DURING March, 1933, while working on the cross-canyon telephone line, I noticed a fresh beaver cutting, one mile above Cottonwood Camp. Nearby in Bright Angel Creek was a newly made dam and house. These structures were interesting to me because in all my previous trips up and down Bright Angel Creek I had never found anything but old cuttings and an occasional limb or two in the creek.

The particular dam and house just mentioned is illustrated in figure l. The house is seen on the right of the picture against a large rock. After examining it very closely I decided that the attempt to build a regular mud and stick house was merely a camouflage to cover or to hide the entrance to a cave under the large rock. On the opposite side of the creek and downstream from the dam there was another entrance to a cavelike dwelling. It was also covered with sticks and reeds to hide it. The dam itself was made of interwoven sticks and small logs. There did not appear to be any evidence of mud mixed with the sticks, and all bark had been removed. On the west side of the creek a pathway led out of the stream near the dam, over to a freshly cut cottonwood tree (See Figure 2) which was about fifty feet from the water. A log about ten inches in diameter lying parallel with the creek and some ten feet from it had a section cut out of it so that the pathway led straight to the tree. One piece that had been carried from the tree had become wedged in the opening made in the log so it had evidently been abandoned for other pieces, more easily carried.

Markley,¹ in discussing the Sonora Beaver, states that "The force of the rushing waters tears down the dams he builds in an attempt to calm them. He is unable to find a suitable place to build his lodge." My observations were made at the season of low water. The beaver here had had time to carry out to a certain extent their age-old instinct to build and to colonize. So far as I can determine, however, this dam and lodge was not observed again after the time of my visit. It, too, probably suffered the fate of other beaver structures in the region when the high water occurred a month or two later. Thus the beaver must have been left stranded with only a dreary hole under some rock for refuge.

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1. Markley, Chester, "The Sonora Beaver". Grand Canyon Nature Notes, Volume 5, No. 8, July 1931.

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