Some distance farther down the whole bed of the river is narrowed by rocks which advance into it from both sides, and the stream flows rapidly through the Narrow of Baraguan, which is 1893 yards wide. From the junction of the Apure the course of the Orinoco lies cast ward to the point where it empties itself into the Atlantic Ocean. In this part of its course the navigation for boats is rendered dangerous by the floating rafts, which consist of forest-trees torn from their natural seat by the inundations of the river, and covered with aquatic plants; but vessels of 300 tons can ascend as high as the mouth of the Apure. Near the town of Angostura the river again runs between rocks for a short distance, but though in one place it is not more than 710 yards wide, this narrow (Angostura) may be passed without danger. Below Angostura vessels of considerable burden ascend the river with the trade-wind, which blows constantly from November to May; but the numerous sand-banks are dangerous when the water is low, especially after the mouth of January.
Several islands occur in the Orinoco below Angostura. They aro generally of moderate size, partly low and partly rocky. About 130 miles from its mouth the delta of the Orinoco begins. Tho river sends off to the north a branch which soon divides into a great number of other branches, all known by the general name of Baena Chicas (small mouths). They are all narrow when compared with the principal branch of the river, called Boca de Navies, but most of them are deep enough to admit vessels of considerable size. Of late these branches have been much frequented by smugglers, but they can only be navi gated under the guidance of the Indians who inhabit the islands of the delta, and who are well acquainted with the numerous channels which the river bas formed in the soft alluvial soil of the delta. The Bocas Chicas empty themselves partly into the Atlantio and partly into the Gulf of Paris, between the continent of South America and the island of Trinidad. Nine of them are rather large rivers : their names, enumerating them from east to west, aro—Cano de Laumn, Qum do Nuina, Cano Chico da Medusas, 'Calm Grande de Mariusas (navigable), Cano do Alaeareo (navigable), Cane de Cucnina (narrow, but deep), Cano de Pedernales (navigable), Cano de Manamo Chico, and Cano do Manaruo Grande. The three last mentioned fall into the Gulf of Paria. The Boca de Navies, or principal branch of the Orinoco, runs eastward to the ocean, and is divided for a distance of about 40 miles into two channels by a series of islands which lie nearly in the middle of the stream. These channels are known by the Indian names
of Zacupana and Imataca, and their eastern extremity is not quite 30 miles from Cape Barima, which is situated at the mouth of the river. Both are navigable, but that on the south, called the Channel of Imataca, though wider has less water; it is however commonly used by large vessels. Each of these two channels is more than 2 miles wide, and the whole width of the river, including the islands, con siderably exceeds 5 miles. From this point farther down the breadth continues to increase, and at the mouth, between Punta Barinia on the south and the island of Cangrejos on the north, it is more than 60 miles wide. The navigable channel, which lies in the middle, is crossed by a sand-bar with 17 feet of water, and in breadth varying from 24 miles to 3 miles or a little more. Within the bar the water deepens on the side of the island of Cangrejos to 4 and 5 fathoms, and the navigablo channel is more than 12 miles wide. Though no arms branch off from the Boca de Navios to this south, the low country which extends from the Punta Berlina to the mouth of the Essequibo River, and is watered by several small streams, is traversed by narrow natural canals called etabbos,' which generally lie parallel to the shores of the Atlantic, and connecting the small streams, constitute an internal water-communication for small boats between the Orinoco and Po me root: rivers.
The tributaries of the Orinoco are very numerous, and many of them have both a long course and a great volume of water. Those which join it on the left are navigable through nearly the srhole of their course, and are rarely impeded by rapids; but the rivers which fall into it on the right, originating on the elevated region of the Paritne Mountains, descend from them by numerous rapids and cata racts, so as to be, at least for a great part of their course, entirely unfit for navigation. We shall only mention a few of them.
The Onaviare rises near 3' N. 1st., in the declivities of the Femme de Somme Paz, a portion of the great chain of the Andes, brit the upper part of its course is not known. The lower course of the Gnaviare does not aeons to oppose arty obstacles to navigation, but as no European settlements have yet been established on the banks, it is only navigated by the native tribes. It falls into the Orinoco near 4' N. lat., after a course of more than 500 miles.