The Denay Limestone was named for the Denay Valley, separating the Simpson Park and Roberts Mountains. The type locality is on the east flank of Willow Creek Canyon in the Roberts Mountains (Johnson, 1966).

The Denay is Middle Devonian (Eifelian) in age and is partially equivalent to the Oxyoke Canyon Sandstone. It is also a lithostratigraphic equivalent of the Woodpecker Limestone of the Newark Mountain-Alhambra Hills section.

At its type section in the Roberts Mountains, the Denay overlies the McColley Canyon Formation and is overlain by the Devils Gate Limestone. In the Antelope Range, the overlying unit is the Fenstermaker Wash Formation (Hose and others, 1982).

In the Antelope Range, the Denay is predominantly a grey to brown carbonaceous, argillaceous, dolomitic lime mudstone to wackestone with minor packstone and grainstone (Hose and others, 1982). In the Simpson Park Mountains, the Denay consists of a lower flaggy limestone member, a middle argillaceous limestone with darker limestone and dolomite near the base of the unit, and an upper black limestone with reddish-brown dolomite near the top of the formation (Johnson, 1966; Roberts and others, 1967).

In the northern Roberts Mountains, Murphy (1977a) described two units within the Denay Formation. The lower member consists of laminated and thinly bedded micrites overlain by coarse-grained allodapic limestone beds. The upper unit is cherty, laminated, very thin-bedded limestone.

In the Monitor Range near Dobbin Summit, the Denay overlies the Devonian Rabbit Hill Limestone (Wise, 1977). The lower member of the Denay is exposed and consists of dark-gray, fetid, fine-grained blocky lime mudstone and wackestone and allodapic limestone beds with sole markings and flute casts. These limestones contain interclasts, large broken tabulate corals, and brachiopods.

Nearly 15 miles to the southeast in the northern Hot Creek Range, the Denay can be divided into three portions (Potter, 1976). The lower part is composed of 210 feet of quartz-rich micrite which grades upsection into packestone and platy wackestone beds with crinoids and brachiopod fragments. The middle part of the formation is about 310 feet of medium to thick, graded beds of bioclastic packstone with a few thin platy weathering argillaceous interbeds in the lower part of the unit. Crinoids are very abundant and brachiopods, trilobites, and horn corals are also present. The upper portion of the formation is composed of 275 feet of thinly laminated, pelletal lime mudstones and wackestones which show soft-sediment contortion (Potter, 1976).

The Denay is about 750 feet thick in the northern Roberts Mountains (Murphy, 1977a), 852 feet thick in the Antelope Range (Hose and others, 1982), about 1,600 feet thick in the Simpson Park Mountains (Johnson, 1966), 785 feet in the northern Hot Creek Range (Potter, 1976), and only 160 feet in the Dobbin Summit area of the Monitor Range (Wise, 1977).

The Denay Limestone has only been recognized within a 25 to 35 mile wide, north-trending belt in Eureka and Lander Counties. It is exposed within the Antelope Range, Roberts and Simpson Park Mountains and the Dobbin Summit area of the Monitor Range and northern Hot Creek Range.

Argillaceous lime mudstones in the Denay Limestone accumulated in low-energy basinal environments where bottom conditions prohibited homoginization of original laminations (Kendall and others 1983; Hose and others, 1982). A conglomerate containing broken corals, bryozoans, and quartz sands in the Antelope Range may represent a debris flow (Hose and others, 1982). Potter (1976) suggested that the lower portion of the Denay in the Hot Creek Range represented quiet-water outer shelf or upper slope deposition, the middle portion of the unit probably represents submarine debris flows, and the upper portion was probably deposited in a shallow water slope environment. Murphy (1977b) suggested similar environments for the Denay in the Roberts Mountains.