A Colorado scientist says he’s “over the moon” after a construction crew in the city of Thornton reportedly stumbled upon a triceratops fossil last week.

The construction workers were breaking ground for a new fire and police building when they encountered an obstruction in the dirt, The Denver Post reports. After a crew member pointed out that it could be a fossil, paleontologists from the Denver Museum of Nature and Science were called in to investigate.

Joe Sertich, the museum’s curator of dinosaurs, arrived at the site Monday and discovered to his delight that the workers had indeed unearthed something remarkable.

“My heart was racing,” Sertich said in a statement posted on the city of Thornton’s website. “I realized it was a pretty important dinosaur find.”

Joe Sertich, at left, works to excavate the fossilized bones in Thornton, Colorado. (Photo: City of Thornton)

Sertich believes the crew uncovered parts of a skull and skeleton of a triceratops. He says it’s “one of only three” triceratops skulls ever found in the Front Range of the Rocky Mountains. Most fossils found in the Front Range are about 10,000 to 12,000 years old, he said, but the bones discovered in Thornton appear to be much, much older.

“This dinosaur has been laying here for at least 66 million years,” Sertich said. “I’m over the moon right now about this dinosaur fossil.”

(Photo: City of Thornton)

Construction at the fossil site has reportedly been halted as scientists search for any other fossils potentially awaiting discovery.

“A lot of times [fossils] will be plowed up and they won’t be recognized,” Sertich said. “We’re really lucky in this case that it was recognized as fossils and we got the call.”

It's taking shape! Our team has uncovered a rib, scapula and 2 telltale #triceratops brow horns in Thornton so far pic.twitter.com/i0OpoHQyLf — Denver Museum (@DenverMuseumNS) August 30, 2017

As Smithsonian magazine notes, the herbivorous triceratops was among the last species of dinosaur to roam the Earth.

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The dinosaur’s three-horned skull has been described as “one of the largest and most striking of any land animal.”

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Qijianglong, or The Long-Necked Dragon

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Yi qi, or The Mysterious Bat Pigeon

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Zhenyuanlong suni, aka The Fluffy Chicken From Hell

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"The real Velociraptors," a paleontologist said, "would have been feathery, fluffy, winged Chickens from Hell."



While Zhenyuanlong suni may have had a set of birdlike wings, it was too short to fly and was likely used for show and egg protection.

Lightning Claw, aka T. Rex's Little Cousin

With 10-inch claws, what else could scientists name this thing? The extraordinary meat-eating dinosaur was discovered in an opal mine in Australia, making its fossils a gorgeous blue color. The 22-foot-long beast was certainly no match for T. rex, but its huge hook-like claws definitely made it ferocious.

Ugrunaaluk kuukpikensis, aka The Arctic Nightowl

Ugrunaaluk kuukpikensis were "truly polar," according to scientists. Their fossils were discovered in northern Alaska, which means the large, duck-billed herbivore had the resilience to live in darkness for months at a time and endure the unforgiving environment. Scientists still aren't sure what they did for food during the long, hard winters.

Hualianceratops wucaiwanensis, aka The Big-Headed Dog Dino

Fossils found in China suggest the Triceratops had a super-weird relative. "It was probably about the size of a spaniel dog, with a relatively large head, and walked on its hind legs," a paleontologist told HuffPost. H. wucaiwanensis is thought to be the oldest known member of the ceratopsians genus (which includes the Triceratops) and its remains have helped scientists better understand the early evolution of horned dinosaurs.

Morelladon, aka The Humpback Sail

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This article originally appeared on HuffPost.