Peterson 1935. Castor canadensis. July 6. Marys River, s80oft., 25 mi. N Deeth, Elko Co., Nevada. Party arrived & investigate evidence of presence of beaver above Buena Vista ranch. Mr. Russell & Mr. Richardson worked upstream from ranch house, Dr. Hall & myself drove up couple miles & worked downstream. Located 3 places where beavers had recently cut willows. Dr. Hall located a dam & found several tracks. Places bearing such evidences marked by piece of white cloth in anticipation of making trap sets. Upon members of party meeting, drove back & first prospective set & set a #3 trap (steel), then & first placed found & make another set, finally several more sets made at dam & upstream in immediate vicinity. Noted that during interval of my first location of first evidence of the presence of beaver & return to set trap - about 2 hours - a beaver had recently visited the place, as fresh water drippings were found on dry sand. Sets made by setting trap under about 2 inches of water near bank, another edge of water, a stake driven down 1/2 inch below water line to each side of trap, stake driven into bank, another in deep water with a wire being backward (stream - used) directed barbs connected to both little above