The numerous fossils discovered in the heart of the Cloup d'Aural phosphate mines are dated back to 30 to 50 million years ago. They are, however, in an excellent state of preservation. It is due to the presence of phosphate in the clay pockets from which they are excavated. There are 300 phosphate mines in Quercy, and 200 of them are currently studied by paleontologists. The fossils entrusted to scientists by the miners have traveled as far as Australia and South America to be examined by specialists.