Near the Gregory River in northwest Queensland lies Australia’s most famous fossil ground: about 100 square kilometres of freshwater limestone holding animals from as long as 25 million years ago, when this was wet rainforest slowly drying toward grassland. The limestone was never compacted, so the bones keep their three-dimensional shape instead of being crushed flat, and many were found in old caves and crevices that worked as pitfall traps, where bat guano helped preserve whole assemblages of bats. More than 290 species have been described, many known from nowhere else: the 15-million-year-old monotreme Obdurodon dicksoni, ancestors of the thylacine, and the koala-like Nimbadon. Palaeontologists from the University of New South Wales, Mike Archer among them since 1983, found that dilute acetic acid was the best way to free the bones from the rock. Riversleigh was listed as a World Heritage Site in 1994 together with the Naracoorte Caves, and it is part of Boodjamulla National Park.
Oligocene and Miocene mammals, birds and reptiles · Late Oligocene to Miocene, 25 mya onward
This ground is protected. Photograph it, record it, leave it where it lies. On US federal land the Paleontological Resources Preservation Act 2009 makes collecting vertebrate fossils an offence, and penalties are real.
Australia
See it on the map
This is remote ground. The closest other places on the map are a long way off.
