Dinosaur Footprints Found in Brisbane's Heritage Sandstone
Some of Brisbane's oldest heritage-listed buildings are sitting on evidence of a prehistoric world. The stone holding them up preserved the footprints of dinosaurs that walked the land roughly 230 million years ago.
The footprints are fossilised and pressed into the same sandstone used for the General Post Office and other landmarks that define the city's centre. You could walk past them every day without knowing what's in the rock.
"These buildings certainly capture my eye, and I do glance twice to see what evidence might be hidden within their own architecture," palaeontologist Dr Anthony Romilio said. That habit of looking twice is how this story surfaced.
Tracks in the stone
Two separate pieces of Brisbane-mined sandstone went to the University of Queensland's Dinosaur Lab. Both appear to carry the tread-marks of a sauropodomorph, a group of long-necked plant-eaters.
Romilio's description of the animal is the most striking part. "Instead of walking on all four legs, they walked on their back legs. They still retained a very long neck and tail, but they were more ancient than the more typical than the brontosaurus," he said. Picture a creature that stood up on its hind legs, carried a long neck and tail, and belonged to a lineage older than the brontosaurus most people imagine.
One of the prints came from Petrie's Quarry, where a teenager spotted it more than six decades ago. It sat in plain view for generations before anyone thought to look at it properly.
A quarry that built a city
Before Albion became the leafy, sought-after inner-north suburb it is today, it was Petrie's Quarry. That's the part of the story most Brisbane residents have never heard, and it's arguably the bigger one.
Educator Sue-Belinda Meehan says the Petrie family opened the quarry in the 1860s, about 30 years after they settled in Brisbane, which was then the Moreton Bay Penal Colony. Stone is what turned a penal settlement into a city, and the Petries were the ones who spotted the stone's value.
"If the Petrie's hadn't recognised the quality of that sandstone, we wouldn't have the sandstone that literally built Brisbane," Meehan said.
The list of buildings is long. The General Post Office, All Hallows School and the Old Customs House were all built from the creamy white stone. St Stephen's Cathedral, St John's Cathedral and St Paul's Presbyterian Church also used Petrie sandstone.
"When you think about the number of buildings that were constructed from it, it's quite extraordinary … it's probably easier to mention buildings that weren't made from it, then buildings that were," Meehan said. She also pointed out that the quarry didn't pick sides. "They were very much equal opportunity builders. It didn't matter what brand of religion you were, the Petries would build you a church," she said.
Here's the thing that gets me: the masons were quarrying rock that already held dinosaur footprints, and nobody flagged it as a discovery.
"The thing that really tickles me is that there were stone masons looking at big blocks of sandstones going, 'oh heaven's there's a flaw in it, there's a footprint' … and cutting it out."
Albion's older residents
Once quarrying stopped, the site became a magnet for school children and aspiring geologists, and the suburb of Albion gradually grew up around it. The quarry didn't disappear entirely, though. Meehan says its remains are still visible today.
"If you go out to Albion and drive down Crosby Road, and look up to St Margaret's, you can see the scar in the mountain that was Petrie's Quarry."
Romilio explains what those white hills actually are. They're layers of sand laid down while dinosaurs were moving across the landscape. Go back 230 million years and you'd find a flat, nearly treeless plain crossed by a very wide river. It was shallow enough for a two-legged dinosaur to wade across.
The river wasn't empty. "It would have also been an environment in which aquatic creatures lived as well. So giant salamander like animals are known to have existed in that same time as well," Romilio said. So the sauropodomorph wasn't the only prehistoric creature moving through what is now Albion.
Footprints hiding in plain sight
The two sandstone slabs etched with dinosaur footprints were found in the 1950s. That's the detail that stays with me. The stone has been sitting in Queensland for decades, and the interest is only now catching up to it.
The real work is in the modern analysis. University of Queensland palaeontologist Anthony Romilio built a 3D map of one fossil, and that model is what helped pin down which kind of dinosaur made the print. Look at the before-and-after comparison below. The raw image shows a faint trace in sandstone. The 3D version makes the shape legible.
Romilio is regularly contacted with tips about Brisbane's Petrie Quarry site. Most people expect a dinosaur lead to come from a dusty outback town, not a city of several million people. Romilio's view is more useful than the expectation. "It may seem unusual in a capital city, that we find evidence of dinosaurs, but really all you need is the right aged material and a keen eye, and some conviction to investigate," Dr Romilio said.
That's the part that matters if you're in this field. The bottleneck usually isn't the rock. It's whether someone with the training looks at it and follows up.
Brisbane's geology also has a visual side that's easy to overlook. St Stephen's Cathedral now stands in a forest of modern towers, and the contrast is a reminder that the city has grown up over a much older, deeper record.
Ms Meehan argued that the dinosaur story isn't confined to the outback. "Queensland is just awash with wonderful dinosaur relics from the past, and to know that we have them here in Brisbane, just makes it an even more fabulous city," she said.
