The type locality for the Sadler Ranch Formation is located "west of Sadler Ranch on a spur that extends up to the saddle directly north of Summit 7466 on the eastern side of the Sulphur Spring Range, Garden Valley 15-minute Quadrangle" (Kendall and others, 1983). The Sadler Ranch was formerly considered part of the Union Mountain Formation (Carlisle and others, 1957).

The Sadler Ranch Formation contains the Lower-Middle Devonian Boundary. In the Sulphur Spring Range, the Sadler Ranch overlies the Bartine Member of the McColley Canyon Formation and conformably overlies the Oxyoke Canyon Formation (Kendall and others, 1983). It overlies the Coils Creek Member of the McColley Canyon and underlies the Sentinel Mountain Dolomite in the Mahogany Hills (Kendall and others, 1983). At Lone Mountain, the formation conformably overlies the Coils Creek Member of the McColley Canyon and underlies the Denay Limestone (Murphy and Gronberg, 1970). At Union Mountain in the Pinon Range, the Sadler Ranch is interlayered with and overlain by the Oxyoke Canyon Formation (Kendall and others, 1983).

The Sadler Ranch Formation is equivalent to the Coils Creek Member of the McColley Canyon Formation, and interfingers with the Oxyoke Canyon Sandstone. The upper portion of the Sadler Ranch is equivalent to the lower portion of the Denay Limestone.

The Sadler Ranch has been divided into an upper and lower dolomite and middle crinoidal dolomite (Kendall and others, 1983). All three units are present in the Sulphur Spring Range and Mahogany Hills. The lower dolomite is a medium to thick-bedded, very fine grained, light gray to yellowish-gray dolomite with a sharp planar to scoured basal surface (Kendall and others, 1983). Most beds are finely laminated and/or burrowed mudstone, packstone, and crinoidal wackestone. Much of the original texture in these carbonate muds is obscured by dolomitization (Kendall and others, 1983). White to light grey, quartzose dolomite to quartz arenite with well-rounded, moderately sorted, fine to medium-grained quartz are present in the upper portion of the member. These sandstones show poorly defined horizontal and low-angle cross-laminae (Kendall and others, 1983). The upper contact of the lower dolomite is gradational with the overlying crinoidal dolomite.

The middle crinoidal dolomite is a light to medium-gray, poorly bedded (1 to 2 feet thick), laminated to cross-laminated, crinoidal packestone with thin lenses of mudstone and packstone. Thin, white to grey, beds of quartz-rich sandstone are locally present in the crinoidal member (Kendall and others, 1983).

The upper dolomite is very similar to the medium to thick-bedded, very fine-grained, light-grey laminated lower dolomite of the Sadler Ranch Formation with a conspicuous absence of quartz arenite (Kendall and others, 1983). Quartzose dolomite beds are present near the top of the dolomite. Crinoidal packstone beds are also present in the upper dolomite.

The Sadler Ranch Formation varies from 90 to 450 feet in thickness across the area discussed (Kendall and others, 1983). It is 234 feet thick at Modoc Peak (Kendall, 1975), 450 feet at Table Mountain, 410 feet at Lone Mountain (Gronberg, 1967), and 408 feet at the type section in the Sulphur Spring Range.

The Sadler Ranch is present within the eastern Sulphur Spring Range, Mahogany Hills, Lone Mountain, and at Union Mountain in the Pinon Range.

The Sadler Ranch occupies a belt parallel to depositional strike between the Coils Creek Member of the McColley Canyon Formation and Denay Limestone which represents open marine deposition to the west, and shallow-water restricted dolomites of the Oxyoke Canyon Formation to the east (Kendall and others, 1983).

The Sadler Ranch was deposited in shallow nearshore, shelf-slope environments (Kendall and others, 1983). Preservation of fine laminations and unfragmented crinoid stalks suggest low-energy as well as low oxygen depositional conditions for much of the formation. Strong current action and deposition in offshore bars or tidal channels is suggested by horizontally and cross-laminated quartzose interbeds and thin lenses of crinoidal debris abundant throughout the formation (Kendall and others, 1983). Sands may have entered the shelf ramp during maximum sea-level regressions which exposed the carbonate platform, with crinoid meadows developing on higher portions of the ramp as sea level rose (Kendall and others, 1983).

Kendall (1975) reports one sample of the lower member of the Sadler Ranch which contains about 4 percent organic carbon. It is possible that the Sadler Ranch may locally provide a source facies.