SOIL SURVEY OF THE EED BLUFF AREA, CALIFORNIA, 



29 



Avill always be expensive to supply irrigation water for this type and 

 this will no do'ubt be one of the last soils of the area to be completely 

 developed. 



The following table gives the average results of mechanical analy- 

 ses of the soil and subsoil of this type : 



Mechanical analifscs of Corning gravelly loam. 



TEHAMA GRAVELLY LOAM. 



The Tehama gravelW loam is a loam of medium texture, carries 

 varying quantities of waterworn gravel, coarse sand, and angular rock 

 fragments, and extends to a depth of from 18 to 72 inches. It varies 

 in color from a yellowish brown to a reddish gray and is always very 

 compact and hard upon drying, though easily tilled under proper 

 moisture conditions. The coarse material with which it is mingled 

 corresponds to the finer and medium-sized fragments of gravel, often 

 principally quartz, so prevalent in the Corning gravelly loam, and 

 the Redding gravelly sandy loam with which types the Tehama soil 

 is associated in origin and in position. In those instances where the 

 type is less than 6 feet deep, it is underlain by a compact clay loam 

 or clay similar to the subsoil of the Tehama silt loam. 



It occurs as numerous small bodies of elongated outline bordering 

 present intermittent streams or as terraces or benches along former 

 stream courses somewhat above existing drainage ways. In the lat- 

 ter position the bodies are sometimes slightly uneven from gentle 

 erosion. 



In elevation, age, and method of formation this type compares 

 Avith the Tehama silt loam, except that some of the bodies of Tehama 

 gravelly loam occur along present minor drainage w^ays and derive 

 the soil material as direct wash from the higher lying types of the 

 Corning and Redding series. Along such streams heading in and 

 having their short courses through the two latter series, the Tehama 

 gravelly loam occurs as level strips and gentle slopes of poorly de- 

 fined outline. It has the typical sparse grass vegetation of the series 

 and is likewise treeless. It is well drained. 



A few^ small bodies are farmed to grain, which practically consti- 

 tutes the agricultural use to which the soil is given. It is capable of 

 intensive development with irrigation, and while a great deal of it 

 lies surrounded by types of pooler soil there are bodies of sufficient 



