The type section of the Goodwin Limestone is at Goodwin Canyon 1.5 miles southwest of Eureka, in T. 19 N., R. 53 E. (Nolan and others, 1956).

The Goodwin Limestone is Lower Ordovician (Tremadocian) in age with regionally diachronous upper and lower contacts.

The Goodwin Limestone is generally a very fine-grained, massive, light gray to blue gray limestone, with white and gray chert lenses, and nodules in the lower few hundred feet of the formation. In the Antelope Range, the lower portion of the formation is composed of calcareous shales which "resemble organic-rich shales of the Vinini" (Merriam, 1963). Worm tracks and castings are abundant within the lower portion of the formation, as are brachiopods and trilobite fragments (Merriam, 1963). The limestones are locally dolomitized, apparently as a result of hydrothermal, rather than sedimentary processes.

In the Clear Creek area of the Monitor Range, the Goodwin Limestone has been divided into lower and upper units (Wise, 1977). The lower member is about 600 feet of thin-bedded, laminated, gray lime mudstones, and well-bedded, platy, calcareous gray shales with burrows, ripple marks, sole markings and load casts. The upper member is about 650 feet of nonfossiliferous gray lime mudstone with yellow weathering argillaceous laminations and light gray chert lenses and stringers (Wise, 1977).

Kleinhampl and Ziony (1985) report that the Goodwin is a thick-bedded, massive limestone with abundant white to black chert in the Grant Range, and is thinner bedded and more silty in the Hot Creek Range near Tybo. In the southern Grant Range, the Goodwin is composed of thick-bedded to massive, black to gray limestone with abundant chert nodules and stringers (Cebull, 1967). The lower few hundred feet of the unit are thinner bedded, and the upper few hundred feet are silty and distinctly bedded. Both the lower and upper portions locally contain as much as 70 percent chert (Cebull, 1967).

Quinlivan and Rogers (1974) broke the Goodwin Limestone in the Hot Creek Range into an upper medium to dark-gray, cliff forming, fine-grained limestone and silty to sandy limestone with beds of intraformational chert conglomerate; a middle portion of buff to yellow laminated silty to sandy limestone; and a basal section of poorly exposed, platy, laminated limestone and highly fissile, slightly phosphatic, black shale.

In the Buck Mountain-Bald Mountain area to the south of the Ruby Mountains, the Goodwin is composed of well bedded, dark-gray bioclastic limestone with minor interbedded shaly limestone and locally alternating gray crystalline dolomite. Flat-pebble conglomerate is abundant in the lower portion of the formation (Rigby, 1960).

The Goodwin Limestone is 900 and 1,800 feet in the Eureka and Antelope Range areas respectively, and is about 1,250 feet thick at Clear Creek in the Monitor Range (Wise, 1977). In the southern Grant Range, it is 1,800 feet thick (Cebull, 1970), 1,700 feet thick in the Hot Creek Range (Kleinhampl and Ziony, 1985), about 350 feet thick in the northern Pancake Range (Kleinhampl and Ziony, 1985), and about 2,100 feet thick in the Buck Mountain-Bald Mountain area where the overlying Ninemile Formation is faulted out (Rigby, 1960).

The Goodwin Limestone has been described in the Monitor and Antelope, Pancake, and Hot Creek Ranges, Eureka area, Ruby Mountains, and the Buck Mountain-Bald Mountain area south of the Ruby Mountains.

The lower portion of the Goodwin shows upward progradation and a shallowing environment. As far west as the Toquima Range, the formation contains stromatolitic algae and is believed to represent subtidal or shallow intertidal conditions (Ross, 1977). In general the formation represents deposition along the broad and shallow Ordovician shelf and may in part represent upper slope deposition in the Monitor Range area.