Geology of the Talbragar fossil fish bed area

Chert containing Jurassic plant and fish fossils occurs as loose blocks floating in soil derived by weathering from Jurassic Purlawaugh sediments overlain by remnants of Pilliga sandstone and underlain by Triassic Narrabeen sandstone.From field investigations it is concluded that the loose blocks of chert represent displaced erosional remnants, and all that is left, of an isolated lake-bed deposit now almost completely removed by erosion.The chert bed appears to have accumulated over a relatively short period of time, probably less than 250 years, and possibly as little as several seasons.Dulhunty, John Allan.1969."Geology of the Talbragar fossil fish bed area."