1912} CURRENT LITERATURE 349 
moving dunes or the swamp vegetation of the dune depressions to a meso- 
phytic climax forest of beech and maple. By the British concept all of these 
are to be considered as composing a single formation! It must be admitted 
that the British concept of formation is the most workable yet proposed, for 
it represents in essence the aggregate of plant associations which compose a 
successional series on a given habitat. It must be admitted also that those 
who oppose the British concept are not agreed among themselves, when it 
comes to actual field discriminations between associations and formations. 
However, the British concept proposed by Moss and adopted by the com- 
mittee, represents a most radical departure from all past formational concepts, 
and seems to be out of harmony with the proposals internationally agreed 
upon in Brussels in roto. 
Whatever may be said concerning concepts and modes of classification, 
nothing but praise can be rendered for the detailed presentation of Britis 
vegetation. The editor presents the chapter on British climate, as well as a 
part of that on the soil; W. G. Samir gives the part on Scottish soils, and 
G. A. J. Cote that on Irish soils. Following a description of the general dis- 
tribution of British vegetation by the editor is an account of the plant forma- 
tion of clays and loams, also by the editor. The chief association here is that 
dominated by Quercus pedunculata, with an undergrowth dominated by the 
hazel. This formation includes also retrogressive associations of scrub (domi- 
nated largely by Rosaceae) and grassland. The editor contributes also the 
chapter on the formation of sandy soil. The chief association is that of oak- 
wood, in which Q. sessiliflora, as well as Q. pedunculata, is a prominent 
member. The chapter on the heath formation is presented as a whole by the 
editor, the part on Scottish heaths being contributed by W. G. Smiru. As 
was well shown at various points in the 1911 excursion, the heath often has 
originated retrogressively through the degeneration of woodland. The first 
step in such retrogression appears to be the invasion of oakwood by birch and 
heather; after a time the heath may become dominant. The heath in time 
may be invaded by pine or birch, illustrating progressive succession. 
Most of the chapter on formation of the older siliceous soils is contributed 
by Moss. The chief association is an oakwood dominated by Q. sessili- 
flora. Retrogression from forest through scrub to grassland is well illustrated 
in this formation. The splendid oak woods of Killarney, with their Mediter- 
ranean components, notably Arbutus Unedo, are classed here; the Killarney 
forest proved to be one of the most fascinating areas visited by the ror1 excur- 
sionists. In the preparation of the extensive and interesting chapter on the 
formation of calcareous soils, the editor was aided by Moss and also by W. M. 
RANKIN. Three subformations are here recognized, that of the older lime- 
stones, that of the chalk, and that of the marls and calcareous sandstones. 
The first is presented by Moss, who also conducted the excursion to the Derby- 
Shire dales, where it is well illustrated. The chief association is dominated by 
the ash, Fraxinus excelsior, and retrogressive stages to scrub and later to 
