The Wullersdorf Association is extensive to the north of Tawau and it also occurs to the east of the Kalumpang estuary. It occurs on mountain ranges with prominent peaks including Magdalena, Lucia, Maria and Wullersdorf. The mountains are formed of a variety of parent materials broadly described as intermediate and acid igneous rocks. Paton (1963) describes soils on andesitic ashes, rhyolitic laves and dacitic lavas and ashes.