1902.] DAVIS — SYSTEMATIC GEOGRAPHY. 257 



the traditional classification of geographical topics that the division 

 of mankind into races is commonly taught under physical geography. 

 The races may be fairly enough introduced there as illustrations of 

 ontographical consequences following from physiographical con- 

 trols; but to regard them as essentially physiographic topics shows 

 a regrettable failure to recognize the essential quality of geographi- 

 cal discipline. 



The simple physiographic factor of distance is of great impor- 

 tance. It involves the separation of the people of a race into 

 many families, and thus is a determining cause of difference of 

 language and of many other habits. The unevenness of surface 

 exhibited in mountain ranges is of small measure in comparison to 

 the dimensions of the earth, and yet it suffices to make movement 

 so difficult that the occupants of one valley may have a distinctly 

 different dialect from those in a neighboring valley. How circum- 

 scribed would have been the migrations of the earth's inhabitants 

 if the height of mountain ranges were a large part of the earth's 

 radius ! The sheet of loose rock waste by which the lands are so 

 largely covered not only supports the growth of plants, but has 

 been adopted as a home by many kinds of animals ; and according 

 as the waste is a coarse talus lying on the steep slopes of a young 

 mountain side, or a fine, deep soil blanketing a peneplain, its oc- 

 cupants are of different kinds. Instances of this kind might be ex- 

 tended without number. 



Examples of modern responses to physiographic controls are 

 best found in those new-fashioned characteristics of mankind that 

 are seen in sites of settlement, routes of travel, and in the develop- 

 ment of trades and of commerce. 



Settlements in deserts offer particularly striking illustrations of 

 the dependence of population on water supply. Settlements on 

 rivers are largely determined by head of tide, by falls, and by 

 fords. Settlements on coasts are influenced by protection from the 

 open sea, and by ease of access from sea and land. The routes of 

 trade and commerce are guided by physiographic factors literally 

 at every turn. Straight roads are laid out on plains, but winding 

 valleys are commonly followed in regions of strong relief; tunnels 

 are driven through mountains ; short-cuts are made through isth- 

 muses. Here as before, illustrations are endless; yet abundant as 

 they may be, they have not yet been well classified. At the present 

 day, ontography is less developed than physiography. 



