The geologic information in this report may be useful in other geologic or related scientific studies and resource land management programs such as range management and flood control for all federal and state agencies and private affairs. The map area lies in a remote region of the Arizona Strip of northwest Arizona about 64 km (40 mi) south of St. George, Utah, the nearest significant town (fig. 1). Elevations range from about 2,057 m (6,748 ft) at Hudson Point on Hidden Rim of the upper Grand Wash Cliffs (west-central edge of the map area) to about 1,300 m (4,260 ft) in Pigeon Canyon on the Sanup Plateau (southwest edge of the map area). Primary vehicle access is by dirt road and unimproved jeep trails that traverse various parts of the map area, except within the Grand Wash Wilderness Area. Maps, extra fuel, two spare tires, extra food, and water are highly recommended when traveling in this remote region. Land in the map area is managed by the Bureau of Land Management, but also includes 12 sections of land belonging to the State of Arizona and about three sections of private land in the Wildcat Ranch area on the Shivwits Plateau, southeast quarter of the map area (U.S. Department of the Interior, 1993). The Grand Wash Cliffs Wilderness Area was designated as a wilderness in 1984 (Becky Hammond, Bureau of land Management, written commun., summer 1998). Lower elevations of the Sanup Plateau support a sparse growth of sagebrush, cactus, grass, joshua trees, and a variety of desert shrubs. Sagebrush, grass, cactus, cliffrose bush, pinion pine trees, and juniper trees thrive at higher elevations above 1,525 m (5,000 ft) on the Shivwits Plateau. Surface runoff in the western two-thirds of the map area drains west towards the Grand Wash Trough through numerous canyon drainages that have eroded into the Grand Wash Cliffs and Hidden Hills area. Hidden and Pigeon Canyons are the two principal drainages. The eastern one-third of the map area drains east toward the Grand Canyon down two principal drainages, Parashant Canyon and Agway Valley, which become Andrus Canyon southeast of the map area. The entire map area eventually drains to the Colorado River south of the map. PREVIOUS WORK Early reconnaissance photo geologic mapping of this area is compiled onto Arizona state geologic maps by Wilson and others (1969) and Reynolds (1988). A preliminary geologic map of the Grand Wash Wilderness Area was produced by Billingsley and others (1986). A geologic map of the Poverty Spring quadrangle is compiled onto the northeastern quarter of this map (Billingsley, 1997). Geologic mapping of adjacent areas include (1) the Sullivan Draw and vicinity which adjoins the northern edge of this map area (Billingsley, 1994), (2) the upper Hurricane Wash and vicinity which adjoins the northeast corner of the map area (Billingsley and others, unpub. data), (3) the upper Parashant Canyon and vicinity which lies along the east edge of the map area (Billingsley and others, 2000), (4) the lower Granite Gorge and vicinity map which borders the sou...
