Some 16 miles outside of the town of Gulgong in southeastern Australia, landowner Nigel McGrath spent one day a few years ago working a particularly tough part of his fields. The patch of land was strewn with heavy, iron-rich rocks that menaced his farm equipment, so McGrath had to haul the loose blocks into piles by hand. That’s when he noticed them: immaculately preserved fossil leaves, tucked into the rocks like pressings in a book of stone.

Now scientists have confirmed that these ironstones—strewn over an area no bigger than half a football field—contain one of the most astonishing records ever found of life in an ancient rainforest.

There are other Miocene fossil sites in Australia that are famous for mammal and