Construction workers in Brisbane have unearthed animal and plant fossils believed to be about 50 million years old.
The fossils were contained in a layer of oil shale more than 15 metres underground at Geebung on Brisbane's northside.
The surprise discovery was brought to the surface by a piling rig last month during building excavation works.
Project engineers have been talking to experts from the Queensland Museum, who say the fossils are those of ancient crocodiles, fish, freshwater shells and plants.
Academics say the suburban site was completely unknown to them.
Professor Suzanne Miller, the chief of the Queensland Museum, says the find is not only unusual but significant.
"It's very unusual to find materials being uncovered in these urban sites. I mean, most discoveries of this nature are found miles from anywhere," she told The World Today.
"First of all it's very unusual to have an urban construction site that finds it, and secondly to have the people on the construction team realise that there was something unusual and to make that call was incredibly fortunate for us."
Professor Miller says the museum now needs to find a site for the five tonnes of soil that road workers have set aside, and a team of community volunteers to help sift through the material.
She says the fossils could fill in a missing link in worldwide knowledge of what happened after the dinosaurs were wiped off the planet.
"We believe that there's real potential in this site to uncover something that will be absolutely unique for Queensland and really unique for Australia," she said.
