Basin (geography)

“ Now suppose the water basins which hold the lakes to be over a thousand fathoms (six thousand feet) deep. We know they are not more than four hundred and twenty feet deep; but suppose them to be six thousand feet deep. The process of evaporation, after the St. Lawrence has gone dry, might go on until one or two thousand feet or more were lost from the surface, and we should then have another instance of the level of an island water-basin being far below the sea-level, as in the case of the Dead Sea; or it would become a rainless district, when the lakes themselves would go dry. ”

“ The number of tributaries is uncommonly large, the area drained is increased about 9855 miles beyond that of the Vistula; and the entire basin (88,257 square miles) is one which has been of the greatest import in the history of all central Europe.
All the rivers and all the terrace lands of the globe exhibit the same relation which we have been briefly indicating [172] in a few European ones; in some of the great rivers of the world they are to be traced on a scale of grandeur of which in those which have been touched upon scarcely a suggestion is given. ”

“ Another class of lake basins occurs in valleys, the basins being partly rock and partly drift. If a thick deposit of drift be made at one point in a valley, while above there is little or none, the thick deposit will form a dam, above which waters may accumulate, forming a pond or lake. Again, a ridge of drift may be deposited in the form of a curve with its ends against a rock-ridge, thus giving rise to a basin. ”

“ Where sea and river meet, Nature draws no sharp dividing line. Here the indeterminate boundary zone is conspicuous. The fresh water stream merges into brackish estuary, estuary into saltier inlet and inlet into briny ocean. Closely confined sea basins like the Black and Baltic, located in cool regions of slight evaporation and fed from a large catchment basin, approach in their reduced salinity the fresh water lakes and coastal lagoons in which rivers stretch out to rest on their way to the ocean. ”

“ To acquire just conceptions of the topographic and other characteristics of the several regions of mild relief which make up the Continental basin is a difficult task, as each one is of great extent and possesses many peculiarities of its own, and besides, in two separate regions, each embracing many hundreds of square miles, movements in the earth's crust have occurred of such a nature as to elevate the rocks and give them the general structure commonly found in mountain ranges. ”

“ The most conspicuous topographic features of the better known portion of the Great Basin are long, narrow, and frequently sharp-crested ridges, with a gentle slope on one side and a steep escarpment on the other. The steeper side in a large number of instances is known to be the upraised side of a fault. Each of these basin ranges, as they are termed, may be considered as the upturned edge of a block of the earth's crust, in general from 60 to 100 or more miles long, and 10 to perhaps 20 miles wide. ”

“ What we see immediately before us is a basin, it may be a quarter of a mile, it may be half a mile broad, and two miles long; a wild expanse of broken granite rocks and boulders strewn hap-hazard, some of them showing the red of the syenite and others black and polished and shining in the sun; a field of rocks, none of them high, of fantastic shapes; and through this field the river breaks in a hundred twisting passages and chutes, all apparently small, but the water in them is foaming and leaping and flashing white; and the air begins to be pervaded by the multitudinous roar of rapids. ”

“ The “Basin” is a basin only in the sense that it is all lower than the ranges enclosing it—the Mogollon, the Matitzal and the Sierra Ancha—but its whole triangular area is so cut up by ravines, arroyos, small stream beds and hills of very good height, that it may safely be pronounced one of the roughest spots on the globe. ”

“ Turning now to the question of how lake basins are formed, we note a great variety in the conditions which may bring about their construction. The greatest agent, or at least that which operates in the construction of the largest basins, are the irregular movements of the earth, due to the mountain-building forces. Where this work goes on on a large scale, basin-shaped depressions are inevitably formed. If all those which have existed remained, the large part of the lands would be covered by them. ”

“ Between the watersheds are hundreds2 of little streams and rivers. To get from the basin of one stream to that of another is so difficult, except along the coast, that each basin forms, as it were, a little world in itself. ”

“ The basin type of topography calls into existence a set of relations quite distinct from either of those we have just described. Figure 34 represents the main facts. The rich and comparatively flat floor of the basin supports most of the people. ”

“ When we first approached this valley, there was not a man upon the face of the earth who ever had beheld these valleys of the mountains, or knew anything of the Great Basin, who knew that corn, or any other kind of grain could be raised here. ”

“ If a lake, for example, be encircled on two sides by lofty mountains, receiving from them many rivers and torrents of different sizes, and if it be bounded on the other sides, where the surplus waters issue, by a comparatively low country, it is not difficult to define some of the leading geological features which must characterize the lacustrine formation, when this basin shall have been gradually converted into dry land by the influx of sediment. ”

“ In all the valleys throughout the Great Basin are to be seen traces of water, and on the sides of the hills water-marks have been left that are visible at the distance of a mile, and can be traced for many miles. ”

“ FIG. 45.—FREIGHTING BORAX ACROSS THE DESERT The slow crumbling of the rocks, and the setting free of those constituents which are soluble, the work of the streams in gathering the rock waste into the lakes, the dry air and the heat of the long summer days, have all conspired together to give us these valuable deposits in the dried-up lakes of the Great Basin.
No portion of the earth seems to be without value to man. The great bodies of water are convenient highways. The rich valleys and timbered mountains offer useful products. ”

“ The hills rise abruptly; those we examined are of sandstone formation. The basin is very shoal, but there is a narrow channel in the centre, with from five to nine fathoms water. The shore, opposite the Bastion Hills, is low, and the gulf trends gradually round to the South-West for five miles, when it is contracted into a narrow communication, called The Gut, leading to an interior shoal basin, strewed with low marshy islands, which the tide covers. ”

“ The crossing of the Great Basin was dreaded by the early emigrants on their way to the Pacific coast. In many cases the locations of the few springs and water-courses were unknown, and the journey over the vast barren stretches was fraught with danger.
Stand upon a mountain in the desert some clear day in summer and you will see range after range, with intervening sandy wastes, stretching away to the horizon. The air below is tremulous with heat, and every living thing that can move has sought the shade of some rock or cliff. ”

“ This is the case with the Tay, Forth, Tweed, Tyne, Humber and Thames, the Clyde and Severn being the most remarkable exceptions to this direction. The whole extent of country from which a river receives its supply of water, by brooks and rivulets, is termed its basin, because a region generally bounded by a rim of high lands, beyond which the waters are drained off into another channel. The basin of a superior river includes those of all its tributary streams. ”

“ This Great Basin is yet to be adequately explored. And here, on quitting the banks of a sterile river, to enter on arable mountains, the remark may be made, that, on this western slope of our continent, the usual order or distribution of good and bad soil is often reversed; the river and creek bottoms being often sterile, and darkened with the gloomy and barren artemisia; while the mountain is often fertile, and covered with rich grass, pleasant to the eye, and good for flocks and herds. ”

“ OF the many characteristic features of the arid region of the far West known as the Great Basin, none attract the attention of the traveler more forcibly than the desert mud-plains that have been left by the evaporation of former lakes. ”

“ Thus a small rapid stream with abundance of loose transportable material within its reach may fill up an extensive basin in a few centuries, while a large perennial trunk stream, flowing over clean, enduring pavements, though ordinarily a hundred times larger, may not fill a smaller basin in thousands of years. ”

“ The water is agitated in the basin, it boils up suddenly, subsides, the earth beneath our feet trembles and a mass of steaming water rises in the center of the basin to an elevation of fifteen feet and overflows the rim with a noisy splash. ”

“ Guided by the principle that great oceanic basins are to be considered rather as original marine areas that have been limited by the elevation of their boundaries, than as having been formed by the excavation of terrestrial areas, we have to inquire what evidence there is that the basin of the Atlantic has undergone any considerable change within a compara tively recent period. ”

“ A simple continental structure gives to those movements a few simple features and a wide monotonous distribution which checks differentiation. A manifold, complex build, varied in relief and ragged in contour, breaks up the moving streams of peoples, turns each branch into a different channel, lends it a distinctive character through isolation, finally brings it up in a cul de sac formed by a peninsula or mountain-rimmed basin, where further movement is checked and the process of local individualization begins. ”

“ By means of conduits cut in the living rock, they had managed to lead the water of the stream to a series of basins cut one below the other. The sketch we reproduce shows the lowest basin, which is close to the path. ”

“ New rivers would then flow over these increased elevations, and the ultimate effect would be to raise that part of the continent of North America several hundred feet above its present level. Even the very place on which I stand was, according to Webster, once a vast basin, extending from the Nore to near Reading, but now filled up with vegetable and animal remains; and the illustrious Cuvier has discovered a similar basin round the site of Paris. ”

“ If we assume that the unknown regions are principally sea, then the polar basin, including the area drained by all rivers flowing into the Arctic Sea, may be roughly estimated to contain about 14,000,000 square miles, of which half is land and half water. ”

“ The basin of a loch or sea consists of the basins of all the rivers which run into it.—In geology a basin is any dipping or disposition of strata towards a common axis or centre, due to upheaval and subsidence. ”

“ The size of the largest river basin of any country depends on the extent of the continent in which it is situated, its position in relation to the hilly regions in which rivers generally rise and the sea into which they flow, and the distance between the source and the outlet of the river draining it. ”

“ Evidently, then, this basin was a fresh-water basin; these deposits are fresh-water deposits. But as the Valley of the Amazons exists to-day, it is widely open to the ocean on the east, with a gentle slope from the Andes to the Atlantic, determining a powerful seaward current. When these vast accumulations took place, the basin must have been closed; otherwise the loose materials would constantly have been carried down to the ocean. ”

“ When we examine in some detail the shape of the land surface, we readily perceive that the continuous down slopes are due to the cutting action of rivers. In the basin of a stream the waters act to wear away the original heights, filling them into the hollows, until the whole area has a continuous down grade to the point where the waters discharge into the ocean or perhaps into a lake. ”

“ But some swift rivers, rolling mountains of fine earth, discharge themselves into deeply scooped gulfs or bays, and in such cases the deposit amounts, in the course of a few years, to a mass the transfer of which from the surface of a large basin, and its accumulation at a single point, may be supposed to produce other effects than those measurable by the sounding-line. ”

“ The diversity of scenery in the Great Basin is increased by mountains of volcanic origin, including several modern craters, some of which hold lakes, and by lava-flows of recent date, and by great alluvial fans or detritus cones which stream out into the valleys from the mouths of gorges in the bordering mountains.
The Great Basin proper, with its rugged topography and arid climate, is not an agricultural region. Small portions of it, however, when water can be had for irrigation, have been transformed into fruitful farms and gardens which yield bountiful returns. ”

“ Hold out one hand, palm uppermost, and straighten it as much as possible—the hollow in the palm is yet far too deep to represent with truth the natural rock basin. Soundings taken in lakes throughout the district all show the same thing—the basins are very shallow compared with their size and the height of the surrounding hills. ”

“ Such is the doctrine of permanency of oceanic basins. It is undoubtedly a true doctrine, but must not be held in the rigid438 form characteristic of early thought. The forces originating oceanic basins still continue to deepen them and to increase the size and height of continents, but other forces are at work, some antagonizing (i. e., cutting down the continents and filling up the ocean beds) , and still others determined by causes we little understand, by oscillations over wide areas, greatly modifying and often obscuring the effects of the basin-making movements. ”