Commuters on U.S. 6 stuck in construction traffic can sometimes feel like they are fossilizing, but it turns out they’re driving past the real thing.
On March 17, excavating crews on the Linking Lookout project, which is taking place near U.S. 6 and 19th Street in Golden, discovered baculite fossils, estimated to be about 70 million years old. Two pieces were found, which are about 4 or 5 inches long.
Baculites swam with the mosasaur — a giant sea lizard — and a fish called the Xiphactinus during a time when Colorado was covered in saltwater.
Finding baculite fossils is an interesting discovery, said Nicole Peavey, paleontologist for the Colorado Department of Transportation, but not unexpected because they’re quite common in this area.
“It’s always cool when the crews find fossils,” she said. This discovery is “like finding a really cool seashell.”
The find was not significant enough to stop the construction project. However, “we’ll definitely be keeping an eye out going forward,” Peavey said.
The Golden area is known for fossil finds, said Karlyn Tilley, the city’s communications manager.
“In fact, our golf course is named Fossil Trace, in part, because fossils were found there as they were creating the golf course,” Tilley said. The discoveries are “just one more thing that makes our city an incredible place.”
The baculite was a cephalopod, meaning it was a squid-like creature, and it lived late in the Cretaceous period of the Mesozoic Era. Peavey’s best guess is that the fossils are about 70 million years old.
“It represents Colorado right around the time at the end of the dinosaurs,” Peavey said. The fossils provide “a cool snapshot of what the Golden area looked like back then.”
Baculites are believed to have varied in size, and grew cone-shaped shells, that could grow to 10 feet long in some species, they kept for their entire lives, said Matthew Mossbrucker, director and chief curator at the Morrison Natural History Museum.
Although dozens of the baculite have been found here, and they’re usually well-preserved, Mossbrucker said he commonly finds segments of the shell. It’s “very rare to find one whole.”
The fossils found during the Linking Lookout project will be spending more time with Peavey for study, but she will eventually offer them to the Denver Museum of Nature and Science. If the fossils are not needed at the museum, they will stay with CDOT to be used as a teaching tool for construction crews.
The first discoveries of baculites in the area helped people learn that Colorado was once covered under a body of saltwater, Mossbrucker said. Cephalopods only live in saltwater, and baculites only existed during a certain time period.
“The Denver-metro area is full of fossils that help us know what Colorado was like before there were people here,” he said. “All fossils tell stories on what life was like then.”