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Dinosaur Dig in Emery County

Dinosaur excavation near Castle Dale, UT
Dan Bammes KUER
Dinosaur excavation near Castle Dale, UT

By Dan Bammes

Castle Dale, UT – Bit by bit, volunteers and professional paleontologists are scraping away the gray soil on a hillside just northeast of Castle Dale in Emery County. They're removing the fossilized bones of a juvenile allosaurus, a meat-eating dinosaur that lived about 140-million years ago. Dinosaur bones are not uncommon in the Morrison Formation of eastern Utah. But John Bird with the College of Eastern Utah says it's rare to find an articulated specimen, where they can see how the bones fit together.

"It's nice digging," Bird says. "I'm used to a lot harder digging. And this is nice. We're using knives and small screwdrivers and the mudstone just peels off. We're taking it off a thin layer at a time. You don't want to take too much at a time because if you get into a bone you can break it."

For a few days last week, the site was open to the public. It's just a short walk from a well-traveled road leading to the San Rafael Swell. Bill Heffner found the fossil last November, explained to visitors what the area was like when the dinosaur died here and its bones were covered by silt.

"This was a coastal area," Heffner explained to visitors. "There must have been lots of waterways and river channels, and almost all of our quarry sites are in river channels . . . a lot of dinosaurs died in river channels and all their carcasses wash down into a log jam somewhere."

The area they've excavated is not much bigger than a car, maybe six feet by twelve feet. Volunteer Barb Benson is using a hammer and chisel to remove the gray mudstone. She was working around the bones of yet another dinosaur that have been uncovered at this site.

"It looks like I have a sauropod over here," she said, indicating a large bone just emerging from the gray earth. "It's either a limb bone for an allosaur or it's a rib bone for a sauropod. Not sure which."

A 5th grader from Sandy was in the crowd watching her work. "They're scraping away the dirt with brushes and loosening the dirt with a little bit of pickaxes and screwdrivers."

The Bureau of Land Management is often accused of limiting access to public land, but regional paleontologist Scott Foss says the agency was delighted to give visitors a close-up look.

"Utah is one of the only places where you just have this wealth of dinosaurs," Foss said. "On the East Coast, people don't have this opportunity and so and so we wanna show this off. It's really exciting for us."

Work has now wrapped up at the site. The bones have been taken to the prehistoric museum at the College of Eastern Utah. When they've been cleaned, reassembled and thoroughly studied, they'll be on display there.

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