SURVEYS BY THE UNITED STATES BUREAU 127 



when irrigable are devoted to orchard fruits, the heavier types to alfalfa and 

 sugar beets. 



Jordan series. Light to dark-colored lacustrine desposits. These soils 

 are utilized principally in the production of alfalfa, sugar beets, truck crops, 

 and grains under favorable conditions for irrigation and drainage, but consider- 

 able areas covered by some of the members of this series are not utilized on 

 account of the accumulation of alkali, poor drainage, or because of their drift- 

 ing character. 



Malade series. Dark-colored alluvial soils underlain by light-colored sands, 

 sandy loams, or heavy reddish material. These soils are devoted chiefly to 

 sugar beets, alfalfa, grain, and some orchard fruits. 



Redfield series. Red soils consisting of colluvial and alluvial materials 

 derived from red sandstones and other rocks. The lighter members are 

 adapted to the production of alfalfa, grain, and general farm crops when 

 irrigable and well drained. The heavier members, as far as encountered, are 

 poorly drained and have not been developed. 



Salt Lake series. Dark-colored soils underlain by stratified sediments of 

 lacustrine origin. These soils, as far as encountered, occupy very low, flat 

 positions around the lake, and have not been developed to any extent. 



NORTHWESTERN INTERMOUNTAIN REGION 



The most extensive and uniform soil types of this region consist of residual 

 materials overlying and derived from extensive basaltic lava plains and in 

 some cases from granite rocks or of ancient lacustrine sediments or extensive 

 lake beds now more or less modified by erosion or aeolian agencies. Owing 

 to erosion by streams and to movements of the earth's crust, these soils now 

 generally' occupy more or less elevated sloping or rolling plains. About the 

 margins of the lacustrine or residual deposits they are covered by sloping plains 

 and fans of colluvial wash from the adjacent mountain borders, while in the 

 vicinity of the larger streams, which have carved and terraced the lacustrine 

 beds and residual soils, occur other series of recent alluvial stream sediments 

 derived from reworked materials of the lake beds or from the weathered prod- 

 ucts of the mountains. It is the soils of this region that constitute a large 

 portion of the great grain -producing lands of the Northwest. 



Bridger series. Dark-colored soils with sticky yellow subsoils, of colluvial 

 and alluvial origin. These soils generally occupy elevated foot slopes or sloping 

 valley plains and have not been developed to a great extent. They are most 

 extensively used for the production of grain, and, when irrigated, are utilized 

 in the production of alfalfa and other hay crops and, under favorable climatic 

 conditions, are adapted to fruits. 



Gallatin series. Light to dark-colored soils with yellowish to dark com- 

 pact subsoils, of recent alluvial origin from basaltic and volcanic rocks. These 

 soils generally occupy low positions, very frequently poorly drained, often 

 subject to overflow, and have not been extensively developed for agricultural 



