The area about Leader Lake is primarily underlain by rock of the Early to Middle Jurassic Island Plutonic Suite. These plutonic rocks vary in composition from gabbro to quartz monzonite but are mainly granodiorite and quartz diorite. The deposit is reported to be as- sociated with diabase intrusive, limestone, tuff, argillite, and porphyry dykes of the Upper Triassic Karmutsen Formation, Vancouver Group.

Patchy lensoidal pods of sulphide consisting of chalcopyrite, galena, and pyrite occur along a northeast trending fault zone. The zone strikes at 315 degrees and dips from 50 to 70 degrees northeast. It measures from 9 to 37 metres in length and from 1.5 to 3 metres in width. A grab sample assayed 24.00 grams per tonne silver, 6.19 per cent copper, 0.58 per cent lead and a trace of gold (Property File - MINFILE Coding Card, 1965).