The area of the Churn Creek placer showing is underlain by Cretaceous volcanic and sedimentary rocks of the Upper Cretaceous Kingsvale Group, overlain by Eocene volcanic rocks. Glacial gravels of Pleistocene age and postglacial Quaternary fluvial deposits cover much of the area and exposures of bedrock are sparse. The Churn Creek alluvial deposits comprise a basal clay layer resting directly on bedrock, overlain by a succession of gravel, sand and clay to a thickness of up to 30 metres. Alluvial gold concentrations have been determined in gravel layers. Random samples of the gravel indicate grades of 1.7 to 2.5 grams per cubic metre (Crescent Mines Ltd., 1977; Prospectus).