The type section of the Garden Valley Formation is along the east side of Garden Valley on the western slope of the Sulphur Spring Range (Nolan and others, 1956). The best exposures of the formation are north and south of Tyrone Gap in the southeast corner of the Garden Valley Quadrangle.

The lower fossiliferous limestones within the Garden Valley Formation are considered Early Permian (Wolfcampian) in age. The upper unfossiliferous units are post-Wolfcampian to Pre-Cretaceous in age.

In the Twin Spring Hills (Merriam, 1963) and Sulphur Spring Range (Nolan and others, 1956), the Garden Valley rests unconformably upon the Vinini Formation, and is unconformably overlain by the Cretaceous Newark Canyon Formation. Angular fragments of Vinini chert are reworked into the lower portion of the Garden Valley at Tyrone Gap but not in the Twin Spring Hills section (Merriam, 1963).

In the Twin Spring Hills, 90 percent of the Newark Canyon is a light-grey to yelowish or pinkish weathering limestone-cobble conglomerate with subrounded to angular limestone, and gray and green chert fragments up to 10 inches in diameter (Merriam, 1963). The lower unit of the Garden Valley (500 feet) is composed of pinkish, platy weathering, fine-grained, silty to sandy limestone which is crossbedded where siliceous, and contains a coraline and brachiopod fauna. Lenses of chert-pebble conglomerate are also common. A thin unit of reddish to brown coarse to fine grained sandstone, siltstone and shale is overlain by 4,500 feet of an unfossiliferous limestone cobble conglomerate unit.

In the Garden Valley Quadrangle (Sulphur Spring Range) the Garden Valley can be subdivided into four members: 1) a basal limestone member; 2) a conglomerate, sandstone, and shale member; 3) resistant siliceous conglomerate, and; 4) an upper "red beds" member composed of purple and red shales and conglomerates (Nolan and others, 1956).

The basal limestone member is 450-500 feet thick and lithologically equivalent to the lower member in the Twin Spring Hills. It is composed of thin-bedded, brownish, sandy limestones and limey sandstones with lenses of chert pebble conglomerate with cobbles as much as 6 inches in diameter (Nolan and others, 1956). Disconformably above the basal limestone member is a member which upsection is composed of siliceous channel-type conglomerates with cobbles and boulders of chert and quartzite; carbonaceous sandy shales with fish and plant remains; and tan carbonaceous sandstones with a total thickness of 800 to 1,000 feet (Nolan and others, 1956). The siliceous conglomerate member conformably overlies the second member, and is composed of dark reddish brown conglomerates with cobbles of quartzite and chert, and interbedded arkosic sandstones or quartzites with an aggregate thickness of about 1,000 feet. The upper "red beds" member is 550 feet of purple, red, and chocolate limestone pebble and cobble conglomerates, shales, and sandstones (Nolan and others, 1956). Upper limestone cobble conglomerates are conformable over the underlying siliceous chert-quartzite pebble units.

In the northern Diamond Mountains, rocks correlated with the Garden Valley are composed of light to medium-gray, fine to medium-grained, thick-bedded to massive limestone with up to 5 percent sub-angular chert and quartz sand, and a few thin lenses of sub-rounded chert and quartzite pebbles. Locally the limestone is up to 30 percent crinoid, fusulinid and brachiopod fragments (Haworth, 1979). Interbedded with, and overlying the limestone, is massive conglomerate in beds up to 10 feet thick composed of sub-angular to rounded pebbles of chert and quartzite, and beds of pebbly sandstone with up to 50 percent pebble in a siliceous silty and sandy matrix.

The Garden Valley Formation is about 5,000 feet thick in the Twin Spring Hills, is 3,000 feet thick in the Sulphur Spring Range, and is over 1,600 feet thick in the northern Diamond Mountains (Haworth, 1979).

The Garden Valley is exposed within the Sulphur Spring and Diamond Ranges, Twin Spring Hills (Monitor Range), and at Lone Mountain.

The lower brachiopod and coral-bearing limestones of the Garden Valley Formation are shallow marine in origin. Pebbles in Garden Valley conglomerates indicate short transport distances and may in part be derived from the Goodwin Limestone (Merriam, 1963). Bissell (1964b) suggests that the Garden Valley represents fan delta deposition of conglomerate, sandstone and shale in delta front, delta plain, and bar-finger deposits. The Garden Valley, along with the Carbon Ridge Formation, was deposited in a generally north-south-trending Permian depocenter across what are now the Sulphur Spring Range and Diamond Mountains.