Lake basin

“ You are now more than thirteen thousand feet above the sea, and to the north and south you behold a sublime wilderness of mountains in glorious array, their snowy summits towering together in crowded, bewildering abundance, shoulder to shoulder, peak beyond peak. To the east lies the Great Basin, barren-looking and silent, apparently a land of pure desolation, rich only in beautiful light. Mono Lake, fourteen miles long, is outspread below you at a depth of nearly seven thousand feet, its shores of volcanic ashes and sand, treeless and sunburned ”

“ The ice-flow itself passed along over where the terminal moraine now stands, cutting out Fallen Leaf Lake basin in its movement, and finally rested in the vast bowl of Lake Tahoe.
To the careful student every foot of Glen Alpine basin is worthy of study, and he who desires to further the cause of science will do well to make a map of his observations, recording the direction, appearance, depth, length and width of all the glacial markings he discovers. ”

“ A river that spreads out into the indeterminate earthform of a marsh is an effective barrier; but one that gathers waters into a natural basin and forms a lake retains the uniting power of a navigable stream and also, by the extension of its area and elimination of its current, approaches the nature of an enclosed sea. Mountain rivers, characterized by small volume and turbulent flow, first become navigable when they check their impetuosity and gather their store of water in some lake basin. ”

“ 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. ”

“ On the sides of the basin where this fresh lining rests on steep slopes there are beautiful frettings made by rills in the soft sediment. The stream from the glacier now meanders across this sand plain, dividing as it goes into many branches, which unite on [p. 117] approaching the dark archway below. The lake is extremely irregular in its behavior, and may be filled and emptied several times in a season. The waters are either restrained or flow freely, according as the tunnel through which they discharge is obstructed or open. ”

“ The little moisture that remains falls upon the highlands of the Great Basin, and so relieves its surface from utter barrenness. The adjacent slopes of the Sierra Nevada and Wasatch ranges furnish numerous perennial streams which feed the lakes about the borders of the Basin, such as Great Salt Lake, Pyramid, Walker, Mono, Honey, and Owens lakes. The wet weather streams, flowing down the desert mountains for a short time each year, frequently form broad, shallow lakes which disappear with the coming of the summer sun. ”

“ This time taking the right hand, that is, following the northern shore, we came to a canal overhung by trees, through which we pushed our way as well as we could. It led to an extremely picturesque, large western basin, a long narrow arm of which branches off in a northwesterly direction (Plate V, 6) . This part of the lake is also surrounded on all sides by mountains. The most beautiful vegetation extends close to the water's edge, while in several places perpendicular cliffs rise to a height of twenty to thirty metres (Plate V, 3) . ”

“ It is a true rock basin. The Upper Lake is, for the most part, a level plain, filled by the greyish-muddy Rhône which uses it as a sort of clearing-house. Being denser than the lake, the water of the river sinks and leaves on the bottom its perpetual deposits of mud, coarser near the shore, finer the farther out one goes. When the bottom of the Grand Lake is once reached, it is as flat as a billiard-table. Sixty meters from the Castle of Chillon it is sixty-four meters deep and shelves rapidly to three times that depth. ”

“ Lakes having outlets are drained away as their basin rims are cut down by the outflowing streams,—a slow process where the rim is of hard rock, but a rapid one where it is of soft material such as glacial drift.
Lakes are effaced also by the filling of their basins. Inflowing streams and the wash of rains bring in waste. Waves abrade the shore and strew the débris worn from it over the lake bed. Shallow lakes are often filled with organic matter from decaying vegetation. ”

“ The whole basin, even where the enclosing rocks are steepest, indeed, almost perpendicular, and thence up to the 230summits of the loftiest peaks, is densely covered with trees, reeds, and creepers, especially scitamineæ, the brilliant green hues of which are reflected in the mirror-like surface of the lake below. All the forests here are of wild plantain, and the sugar-cane is found growing wild in a variety of places. ”

“ In the course of time, the lakes and ponds in the depressions made or occasioned by the drift will be destroyed by drainage. Remembering how valleys develop (p. 46) it is readily understood that the heads of the valleys will sooner or later find the lakes, and drain them if their bottoms be not too low.
Drainage is hostile to lakes in another way. Every stream which flows into a lake brings in more or less sediment. In the standing water this sediment is deposited, thus tending to fill the lake basin. ”

“ The length of the life of any lake depends ordinarily upon the capacity of its basin, as compared with the carrying power of the streams that flow into it, the character of the rocks over which these streams flow, and the relative position of the lake toward other lakes. In a series whose basins lie in the same canyon, and are fed by one and the same main stream, the uppermost will, of course, vanish first unless some other lake-filling agent comes in to modify the result ”

“ When a mountain lake is born,—when, like a young eye, it first opens to the light,—it is an irregular, expressionless crescent, inclosed in banks of rock and ice,—bare, glaciated rock on the lower side, the rugged snout of a glacier on the upper. In this condition it remains for many a year, until at length, toward the end of some auspicious cluster of seasons, the glacier recedes beyond the upper margin of the basin, leaving it open from shore to shore for the first time, thousands of years after its conception beneath the glacier that excavated its basin. ”

“ Every hidden nook in the depths of the woods is searched and refreshed, leaving no stagnant air; beaver meadows and lake basin and low and willowy bogs, all are kept wholesome and sweet the year round. Cloud and sunshine alternate in bracing, cheering succession, and health and abundance follow the storms. The outer sea margin is sublimely dashed and drenched with ocean brine, the spicy scud sweeping at times far inland over the bending woods, the giant trees waving and chanting in hearty accord as if surely enjoying it all. ”

“ In rising one foot a lake may store away more water than the river by its consequent rise at the point of outflow will carry away in many months, and this for the simple reason that the lake may be many hundred or even thousand times as wide as the stream. Moreover, as before noted, the sediment gathered by the stream above the level of the lake is deposited in its basin, and does not affect the lower reaches of the river. ”

“ The great river, and the great lake, reported, may not be equal to the report; but where there is so much snow, there must be streams; and where there is no outlet, there must be lakes to hold the accumulated waters, or sands to swallow them up. In this eastern part of the Basin, containing Sevier, Utah, and the Great Salt lakes, and the rivers and creeks falling into them, we know there is good soil and good grass, adapted to civilized settlements. In the western part, on Salmon Trout river, and some other streams, the same remark may be made. ”

“ It is made up of innumerable faulted crust blocks, the elevated ones giving rise to the north and south ranges of mountains and the depressed ones to the desert basins lying between. Each local basin or valley has its own watershed limited by the mountains which surround it, but if for any cause the water supply from these mountains is in excess of the evaporation in the valley, a lake results, and if the supply is sufficient the lake will overflow its own basin and spread into the adjoining basins, rising to a height at which the water lost by evaporation exactly balances the inflow. ”

“ Entering the neighboring valley, and crossing the bed of another lake, after a hard day's travel over ground of yielding mud and sand, we reached the springs, where we found an abundance of grass, which, though only tolerably good, made this place, with reference to the past, a refreshing and agreeable spot.
This is the most extraordinary locality of hot springs we had met during the journey. The basin of the largest one has a circumference of several hundred feet; but there is at one extremity a circular space of about fifteen feet in diameter, entirely occupied by the boiling water. ”

“ The stream from the glacier has formed a fan-shaped delta, and its muddy current may be seen extending far out into the lake, polluting its crystal water and helping to fill its basin with sand and gravel till in the course of ages a flat meadow only will mark the place of an ancient lake. ”

“ The land animals indicate that a rather wide range of ecologic niches existed over the basin before the lake came into being, around the lake during its presence, and again all over the basin after the lake disappeared. Many of the smaller mammals, some of the rodents, and most of the primates were almost certainly arboreal. ”

“ 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. ”

“ The shore and bottom of the lake consist chiefly of clay cemented together by crystallized salt into slabs and blocks as hard as stone, so that great care must be exercised when the boat is pushed into the water, for these slabs have edges and corners as sharp as knives. The lake is a salt basin of approximately elliptical outline with very low banks; nowhere do mountains descend to the strand. ”

“ In many of these ancient lake-basins the draining is not yet completed, the lowest parts being still marshes or ponds of water. The Mohawk and the Connecticut flow each through a bead-roll of small lake-basins, walled around by solid rock. Through their margins the rivers for untold ages have been deepening their channels until the lake-bottoms have become dry land, and the homes of men. The Great Lakes themselves have, from a like cause, been much reduced from their former dimensions. ”

“ Tributary to the Wild Basin, which corresponds, south of Longs Peak, to the Wild Gardens north of it, are gorges of loveliness the waters of whose exquisite lakes swell St. Vrain Creek.
The Wild Basin is one of Rocky Mountain's lands of the future. The entire west side is another, for, except for the lively settlement at Grand Lake, its peaks and canyons, meadows, lakes, and valleys are seldom visited. ”

“ The wind had subsided, and the great lake, which serves as a filtering basin for the turbid waters entering it from the Slave River, was here as clear as that of the great inland lakes of Eastern Canada—Huron, Erie or Ontario. Wherever a river contains muddy water, you may at once conclude that it has no large lake expansions above it. In nearly every stream pouring its waters into the great clear water lakes of the St. Lawrence basin the water is dark and more or less impure ”

“ Masses of upheaved granite, with overlying slates and limestones, form the main materials of the cordon of surrounding hills. During the Cretaceous and Tertiary periods the entire basin, from the Rocky Mountains to the Blue Mountains of Oregon, was a fresh-water lake, on whose bottom was deposited a curious succession of sand and clay beds, including, near the surface, a layer of white, infusorial silica. At the exposures of these rocks in the cañon-walls of the present drainage system are found ample evidences of the kind of life which flourished in the lake itself and lived upon its borders. ”

“ Without these mountains, whose gorges are fed during the spring, and even in the summer, by melted snow, there would be no water. The levels of the valleys are still unknown; it is yet a question how far they are irregular in elevation, whether they have formed detached lakes, or whether they slope uniformly and by steps toward the Great Salt Lake and the other reservoirs scattered at intervals over the country.
The water-shed of the Basin is toward the north, south, east, and west: the affluents of the Columbia and the Colorado rivers carry off the greatest amount of drainage. ”

“ It seems very probable that a portion at least of the areas of Lakes Ontario, Erie, and Huron may be due to this removal of ancient salt deposits, remains of which lie buried in the earth in the region bordering these basins.
By far the commonest cause of lake basins is found in the irregularities of the surface which are produced by the occupation of the country by glaciers. When these great sheets of ice lie over a land, they are in motion down the slopes on which they rest; they wear the bed rocks in a vigorous manner, cutting them down in proportion to their hardness. ”