 The Bhutanese foothills are separated from Precambrian crystalline rock by the 35 kilometer foreland, where rocks are fold and faulted newer tectonic events and covered in Quaternary sediments.The South Himalayan molasse is represented by the Siwalik Belt, with four kilometers of siltstone, sandstone and conglomerates in the southeast.The Damuda Belt dates to the Carboniferous and Permian in the Paleozoic with coal seams, plant remnants and lenses of much younger Eocene limestone included during the Himalayan orogeny.