Copper Canyon's alluvial fan is often used in illustrations because of its near perfect symmetry and limited extent. The fan shows a radial drainage pattern extending outward from its sediment source (Copper Canyon in the Black Mountians) and shows gradation form coarser, dark alluvial sediments high on the fan that grade to finer, light colored sediments in trunk stream channels that run along the toe of the fan. North is toward the top.