In the mid-1800s, ranchers across Sioux County, in the US state of Nebraska, began unearthing strange, spiral structures of hardened rock-like material sticking vertically out of the ground. The spirals were as thick as an arm and some of them were taller than a man. Not knowing what they were, the ranchers began calling them “devil’s corkscrew.”

The puzzling structures first came to the notice of the scientific community through geologists Dr. E. H. Barbour in 1891, when he was asked to investigate a nine-foot long specimen that a local rancher had discovered on his property along the Niobrara River. Barbour found that the spirals were actually sand-filled tubes with the outer walls made of some white fibrous material. Barbour knew they were fossils but of what he wasn’t sure. He named them Daemonelix, which was just the Latin equivalent of its local name, devil’s corkscrew.

Nuroanatomist Frederick C. Kenyon stands next to a Daemonelix burrow, discovered in the late 19th century at Agate Fossil Beds National Monument.