SOIL SUEVEY OF THE RED BLUFF AREA, CALIFORNIA. 



55 



cessful upon all the more elevated parts. It will be very difficult to 

 relieve flood conditions on islands and areas in the river bends. At 

 present clearing areas of this sort is not advisable, as erosion would 

 damage the surface beyond repair. 



The following table gives the results of a mechanical analysis of 

 the soil of this type : 



Mechanical analysis of Sacramento fine samly loam. 



SACRAMENTO SILT LOAM. 



The Sacramento silt loam consists of a brownish-gray silt loam 

 of smooth texture, and slightly compact structure. It is usually 

 micaceous. Typically it extends to a depth of 6 feet, bands of lighter 

 material only occasionally intervening. The surface is often marked 

 by patches of sand distributed along overflow channels or across 

 relatively low bodies swept by flood waters. The type below 30 to 

 36 inches often assumes a texture closely approaching a fine sandy 

 loam in appearance, but still carrying large quantities of silt. The 

 soil is retentive of moisture. It is modified .slightly in certain sec- 

 tions by the addition of material from other soils, but in general 

 the texture and structure are uniform. Below 6 feet are found 

 materials of varying character but similar origin, and at some depth 

 it is underlain by the coarse alluvium laid down by swift water. 



The type occurs as extensive elongated bodies bordering the Sac- 

 ramento River and forms a large part of the low-lying bottom lands. 

 The areas often lie next the river, there being a sharp drop of from 

 20 to 30 feet to the water. In other places strips of Riverwash or 

 other types of the Sacramento series intervene, but never types of 

 other series. 



A terrace usually bounds the type on the outer edge of the Sacra- 

 mento bottoms. A very definite boundary occurs in these cases, except 

 where the terrace gives way to permit the entrance of lateral drain- 

 age and alluvial strips of foreign origin, which finally lose their 

 identity in the great mass of Sacramento material. There are no 

 great differences in elevation within the bodies of this type, but the 

 surface is usually marked by overflow sloughs or abandoned channels 

 paralleling the river in a general way. Over the greater part of the 

 type these depressions with sloping banks carry water during floods, 

 often in sufficient volume to cover the flatter portions as a sheet or 

 submerge all but the highest parts. It is only in the slightly lower 



