Youngs, F.O., Bartholomew, O.F., Jennings, D.S., Wilson, L., Zobell, I.D., Wallace, M.H., Fletcher, J.E., and Baugh, W., 1942, Soil survey of the Virgin River Valley area, Utah-Arizona: U.S. Department of Agriculture, Bureau of Plant Industry, series 1936, no. 13, 67 p., 1 sheet, scale 1:63,360.