For a while, prospectors scouring the plains of Nebraska and Wyoming in search of new fossils had been confounded by massive, twisted objects buried underground. The confusion began around the 1800s when these were first found. Some of the structures were as much as three meters tall, and twisted like the familiar shape of a corkscrew. They were first made popular by geologist and paleontologist Erwin Hinckley Barbour when his workers found these weird fossils in 1891. He and many others were perplexed by their size and shape. What he found were spiral, sand-filled tubes with the outer walls made of some form of twisted fibrous material. Barbour’s first theory was that these objects might have formed at the bottom of an enclosed lake. He even assumed them to be the fossils of extinct freshwater sponges at one time, a rather ridiculous notion but the only one he had.
In response to their size and shape, they were called Daemonelix. The name literally translates as “Devil’s Helix” or “Devil’s Corkscrew.” Despite not knowing what they were, the name stuck and for a while, many more of them were unearthed. Further examination revealed that the rocks surrounding Daemonelix had more in common with arid, open plains rather than with lakes, and Barbour’s newest theory was that they were a type of giant plant. The odd theories continued for the next two years and for a while, Daemonelix became just that, one of the many unidentifiable oddities from the fossil record.
Yet the one thing that confounded the scientific community at the time was the presence of rodent bones preserved inside what appeared to be chambers. They were not the most unique of rodents either, with the fossils showing animals that looked like a prairie dog or a groundhog. Had they fallen into the spiral chambers of Daemonelix’s body, or was there something slightly less bizarre going on? Two years after Barbour’s wild theories, paleo-pioneer Edward Drinker Cope hit upon the conclusion that they were the entrances to the burrows of rodents that lived underground. Cope was right, for they were indeed a new species of burrowing rodent and the corkscrews were trace fossils. In the scientific community, trace fossils or ichnofossils include objects like preserved footprints and just about anything else that is not a body fossil. They are instrumental in revealing the lifestyles of extinct animals far better than bones and body fossils can. The famous Daemonelix was no different of course. Cope and his colleagues were also able to pin down the animals found at the bottom of the burrows. The rodent fossils for example were identified as belonging to a family of strange extinct beavers and not more traditional burrowing fare like prairie dogs. Beavers though they were, none of them were ancestors of the modern beavers. Instead, today’s American beavers are descended from migrants hailing from Eurasia while the ancient burrowing beavers died out millions of years earlier. The most common of these was Palaeocastor. Their fossils show us that they were almost identical to modern burrowing rodents today, with small ears and short legs and a rather long body to fit into narrow tunnels underground. They were about 30 centimeters in length, as big as a large rat.