Most of Nebraska is just endless miles of flat grass and farmland. But if you drive up to the far northwest corner of the state, the ground suddenly breaks open. You leave the prairie behind and step into a dry, dusty badland.
It looks like a moonscape. And scattered across this landscape are giant rock formations that look exactly like stone mushrooms.
Welcome to Toadstool Geologic Park.
Hard Rocks on Soft Stems
The strange shapes here come down to how the rocks are stacked. Millions of years ago, this area was a massive river valley. Layers of mud, volcanic ash, and sand piled up on top of each other.
Over time, that mud turned into very soft clay. The sand on top turned into a much harder sandstone.
When wind and rain hit the area today, they easily wash away the soft clay. But the heavy sandstone blocks on top act like umbrellas. They protect the column of soft clay directly underneath them from the rain.
Eventually, the ground around the rocks washes away. What is left behind is a wide, heavy slab of sandstone balancing perfectly on a thin, fragile stem of clay. They look just like giant toadstools.
A Very Slow Collapse
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Here’s the thing. These rocks are not permanent.
The clay stems are constantly weathering away. Every time a heavy rainstorm rolls through the park, the stems get a little bit thinner. Eventually, the stem gets too weak to hold the heavy cap. The whole thing tips over, and the sandstone block crashes to the ground.
You can actually see this happening all over the park. Large sandstone slabs sit broken on the valley floor right next to fully standing mushrooms. It shows how the landscape is still actively falling apart and rebuilding itself.
Walking Through Deep Time
Because water is always washing the dirt away, the ground is constantly spitting out fossils.
About 30 million years ago, strange animals lived around that ancient river. Today, scientists and hikers regularly find the fossilized bones of ancient horses, giant tortoises, and rhino-like animals sticking right out of the clay.
You cannot take the fossils home. But there is a short loop trail that lets you walk right past the bones and the towering rock mushrooms. It is a strange, quiet spot that totally breaks the rules of what Nebraska is supposed to look like.
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