The Mary McQuilton past producer is located in the head waters of Mine Creek, a southerly flowing tributary of Cotter Creek.

The oldest rocks in the area are sedimentary rocks of the Paleozoic Sicker Group, which elsewhere on Vancouver Island are correlative with the upper part of the Myra Formation of that group. In the Cowichan uplift this package has been reassigned to the newly created Mississippian to Pennsylvanian Fourth Lake Formation of the Buttle Lake Group.

These rocks are bounded on the west by Herbert Inlet while on the north, south and east they are overlain by mafic to intermediate volcanics of the Upper Triassic Karmutsen Formation, Vancouver Group. These volcanics include tuffs, breccias, feldspar porphyry dykes and andesitic flows, dykes and sills. A small area of diorite, belonging to the Early to Middle Jurassic Island Intrusions, is exposed along the east side of Herbert Inlet.

Fourteen distinct mineral showings are exposed in a creek bed, mainly between 440 and 770 metres elevation (see Assessment Report 16224; Drawing No. 5). The showings consist of shears and fractures, with various strikes and dips, hosting quartz- carbonate veins. Occurring sparingly within the veins are pyrite, galena, sphalerite and minor chalcopyrite. Free gold can be found in many of the veins and in one case was observed in the adjacent andesitic breccia. The host rocks are described as greenstone, predominantly dacite, and feldspar porphyry dykes.

The Mary McQuilton lode is the most significant of the showings, occurring at 770 metres elevation. The deposit consists of a shear zone, up to 3.7 metres in width, containing parallel veins separated by shattered andesite (dacite?). The strike of the zone is 045 degrees and the dip is 50 to 60 degrees northwest. As of 1935, the vein had been exposed along its length for over 27 metres. Two parallel veins along the hangingwall host pyrite and chalcopyrite. The upper vein, from 15 to 46 centimetres in width, is sparsely mineralized with sulphides. A sample assayed 448.80 grams per tonne gold and 212.57 grams per tonne silver (Geological Survey of Canada Memoir 204). The second vein, 60 centimetres below the first, is 15 to 38 centimetres wide and contains finer sulphides.

According to one mine plan dated July 13, 1940 over 440 metres of tunnelling had been completed, apparently on the Mary McQuilton zone. Seventy-eight tonnes of ore were mined between 1935 and 1938, from which was extracted 7,217 grams of gold, 3,204 grams of silver and 265 kilograms of copper (Mineral Policy data). In 1962, an adit was driven for 137 metres along a strong shear zone at an elevation of 300 metres.

During 1984 through 1987, Consort Energy completed a program of prospecting, geological mapping and rock, silt and soil sampling on the area immediately south as the Lazeo-Klein and Herb claims. In 1988, Gold Parl Resources completed a program of geological mapping, soil sampling and ground magnetic and electromagnetic surveys on the area as the Abco claims.