The Cousin Jack showing is located within the Central Quesnel Belt of the Quesnellia Terrane. The area is underlain dominantly by volcanic and sedimentary rocks of the Upper Triassic to Lower Jurassic Nicola Group. In this region the Nicola Group consists of a lower sedimentary succession overlain by green and grey basalt, in turn overlain by maroon basalt and breccias characterized by the presence of felsic clasts. The contact with the Omineca Belt to the east is a thrust fault and to the west the Nicola Group is in fault contact with the Mississippian to Triassic Cache Creek Group. Middle Jurassic sedimentary rocks overlie both the Cache Creek Group and the Nicola Group along parts of this western contact.

The showing occurs near the western margin of the Quesnellia Terrane. Middle Jurassic sedimentary rocks also occur in the area and an inlier of older rocks, assumed to belong to the Cache Creek Group, has been recognized near Dragon Mountain.

Mineralization consists of galena and pyrite in quartz stringers within a sheared and oxidized zone cutting sedimentary and volcanic rocks. This zone, about 6 metres wide and 150 metres long, strikes at 068 degrees, conformable to the main faulting direction within the Central Quesnel Belt.

Open cuts and pits within the shear zone expose well mineralized stringers about 15 centimetres wide. A sample from one of these assayed 1.37 grams per tonne gold, 143.98 grams per tonne silver and 9 per cent lead (Minister of Mines Annual Report 1934 p. C29).