The sierra is the region of the Andes, and is about 250 m.
The last section through the Andes was finished in 1910.
Along the Brazilian frontier and about the sources of the Orinoco tributaries on the eastern slops of the Andes there are extensive forests, sometimes broken with grassy campos.
The principal silverproducing districts, the greater part on the high table-lands and slopes of the Andes, are those of Salpo, Hualgayoc, Huari, Huallanca, Huaylas, Huaraz, Recuay, Cajatambo, Yauli, Cerro de Pasco, Morococha, Huarochiri, Huancavelica, Quespisisa, Castrovirreyna, Lucanas, Lampa, Caylloma and Puno, but there are hundreds of others outside their limits.
Their advance to the south was checked by the indomitable opposition of the Araucanians, but from the southern Andes the Spaniards overflowed on to the great plains which now form the interior of the Argentine Republic. The first permanent settlement at the mouth of the river Plate at Buenos Aires dates from 1580.
