In breadth and depth the Maranon answers almost every where to its immense length, and it forms throughout its course, innumerable islands, especially between the mouths of the _Napo_ and the _Carori_, which are picturesque in the extreme, from the great variety of their figures, and from the beautiful straits they form between their banks. The depth of the branches formed by these islands, near St. Pablo, or St. Paul de Omaguas, the western Portuguese fort, on the frontiers of New Granada and Peru, is more than a mile. At Coari, where the groups of isles terminate for a short space, the river is nearly a mile and a half broad, and M. de la Condamine, after taking every precaution against the effect of the current, found no bottom with 100 fathoms of line; 400 miles below the mouth of the Negro, the shores of the Maranon approach each other, and this place is called the Straight of Pauxis; the breadth here is only a mile, and the tides are perceptible, though the ocean is still 200 leagues distant. Proceeding onward, with a majestic course, and forming numerous islands and straights, the river directs its course, after receiving the Zingu, towards the north-east, and enlarging its boundaries in the most astonishing manner, it runs, with accumulated force, to its final destination, forming, as it glides along, several very large insulated places; one of these dividing it at last into two mouths, by which it enters the Atlantic Ocean. This island, called Joanes, is 150 leagues in length, and from its Cape Maguari to Cape Norte, on the opposite continent, the largest of the two estuaries is forty-five leagues in breadth, whilst the lesser is twelve leagues broad, from the same Cape Maguari to Tigioca point, on the southern continent. The Maranon is subject to periodical floods during the rainy seasons, at which times it overflows, and fertilizes the country adjacent to its banks. The descent of this river in a straight course of 1860 miles, was found by M. de la Condamine, (who embarked on the Tunguragua and joined the Maranon) to be about 1020 feet, or rather more than six inches in a mile; and the place where the tides are first perceptible, is 90 feet above the level of the sea. Its banks are adorned with every variety of plants peculiar to tropical countries; immense and stately forests are every where observed, inhabited only by the wild animals, or by man in a state of nature. The settlements of the Portuguese, extend only a very short distance from the Atlantic, where they have here and there a fort, in the most open situations of the interior; the rest of the valley of the Amazons is in the possession of its ancient tenants.