P.M.—Up Assabet by boat.

  A cold and blustering afternoon after a flurry of snow which has not fairly whitened the ground. I see a painted tortoise at the bottom moving slowly over the meadow. They do not yet put their heads out, but merely begin to venture forth . . .

  Passing up the Assabet, by the Hemlocks, where there has been a slide and some rocks have slid down into the river, I think I see how rocks come to be found in the midst of rivers. Rivers are continually changing their channels,—eating into one bank and adding their sediment to the other,—so that frequently where there is a great bend you see a high and steep bank or hill on one side, which the river washes, and a broad meadow on the other . . . But this does not explain how so many rocks lying in streams have been split in the direction of the current. Again, rivers appear to have travelled back and worn into the meadows of their creating, and then they become more meandering than ever. Thus in the course of ages the rivers wriggle in their beds, till it feels comfortable under them. Time is cheap and rather insignificant. It matters not whether it is a river which changes from side to side in a geological period or an eel that wriggles past in an instant.