336 MISCELLANEOUS FARM SUBJECTS 



series. The sandy loam is found in Idaho, where it is extensively de- 

 veloped. It is level and fitted for irrigation, but is yet but little used. 

 The fine sand occurs in elevated areas, sometimes wind blown, but 

 when capable of irrigation and cultivation is adapted to tree fruits, 

 vegetables, small fruits, alfalfa, and clover. The fine sandy loam is 

 the most highly developed and intensively cultivated member of the 

 series, and is extensively devoted to the production of choice fruits, 

 consisting of winter apples, peaches, cherries, etc., as well as truck 

 crops, cereals, alfalfa, clover, timothy, and hops. The loam usually 

 occupies elevated positions, and is frequently timbered when occur- 

 ring in the vicinity of Lewiston and Moscow, Idaho, but these tim- 

 bered tracts are now being cleared and devoted to wheat, oats, and 

 flax, while the production of winter apples is successfully being car- 

 ried on to a limited extent. In the Baker Gity area, Oregon, this 

 type is devoted mainly to the production of oats, barley, and hay 

 crops, but under irrigation is capable of successful culture to fruits 

 and truck crops. The silt loam in the Gallatin Valley, Montana, is 

 devoted to dry-farmed or irrigated grains, and when under irrigation 

 also to the production of alfalfa and clover. In the Lewiston area, 

 Idaho, and Walla Walla area, Washington, it covers large areas of 

 the rolling upland, being devoted principally to the production of 

 wheat and to a limited extent to vegetables, apples, cherries, and small 

 fruits. 



ROCKY MOUNTAIN VALLEYS, PLATEAUS, AND PLAINS. 



The soils of the Rocky Mountain valleys, plateaus, and plains 

 are derived from a wide range of igneous, eruptive, metamorphic, and 

 sedimentary rocks. The plateau and plain types occupy a more or 

 less elevated position and have sloping, undulating, or irregular sur- 

 face features. They are derived from underlying sedimentary rocks 

 or consist of the remnants of ancient extensive mountain foot-slope 

 material or of alluvial deposits along streams trenching and terracing 

 the sedimentary rocks of the plateaus and plains. The mountain 

 slope and intermountain valley types consist of residual and colluyial 

 deposits or of ancient lacustrine or later stream sediments, occupying 

 mountain foot slopes and narrow valleys. 



The soils of the mountain slopes are usually of little agricultural 

 value, owing to their rough surface, elevated position, and the conse- 

 quent impracticability of irrigation. Those of the plateaus, valleys, 

 and plains vary widely in economic importance, depending largely 

 upon climatic features, topographic position, and water supply for 

 irrigation. They range from grazing lands of nominal value to soils 

 adapted to the most important and intensively cultivated fruit, melon, 

 sugar beet, and other special crops. 



Billings Series. Compact adobelike gray to dark or brown soils 

 and subsoils, formed mainly by reworking of sandstones and shales 

 and occupying old elevated stream terraces. This is an important 

 series adapted to alfalfa and general farm crops and stock raising; 

 also used to a considerable extent in the production of sugar beets. 



Colorado Series. Light-gray to reddish-brown 'soils and subsoils, 

 derived from colluvial wash. Where irrigable these soils are im- 



