The South Fork (Captain’s Grid) occurrence is located on the south fork of McGillivray Creek, approximately 1.5 kilometres north- north east of Mount Morgan.
In the region, the Cadwallader and Ferguson faults transect sedimentary and volcanic rocks of the Mississippian to Jurassic Bridge River Complex and the Upper Triassic Cadwallader Group. Linear, altered serpentinite zones called the President Ultramafics, correlative with the Permian and older Shulaps Ultramafic Complex, mark faults that have controlled the emplacement of diorite of the Permian Bralorne Igneous Complex. The above sequence lies between bodies of the Jurassic to Tertiary Coast Plutonic Complex and outlying bodies of Cretaceous to Tertiary Bendor pluton granodiorite.
The area is underlain by chloritic phyllites and argillites, which have been intruded by a soda granite, related quartz feldspar porphyry and albitite dikes, near easterly directed splay faults off the Cadwallader Shear. Locally, two mineralized areas (Captain’s Grid and South Fork vein) have been identified.
The Captain's Grid area, covers two possible 070 degree- trending splays of the Cadwallader Shear. In 1989, four samples of quartz veins assayed greater than 1.0 gram per tonne gold and up to 12.09 grams per tonne silver (Assessment Report 19604).
The South Fork quartz vein is 1.5 metres wide but pinches to 10 centimetres over a distance of 50 metres. Minor pyrite and sphalerite occurs peripheral to the vein in the vicinity of an albitite dike. In 1986, a diamond drill hole (No.8) yielded up to 0.62 gram per tonne gold over 0.6 metre (Assessment Report 19604). In 1989, samples (Nos. 73880 and 73885) yielded up to 0.22 gram per tonne gold over 0.6 metre and 2.2 grams per tonne silver over 1.0 metre (Assessment Report 19604).
In 1983, X-Cal Resources completed a program of rock and silt sampling and geological mapping on the area as the Mac and X-Cal claims. In 1985, Hudson Bay Exploration and Development completed a program of geochemical sampling, geological mapping and a ground electromagnetic survey. In 1986, X-Cal Resources drilled eight holes, totalling 950 metres, in the South Fork area. In 1989 and 1990, Teck completed programs of rock, silt and soil sampling, geological mapping and a ground electromagnetic survey on the area. In 1991, Cogema completed a program of geochemical sampling and geological mapping on the area.