A Quarry Worker Felt Strange Bumps While Digging. They Turned Out to Be the Largest Dinosaur Trackway in the U.K.

About 166 million years ago, dinosaurs ambled across a shallow lagoon in modern-day Britain. Some of the Jurassic giants took their sweet time, moving in fits and starts; others might have skulked more urgently. All made the mud squelch beneath their toes as they tromped here.

At the time, such an occurrence was just a mundane event of dinosaurs on the march. But the terrain preserved these fleeting crossings—though the dinosaurs are long gone, the impressions they left behind remain. Now, researchers and volunteers have uncovered the entire trackway where these Mesozoic monsters came and went. Containing around 200 marks in total, the site is the largest collection of fossilized footprints to have been discovered in the United Kingdom.

“This is one of the most impressive track sites I’ve ever seen, in terms of scale, in terms of the size of the tracks,” Kirsty Edgar, a micropaleontologist from the University of Birmingham in England, tells Rebecca Morelle and Alison Francis of BBC News. “You can step back in time and get an idea of what it would have been like, these massive creatures just roaming around, going about their own business.”

The dinosaur stomping ground was first discovered by quarry worker Gary Johnson while he was operating a mechanical digger. As he stripped back the clay from the ground, he felt unusual bumps underneath his machine. These might not usually be anything to gape at, but it was their repetition that caught Johnson’s attention. Every ten feet or so, he would find a similar hump.

Johnson had historical precedent to suspect that the regular impressions could be of paleontological significance: In 1997, a dinosaur crossing with 40 footprints was discovered nearby. He wondered if the holes on the ground could be another hotspot for dinosaur traffic. To find out for sure, he called in the experts.

“I thought, ‘I’m the first person to see them.’ And it was so surreal—a bit of a tingling moment, really,” he tells BBC News.

Last June, researchers from Oxford University and the University of Birmingham led a week-long excavation at the quarry site. More than 100 or so students and volunteers searched the ground for the footprints, then liberated them with brushes.

The team uncovered five trackways in the rock, each made by a different dinosaur. Four of them came from the footfalls of some herbivorous sauropod, likely a Cetiosaurus. These behemoths grew up to 59 feet in length. The final set of footprints were tellingly three-toed, belonging to a fearsome predator: the more than 20-foot-long Megalosaurus. As a species, Megalosaurus was the first dinosaur fossil to ever be named and described, and its study in 1824 kickstarted modern-day paleontology.

The longest of the sauropod trackways spans 490 feet in length. But the footprints disappear under a cliff at the edge of the quarry, which has yet to be fully excavated. So, according to a statement from Oxford University, the series of tracks could extend much farther.

Dinosaur footprints are an uncommon sight, and for good reason—it takes very specific circumstances to maintain them. The recent find was in one of the lucky areas. “It’s rare to find them so numerous in one place and it’s rare to find such extensive trackways as well,” Emma Nicholls, a paleontologist at the Oxford University Museum of Natural History, tells the Agence France-Presse. The research team suspects a storm piled sediment on top of the footprints and protected them from erosion.

The tracks’ preservation is so exquisite that scientists were able to cobble together snapshots of dinosaur behavior. One set of the sauropod tracks intersects with those of the Megalosaurus. From the shapes in the ground, the researchers conclude that the sauropod came by before the carnivore. Perhaps the predator was tracking its potential target, they suggest, though it’s impossible to say for sure. Elsewhere, one of the footprints on the largest sauropod track is out of sequence; researchers think the behemoth could have paused to look back over its shoulder.

“The preservation is so detailed that we can see how the mud was deformed as the dinosaur’s feet squelched in and out,” says Duncan Murdock, an Earth scientist at the Oxford University Museum of Natural History, in another statement. “Along with other fossils like burrows, shells and plants, we can bring to life the muddy lagoon environment the dinosaurs walked through.”

I’m thrilled to have played a small role in the excavation of the UK's biggest ever dinosaur trackway site at Dewars Farm Quarry, Oxfordshire, in June 2024!

The excavation uncovered over 200 footprints, including those of Megalosaurus and Cetiosaurus pic.twitter.com/UCrY2Uqf2t

— Dr Emily Swaby (@EmilyJSwaby) January 2, 2025

Modern analytical tools and digital recording equipment will help scientists glean more insights about the dinosaurs’ day-to-day lives. During the dig, the team created molds from individual footprints and took more than 20,000 photos. These will help researchers create 3D models of the individual markings, as well as the  terrain. The data will help inform scientists about the makers’ size, gait and walking speed, as well as how they might have interacted. Using computer models, the researchers can potentially recreate the scenes of dinosaurs on the move.

Prehistoric footprints might not be as glamorous as a dinosaur skeleton, but they give beholders a different kind of view into history. Bones provide largely static information—like shape and anatomy—but footprints are records of life, when the dinosaurs were still moving.

“To me, dinosaur trackways are much more ‘alive’ than fossilized bones, which can only be from dead animals,” says Emily Howard, an Oxford University earth sciences undergraduate student, in the statement. She was involved in the efforts to excavate the tracks last summer. “Similar to when you see human footprints on a path ahead of you, a dinosaur track gives the impression that the creature could be miles away in the direction the tracks march on but was here only a moment ago.”

Taken together with the bones, however—and with some help from modern technology—these earthen imprints give a holistic picture of the prehistoric creatures that sashayed along in their heyday, oblivious to the puny mammals of the future who would gawk at their footprints millions of years later.

Shi En Kim | | READ MORE

Shi En Kim is a Washington, D.C.-based freelance science journalist. Her work has appeared in National Geographic, Scientific American, the Atlantic, Popular Science and others. In 2021, she interned at Smithsonian magazine as an AAAS Mass Media Fellow.