In the Sumpter Valley, one of the largest gold dredges in the United States stands as part of a historic landscape shaped by gold mining and the people who worked the dredge. The valley floor also shows the mining process in the piles of rock called tailings, left behind by the dredge's stacker as it moved through the valley. Shiny flecks visible on the river bottom are mica washed down by spring floods, while real gold is harder to find.