the beds of the rivers being incumbered with trees blown down, and reeds, detained their waters more, which, now they are cleaned, they suffer to run off too fast.
"Another phenomenon observed in America, may perhaps be explained by means of the fact I have just mentioned. You cannot cross any forest in this continent without meeting with fallen trees; and it is remarkable that the root is only a superficial tuft, in the shape of a mushroom, and scarcely eighteen inches deep for a tree seventy feet high. If the trees put out no tap-root, was it not that they might avail themselves of the superficial humidity that covered them, and the rich mould arising from the decayed leaves, in which they found a substance much preferable to the interior strata, that remained dry, and consequently more hard to penetrate? And now, as they have contracted this habit through a lapse of ages, ages are requisite to change it."
