Toadstool Geologic Park - Oglala NG
Markers guide the hiker along a one-mile loop trail through the fanciful mushroom-like toadstools. Located in Oglala National Grassland (NE), these toadstools are created by wind and water that erode the soft clay faster than the hard standstone rock that caps it. Eventually, erosion topples the large toadstools while new ones are forming underneath.
The authors recommend not taking a dog on the hike.