The area is underlain by sediments of the Jurassic to Cretaceous Bowser Lake Group. Auriferous quartz veins are probable sources of coarse gold found in benches along Porcupine and Quill creeks.
Sampling of coarse pyrite from sluicing operations, assayed 39 grams per tonne gold, and 27.4 grams per tonne silver (Geological Survey of Canada, Memoir 329).