Editore: United States Government Printing Office, Washington, 1987
Condizione: near fine. from the summary, "Three U.S. Bureau of Land Management (BLM) wilderness study areas comprise approximately 61,135 acres of Tertiary volcanic rocks exposed along the South Fork of the Owyhee River in northeastern Nevada and Southwestern Idaho." softcover, 11" x 8.5", folded plate 1 inside rear pocket, 15 pages, illustrated.