Swamp peat rests on a layer of soil; coal often rests on a rock layer. No swamp peat has been found partly formed into coal.
Bwawa la majani hukalia safu ya mchanga; makaa ya mawe mara nyingi hukalia safu ya mwamba. Hakuna bwawa la majani lililo patikana kufanyika nusu ya makaa ya mawe.