The Augusta Mountain Formation was named by Muller and others (1951) for outcrops on Augusta Mountains, T. 25 N., R. 39 E., in Pershing County.

Conodonts collected from this formation in the Shoshone Range section indicate a Middle Triassic (late Ladinian) age (Stewart and McKee, 1977). In the New Pass Range, the Augusta Mountain contains a fauna that is Middle to Late Triassic (Ladinian to early Karnian) age (Stewart and McKee, 1977). Pelecypods, gastropods, brachiopods, and nautiloids present in the Augusta Mountain Formation also suggest a Middle-Triassic age (Muller and others, 1951).

At its type section in the Augusta Mountains the formation is about 2,500 feet in thickness. It is divided into a lower member of about 800 feet of massive, gray dolomite and lesser limestone; a middle member with 500 feet of thin-bedded impure dolomite and limestone interbedded with shale; and an upper 1,200 feet of massive cliff-forming bioclastic limestone and minor dolomite (Muller and others, 1951; Stewart and McKee, 1977). At the type section, the Augusta Mountain Formation conformably overlies the Favret Formation and is overlain by the Cane Spring Formation.

In the Shoshone Range and Reese River Valley area, small outcrops of the Augusta Mountain Formation consist entirely of massive, highly fossiliferous limestones that are locally coquina-like (Stewart and McKee, 1977). In the Shoshone Range the Augusta Mountain rests on the Pumpernickel Formation.

In the New Pass Range and Fish Creek Mountains, outside of the study area, the Augusta Mountain is composed of massive to thin bedded, gray, bioclastic, sandy and pebbly limestone and minor interbedded chert pebble-conglomerate, siliceous sandstone, and shale (Stewart and McKee, 1977).

The Augusta Mountain Formation is about 2,500 feet thick in the Augusta Mountains (Muller and others, 1951), 3,000 feet in the New Pass Range (Silberling, 1956) and 1,300 feet in the northern Fish Creek Mountains (Ferguson and others, 1951)

The Augusta Mountain Formation is exposed in the Shoshone Range, and Augusta, and New Pass Ranges, Shoshone and northern Fish Creek Mountains west of the evaluation area.

The depositional setting for the Augusta Mountain Formation is poorly understood. It represents shallow marine terriginous and carbonate sediments that were deposited in shallow basins developed on the Golconda allochthon.