The metamorphic rocks compose the main mass of the tableland, and are exposed in every deep valley in Tigre and along the valley of the Blue Nile.
There is also a dockyard and torpedo arsenal at La Plata, an artillery depot at Zarate, above Buenos Aires, and naval depots on the island of Martin Garcia and at Tigre, on the Lujan river.
The rivers forming this system are the Maranon from Puerto Limon to Tabatinga on the Brazilian frontier (484 m.), the Japura, Putumayo, Javary, Napo, Tigre, Huallaga, Ucayali, Pachitea, Jurua, Purus, Acre, Curaray and Aguarico all navigable over parts of their courses for steamers of 4 to 8 f t.
'AXUM, or Aksum, an ancient city in the province of Tigre, Abyssinia (14° 7 52" N., 38° 31' 10" E.; altitude, 7226 ft.), 12 M.
Of native churches there are two forms - one square or oblong, found in Tigre; the other circular, found in Amhara and Shoa.