 Fluvial action by the Krishna, Bhima, Godavari, Tapi-Purna and Wardha-Wainganga river systems has further aided in the compartmentalisation of the Desh into broad, open river valleys, alternating with plateau interfluves, that form the ribs of the Sahyadrian backbone.In sharp contrast, the hill torrents of the Konkan, barely a 100 km long, tumble down as roaring streams which flow in deeply entrenched valleys to terminate in tidal estuaries.Apart from mainly occurring rock Basalt; other rocks like- Laterites are found in coastal humid and tropical region.