The country rocks in the area of the Silver Bell prospect are pelitic metasedimentary and subordinate andesitic metavolcanic strata of the Jurassic or older Mesozoic Hazelton Group, which is underlain and locally intruded by the Triassic Texas Creek Granodiorite; and the Eocene Hyder Quartz Monzonite, which intrudes the Hazelton and Texas Creek rocks (Smith, 1977; Koch, 1996).

The deposit (Buddington, 1929, p. 44, 97) is a quartz fissure vein about 2 feet thick in brecciated argillite and graywacke; the mineralized breccia zone is nearly parallel to the bedding. The quartz carries inclusions of the country rock and generally sparsely disseminated pyrite, chalcopyrite, and a little galena and sphalerite. Part of the vein is a solid mass as much as 13 inches thick of galena and minor tetrahedrite.