This rise and fall of Walden at long intervals serves this use at least; the water standing at this great height for a year or more, though it makes it difficult to walk round it, kills the shrubs and trees which have sprung up about its edge since the last rise -- pitch pines, birches, alders, aspens, and others -- and, falling again, leaves an unobstructed shore; for, unlike many ponds and all waters which are subject to a daily tide, its shore is cleanest when the water is lowest. On the side of the pond next my house a row of pitch pines, fifteen feet high, has been killed and tipped over as if by a lever, and thus a stop put to their encroachments; and their size indicates how many years have elapsed since the last rise to this height. By this fluctuation the pond asserts its title to a shore, and thus the shore is shorn, and the trees cannot hold it by right of possession. These are the lips of the lake, on which no beard grows. It licks its chaps from time to time. When the water is at its height, the alders, willows, and maples send forth a mass of fibrous red roots several feet long from all sides of their stems in the water, and to the height of three or four feet from the ground, in the effort to maintain themselves; and I have known the high blueberry bushes about the shore, which commonly produce no fruit, bear an abundant crop under these circumstances. Some have been puzzled to tell how the shore became so regularly paved. My townsmen have all heard the tradition -- the oldest people tell me that they heard it in their youth -- that anciently the Indians were holding a pow-wow upon a hill here, which rose as high into the heavens as the pond now sinks deep into the earth, and they used much profanity, as the story goes, though this vice is one of which the Indians were never guilty, and while they were thus engaged the hill shook and suddenly sank, and only one old squaw, named Walden, escaped, and from her the pond was named. It has been conjectured that when the hill shook these stones rolled down its side and became the present shore. It is very certain, at any rate, that once there was no pond here, and now there is one; and this Indian fable does not in any respect conflict with the account of that ancient settler whom I have mentioned, who remembers so well when he first came here with his divining-rod, saw a thin vapor rising from the sward, and the hazel pointed steadily downward, and he concluded to dig a well here. As for the stones, many still think that they are hardly to be accounted for by the action of the waves on these hills; but I observe that the surrounding hills are remarkably full of the same kind of stones, so that they have been obliged to pile them up in walls on both sides of the railroad cut nearest the pond; and, moreover, there are most stones where the shore is most abrupt; so that, unfortunately, it is no longer a mystery to me. I detect the paver. If the name was not derived from that of some English locality -- Saffron Walden, for instance -- one might suppose that it was called originally Walled-in Pond. The pond was my well ready dug. For four months in the year its water is as cold as it is pure at all times; and I think that it is then as good as any, if not the best, in the town. In the winter, all water which is exposed to the air is colder than springs and wells which are protected from it.