18 



FIELD OPEEATIONS OF THE BUEEAU OF SOILS, 1907. 



The fine silty material in these depressions is formed by the ac- 

 cumulation of wash from the higher slopes. This phase of the Red- 

 ding gravelly loam is nearly or entireh^ barren, and is naturally 

 unproductive owing to poor drainage and unfavorable soil structure. 

 To make these depressions productive they must be drained and 

 the compact puddled condition of the soil alleviated by the addition 

 of large quantities of barnyard manure or other coarse organic 

 matter. In cases where the construction of drains is difficult or 

 impossible, blasting the underlying hardpan strata, as in setting 

 fruit trees, would probably promote percolation of the surface waters 

 and lead to a permanent improvement of the soil. 



The results of mechanical analyses of fine-earth samples of the soil 

 and subsoil are given in the following table: 



Mechanical analyses of Redding gravelly loam. 



REDDING LO.\M. 



The Redding loam is quite similar in texture and color to the Red- 

 ding gravelly loam, difl'ering mainly in depth to hardpan and in agri- 

 cultural importance. It consists typically of 8 inches to 12 inches 

 of light-red or reddish-gray loam, usually of fine and somewhat silty 

 texture, l)ut sometimes of light sandy character. It is sticky when 

 wet, somewhat compact in structure, and carries a moderate quantity 

 of small rounded pebbles. 



The surface soil is underlain by a heavy, compact, tenacious dark- 

 red clay loam, with little gravel, extending to a depth of 10 inches 

 to 3 feet. In eroded districts the subsoil may appear very close to 

 the surface. 



The subsoil is underlain by a clay or sand}^ clay hardpan, red or 

 yellowish gray in color, mottled with reddish yellow, or by a heavy 

 dark-red or yellow clay containing hardpan layers. The hardpan 

 may or may not contain cobbles or gravel, and is similar to that of the 

 Redding gravelly loam except that it is generally more dense and im- 

 pervious and usually nearer the surface, sometimes outcropping 

 where the surface soil has been eroded. 



The Redding loam occurs in a few moderately extensive bodies in 

 the southeastern .part of the area, and merges almost imperceptibly 

 into the adjacent bodies of the Redding gravelly loam or is separated 

 from the lower lying soils of the valley slopes and the stream bottoms 

 by bluff or terrace lines. The areas of this type occupy slightly slop- 



