TENURE AND USE OF ARID GRAZING LANDS. 
crop farming can not be made to support families on land where 
periods of drought lasting one, two, three, and even four or five sea- 
sons in succession are known to occur with more or less regularity — 
periods of drought so severe that no known cultivated plants can be 
expected to endure them and produce a crop. 
The approximate geographical distribution of the lands of each 
class is shown in the accompanying diagrammatic map (fig. 1). At 
Fig. 1.— Diagrammatic map of the western half of the United States, showing roughly the geographic 
distribution of the different classes of land as determined by the dominant agricultural use. 
no place are the boundaries between areas of the different classes as 
well defined as the lines on the map would suggest. Many small 
areas of irrigated or dry-farming land occur in the forest and wood- 
land area, and some occur in the arid grazing area. Likewise in the 
semiarid area there are many places, usually of relatively small size, 
where the land can be used only for grazing. Irrigable land is, of 
course, always capable of intensive, cultivation and occurs wherever 
