ABSTRACT

Four widespread and distinctive lithologic subdivisions of the autochthonous Devonian strata, the “Nevada limestone” of Hague, are recognized in an area 25–70 miles north of Eureka, Nevada. The three lower units, (1) the McColley Canyon member of limestone and dolomitic limestone, (2) the Union Mountain member of quartzite, quartzitic dolomite, and dolomite, and (3) the Telegraph Canyon member of light- and dark-banded mottled dolomite with a minor limestone tongue, are placed within the Nevada formation as redefined by Nolan, Merriam, and Williams. The uppermost unit, consisting of limestone truncated above by the Roberts Mountains overthrust, is assigned to the Devils Gate limestone, similarly redefined.

The Nevada formation contains faunas ranging from those of the Trematospira (Oriskany) zone to Stringocephalus and Stromatoporoid-Cladopora (Middle Devonian). The Devils Gate limestone faunas range in age from Middle Devonian to early Late Devonian.

The Nevada formation is regarded as a lithic correlative of the Simonson and the major part, if not all, of the Sevy dolomites of western Utah and possibly of parts of the Hidden Valley and Lost Burro formations of the Panamint Range, California. The Devils Gate limestone is considered an equivalent of the Guilmette formation of western Utah.

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