The northern and eastern portions of Mewar are made up of an elevated plateau while the western and southern portions were rocky and hilly with dense forests. The watershed divide between drainage of the Bay of Bengal and drainage of the Gulf of Khambhat runs almost through the centre of Mewar. The northern and eastern part of Mewar is a gently sloping plain, drained by the Bedach and Banas River and its tributaries, which empty northwest into the Chambal River, a tributary of the Yamuna River. The southern and western part of the region is hilly, and marks the divide between the Banas and its tributaries and the headwaters of the Sabarmati and Mahi rivers and their tributaries, which drain south into the Gulf of Khambhat through Gujarat state. The Aravalli Range, which forms the northwestern boundary of the region, is composed mostly of sedimentary rocks, like marble and Kota Stone, which has traditionally been an important construction material.