The whole number in the Sierra can hardly be less than fifteen hundred, not counting the smaller pools and tarns, which are innumerable.

Perhaps two thirds or more lie on the western flank of the range, and all are restricted to the alpine and subalpine regions.

At the close of the last glacial period, the middle and foot-hill regions also abounded in lakes, all of which have long since vanished as completely as the magnificent ancient glaciers that brought them into existence.
Though the eastern flank of the range is excessively steep, we find lakes pretty regularly distributed throughout even the most precipitous portions.

They are mostly found in the upper branches of the canons, and in the glacial amphitheaters around the peaks.
Occasionally long, narrow specimens occur upon the steep sides of dividing ridges, their basins swung lengthwise like hammocks, and very rarely one is found lying so exactly on the summit of the range at the head of some pass that its waters are discharged down both flanks when the snow is melting fast.

But, however situated, they soon cease to form surprises to the studious mountaineer; for, like all the love-work of Nature, they are harmoniously related to one another, and to all the other features of the mountains.