In 1669 he published his Physica subterranea, and the same year was engaged with the count of Hanau in a scheme for settling a large territory between the Orinoco and the Amazon.
Of the Orinoco and Apure, with the Yuruari territory on the E., the Caroni river forming the boundary, and the Amazonas territory and Brazil on the S.
The capital is Ciudad Bolivar, formerly called Angostura, which is situated on the right bank of the Orinoco about 240 m.
Vessels of light draught easily ascend the Orinoco to this point, and a considerable trade is carried on, the exports being cocoa, sugar, cotton, hides, jerked beef and various forest products.
State of Venezuela, between the Caribbean Sea and the Orinoco river, bounded E.
Humboldt found it among the native tribes of the Orinoco valley, where it is called pirijao.
And N.; (2) the Orinoco basin with the llanos on its northern border and great forested areas in the S.
The sierra contains the water-parting between the basin of the Orinoco and those of the small rivers on the north-west.
It consists of two portions - a vast, hilly or mountainous area, densely wooded, in the south-east and south, and level plains in the north-west between the Orinoco and the Apure and the mountains.
The latter is known as the llanos of the Orinoco, a region described by Humboldt as a vast " sea of grass," with islands of wood scattered here and there.
From the Galera, the southernmost range of hills north of the Orinoco basin, the traveller saw a vast plain thickly grown with low trees.
Along the Brazilian frontier and about the sources of the Orinoco tributaries on the eastern slops of the Andes there are extensive forests, sometimes broken with grassy campos.
When the Orinoco is reached its lower basin is contracted between the Guiana highlands and the northern sierras, and its tributaries begin to come in more nearly at right angles, showing that the margins of the actual valley are nearer and higher.
The surface again rises into mountain ranges, which include the Parima and Pacaraima sierras on and adjacent to the Brazilian frontier, with a number of short spurs reaching northward toward the Orinoco, such as the Mapichi, Maraguaca, Maigualida, Matos, Rincote and Usupamo.
All this region belongs to the drainage basin of the Orinoco, and rivers of large volume flow down between these spurs.
Some of the culminating points in these ranges are the Cerros Yaparana (7175 ft.) and Duida (8120 ft.) in the Parima sierras near the upper Orinoco, the Sierra de Maraguaca (8228 ft.), and the celebrated flat-topped Mt Roraima (8530 ft.) in the Pacaraima sierras on the boundary line with Brazil and British Guiana.
Near the Orinoco the general elevation drops to about 1500 ft.
Probably not less than four-fifths of the territory of Venezuela belong to the drainage basin of the Orinoco (q.v.).
The Orinoco is supposed to have 436 tributaries, of which, among the largest, the Caroni-Paragua, Aro, Caura, Cuchivero, Suapure, Sipapo and Ventuari have their sources in the Guiana highlands; the Suata, Manapere and Guaritico in the northern sierras; and the Apure, Uricana, Arauca, Capanaparo, Meta, Vichada and Guaviare (the last three being Colombian rivers) in the llanos and Andes.
- Geologically Venezuela consists of three distinct regions: (1) South of the Orinoco a great mass of granite, gneiss, pyroxenite and other crystalline rocks, continuous with that of Guiana and probably of Archean age.
This mass also forms the bed of the Orinoco from its junction with the Apure nearly to its mouth, and it probably extends northwards for some distance beneath the more recent deposits of the plain.
The fauna and flora of Venezuela are similar in nearly all respects to those of the neighbouring regions of Guiana, Brazil and Colombia, the open llanos of the Orinoco being something of ' See G.
On the coast and in the Orinoco there may be found the manatee and the dolphin.
The coastal zone and lower slopes of all the mountains, including the lower Orinoco region and the Maracaibo basin, are clothed with a typical tropical vegetation.
One of the most remarkable palms of the Orinoco region is the " moriche " (Mauritia flexuosa).
A regular service is maintained on Lake Maracaibo, one on Lake Valencia, and another on the Orinoco, Apure and Portuguesa rivers, starting from Ciudad Bolivar.
The Orinoco trade is carried on almost wholly through Port of Spain, Trinidad, where merchandise and produce is transferred between light draught river boats and foreign ocean-going steamers.
The climatic conditions are not so favourable as in Argentina, but these are counterbalanced to some extent by the great river system of the Orinoco, whose large navigable tributaries cross the plains from end to end, and whose smaller streams from the surrounding highlands provide superior opportunities for water storage and irrigation.
The rubber forests are on the Orinoco and its tributaries of the Guiana highlands.
Of the principal mouth of the Orinoco and near the borders of British Guiana, where the famous El Callao mines are.
In 1901 there was one saladero, or meatpacking establishment, in the Orinoco-Apure region, but it did not.
These plains include the extensive llanos of the Orinoco tributaries where coarse, hardy grasses and occasional clumps of palms are almost the only vegetation to be seen.
Thence the line runs south and south-east along the Orinoco, Atabapo and Guainia to the Pedra de Cucuhy, which serves as a boundary mark for three republics.
Of the rivers of the great eastern plains, whose waters pass through the Orinoco and Amazon to the Atlantic, little can be said beyond the barest geographical description.
The largest of these rivers flow across the plains in an easterly direction, those of the Orinoco system inclining northward, and those of the Amazon system southward.
Farther north, on the open llanos of the Orinoco tributaries, the year is divided into equal parts, an alternating wet and dry season, the sun temperatures being high followed by cool nights, and the temperatures of the rainy season being even higher.
Lastly there are two species of true crocodiles in America, C. intermedius of the Orinoco, allied to the former, and C. americanus or acutus of the West Indies, Mexico, Central America to Venezuela and Ecuador; its characteristic feature is a median ridge or swelling on the snout, which is rather slender.
ORINOCO, a river in the north of South America, falling north-east into the Atlantic between 60° 20' and 62° 30' W.
In 1498, Columbus, when exploring the Gulf of Pal-la, which receives a large part of the outflow of the Orinoco, noted the freshness of its waters, but made no examination of their origin.
At the date of the discovery, the Orinoco, like the Amazon, bore different names, according to those of the tribes occupying its margins.
_ The principal affluent of the Orinoco from the Guiana district is the Ventuari, the head-waters of which are also unknown.
It is an important stream, which, running south-west, joins the Orinoco about 90 m.