359 W.B. Davis 1935. Castle Creek, 8 mi. S Oreana, Owyhee Co., Idaho, May 22. look as if they mark the bounds of this old lake bed- and I believe) the whole area is that of Lower Sonoran. The upper benches are Upper Sonoran and possibly up higher, Transition. The ranch at which we are camped is along Castle Creek, beginning at the point where it breaks from the foothills in a narrow, precipitously walled canyon and extending on both sides of the creek for a distance of perhaps a mile or so. The riparian growth is chiefly willow and wild roses. In this habitat were found Yellow Warbler, Lazuli Bunting, Robin, Song Sparrows and Yellow-throats and Western Warbling Vireos. In the area outside the limits of cultivation Atriplex and Grayia were the common shrubs, the former in dominance. This last area was practically devoid of bird life. The soil was clay-loam in the cultivated areas and appeared to be heavily alkaline in places especially outside the irrigated areas. I spent the greater part of my