Natural gas is obtained along with oil in all oil fields but exclusive reserves have been located along the eastern coast as well as Tamil Nadu, Orissa, Andhra Pradesh, Tripura, Rajasthan and off-shore wells in Gujarat and Maharashtra — not Gondwana beds. Crude petroleum occurs in sedimentary rocks of the tertiary period — not Dharwars (which are igneous/metamorphic). Kodarma (Jharkhand) is indeed famous for mica.