Underlying rocks include conglomerate, sandstone, greywacke, argillite, arkose, and interbedded tuffs of the Jurassic to Cretaceous Bowser Lake Group. To the northeast, the sediments are intruded by a stock which forms the core of the Seven Sisters Mountain. This intrusion resulted in the folding and faulting of the strata and the emplacement of quartz veins and mineralized zones.

A replacement zone, striking 170 degrees and dipping 65 degrees west, consists of pyrite, pyrrhotite, galena, sphalerite, chalco- pyrite and arsenopyrite. The zone averages 2.4 metres wide and is traced for 120 metres. A 60 centimetre sample assayed 0.17 grams per tonne gold, 305 grams per tonne silver, 0.52 per cent copper, 6.70 per cent lead and 24.1 per cent zinc (Property File: Lorimer, 1972). A parallel zone, to the west, is up to 10.6 metres wide and a 4 metre sample assayed 58.3 grams per tonne silver, 0.55 per cent copper, 1.00 per cent lead, 23.30 per cent zinc and 0.17 grams per tonne gold (Property File: Lorimer, 1972). Smaller zones occur to the north over 600 metres.

A 22.1 kilogram sample, shipped for assaying, returned trace gold, 720 grams per tonne silver, 0.3 per cent copper, 14.7 per cent lead, 11.7 per cent zinc and 0.15 per cent antimony (Minister of Mines Annual Report 1940).

In 1969, a shipment of 13.6 tonnes graded 1717 grams per tonne silver, 3.4 grams per tonne gold and 9.55 per cent copper (George Cross Newsletter #184, 1984).