The quaking bog is one of the most novel features of forests of the northern United States, especially those in New England and Wisconsin. It’s an area of sphagnum moss, rushes, sedges, and decaying vegetation, the whole mass of which is ﬂoating on a pool of water. The surface appears solid and stable, until trusted with the weight of a step. What seems to be ﬁrm ground then shivers, sinks, and rises, like a natural trampoline or waterbed. If the ﬁrst shimmy of this rich root mass underfoot is not heeded, one might easily break through the entangled mat into water and loose mud below, as if one had stepped into quicksand. The quaking bog suggests in perceptible human time the larger ripple, rise and fall, and shifting of the Earth’s surface in geologic time.