The claims straddle the axis of the American Creek anticline, an open slightly inclined regional fold. The property is entirely underlain by Lower Jurassic, red and green volcanic conglomerates and sandstones of the Unuk River Formation. Middle Jurassic volcanic conglomerates, breccias, and crystal and lithic tuffs of the Betty Creek Formation unconformably overlay the Unuk River rocks immediately west of the property. Faulting on the claim block is aligned parallel with the axial plane of the American Creek anticline and also crosscuts the stratigraphy near the north and south boundaries of the property.