Much of the watershed consists of one canyon generally paralleling the crustal convergence of the Indian subcontinent and mainland Asia. When India collided with Asia approximately 50 million years ago, many geographical features in the region were forced upwards to great heights, forming such landmarks as the Himalayas, Qinghai Mountains, the Tibetan Plateau, and the eastern Burma massif. To date, India's plate has pushed the boundary of the original Asian continent nearly northwards. Evidence suggests that the southern Tibetan Plateau saw uplift as recently as 15-10 million years ago. The orogenic belt generally trends east to west near the northern part of the Subcontinent and makes a southward arc along with the Salween River on the eastern side. The upper course of the Salween flows through a region dominated by marine sedimentary rock that originally lay at the bottom of the Indian Ocean. This rock was uplifted to a height of thousands of metres by the India-Asia orogeny and is rapidly being eroded away by the Salween. Fault lines are strewn throughout the Salween basin, also generally following the pattern of the mountains and river.