the park dip about 12° and are estimated to be some thick altogether. From 2 million years ago to 10,000 years ago a series of glacial periods repeatedly covered the region with ice, scouring the bedrock and scooping out the accumulated rock in the great basin. As the glaciers began to melt at the end of the last glacial period, pockets of rock and dirt till were left behind while the basin filled with meltwater, forming glacial Lake Duluth. A layer of red sediment with clay minerals remains from this time on flat, inland areas of the park. The changing configuration of the receding glaciers, plus post-glacial rebound of the surrounding land, altered the depth and area of the glacial Great Lakes. The succession of lake levels left a series of beach ridges, wave-cut bluffs, and terraces at several elevations. These land forms are visible all along Minnesota's North Shore, but Judge C. R. Magney State Park is the only park bearing the complete series from the high water of Glacial Lake Duluth to the level of Glacial Lake Nipissing just above the current Superior shore. As the lake levels changed, so too did the rivers flowing into them. Several former stream beds and deltas can be identified at the southern end of the park. The campground sits on a delta, and a former stream bed lies directly opposite the park entrance. Devil's Kettle The park is best known for "The Devil's Kettle", an unusual waterfall located on the Brule River from its mouth. The river splits in two to flow around a mass of rhyolite rock. The eastern flow goes over a two-step, waterfall and continues downstream. The western flow surges into a pothole, falling at least , from where it was popularly understood to "disappear underground". Visitors have reportedly dropped sticks, ping pong balls, and GPS trackers into the Devil's Kettle without seeing them resurface downstream. According to legend, someone even pushed a car into the fissure, but given that the Devil's Kettle is wholly inaccessible by road, most commentators have dismissed this as hyperbole. These stories have led to speculation that the channel had a separate outlet into Lake Superior, or more implausibly plunged deep underground or connected to another watershed entirely. For decades, no satisfactory geological explanation was offered for the Devil's Kettle phenomenon, and it was a popular regional mystery. The underlying rock is not