The area is underlain by Upper Triassic Karmutsen Formation volcanic rocks of the Vancouver Group. These are interbedded with, and overlain to the northeast by a northwest trending belt of Quatsino Formation limestone (Vancouver Group) known historically as the "lime-belt". The Vancouver Group rocks are in fault and/or intrusive contact to the northeast with intrusive rocks of the Juro-Cretaceous Coast Plutonic Complex.

The Gold Thread showing consists of a lenticular quartz vein striking 155 degrees and dipping 70 degrees to the northeast. The vein follows tight shearing occurring within porphyritic andesite that is also cut by numerous fine-grained andesite dykes.

The vein/lens ranges from 2 to 30 centimetres in thickness. The quartz is sparsely mineralized containing occasional particles of chalcopyrite, pyrrhotite, pyrite, native gold and a black lustrous telluride identified as sylvanite. Two samples, 20 and 30 centimetres in width, both assayed nil in gold and silver (Stevenson, J.D., 1938).