APPENDIX B: DEFINITIONS AND PHYSICAL VALUES FOR FIELD 

 QUANTIFICATION OF %COBBLES AND STRUCTURAL PED SIZE 

 (FROM FOSBERG AND FALEN 1983) 



Cobbles - Rock fragments of rounded, subrounded angular or irregular shape. Size range of 7.6 to 25 cm 

 (3 to 10 in) diameter. 



%Cobbles - Visual estimate of percent of soil volume occupied by rock fragments of cobble size class. 



Structural Red Size - all ped shapes should be measured by the size classes for angular and sub- 

 angular blocky structure. 



Size Diameter Size Diameter 



Class Class 



1 <5 mm 4 20 to 50 mm 



2 



5 to 10 mm 



3 



10 to 20 mm 



16 



