Note 18 — Chapter VIII

"In the River St. Lawrence," says Sir Charles Lyell, "the loose ice accumulates on the shoals during the winter, at which season the water is low. The separate fragments of ice are readily frozen together in a climate where the temperature is sometimes thirty degrees below zero, and boulders become entangled with them; so that in the spring, when the river rises on the melting of the snow, the rocks are floated off, frequently conveying away the boulders to great distances. A single block of granite, fifteen feet long by ten feet both in width and height, and which could not contain less than fifteen hundred cubic feet of stone, was in this way moved down the river several hundred yards, during the late survey in 1837. Heavy anchors of ships, lying on the shore, have in like manner been closed in and removed. In October 1836, wooden stakes were driven several feet into the ground, at one point on the banks of the St. Lawrence, at high-water mark, and over them were piled many boulders as large as the united force of six men could roll. The year after, all the boulders had disappeared, and others had arrived, and the stakes had been drawn out and carried away by the ice."—'Elements,' first edition, p. 138.