Table 1: Descriptive terminology modified from Krumbein and Pettijohn [19].

Sorting Skewness Kurtosis

Very well sorted<0.35Very fine skewed>+1.30Very platykurtic<1.70
Well sorted0.35–0.50Fine skewed+0.43 to +1.30Platykurtic1.70–2.55
Moderately well sorted0.50–0.70Symmetrical−0.43 to +0.43Mesokurtic2.55–3.70
Moderately sorted0.70–1.00Coarse skewed−0.43 to −1.30Leptokurtic3.70–7.40
Poorly sorted1.00–2.00Very coarse skewed<−1.30Very leptokurtic>7.40
Very poorly sorted2.00–4.00
Extremely poorly sorted>4.00