‘74 DRY-FARMING 
Sol divisions 
The dry-farm territory of the United States may 
be divided roughly into five great soil districts, each 
of which includes a great variety of soil types, most 
of which are poorly known and mapped. These 
districts are : — 
. Great Plains district. 
. Columbia River district. 
. Great Basin district. 
. Colorado River district. 
. California. district. 
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Great Plains district.—On the eastern slope of 
the Rocky Mountains, extending eastward to the 
extreme boundary of the dry-farm territory, are the 
soils of the High Plains and the Great Plains. This 
vast soil district belongs to the drainage basin of the 
Missouri, and includes North and South Dakota, 
Nebraska, Kansas, Oklahoma, and parts of Mon- 
tana, Wyoming, Colorado, New Mexico, Texas, and 
Minnesota. The soils of this district are usually of 
high fertility. They have good lasting power, 
though the effect of the higher rainfall is evident in 
their composition. Many of the distinct types of 
the plains soils have been determined with consider- 
able care by Snyder and Lyon, and may be found 
described in Bailey’s ‘‘Cyclopedia of American Agri- 
culture,’ Vol. I. 
Columbia River district.— The second great soil 
