Unnamed Covering Most of Castle Islands

U.S. Bureau of Mines, 1980, Claim map, Petersburg quadrangle, Alaska: U.S. Bureau of Mines Map No. 117, 1 sheet, scale 1:250,000.Grybeck, D. J., Berg, H. C., and Karl, S. M., 1984, Map and description of the mineral deposits in the Petersburg and eastern Port Alexander quadrangles: U.S. Geological Survey Open-File Report 84-837, 86 p., 1 sheet, scale 1:250,000.Brew, D.A., 1997, Reconnaissance geologic map of the Petersburg C-4 quadrangle, southeastern Alaska: U. S. Geological Survey Open-File Report 97-156-J, scale 63,360, one sheet, 21 p. pamphlet.