The country rocks in the area of the Virginia prospect are pelitic metasedimentary and subordinate andesitic metavolcanic (greenstone) strata of the Jurassic or older Mesozoic Hazelton Group; the Triassic Texas Creek Granodiorite, which underlies and locally intrudes the Hazelton; the Eocene Boundary Granodiorite, which intrudes the Hazelton and Texas Creek rocks; and still-younger Tertiary lamprophyre dikes that cut all the other rocks (Smith, 1973, 1977; Koch, 1996).
The deposit (Buddington, 1925, p. 74, 84; 1929, p. 43, 88-89) is in a mineralized shear zone in porphyritic greenstone cut by granodiorite and lamprophyre (?) dikes. An interval 12-16 feet wide in the 50-foot wide shear zone contains an oreshoot of nearly solid sulfides, accompanied by quartz gangue. The sulfides are pyrrhotite, sphalerite, pyrite, and a little galena and tetrahedrite. The greenstone also contains disseminated sulfide minerals, stringers of quartz, calcite, and sulfide minerals. Near contacts of granodiorite porphyry dikes, the greenstone also contains the contact-metamorphic minerals garnet and epidote. A little chalcopyrite occurs along with the other sulfides in some of the epidote-rich greenstone.Selected samples of the ore reportedly assayed as high as 4.5 oz Au per ton.