Below the western foothills of the ranges, such as the Hsinchu Hills and the Miaoli Hills, lie raised terraces formed of material eroded from the ranges. These include the Linkou Plateau, the Taoyuan Plateau and the Dadu Plateau. About 23% of Taiwan's land area consists of fertile alluvial plains and basins watered by rivers running from the eastern mountains. Over half of this land lies in the Chianan Plain in southwest Taiwan, with lesser areas in the Pingtung Plain, Taichung Basin and Taipei Basin. The only sizable plain on the east coast is the Yilan Plain in the northeast.