The city is situated in an elevated valley between the Central and Western Cordilleras, 9400 ft.
America down to the slopes of Chimborazo; the Cordilleras of the Andes separating the Castilloas from the Heveas of Brazil.
The region of the Cordilleras of the Andes is divided into Puna, or lofty uninhabited wilderness, and sierra, or inhabitable moun- Sierra.
This great mountain-system, running south-east to north-west, consists of three chains or cordilleras.
The great rivers of the sierra are the Maranon, rising in the lake of Lauricocha and flowing northward in a deep gorge between the Maritime and Central Cordilleras for 350 m., when it forces its way through the mountains at the famous Pongo de Manseriche and enters the Amazonian plain.