Peninsular Malaysia covers the southern half of the Malay Peninsula, and extends from north to south, and its maximum width is . It is mountainous, with more than half of it over above sea level. About half of Peninsular Malaysia is covered by granite and other igneous rocks, a third more is covered by stratified rocks older than the granite, and the remainder is covered by alluvium.Encyclopædia Britannica. The Land (West Malaysia).
