Amazon Basin

“ We see a cluster of wonders, from the hot springs of Agua Caliente post-house to the frozen peaks of the Sorata; extremes of heat and cold, large mountains, and small streams, dry winds, and lakes of water, in the richest gold region of South America.
The Beni creeps along the ridge of mountains as though seeking an outlet to the north. A passage letting the water through into the Amazon basin at the base of the Andes would probably make the Beni a tributary of the Madre-de-Dios, as it is erroneously laid down on some maps. ”

“ The region of Mr. Lange's almost fatal experiences, the region of the Javary River (the boundary between Brazil and Peru) , is one of the most formidable and least known portions of the South American continent. It abounds with obstacles to exploration of the most overwhelming kind. Low, swampy, with a heavy rainfall, it is inundated annually, like most of the Amazon basin, and at time of high water the rivers know no limits. Lying, as it does, so near the equator, the heat is intense and constant, oppressive even to the native. ”

“ Large areas of these great river plains are annually flooded, the flood-plains of the Amazon extending nearly across the whole country and comprising thousands of square miles. The Amazon plain is heavily forested and has a slope of less than one inch to the mile within Brazilian territory—one competent authority placing it at about one-fifth of an inch per mile. The La Plata basin 440 is less heavily wooded, its surface more varied, and its Brazilian part stands at a much higher elevation. ”

“ While in area South America is ranked as smaller than North America, it may be a trifle larger in land surface, especially in habitable regions, if the opinion of Humboldt is correct that the Amazon Basin will one day support the densest population on the globe. ”

“ After such statements we are safe in affirming that the basin of the Amazon has none of the burning heats of countries like Asia and Africa, which are crossed by the same parallels.
The vast plain which serves for its valley is accessible over its whole extent to the generous breezes which come from off the Atlantic. ”

“ It rises on the Ecuadorian tableland, where a branch from the valley of Riobamba unites with one from the Latacunga basin and breaks through the inland range of the Andes; and joined, afterwards, by several important tributaries, finds its way south-east among the gorges; thence it turns southward into the plains, and enters the Amazon at a point about 60 m. west of the mouth of the Huallaga. So far as known, it is a stream of no value except for canoe navigation. Its rise and fall are rapid and uncertain, and it is shallow and full of sandbanks and snags. It is a terrible river when in flood. ”

“ To the beauties of this unrivaled river, which waters the finest country in the world, and keeps along its whole course at a few degrees to the south of the equator, there is to be added another quality, possessed by neither the Nile, the Mississippi, nor the Livingstone--or, in other words, the old Congo-Zaira-Lualaba--and that is (although some ill-informed travelers have stated to the contrary) that the Amazon crosses a most healthy part of South America. Its basin is constantly swept by westerly winds. ”

“ THE mightiest river in the world is the Amazon. It runs from west to east, from the sunset to the sunrise, from the Andes to the Atlantic. The main stream flows almost along the equator, while the basin which contains its affluents extends many degrees north and south of the equator. The gigantic equatorial river basin is filled with an immense forest, the largest in the world, with which no other forest can be compared save those of western Africa and Malaysia. ”

“ Natural resources:
bauxite, gold, iron ore, manganese, nickel, phosphates, platinum,
tin, uranium, petroleum, hydropower, timber
Land use: arable land: 6.3% permanent crops: 1.42% other: 92.28% (1998 est.)
Irrigated land:
26,560 sq km (1998 est.)
Natural hazards:
recurring droughts in northeast; floods and occasional frost in
south
Environment - current issues:
deforestation in Amazon Basin destroys the habitat and endangers a
multitude of plant and animal species indigenous to the area; there
is a lucrative illegal wildlife trade ”

“ Amazon, a river in S. America and the largest on the globe, its basin nearly equal in extent to the whole of Europe; traverses the continent at its greatest breadth, rises in the Andes about 50 m. from the Pacific, and after a course of 4000 m. falls by a delta into the Atlantic, its waters increased by an immense number of tributaries, 20 of which are above 1000 m. in length, one 2000 m., its mouth 200 m. wide; its current affects the ocean 150 m. out; is navigable 3000 m. up, and by steamers as far as the foot of the Andes. ”

“ South America is well nigh quartered by its river system: the Amazon starts within sixty miles of the Pacific; the Tapajos and Madeira reach down to the La Plata; while the Negro mingles its waters with those of the Orinoco. The tributaries also communicate with each other by intersecting canals, so numerous that central Amazonia is truly a cluster of islands. Wagons [Pg 276] and railroads will be out of the question for ages hence in this aquatic basin. No other river runs in so deep a channel to so great a distance. ”

“ It is reversing the natural order of things to give results without the investigations which have led to them; and I should not have introduced the subject here except to show that the fresh-water denudations and the oceanic encroachments which have formed the Amazonian Valley, with its river system, are not isolated facts, but that the process has been the same in both continents. The extraordinary continuity and uniformity of the Amazonian deposits are due to the immense size of the basin enclosed, and the identity of the materials contained in it. ”

“ All that we hear or read of the extent of the Amazons and its tributaries fails to give an idea of its immensity as a whole. One must float for months upon its surface, in order to understand how fully water has the mastery over land along its borders. Its watery labyrinth is rather a fresh-water ocean, cut up and divided by land, than a network of rivers. Indeed, this whole valley is an aquatic, not a terrestrial basin ”

“ A heavy precipitation on the windward side of a mountain range, by increasing the mechanical force of its drainage streams, makes them bite their way back into the heart of the system and decapitate the rivers on the leeward side, thus diminishing the volume of water left to irrigate the rainless slope. Thus the hydra-headed Amazon has been spreading and multiplying its sources among the Andean valleys, to the detriment of agriculture on the dry Pacific slope ”

“ The tide, however, does not flow up; there is only a rising and falling of the waters—the momentary check of the great river in its conflict with the ocean. The "bore," or piroróco, is a colossal wave at spring tide, rising suddenly along the whole width of the Amazon to a height of twelve or fifteen feet, and then collapsing with a frightful roar.
The Amazon presents an unparalleled extent of water communication. So many and far reaching are its tributaries, it touches every country on the continent except Chile and Patagonia. ”

“ And, finally, from Manaos to the sea it is the Amasenas, or river of the Amazons, a name given it by the old Spaniards, the descendants of the adventurous Orellana, whose vague but enthusiastic stories went to show that there existed a tribe of female warriors on the Rio Nhamunda, one of the middle-sized affluents of the great river.
From its commencement the Amazon is recognizable as destined to become a magnificent stream. There are neither rapids nor obstacles of any sort until it reaches a defile where its course is slightly narrowed between two picturesque and unequal precipices. ”

“ A great number of tributaries pour their waters into the Amazon in the lower part of its course. On the north side the first from the west, below the rapids of Manseriche, is the Morona, and then come in succession the Pastaça, Tigre, Napo, Iça, Yapurà, Rio Negro, and Oximina. From the south it receives, proceeding from west to east, the Huallaga, Ucayali, Yavari, Jutai, Jurua, Teffé, Coavy, Purus, Madera, Tapajos, Xingù, and Tocantins. Most of these affluents discharge their waters into the Amazon by more than one mouth, which frequently are widely apart. ”

“ Mention has been already made of this noble stream in the Hermit’s Story; but it is worthy of more particular notice, for truly the Amazon is in many respects a wonderful river. It is the largest, though not quite the longest, in the world. Taking its rise among the rocky solitudes of the great mountain range of the Andes, it flows through nearly four thousand miles of the continent in an easterly direction, trending northward towards its mouth, and entering the Atlantic Ocean on the northern coast of South America, directly under the Equator. ”

“ This resemblance has, no doubt, led to the identification of the Amazonian deposits with the more ancient formations of Europe. At Monte Alégre, of which I shall presently speak more in detail, such a clay bed divides the lower from the upper sandstone. The thickness of these sandstones is extremely variable. In the basin of the Amazons proper, they hardly rise anywhere above the level of high water during the rainy season; while at low water, in the summer months, they may be observed everywhere along the river-banks. ”

“ It would take many long years to make a thorough survey of the waters of the Amazon, which is, in fact, more of an inland sea than a river, with hundreds of branches forming a network of communicating channels extending for sixty or seventy miles on each side of the main stream. At the height of the annual floods the whole country, with the exception of the highest land, on which the towns are invariably built, is covered with water, forming a vast swamp and jungle, traversed in every direction by navigable channels, which at the season of low waters become rivers or natural canals. ”

“ Venezuela, Colombia, Ecuador, Peru, Bolivia, and Brazil, six mighty states, spreading over a country far larger than Europe, had each contributed to form the flood which bore us so peacefully on its bosom.
The most striking features of the Amazon are its vast 292 expanse of smooth water, generally from three to six miles wide; its pale, yellowish-olive colour; the great beds of aquatic grass which line its shores, large masses of which are often detached and form floating islands ”

“ At the commencement of this period, the greater portion of the valleys of the Amazon, Orinooko, and La Plata must have formed a part of the ocean, separating the groups of islands (which those elevated lands formed on their first appearance) from each other. The sediment carried down into this sea by the rapid streams, running down the sides of these mountains, would tend to fill up and level the deeper and more irregular depressions, forming those large tracts of alluvial deposits we now find in the midst of the granite districts. ”

“ Among the most important rivers having their source in the Montaña—generally 279in a ledge branching off from the foothills of the Andes, are the Yavary, Yuruá, Purús, and some tributaries of the Madeira River. The great waterways, with their affluents, form a network of communication in the Amazon country, and contribute greatly to the development of the rich resources of this vast zone, which is essentially tropical, yielding the valuable products of the rubber tree, the dyewoods, medicinal herbs and hardwoods of commerce, and other precious gifts of nature. ”

“ But the fact appears to be, that the tide never does flow up the river at all. The water of the Amazon rises, but during the flood as well as the ebb the current is running rapidly down. This takes place even at the very mouth of the river, for at the island of Mexiana, exposed to the open sea, the water is always quite fresh, and is used for drinking all the year round. But as salt water is heavier than fresh, it might flow up at the bottom, while the river continued to pour down above it ”

“ Owing to the lofty mountain range situated along its western margin, the moisture-laden trade winds from the Atlantic have free access to the interior. A sufficient proportion of this moisture reaches the higher slopes of the Andes, where its condensation gives rise to innumerable streams, which cut deep ravines and carry down such an amount of sediment, that they have formed the vast plains of the Amazon, of Paraguay, and of the Orinooko out of what were once, no doubt, arms of the sea, separating the large islands of Guiana, Brazil, and the Andes. ”

“ Of the history of the Amazonian Valley during the periods immediately following the Cretaceous, we know little or nothing. Whether the Tertiary deposits are hidden under the more modern ones, or whether they are wholly wanting, the basin having, perhaps, been raised above the sea-level before that time, or whether they have been swept away by the tremendous inundations in the valley, which have certainly destroyed a great part of the cretaceous deposit, they have never been observed in any part of the Amazonian basin. ”