SURVEYS BY THE UNITED STATES BUREAU 131 



large extent for sugar beets and lima beans, and, where irrigation is not practi- 

 cable, extensively used for grain. 



Placentia series. Reddish soils derived largely from the weathering of allu- 

 vial and colluvial deposits, generally underlain by heavy compact red material 

 with an impervious adobe structure. Large areas of these soils are devoted to 

 dry farming of grain, and occur throughout southern California and in some of 

 the coastal valleys, viz., Bakersfield, Salinas, and San Jose*. These are exten- 

 sive areas under irrigation, which are valuable for producing both deciduous 

 and citrus fruits. The heavier members of this series have been more success- 

 fully used for grain production in southern California. They seem particularly 

 well adapted to English walnuts and olives. The soils are usually well drained. 

 The English walnut does not thrive on poorly drained soils. 



Redding series. Ancient alluvial valley deposits of red and deep red color, 

 generally gravelly. Heavy red subsoils with hardpan. The soils of this 

 series, when not carrying an excess of cobbles or underlain at shallow depths 

 by hardpan, are excellently adapted to the production of choice peaches and 

 small fruits. 



Sacramento series. Gray alluvial soils consisting of recent stream sedi- 

 ments. The lighter members of this series are used mainly for the production 

 of prunes, pears, and peaches. The members of the series having a medium 

 texture are adapted to sugar beets, alfalfa, and prunes. The heavier members 

 are at present poorly drained, and have not been highly developed, being used 

 mostly for grain and grazing. 



Salem series. Residual, alluvial, or colluvial soils, either red or .dark in 

 color, derived from rocks of basaltic, schistose, crystalline, or arenaceous 

 character. These soils, so far as they have been encountered, seem particularly 

 adapted to hops, potatoes, and have been used to some extent for apples, 

 peaches, and grain. They have not been very highly developed in the areas 

 in which they have been encountered. 



San Joaquin series. Compact red soils and subsoils derived from old 

 marine sediments, usually underlain by red hardpan. These soils have been 

 used almost exclusively for dry farming to grain on account of the general 

 occurrence of hardpan and very stiff and impervious subsoils. Recently, in 

 the Sacramento area, some members of this series have been very successfully 

 used for the production of the Tokay grape and strawberries. 



Sierra series. Light gray to red and frequently gravelly soils, often under- 

 lain by red adobe. Members of this series constitute some of the most valu- 

 able deciduous fruit soils of the foothills in northern California. 



Sites series. Residual and colluvial soils of reddish gray or dark brown color, 

 derived from sandstones, shales, conglomerates, and volcanic or altered ma- 

 terial occupying low, rolling foothills and their valley slopes, usually underlain 

 at shallow depths by sandstones, conglomerates, or heavy subsoils. The Sites 

 loam and clay loam adobe are the important soils of this series and are pro- 

 ductive, but, owing to their positions, are generally unirrigable and adapted to 

 dry farming to grains. 



