Distinguishes Major

"Gelisols form under permafrost, Histosols contain accumulated organic matter, and Spodosols form through movement of organic matter and metals under acidic conditions. Andisols develop from volcanic ash, Oxisols and Ultisols are highly weathered, Vertisols contain shrink-swell clays, and Aridisols form in dry climates. Mollisols have dark, organic-rich surface horizons, Alfisols generally have clay-accumulation horizons and high base saturation, while Inceptisols and Entisols show weak or minimal development."