228 University of California Publications in Agricultural Sciences [Vol. 1 



The soil from Springville in the delta of Santa Clara River 

 is not so rich in humus as its dark color would lead one to 

 suppose, and the entire column of eight feet is quite light though 

 the land is highly productive. A soil from near Oxnard pre- 

 viously examined was found to contain as much as 1.60 per cent 

 of humus, and it would seem that the great body of land farther 

 out in the valley is richer than that near the hills. An inter- 

 esting example of the penetration of plant roots and their 

 humification in a sandy soil is seen in the column from the hill- 

 side slope north of Camarillo station in Pleasant Valley. It is 

 interesting to note that this soil in the three upper feet has the 

 same percentage as that of the Springville column, although so 

 different in color and texture. 



San Fernando Valley. — The valley of San Fernando lies north 

 of Los Angeles and includes about two hundred square miles. 

 ]Much of the valley on the east is covered by debris of cobble- 

 stones, gravel, and sand washed from the caiions on the northeast, 



Table 29. — Humus in Soil Columns of San Fernando Valley, 



Los Angeles County 



Range of most annual plant roots. 



