Plate 4. Conversion nomograms for percentage sand (A) from the ISSS to USDA and (B) from the USDA to ISSS systems. For each texture triangle, the dashed lines are the percentage sand being converted, and the solid lines represent values after conversion. Conversion of percentage sand from the ISSS to USDA system is independent of the clay content of a sample, thus the dashed lines in (A) are linear. Because conversion of percentage sand from the USDA to ISSS system is a function of clay content, the dashed lines in (B) are curved and concentrated together at low percentage clay values
