SILTSTONE-SANDSTONE-GREYWACKE OF THE SALMON RIVER FORMATION ARE FOLDED INTO A CANOE-SHAPED TROUGH OVERLYING VOLCANICS OF THE UNUK RIVER FORMATION (LATE LOWER JURASSIC). BOTH UNITS ARE INTRUDED BY THE GLACIER CREEK AUGITE PROPERTY (TO THE EAST) AND BY A SATELLITE STOCK OF QUARTZ MONZONITE OF THE TERTIARY AGE HYDER BATHOLITH (TO THE WEST). HIGH-GRADE LENSES OF ARGENTIFEROUS MINERALIZATION OCCUR IN QUARTZ SULPHIDE VEINS CUTTING THE SILT- STONES, ACCOMPANIED BY LEAD-ZINC VALUES. ARSENO- PYRITE-PYRRHOTITE MINERALIZATION HAS ALSO BEEN REPORTED IN SEPARATE STRUCTURES.