Table 3. Grain-size scales--soil classification (modified from U.S. Army 

 Corps of Engineers, Coastal Engineering Research Center, 1977). 



Unified Soils 

 Classification 



COBBLE 



/>, 



W////Mm^^^^ 



CLAY 



ASTM 

 Mesh 



mm 

 Size 



Phi 

 Value 



Wentworth 

 Classification 



256.0: -8.0 



BOULDER 



COBBLE 



d%^k;.::^o;t)039 s.o ZI^ ^ 



'' ;d:0024 12.0 / 



CLAY 

 COLLOID 



33 



