[Illustration:  LAKE TENAYA, ONE OF THE YOSEMITE FOUNTAINS.]

The Merced River, as a whole, is remarkably like an elm-tree, and it requires but little effort on the part of the imagination to picture it standing upright, with all its lakes hanging upon its spreading branches, the topmost eighty miles in height.  Now add all the other lake-bearing rivers of the Sierra, each in its place, and you will have a truly glorious spectacle,—­an avenue the length and width of the range; the long, slender, gray shafts of the main trunks, the milky way of arching branches, and the silvery lakes, all clearly defined and shining on the sky.  How excitedly such an addition to the scenery would be gazed at!  Yet these lakeful rivers are still more excitingly beautiful and impressive in their natural positions to those who have the eyes to see them as they lie imbedded in their meadows and forests and glacier-sculptured rocks.

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.  The landscape, cold and bare, is reflected in its pure depths; the winds ruffle its glassy surface, and the sun fills it with throbbing spangles, while its waves begin to lap and murmur around its leafless shores,—­sun-spangles during the day and reflected stars at night its only flowers, the winds and the snow its only visitors.  Meanwhile, the glacier continues to recede, and numerous rills, still younger than the lake itself, bring down glacier-mud, sand-grains, and pebbles, giving rise to margin-rings and plats of soil.  To these fresh soil-beds come many a waiting plant.  First, a hardy carex with arching leaves and a spike of brown flowers; then, as the seasons grow warmer, and the soil-beds deeper and wider, other sedges take their appointed places, and these are joined by blue gentians, daisies, dodecatheons, violets, honeyworts, and many a lowly moss.  Shrubs also hasten in time to the new gardens,—­kalmia with its glossy leaves and purple flowers, the arctic willow, making soft woven carpets, together with the heathy bryanthus and cassiope, the fairest and dearest of them all.  Insects now enrich the air, frogs pipe cheerily in the shallows, soon followed by the ouzel, which is the first bird to visit a glacier lake, as the sedge is the first of plants.

So the young lake grows in beauty, becoming more and more humanly lovable from century to century.  Groves of aspen spring up, and hardy pines, and the Hemlock Spruce, until it is richly overshadowed and embowered.  But while its shores are being enriched, the soil-beds creep out with incessant growth, contracting its area, while the lighter mud-particles deposited on the bottom cause it to grow constantly shallower, until at length the last remnant of the lake vanishes,—­closed forever in ripe and natural old age.  And now its feeding-stream goes winding on without halting through the new gardens and groves that have taken its place.