Named as member of Carefree Formation (new). Named for Galloway Wash. Type locality along bottom and sides of wash, a few hundred feet downstream from Spur Cross Rd, Cave Creek quad, northern Maricopa Co., central AZ. Below surface veneer, Galloway Member covers approx 1.3 sq mi of southwestern Carefree basin and 1.4 sq mi of basin extending west of Cave Creek. Consists of gray to light-gray, moderately consolidated, horizontally bedded, poorly to moderately sorted fanglomerate in silty-sand matrix; widely interbedded with prominent sand lenses up to 7 feet thick, 50 feet long, and cross-bedded; characterized by abundance of meta-argillite-basalt clasts (52% meta-argillite, 21% basalt) with red and maroon chert. Maximum thickness is >100 feet, based on well log measurements; possibly up to 400 feet, from data on gravity model cross sections (this study). Conformably overlies Miocene tuff and basalt; where Tertiary volcanic rocks have been removed, unconformably overlies Precambrian meta-argillite--phyllite complex. Grades laterally into late Miocene and early Pliocene Naked Girl Canyon Member to north, Grapevine Member to east, and Church Member to southeast (all new). Unconformably overlain by Pleistocene Mesquite Tank, Cahava Ranch, and Hidden View Terrace deposits of Cave Creek (all new, informal); Pleistocene Schoolhouse Glacis Alluvium (new) and Pleistocene Horny Toad Terrace deposits of White Eagle Wash (new, informal), as well as Holocene modern channel deposits named Cave Creek Alluvium, Vermeersch Alluvium, and Rowe Wash Alluvium (all new). Age is late Miocene and early Pliocene based on constraining minimum radiometric date of <13.4 Ma of underlying White Eagle Mine Formation (new). Report includes geologic map and cross section, and stratigraphic nomenclature table.

Source: GNU records (USGS DDS-6; Denver GNULEX).