a more natural if rather more complex classification, in which 
physiographical factors are given greater importance, such as was recently 
outlined in the Scottish Botanical Review (3). 
The fieldsman beginning such studies will probably find a working 
knowledge of natural history and physiography the most useful weapon. His 
first need is to distinguish natural from artificial conditions, and here a 
knowledge of physiography is his mainstay; while the detection of the natural 
or artificial association of the various forms of life depends chiefly on his 
field experience of natural history. A simple classification of habitats 
is into: 
(1) Artificial, such as we find in plantations, hedgerows, gardens, fields, 
railway cuttings and embankments, quarries, and other types of 
