The rock in the scree slope is predominantly pyritic, hornfelsed, sedimentary rocks of the mid-Cretaceous Skeena Group. These rocks are downdropped into the Bulkley graben. The same rocks occur at much higher elevation on the steep east facing slope of Hudson Bay mountain where they overlie Telkwa Formation volcanics.

Looking west we see the twin falls of Glacier gulch and above the falls the toe of the Hudson Bay mountain glacier. Rocks on either side of the glacier are orange weathering due to the oxidation of abundant disseminated pyrite. This pyritic zone defines the extent of hydrothermal activity related to formation of the Glacier Gulch porphyry molybdenum deposit in late Cretaceous time. This deposit, which lies beneath the glacier and ridge to the south, has been periodically explored since the late 1960’s. Drilling has been done mostly from underground workings.