Andhra Pradesh has varied topography ranging from the hills of Eastern Ghats and Nallamala Hills to the shores of Bay of Bengal that supports varied ecosystems, the rich diversity of flora and fauna. There are two main rivers namely, Krishna and Godavari, that flow through the state. The seacoast of the state extends along the Bay of Bengal from Srikakulam to Nellore district. The plains to the east of Eastern Ghats form the Eastern coastal plains. The coastal plains are for the most part of delta regions formed by the Godavari, Krishna, and Penner Rivers. The Eastern Ghats are discontinuous and individual sections have local names. The Eastern Ghats are a major dividing line in the state's geography. The Kadapa Basin[better source needed] formed by two arching branches of the Eastern Ghats is a mineral-rich area. The Ghats become more pronounced towards the south and extreme north of the coast. Most of the coastal plains are put to intense agricultural use. The Rayalaseema region has semi-arid conditions.