LOCALITIES STUDIED 



have not only this, but we must make a still more important choice, 

 namely, that of the locality of study. To make this selection one must 

 possess a good knowledge of animal environments, such as we have 

 touched upon in the preceding pages. 



i. 



BASIS OF SELECTION AND SUBDIVISION 



Such knowledge can be acquired from texts of physiography and 

 plant ecology, and from special works on the area at hand. The basis 



FIG. 8. Map showmg the location of the plains, savanna (prairie), and forest 

 regions of North America, with area of special study inclosed in rectangle (from 

 Transeau after Sargent). 



of selection is either that of age or of present conditions, or both. The 

 points selected for study are called stations. Stations are subdivided 

 on the basis of plant and animal habitats into substations. The sub- 

 stations may represent either formations or divisions of formations. 

 For example, a station like Wolf Lake may be divided into sandy 

 shore substation, vegetation of open- water substation, and embayment 

 substation. 



2. ENUMERATION OF STATIONS GUIDE 



In the study at hand we have made use of a large number of stations 

 which are enumerated below and are referred to in the text. The list 



