The extent of Maynas cannot be computed, as the greater part of it consists of the immense forests of the vale of the Amazons.
Its capital is St. Francisco de Borja, or Borja, in 4° 28ʹ south latitude, and 76° 24ʹ west longitude. The inhabitants are not numerous, being mostly creoles and Indians; but the governor resides here, who is styled governor of Maynas and Maranon. The western district of Maynas contains, besides the city of Borja, the town of Santiago de la Laguna or Cocamas on the eastern bank of the river Guallaga. This is the seat of the superior of the missions, which are spread among the Cocames, the Maynas, Xibaros, Panos, Omaguas, Chamicuros, Aguanos, Muniches, Otanabes, Roamaynas, Gaes, Napeanos, Yurimaguas, and several other Indian tribes. On the river Napo these missionaries have twelve villages, and on the False and True Maranon, as far as the Rio Negro, upwards of twenty-four, with many infant settlements. In the interior, and on the banks of other rivers which flow into the Maranon, they have also many populous and flourishing places, among various tribes of Indians, but most of which are little known.
All these nations of Indians have a great affinity to each other in appearance and manners, but their languages differ as much as those of the northern continent; many of them have also very singular customs; the Omaguas flattening the heads of their infants, by compressing them constantly between boards, and fancying that this gives them a very beautiful appearance; these people were converted by father Fritz, in 1686.
Other tribes bore holes in the septum of the nose, in the lips, or in their chins, sticking in these fine feathers or other ornaments, whilst some extend the lobes of their ears, by constantly hanging weights to them, till they descend to the shoulders.
Maynas is chiefly remarkable as being the country which was supposed to contain such invaluable forests of cinnamon, that the brother of Pizarro nearly lost his life in endeavouring to find it. This exploratory march of the governor of Quito led to the discovery of one of the finest rivers in the world; a part of which traverses this district.
The river Maranon rises in the southern Andes of Peru, and if its length is estimated from its known parts only, to the Atlantic, it rolls its waters through a space equal to 4500 miles, and it is said that a vessel of 4 or 500 tons, might actually navigate it throughout this immense extent. It receives on every side along its majestic course, streams which are themselves longer and deeper than most of the great rivers of Europe; the Beni, the Lauricocha or Tunguragua, the Madera or Llavari, and the Negro, are all of this description; besides which, as a late traveller in Brazil has observed, it may be said to receive thousands of others into its bosom. Near its supposed sources, this noble stream, or rather inland sea, is called the Apurimac, and rises to the south of the mountains of Cailloma, between 16 and 17 degrees of south latitude, near the city of Arequipa, where it is joined by the Monigote or Panguana, and is so deep that on entering the province of Canes, a rope bridge becomes necessary. Eight miles below this bridge it passes through the Andes, amid awful precipices, and is joined by the Pampas or Charcas in 13° 10ʹ south latitude from the west. The Vilcamayo, nearly equal in size to the Apurimac, falls into it, at 12° 15ʹ south latitude, and the Rio Jauja, or Mantaro in 12° 6ʹ south latitude. At the junction of this stream with the Apurimac, the current which had before run from north-west, changes to the north-east. The Perene at 11° 13ʹ, and the Ynambari, or Paucartambo, at 10° 45ʹ, augment its swelling waters, after which, from hence to 8° 26ʹ south latitude, it receives forty large streams; but none so considerable as the Beni, whose sources lie in the province of Sicasica, in 19° south latitude. At its confluence with this river, the Apurimac is called the Grand Para, and is two miles in width; and at 8° 26ʹ south latitude; the Pachitea throws in its tributary waters.
Northward of this last the Piachiz joins it, and here the river changes from north to north-east. At 7° 35ʹ south latitude, the Aguaytra falls into it, and in 7° south latitude, the Manoa or Cuxniabatay, the Sariacu at 6° 45ʹ south latitude, and the Tapichi at 5° south latitude. The stream has now borne for some time the name of Ucayale, and proceeding under this appellation, with an immense volume, it receives at 4° 55ʹ south latitude, the Tunguragua, Lauricocha, or False Maranon. It now divides into three branches, the largest of which is 55 fathoms in depth, and turns directly to the east. Before describing its farther progress, it is necessary to say that some authors have doubted whether the Beni is not the true Maranon, as its sources are farther south than those of the Apurimac; and it is of such force, and has such an immense width on its junction with that river, that it actually drives the Apurimac towards the west for some distance.
The Tunguragua was formerly considered to be the Real Amazons, but that opinion is now quite exploded; it rises in the province of Tarma in Peru, in the lake Lauricocha, near the city of Guanuco, in 11° south latitude, and flows through Peru to Bracamoros, where passing by Jaen, it turns to the east, and pours itself, after intersecting the Andes at the Pongo de Manseriche into the Maranon by an immense mouth, below the village of St. Regis.
The Tunguragua receives many large tributary streams, in the kingdom of Peru, one of which, the Guallaga, rising in the southern Andes, east of Guamanga, is at its conflux with the Lauricocha, 450 yards wide, and thirty-four fathoms deep.
The Ucayale, or True Maranon, is navigable at all seasons; it was explored in 1794 by father Girval, who ascended it from St. Regis to the river Pachitea, and found its current gentle, abounding with fish, and its banks crowned with superb forests stored with wild animals. The native tribes on its shores were generally of a pacific nature, and in the course of 300 leagues he found 132 islands.