Cobb Cave is located at the upper-end of Lost Valley near Eden Falls, and so-named because archaeologist from the University of Arkansas found stashes of corn cobs left from a time when Native Americans used it. This cave is more accurately called a Rock Shelter, though there are a few true caves in the area – including one that contains a 30-foot tall underground waterfall (Eden Cave). In fact, all of Lost Valley was probably one HUGE rock shelter at one time – and this upper-end of it would have been way at the back and mostly in darkness. Geologists call this a collapse valley – and you’d have to imagine it like a giant cave large enough for a small town, with an overarching roof of sandstone hundreds of feet thick. But at some point in prehistory, erosion and/or seismic activity caused the roof to collapse and expose the valley as it is now – leaving house-sized boulders scattered on the floor which today are known as the Jigsaw Rocks.