High Quality Content by WIKIPEDIA articles! A Regosol in the FAO World Reference Base for Soil Resources is very weakly developed mineral soil in unconsolidated materials. Regosols are extensive in eroding lands, in particular in arid and semi-arid areas and in mountain regions. Internationally, Regosols correlate with soil taxa that are marked by incipient soil formation such as Entisols in the USDA soil taxonomy or skeletal soils in the Australian soil classification.