Upper Jurassic to Lower Cretaceous Bowser Lake Group sediments are intruded by the Early Tertiary age Seven Sisters stock which forms the core of the Seven Sisters Peaks. The sediments are mainly siltstone and greywacke with minor conglomerate, greenstone and rhyolite. Near the stock, they are sharply crenulated and deformed. The stock is largely granodiorite with lesser granite and diorite. Quartz feldspar porphyry is gradational with the intrusive and forms dykes cutting the sediments. Aplitic dykes extend from the intrusive into the sediments.

Molybdenite occurs in fractures within granodiorite in contact with siltstones. A sample assayed 1.46 per cent molyb- denum and another, 300 metres west, assayed 0.26 per cent molybdenum. Three hundred metres to the east, a five metre wide gossan with malachite and azurite occurs along a fracture in the granodiorite. A sample of this assayed 0.097 per cent molybdenum, 1.26 per cent copper, and 24.7 grams per tonne silver (Assessment Report 9147).