touches that of every South American nation, except Chile, and with each one there has been a boundary dispute at some stage in its political life. The Spanish and Portuguese crowns attempted to define the limits between their American colonies in 1750 and 1777, and the lines adopted still serve in great part to separate Brazil from its neighbours. Lack of information regarding the geographical features of the interior, however, led to some indefinite descriptions, and these have been fruitful sources of dispute ever since. The Portuguese were persistent trespassers in early colonial times, and their land-hunger took them far beyond the limits fixed by Pope Alexander VI. In the boundary disputes which have followed, Brazil seems to have pursued this traditional policy, and generally with success.
Beginning at the mouth of the Arroyo del Chuy, at the southern extremity of a long sandbank separating Lake Mirim from the Atlantic (33°45′ S. lat.), the boundary line between Brazil and Uruguay passes up that rivulet and across to the most southerly tributary of Lake Mirim, thence down the western shore of that lake to the Jaguarão and up that river to its most southerly source. The line then crosses to the hill-range called Cuchilla de Sant’ Anna, which is followed in a north-west direction to the source of the Cuareim, or Quarahy, this river becoming the boundary down to the Uruguay. This line was fixed by the treaty of 1851, by which the control of Lake Mirim remains with Brazil. Beginning at the mouth of the Quarahy, the boundary line between Brazil and Argentina ascends the Uruguay, crosses to the source of the Santo Antonio, and descends that small stream and the Iguassú to the Paraná, where it terminates. This line was defined by the treaty of 1857, and by the decision of President Cleveland in 1895 with regard to the small section between the Uruguay and Iguassú rivers. The boundary with Paraguay was definitely settled in 1872. It ascends the Paraná to the great falls of Guayrá, or Sete Quedas, and thence westward along the water-parting of the Sierra de Maracayú to the cerro of that name, thence northerly along the Sierra d’Amambay to the source of the Estrella, a small tributary of the Apá, and thence down those two streams to the Paraguay. From this point the line ascends the Paraguay to the mouth of the Rio Negro, the outlet of the Bahia Negra, where the Bolivian boundary begins. As regards the Peruvian boundary, an agreement was reached in 1904 to submit the dispute to the arbitration of the president of Argentina in case further efforts to reach an amicable settlement failed. The provisional line, representing the Brazilian claim, begins at the termination of the Bolivian section (the intersection of the 11th parallel with the meridian of 72° 26′ W. approx.) and follows a semicircular direction north-west and north to the source of the Javary (or Yavary), to include the basins of the Purús and Juruá within Brazilian jurisdiction. The line follows the Javary to its junction with the Amazon, and runs thence north by east direct to the mouth of the Apaporis, a tributary of the Yapurá, in about 1° 30′ S. lat., 69° 20′ W. long., where the Peruvian section ends. The whole of this line, however, was subject to future adjustments, Peru claiming all that part of the Amazon valley extending eastward to the Madeira and lying between the Beni and the east and west boundary line agreed upon by Spain and Portugal in 1750 and 1777, which is near the 7th parallel. With regard to the section between the Amazon and the Apaporis river, already settled between Brazil and Peru, the territory has been in protracted dispute between Peru, Ecuador and Colombia; but a treaty of limits between Brazil and Ecuador was signed in 1901 and promulgated in 1905. The boundary with Colombia, fixed by treaty of April 24, 1907, follows the lower rim of the Amazon basin, as defined by Brazil. The Colombian claim included the left bank of the Amazon eastward to the Auahy or Avahy-paraná channel between the Amazon and Yapurá, whence the line ran northward to the Negro near the intersection of the 66th meridian. The Brazilian line ran north and north-west from the mouth of the Apaporis to the 70th meridian, which was followed to the water-parting south of the Uaupés basin, thence north-east to the Uaupés river, which was crossed close to the 69th meridian, thence easterly along the Serra Tunaji and Isana river to Cuyari, thence northerly up the Cuyari and one of its small tributaries to the Serra Capparro, and thence east and south-east along this range to the Cucuhy rock (Pedra de Cucuhy) on the left bank of the Negro, where the Colombian section ends. Negotiations for the settlement of this controversy, which involved fully one-third of the state of Amazonas, were broken off in 1870, but were resumed in 1905. The boundary with Venezuela, which was defined by a treaty of 1859, runs south-eastward from Cucuhy across a level country intersected by rivers and channels tributary to both the Negro and Orinoco, to the Serra Cupuy watershed which separates the rivers of the Amazon and Orinoco valleys. This watershed includes the ranges running eastward and northward under the names of Imeri, Tapiira-peco, Curupira, Parima and Pacaraima, the Venezuelan section terminating at Mt. Roraima. On the 9th of December 1905 protocols were signed at Caracas accepting the line between Cucuhy and the Serra Cupuy located in 1880, and referring the remainder, which had been located by a Brazilian commission in 1882 and 1884, to a mixed commission for verification.
The disputed boundary between Brazil and British Guiana, which involved the possession of a territory having an estimated area of 12,741 sq. m., was settled by arbitration in 1904 with the king of Italy as arbitrator, the award being a compromise division by which Great Britain received about 7336 sq. m. and Brazil about 5405. The definite boundary line starts from Mt. Roraima and follows the water-parting east and south to the source of the Ireng or Mahu river, which with the Takutú forms the boundary as far south as 1° N. to enclose the basin of the Essequibo and its tributaries, thence it turns east and north of east along the Serra Acaria to unite with the unsettled boundary line of Dutch Guiana near the intersection of the 2nd parallel north with the 56th meridian. Negotiations were initiated in 1905 for the definite location of the boundary with Dutch Guiana. Running north-east and south-east to enclose the sources of the Rio Paru, it unites with the French Guiana line at 2° 10′ N., 55° W., and thence runs easterly along the water-parting of the Serra Tumuc-Humac to the source of the Oyapok, which river is the divisional line to the Atlantic coast. The boundary with French Guiana (see Guiana), which had long been a subject of dispute, was settled by arbitration in 1900, the award being rendered by the government of Switzerland. The area of the disputed territory was about 34,750 sq. m.
Physical Geography.—A relief map of Brazil shows two very irregular divisions of surface: the great river basins, or plains, of the Amazon-Tocantins and La Plata, which are practically connected by low elevations in Bolivia, and a huge, shapeless mass of highlands filling the eastern projection of the continent and extending southward to the plains of Rio Grande do Sul and westward to the Bolivian frontier. Besides these there are a narrow coastal plain, the low plains of Rio Grande do Sul, and the Guiana highlands on the northern slope of the Amazon basin below the Rio Negro.
The coastal plain consists in great part of sandy beaches, detritus formations, and partially submerged areas caused by uplifted beaches and obstructed river channels. Mangrove swamps, lagoons and marshes, with inland canals following the coast line for long distances, are characteristic features of a large Relief. extent of the Brazilian coast. Parts of this coastal plain, however, have an elevation of 100 to 200 ft., are rolling and fertile in character, and terminate on the coast in a line of bluffs. In the larger depressions, like that of the Reconcavo of Bahia, there are large alluvial areas celebrated for their fertility. This plain is of varying width, and on some parts of the coast it disappears altogether. In Rio Grande do Sul, where two large lakes have been created by uplifted sand beaches, the coastal plain widens greatly, and is merged in an extensive open, rolling grassy plain, traversed by ridges of low hills (cuchillas), similar to the neighbouring republic of Uruguay. The western part of this plain is drained by the Uruguay and its tributaries, which places it within the river Plate (La Plata) basin.
The two great river basins of the Amazon-Tocantins and La Plata comprise within themselves, approximately, three-fifths of the total area of Brazil. Large areas of these great river plains are annually flooded, the flood-plains of the Amazon extending nearly across the whole country and comprising thousands of square miles. The Amazon plain is heavily forested and has a slope of less than one inch to the mile within Brazilian territory—one competent authority placing it at about one-fifth of an inch per mile. The La Plata basin