Geophysical investigations, maps. Aeromagnetic survey of parts of Baraga, Iron, and Houghton Counties, Mich., with preliminary geologic interpretation [with text]; by J. R. Balsley, H. L James, and K. L. Wler. Aeromagnetic survey in 1947 by J. R. Balsley and M. E. Hill, Scale 1 m. = 0.3 in. n. p.

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