Name applied to rocks above the regional unconformity at top of Ely Limestone and beneath Ferguson Mountain Formation. [The 171.4 ft sequence of "Virgilian" age above the regional unconformity was assigned to upper part of Ely Limestone in Ferguson Mountain area by Berge, 1960. This sequence was beneath his Ferguson Mountain Formation, and above his unquestioned Ely Limestone.] Type section designated in sec. 34, T34N, R65E, Elko Co., NV in the Great Basin province. Name Hogan taken from a railroad siding. Is 750 ft thick at type measured section where it consists of thin- to medium-bedded, silty to quartzite peaty, gray limestone, calcareous siltstone, calcareous shale, and argillaceous limestone, and some interbedded siliceous, cherty limestone, fine crystalline limestone, medium crystalline bioclastic limestone. Fossils include crinoid stems, brachiopods, corals, gastropods, and bryozoans, fusulinids. Considered middle to late Desmoinesian age, [Middle] Pennsylvanian age. Geologic map of the Pequop Mountains, Elko Co. Graphic sections.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Upper contact of Hogan Formation (upper formation of Ely Group) revised. In eastern Nevada and western Utah (Great Basin province), unconformably underlies Riepe Spring Limestone (revised), basal formation of Arcturus Group (rank raised). In northern Confusion Range and Gold Hill mining district, Utah, where the basal Riepe Spring and Riepetown formations of the Arcuturus are not separable, the Hogan unconformably underlies Ferguson Mountain Formation (revised), basal formation of Arcturus Group. Age is Pennsylvanian (Desmoinesian). Report includes correlation chart, graphic section, cross sections.

Source: Modified from GNU records (USGS DDS-6; Denver GNULEX).