According to the Theory of Plate Tectonics, the Earth’s crust was initially a single, giant super-continent called Pangea. Its northern part was the Angara land and the southern part was the Gondwana land. The movement of the molten material below the Earth’s crust caused the crust or the lithosphere to break up into a number of large fragments called lithospheric or tectonic plates. Another important feature of the Earth’s crust at the time was the geosyncline—a narrow, shallow, elongated basin with a sinking bottom in which a considerable thickness of sediments were deposited by the rivers coming from Angara land and Gondwana land—called the Tethys. After separating from the Gondwana land, the Indo-Australian Plate drifted towards the north in the direction of the Eurasian Plate. This resulted in the collision of the two plates, and due to this collision, the sedimentary rocks in the Tethys got folded to form the mountain system of western Asia and the Himalayas.