In low ground the dams backing the water around trees killed them and in course of time they would disappear, leaving in their place an open, boggy space covered with a growth of rank vegetation. These were called by the hunters "beaver meadows." The "beaver canals" were cut through marshy places and were sometimes prominent features of the local landscape, extending four or five hundred feet in length, and having a breadth of three feet, with a depth of fifteen to thirty inches. When in the water the beaver was far more graceful and active than when on land, swimming powerfully by means of its large, strong, webbed hind feet, aided, when speed was desired, by the broad, flat tail used like the blade of a sculling oar, which, indeed, it much resembled, being ten inches long by five wide, and smooth, hard, and scaly, and entirely devoid of the soft fur which covered the body. Besides this use in swimming, the tail served as a prop when the animal desired to sit up on land, and also as a sort of trowel for beating down the mud-mortar used in dam building. At night it was also struck sharply on the surface of the water as a signal of alarm, giving a report which sounded, in the stillness, like a pistol shot and could be heard for a long distance. In regions frequented by man, or where in any way likely to be disturbed, the beaver was nocturnal and did most of its work during the dark hours, but where unmolested it spent much time out in the broad daylight. I saw large numbers swimming about in daytime when on Green River in 1871, in Wonsits Valley, where white men had rarely passed, and they gave no indication of special alarm at sight of us. Perhaps they regarded our boats as nothing more than drifting logs, just as the seal of Alaska is deceived by the trick the natives there have of covering themselves and their canoes with white cloth to resemble floating ice. At one point where we were in camp a whole day within a few hundred yards of a colony actively engaged in their various labours in the sunlight of the river bank, they apparently did not notice our presence, and even a rifle ball sent among them did not seem to derange their equanimity. In this locality the banks were full of burrows, and as we passed along in our boats we could see the beaver swimming around in every direction. We shot at several, but as they immediately sink to the bottom when killed, the gun is not successful in taking them, except in very shallow streams. We would have failed altogether albeit we made no special effort, had not one of the boats been able to head off a large fellow that was wounded, just as he arrived at the opening of his burrow, which happened, at that stage of river, to be a little above the water-level. A moment more and the animal would have been safe from us, but though the bottom was invisible on account of the turbidity of the river, one of our men quickly took the plunge and grasped the beaver from behind