Washington DC: U.S. Geological Survey, 1971. Map, pamphlets. A fine large map in colors, 34.5x28 inches folded to mailing/handling size, 11.5x7 inches, along with two staplebound oblong pamphlets. The three related items together in a printed manila envelope, this envelope a little worn, the 3 items contained in it unmolested and fine. Miscellaneous Geologic Investigations Map I-538.