The Gully showing is underlain by Upper Triassic Stuhini Group rocks, which have been intruded by Late Triassic to Early Jurassic monzonitic intrusions, Eocene granitic dikes, sills and stocks and Miocene basaltic and rhyolitic dikes.

The Gully mineralization is exposed in a northeast-trending, steeply dipping shear zone south of Sphaler Creek. Alteration associated with mineralization occurs over a broad zone, or halo, relative to the 1.5 to 2.5 metre zone of semi to massive sulphide (Assessment Report 23394). Alteration consists of epidote, which gives way to sericite with or without quartz and potassium feldspar alteration. Chlorite-pyrite alteration occurs as patchy replacements, folioform bands, and stockwork that crosscuts earlier developed sericite alteration. Mineralization within the sulphide zones consists of pyrrhotite, chalcopyrite with lesser pyrite, and rare magnetite in volcanic rock. Typical chip and grab samples from this zone from 1988 assayed 8.77 grams per tonne gold, 14.4 grams per tonne silver and 5.31 per cent copper over 3.6 metres and 5.00 grams per tonne gold, 9.6 grams per tonne silver and 3.71 per cent copper, respectively (Assessment Report 18115). In 1993, four holes of BTW core were drilled into the Gully zone, highlights included 10.4 metres of 1.5 grams per tonne gold and 1.49 per cent copper; 1.1 metres of 1.6 grams per tonne gold and 1.13 per cent copper; 6 metres of 3.1 grams per tonne gold and 1.26 per cent copper; and 0.3 metre of 1.7 grams per tonne gold and 1.29 per cent copper (Assessment Report 23394).

Refer to North zone (104G 022) for details of the Trek property work history, of which the Gully showing is part of.