Named for exposure at Locomotive Rock, sec 3, T13S, R6W, Pima Co, AZ in Basin-and-Range province. No type locality designated. Exposed over a large area in Ts12 and 13S, R6W. Is unconformable on Cardigan gneiss (new), Concentrator volcanics (new), and Cornelia quartz monzonite (new). The erosional surface has considerable relief. Interfingers with Ajo volcanics (new). Includes rocks from Paleozoic limestone. The Concentrator, Cardigan, Chico Shunie quartz monzonite (new), Ajo volcanics, and quartzite from an unknown source. The fanglomerate has boulders, cobbles, pebbles and silt-size that are angular to subround and poorly sorted. Has a maximum thickness of 12,000 feet. Thought to be a fan deposit formed in a desert. Assigned to the middle? Tertiary. Geologic map.

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

Crops out at northwest part of map in Pima Co, AZ in the Basin-and-Range province. Consists of reddish-brown, poorly sorted, subangular to subround clasts 0.5 to 4 cm in a well-cemented reddish oxidized sandy matrix. Clasts were derived from Cornelia Quartz Monzonite, Chico Shunie Quartz Monzonite, Cardigan Gneiss, quartzite, limestone, and andesitic material. Minor sandstone lenses. Beds are steeply dipping and rhythmically layered. Unconformably overlain locally by Daniels Conglomerate. Age modified from middle Tertiary to Oligocene and (or) Miocene. Reason for age change not stated.

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