Dr. Anna Gillespie, UNSW palaeontologist (IMAGE) Flinders University Caption Fossil preparator Dr. Anna Gillespie immersing a large block of Riversleigh Limestone in acid. Credit Dr. Anna Gillespie Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.