Discover the ice-sculpted landscape that intrigued and inspired John Muir, Aldo Leopold, and Frank Lloyd Wright. From potholes carved into Precambrian basalt by torrential floods of glacial meltwater to the fossil tracks of ancient sluglike creatures that crawled across tidal flats 500 million years ago, the rocks and landforms of Wisconsin reveal a captivating geologic story that spans 2.8 billion years. Thirty five road quides interpret the geology visible from the state's highways and at more than 60 state, county, and city parks.