The region is underlain to the west by the Coast Crystalline belt and to the east by Mesozoic and Tertiary volcanic and sediment- ary rocks. A hybrid zone along the eastern margin of the Coast Crystalline Belt contains elements of both terranes. In this zone Mesozoic rocks have been incorporated into the plutons and are overlain by Tertiary volcanic rocks. The degree of metamorphism and deformation of the Intermontane Belt supracrustal rocks increases towards the Coast Crystalline Belt.

The MM showing is underlain by quartz monzonite, alaskite and aplite of the Coast Crystalline Complex. Molybdenite and chalcopyrite occur as disseminations along joint and fracture planes cutting the intrusive rocks.