Named for exposures, the type section, at southeast end of Steele Hills on Threelinks Ranch [secs 29, 32, and 33, T14S, R23E?], Cochise Co, AZ in Pedregosa basin. Identified doubtfully in Winchester Mountains. Geologic map. Lies on Cretaceous rocks and lies below Galiuro volcanics. In Steele Hills is a weakly consolidated conglomerate consisting of subangular pebbles and cobbles that were fractured after deposition in a matrix of pink feldspathic sands. Fragments include rocks as old as late Paleozoic and as young as Cretaceous? sedimentary and volcanic rocks. Some of the boulders are several ft in diameter. Is a terrestrial deposit. A basalt flow 60 ft thick is intercalated in the conglomerate in the Steele Hills. An andesite flow crops out at three places on the ranch. A thickness of 50 to 125 ft is inferred at south end of Steele Hills, and 700 ft on east side of hills. Winchester Mountain section may be about 2,000 ft. No fossil evidence. Assigned to middle Tertiary.

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

Shown in Little Dragoon Mountains, Cochise Co, AZ in Pedregosa basin as Eocene--although it is known to be pre-volcanic, or pre-late Eocene--in age. No other basis for age assignment. Correlation with other Eocene units shown on Plate 1.

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