The type section for the Notch Peak Limestone is on Notch Peak in the House Range, Millard County, Utah (Walcott, 1908). Hintze (1951) restricted the formation as used in this report.

The Notch Peak is considered at least locally equivalent to the Windfall and Whipple Cave Formations and is Late Cambrian in age (Moores and others, 1968; Hose and Blake, 1976). In the Kingsley Mountains, the Notch Peak apparently overlies the Windfall Formation (Buckley, 1967; Coats, 1985).

The Notch Peak Limestone is for all intents and purposes lithologically identical to the Windfall Formation. As described in the Snake Range, the formation consists of medium to dark grey limestone which is thinly bedded and weathers a pinkish-gray to pale red or orange near the base. The limestone contains interbedded yellowish siltstone lenses and partings and abundant dark nodules and lenses of chert in beds up to 2 feet thick, which are concentrated near the base of the formation (Whitebread, 1969). Interbedded yellowish and brownish dolomite is present in the upper few hundred feet of the formation.

Buckley (1967) described the Notch Peak as overlying the Windfall Formation in the Kingsley Range on the White Pine-Elko County boundary. The lower 500 feet of the unit is a blue-gray, medium-grained, massive limestone and the upper 750 feet are massive gray dolomite with thin-bedded chert and a few thin beds of quartzite.

In the northern Toana Range, neither the top nor bottom of the Notch Peak Dolomite are exposed. The unit overlies about 2,775 feet of unnamed Cambrian limestone and marble (Pilger, 1972; Coats, 1985). The unit is composed of dolomitic, cherty, laminated and massive, blue-gray limestones, and light to dark-gray, massive dolomite with nodular cherts.

The Notch Peak Limestone is 1,600 to 1,800 feet thick in the Snake Range (Whitebread, 1969), 1250 feet in the Kingsley Range (Buckley, 1967), and 1,447 feet thick in the northern Toana Range (Pilger, 1972).

The Notch Peak has been described in the Cherry Creek Range by Adair (1961) and was later called the Windfall Formation in the southern portion of that area by Fritz (1968). The only other units specifically designated as Notch Peak occur in the southern Snake Range, the Kingsley Mountains, Toana Range, and Silver Island Range. The Notch Peak is probably also present in the southern Pilot Range and Elk Mountains according to Coats (1985).

The depositional setting of the Notch Peak Formation is poorly understood. Its lithologic similarity with the Windfall Formation suggests a shallow shelf origin.