644 TRANSACTIONS OF SECTION E. 



about the exact phase of the cycle, whether ice in addition to water has been an 

 agent in shaping this or that form, and so on. But, after all, these discussions 

 would be more profitable than quarrels as to which descriptive term, or place 

 name, or local usage should be adopted to distinguish it. 



The use of such notations in geographical problems is not unknown. They 

 were employed by Koppen in his classification of climate; and now in the case 

 of climatology, there is coming to be a general consensus of opinion as to what 

 are the chief natural divisions, and the use of figures and letters to indicate them 

 has been followed by several other authors. This should also be attempted for 

 oceanography. 



If any international agreement of symbols and colours could be come to for 

 such things it would be a great gain, and I hope to bring this matter before 

 the next International Geographical Congress. 



The Need for Selecting Natural Geographical Units. 



We have still to come to Geography proper, which considers land, water, and 

 air not merely separately but as associated together. What are the units smaller 

 than the whole Earth with which our science has to deal ? 



When we fix our attention on parts of the Earth, and ask what is a natural 

 unit, we are hampered by preconceptions. We recognise species, or genera, 

 or families, or races as units — but they are abstract rather than concrete units. 

 The reason for considering them as units is that they represent an historical 

 continuity. They have not an actual physical continuity, such as the component 

 parts of an individual have. Concrete physical continuity in the present is what 

 differentiates the geographical unit. Speaking for myself, I should say that every 

 visible concrete natural unit on the Earth's surf ace' consisting of more than one 

 organic individual is a geographical unit. It is a common difficulty not to be 

 able to see the wood for the trees; it is still more difficult to recognise that the 

 wood consists of more than trees, that it is a complex of trees and other vegeta- 

 tion, fixed to a definite part of the solid earth and bathed in air. We may speak 

 of a town or State as composed of people, but a complete conception of either 

 must include the spacial connections which unite its parts. A town is not merely 

 an association of individuals, nor is it simply a piece of land covered with streets 

 and buildings ; it is a combination of both. 



It is true that, in determining the greater geographical units, man need not be 

 taken into account. We are too much influenced by the mobility of man, by his 

 power to pass from one region to another, and we are apt to forget that his 

 influence on his environment is negligible except when we are dealing with rela- 

 tively small units. The geographer will not neglect man; he will merely be 

 careful to prevent himself from being unduly influenced by the human factor in 

 selecting his major units. 



Some geographers and many geologists have suggested that land forms alone 

 need be taken into account in determining these larger geographical units. 

 Every different recognisable land form is undoubtedly a geographical unit. A 

 vast lowland such as that which lies to the east of the ""Rocky Mountains is 

 undoubtedly a geographical unit of great importance, but its geographical sub- 

 divisions are not necessarily orographical. The shores of the Gulf of Mexico 

 could not be considered as geographically similar to those of the Arctic Ocean, 

 even if they were morphologically homologous. The lowlands of the polar regions 

 are very different from those at or near the tropics. The rhythm of their life 

 is different, and this difference is revealed in the differences of vegetation. 



I wish to lay great stress on the significance of vegetation to the geographer 

 for the purposes of regional classification. I do not wish to employ a 

 biological terminology nor to raise false analogies between the individual 

 organism and the larger units of which it is a part, but I think we should do 

 well to consider what may be called the life or movement going on in our units 

 as well as their form. We must consider the seasonal changes of its atmospheric 

 and of its water movements, as well as the parts of the Earth's crust which they 

 move oyer and even slightly modify. For this purpose a study of climatic 

 regions is as necessary as a study of morphological regions, and the best guides 

 to the climatic regions are the vegetation ones. 



By vegetation I mean not the flora, the historically related elements, but 



