The Twisting Truth Behind the Devil’s Corkscrews of the Great Plains

In the grasslands of Nebraska, a curious spiral once puzzled scientists and locals alike. These strange, twisting stone shapes were found across parts of the Great Plains during the late 1800s, and no one could agree on what they were. Some were several meters tall and coiled like giant corkscrews, embedded deep in the earth. Locals gave them a memorable nickname: “devil’s corkscrews.” To scientists, they became known as Daemonelix, which loosely translates from Greek as “devil’s spiral.”

They were first studied in the late 19th century by Erwin Hinckley Barbour, a geologist and paleontologist from the University of Nebraska. Barbour came across these structures in the Harrison Formation, a stretch of sedimentary rock in northwestern Nebraska. The rocks here date back to the Miocene epoch—roughly 20 to 23 million years ago. Barbour was gathering fossils of extinct mammals when he noticed the odd spiral forms preserved in the soft sandstone. He had never seen anything like them.

Barbour’s early theories reflect how little was known at the time. His first guess was that these were the remains of enormous freshwater sponges. This idea made some sense back then—many researchers believed the area had once been the bottom of a large lake. He later changed his mind, thinking instead they might be strange fossilized roots of ancient plants. He was struck by their symmetry and size and described them in detail in his publications.

But neither explanation stuck. Other scientists began to examine the spirals more closely. Some were found with fossilized bones inside. Others showed scratch marks on their inner walls. These clues eventually led researchers to a more accurate explanation: these spirals were burrows. More specifically, they were the ancient homes of an extinct type of beaver called Palaeocastor.

Palaeocastor wasn’t like the beavers we know today. It didn’t build dams or lodges in water. It lived on land and dug into the soft soil of prehistoric grasslands. And it didn’t just dig straight tunnels—it burrowed in long, spiral patterns.

The reason for this spiral shape isn’t fully clear, but some scientists think it might have helped with drainage or made the burrow more stable. Others suggest the shape might have helped the animals regulate temperature or avoid predators.

These corkscrew-shaped tunnels were more than just a quirk of nature. In some fossilized burrows, paleontologists have found the remains of Palaeocastor itself. In others, the bones of predators like Zodiolestes, an extinct relative of the weasel, were found—possibly animals that had tried to hunt the beaver inside its burrow. These discoveries helped confirm that the spirals weren’t plant remains or sponges, but trace fossils—preserved evidence of behavior, not bones or bodies.

Today, you can still see Daemonelix on display at places like the Agate Fossil Beds National Monument in Nebraska. Some are still partially buried in the rock where they formed, and others have been carefully removed and mounted in museums. While they no longer puzzle scientists the way they once did, they’re still surprising to look at: huge spirals carved into stone, remnants of animals that lived millions of years ago.

These fossils tell a story of how much landscapes and life have changed over time. What once looked like a mystery from deep underground turned out to be the preserved traces of animals simply going about their lives. And thanks to curious researchers, both past and present, we now have a clearer picture of what these “devil’s corkscrews” really were—just the handiwork of a prehistoric animal doing something completely normal in its own time.

Sources: 1, 2