Peru

PERU, a republic on the Pacific coast of South America. It extends in a general south-easterly direction from 3° 16' S. to 18° S., with a sea-coast of more than 1,400 miles. Its area is estimated at 522,689 sq.m., an approximate figure, however, since much disputed territory is occupied by neighbouring States, with boundaries as yet undetermined.

Boundaries.

Beginning at the Estero de Machala on the Pacific (3° 16' S.), the boundary with Ecuador runs south to the Chira river, then east to the confluence of the Canchis and Chin chipe. So much is agreed upon. From the Chinchipe, pending settlement of the dispute with Ecuador, Peru still claims all the territory east of the cordillera as far north as the boundary which has now been established between Peru and Colombia. In a treaty of 1922, ratified by Colombia in 1925, and by Peru in 1927, those countries came to an agreement. Their common boundary now runs from the confluence of the Cuembi with the Putumayo down the Putumayo to the mouth of the Yahuas; thence by a straight line to the mouth of the Atacuari in the Amazon ; and from there down the main channel of the Amazon to the Brazilian boundary. By this treaty, the Apaporis-Tabatinga line, defined by treaty in 1851 as the boundary between Brazil and Peru, is now part of Colombia's boundary with Brazil. Furthermore, Colombia is given a corridor to the Amazon (the area between the Yahuas Atacuari and the Apaporis-Tabatinga line) and has been guaran teed freedom of navigation in perpetuity on that river. The Peruvian frontier from Tabatinga on the Amazon is fixed. It ascends the Yavari to its source, running south along the divide between tributaries of the Ucayali and those of the Yurua to 9° 24' 36" S., where it crosses the Yurua, thence to the Puras, which it crosses at the mouth of the Santa Rosa, running south, then east, to the source of the Acre and following it to the Yaverija. Boundaries between Brazil, Peru and Bolivia were defined in this region by the treaty of Sept. 8, 1909. From the junction of Acre and Yaverija the boundary runs south-east to the junction of the Heath with the Madre de Dios. It ascends the Heath in a southerly direction to its source, continuing by an irregular line to the shore line of Lake Titicaca, crossing the lake in a south easterly direction to the Desaguadero. From this point south to

the Chilean frontier the boundary between Peru and Bolivia is undemarcated. The de facto boundary with Chile is the Sama river in the department of Tacna. (See TACNA-ARICA.) Description.—Peru is traversed throughout its length by the Cordillera de los Andes, which runs roughly north-north-west and south-south-east, dividing the country longitudinally into three sharply contrasted regions: (I) coastal zone, 50-1 oo m. wide by over 1,400 m. long; (2) mountainous areas (sierra) consisting of stupendous chains commonly called cordilleras, high plateaux and deep, narrow valleys; (3) and beyond the sierra, heavily forested slopes which lead to the vast, low-lying Amazonian plains (mon tana). The coastal zone of hills and plains is crossed by about 5o intermittent streams. South of Punta Parifias it is a desert, ex cept for irrigated valleys. Imperceptibly this zone merges with the foot-hills and spurs of the cordillera. A transition zone, without clearly defined boundaries, is called Las Cabezas de los Valles (valley-heads), where, in steep-sided, dry, stony quebradas (gorges), the stream-beds narrow as they steepen. Most of the streams shrivel as they approach the coast, because of evapora tion and loss of water by irrigation.

The sierra extends from the lower limit of summer rains on the west to the upper limit of tropical forest on the east. It is approximately 200 m. wide at the south, and less than half that at the north. On the east is the Cordillera Oriental, on the west. the Cordillera Occidental, the continental divide. No other moun tains are continuously so lofty (some over 20,000 ft.) near a coast which drops off to such abyssal depths (20,00o ft.). The highest peaks are covered with perpetual snow. Wide undulating plateaux with a mean altitude of about 12,000 f t. between eastern and western cordilleras are called puna in the south, and jalca north of 8° S. Longitudinal valleys with their tributaries make a labyrinth of ramifying wild gorges on an immense scale.