Ten leagues distant from Cape Barima, the great bed of the Orinoco is divided for the first time into two branches of two thousand toises in breadth. They are known by the Indian names of Zacupana and Imataca. The first, which is the northernmost, communicates on the west of the islands Congrejos and del Burro with the bocas chicas of Lauran, Nuina, and Mariusas. As the Isla del Burro disappears in the time of great inundations, it is unhappily not suited to fortifications. The southern bank of the brazo Imataca is cut by a labyrinth of little channels, into which the Rio Imataca and the Rio Aquire flow. A long series of little granitic hills rises in the fertile savannahs between the Imataca and the Cuyuni; it is a prolongation of the Cordilleras of Parima, which, bounding the horizon south of Angostura, forms the celebrated cataracts of the Rio Caroni, and approaches the Orinoco like a projecting cape near the little fort of Vieja Guyana. The populous missions of the Caribbee and Guiana Indians, governed by the Catalonian Capuchins, lie near the sources of the Imataca and the Aquire. The easternmost of these missions are those of Miamu, Camamu, and Palmar, situate in a hilly country, which extends towards Tupuquen, Santa Maria, and the Villa de Upata. Going up the Rio Aquire, and directing your course across the pastures towards the south, you reach the mission of Belem de Tumeremo, and thence the confluence of the Curumu with the Rio Cuyuni, where the Spanish post or destacamento de Cuyuni was formerly established. I enter into this topographical detail because the Rio Cuyuni, or Cuduvini, runs parallel to the Orinoco from west to east, through an extent of 2.5 or 3 degrees of longitude,* and furnishes an excellent natural boundary between the territory of Caracas and that of English Guiana. (* Including the Rio Juruam, one of the principal branches of the Cuyuni. The Dutch military post is five leagues west of the union of Cuyuni with the Essequibo, where the former river receives the Mazuruni.)