North of the Mondego it includes Montemuro (4534 ft.), separating the Douro from the upper waters of its left-hand tributary the Paiva; Gralheira (3681 ft.) between the Paiva and the Vouga; the Serra do Caramullo (35 11 ft.), between the Vouga and the Dao; and the Serra da Lapa (3215 ft.), which gives rise to the Paiva, Tavora, Vouga and ado.