1919] 



Pendleton : A Study of Soil Types 



381 



In the Hanford, no. 14 is notably heavier than the others, as shown 

 by its silt content, which is nearly half again as great as that of the 

 next highest sample. 



The gravel content (sizes above 2 mm.) is interesting in its uni- 

 formity. In the San Joaquin soils the two samples above 1% are 



C\ay 0Z5 0.5 / 2. 4 8 16 32 64- Grits 



Size of Particles. mm 



Fig. 3. Graph showing the results of the Hilgard elutriator method of 

 mechanical analysis on the eight samples of San Joaquin sandy loam. 



nos. 11 and 26. The material in the latter soil is composed almost 

 wholly of iron concretions, leaving sample no. 11 as the only soil with 

 more than 1% actual gravel. In the Hanford samples none were 

 found to have more than 1.5% gravel. 



The Hilgard method does not include any precise subdivision of 

 the soils into groups or classes according to texture. Dr. Hilgard was 

 not in favor of making the fine distinctions in texture that other 



