Just north of Kanopolis Lake and a mile south of US-40 at Carneiro, KS, is Kansas's smallest state park. It may be a mere five acres, but the tiny park is home to some unique and very unexpected rock formations.
The state park was named, somewhat obviously, for its mushroom rocks. These formations occur when hard rock sits atop softer rock; the soft rock underneath erodes away over time, leaving the harder rock perched precariously on a soft rock "stem."
From Mushroom Rock State Park's website: "...The Dakota formations are the remains of beach sands and sediments of the Cretaceous Period, the interval of geologic time from about 144 to 66 million years ago. Sandstone and sedimentary rock is held together by natural cement. The concretions that make up Mushroom Rocks are cemented calcium carbonate. The largest rock measures 27 feet in diameter."