I saw from the banks here the distant pot-hole formations in the brook, from which the stream had taken its name. As I approached these marble basins, I found three in succession—one above the other—following the course of the stream—a narrow passage eroded through crystalline marble and limestone. The first or lowermost one was like a small lakelet overflowing its brim. The second one was a typical pot-hole, revolving its stones in its whirling waters. The bowl was about six feet deep, of a circular—or rather elliptical form, about twenty-six feet in circumference. The stream entered through the middle of the northern rim, and had eroded a spout-like gutter, causing the water to flow in a rapid, seething manner as if poured into the basin below. Here the greenish water boiled and whirled, finally with an added force leaping forth through a deep spout over the lower rim of the pot, carrying with it small stones and marble dust—the lower rim thus being worn away. As the bowl becomes deeper, layers of rock will be cracked and broken, until finally the pot-hole formation will be destroyed. The upper or third basin is located in the harder portion of the lime and marble bed-rock, portions of the marble being highly polished. The marble brook-bed glittered in the noonday sunshine. Pot-holes are formed originally by a boulder, which—carried in the currents of a stream—lodges in a depression of the bed-rock. It bores gradually into its resting place, until, in the course of ages, it has worn the walls of its basin into a deep hollow, at the same time wearing itself away, at last being carried off as a pebble. It may be that these holes are sometimes formed in a slightly different way. Dimples and fissures often occur in rocks, and if the water and pebbles circle about these cracks they probably eat down through the soft layers of rock, and thus loosen a revolving stone from the bed-rock itself. It would then fit the pot-hole closely for ages, revolving as the currents become forceful in freshets. The pot-holes along the granite ridges in Bronx Park, New York City, as well as on the Canaan Hills—nearly one thousand feet above the Merrimac and Connecticut river-beds,—reveal the erstwhile revolving stones now motionless in their basins. [Illustration: =The Pot-Hole of Wash-Tub Brook, Pownal, Vermont, Showing the Stream Whirling through its Basin.= “The finest workers in stone are not copper or steel tools, but the gentle touches of air and water working at their leisure with a liberal allowance of time.”—THOREAU.]