MECHANICAL ANALYSIS OF SOIL. 41 



The relationship of the surface soil to subsoil in number 1 suggests 

 a residual decomposition. In soil number 2, the surface and subsoil are 

 quite similar, suggesting an alluvial deposit. jSTumber 3 shows a large 

 amount of silt which is apparently tuffaceous and number 4 is largely 

 marine sand. 



More than a suggestion of the relation that exists between the geology 

 of an area and the data of the mechanical analyses of its soils is not pos- 

 sible imless the geologic data are complete. 



