The first details of Phanerozoic stromatolitic phosphorites are reported here. The stromatolites, from the Thorntonia Limestone in the Georgina Basin, northern Australia are of middle Cambrian age. The carbonates interfinger with and underlie the Beetle Creek Formation which contains Australia's largest known phosphate deposits. Phosphatic stromatolites had previously only been found in Proterozoic rocks, from the middle to upper Riphean Aravalli Group of Rajasthan, India and in the USSR and China1. It was generally considered that phosphatic stromatolites were unique to the Precambrian2,3, Indeed this unique association had led to hypotheses that during the Precambrian a different set of phosphogenic processes must have existed4.