 Columbia River basalt flows buried the region some 15 million years ago, the remains of which can be seen today in the rimrock on the benchlands in the western portion of the wilderness.The North Fork John Day drainage bustled with gold and silver mining operations in the mid-19th century, and traces of the thousands of miners who labored here are still visible.Old mining structures, building foundations, and dredged ditches and trash dumps left behind by the miners are all visible.