The County’s soils can be categorized as laterite (55%), which is leached out, alluvial(19%) and sandy and loamy (26%). Alluvial soil is prevalent in the leeward districts. Two onshore sediment-filled basins are located along the coastline: Roberts Basin, which is filled with sediments of the Farmington River formation and Paynesville sandstone; and the Bassa Basin, which is filled with material from the St. John River formation.