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It is now a quarry in Oxfordshire. But nearly 166m years ago it was where a large number of dinosaurs crisscrossed the limestone floor.
Researchers have unearthed 200 large dinosaur footprints – said to be the biggest site of its kind in the UK – from two types of dinosaurs, thought to be the herbivorous cetiosaurus and the carnivorous megalosaurus. The longest trackways are 150 metres in length, and only part of the quarry has been excavated.
“This is one of the most impressive track sites I’ve ever seen, in terms of scale, in terms of size of the tracks,” Prof Kirsty Edgar, a micropalaeontologist from the University of Birmingham, told the BBC. “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.”
In 1997, a trackway of megalosaurus footprints was discovered at Ardley quarry in Oxfordshire. Recollections of that discovery led Gary Johnson, a worker at Dewars Farm quarry, to consider whether bumps and dips he had found in the limestone floor there could be dinosaur footprints.
“I was basically clearing the clay and I hit a bump, and I thought it’s just an abnormality in the ground,” Johnson told the BBC. “But then it got to another, 3 metres along, and it was a hump again, and then it went another 3 metres, hump again.”
Over the summer a team of more than 100 scientists, students and volunteers joined an excavation at the site, which will feature on the TV series Digging for Britain next week.
The team found five trackways, four of which were believed to have been made by sauropods, plant-eating dinosaurs that walked on four legs. Another track is believed to have been created by a megalosaurus, a carnivorous dinosaur that walked on two legs.
The latter was “almost like a caricature of a dinosaur footprint”, Dr Emma Nicholls, a vertebrate palaeontologist from the Oxford University Museum of Natural History, told the BBC. “It’s what we call a tridactyl print. It’s got these three toes that are very, very clear in the print. The whole animal would have been 6-9 metres in length. They were the largest predatory dinosaurs that we know of in the Jurassic period in Britain.”
The trackways were studied in detail during the excavation, and casts of the tracks were made and more than 20,000 photographs taken, to create 3D models of the entire site and individual footprints.
Prof Richard Butler, a palaeobiologist at the University of Birmingham, said dinosaur footprints provided a snapshot of the life of the animal, including how they moved and the environment in which they lived – information that would not be available from the bone fossil record alone.
Why these particular trackways were preserved remains unknown. “Something must have happened to preserve these in the fossil record,” Butler said. “We don’t know exactly what, but it might be that there was a storm event that came in, deposited a load of sediments on top of the footprints, and meant that they were preserved rather than just being washed away.”
