The two peninsular rivers that flow through trough valleys are the Narmada River and the Tapi (or Tapti) River. These rivers flow through rift valleys or troughs formed due to tectonic movements, flowing westward into the Arabian Sea, which is unusual compared to most peninsular rivers that flow eastward into the Bay of Bengal. Both the Narmada and Tapi originate in central India, flowing through distinct troughs between mountain ranges such as the Vindhyas and Satpuras (for Narmada) and the Satpura range for Tapi.