Named for Angelica Wash, Pima Co, AZ, Basin-and-Range province. Composite type section in secs 10 and 11, T17S, R12E; sec 10, T17S, R13E; and S1/2 secs 10 and 11 and SW1/4 sec 12, T17S, R12E, Pima Co, AZ. Chief outcrop area is south and west of Helmet Peak. Pieced together from isolated exposures. Basal conglomerate characterized by ill-sorted, subround pebbles and cobbles in a matrix of ill-sorted coarse-grained sandstone. Clasts are mostly silicic and intermediate volcanic rocks, and quartzite, graywacke, chert, limestone, porphyry, and aplite. Up to 500 ft thick. Middle member about 2,000 ft thick consists of fine- to coarse-grained, well-sorted gray arkosic sandstone and lesser amount of massive to weakly fissile argillaceous sandstone. Sandstone is 40-45 percent quartz, 25 to 35 percent feldspar. Upper member consists of about 1,600 ft of light-gray to brown arkosic grit and pebble conglomerate and arkosic grit interbedded with gray siltstone. Overlies Whitcomb Quartzite (new) of Early Cretaceous? age disconformably and conformably overlain by Demetrie Volcanics (new) of Late Cretaceous age. Is assigned an Early Cretaceous age. Geologic map.

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