The 
Scottish Botanical Review 
No. 1] 
1912 [January 
Whe Geological Relations of Stable and Migratory 
Plant Formations. By C. B. Crampton, M.B., 
C.M., of H.M. Geological Survey. 
PART INTRODUCTION 3 : ‘ ; 3 . é I 
Part II. THE REGIONAL SUCCESSION OF STABLE PLANT 
FORMATIONS . ; . ; 3 : ; 8 
Part III. THE RELATION OF SOILS TO CLIMATE AND 
PHYSIOGRAPHY (40 be continued) : F = 14 
PART I. INTRODUCTION. 
THE nature of a plant formation is still largely a matter for 
investigation, even though certain groups of plant associations, 
for instance those of the moorland, are usually conceded as 
plant formations. On the other hand, it is pretty generally 
admitted that it is the habitat that determines plant associa- 
tion in at least its more comprehensive units ; but the factors 
which contribute to the habitat in such cases are so complex 
and interwoven that plant formations have often been defined 
by limited groups of factors considered in conjunction to 
be the master-factors under existing conditions. Thus 
Schimper (1) emphasised the climate as a master-factor in 
formations he distinguished as climatic formations from 
others he termed edaphic formations, where he considered 
the soil factors of greater importance ; and Graebner has 
proposed a classification based on the richness or poverty of 
the soil waters in mineral matters (2). The soil, again, is 
I 
