Fossil of Burrow Activity in Sediment (IMAGE) University of Southern Denmark Caption This image depicts a 530-million-year-old fossil of burrow activity in sediment. Credit Martin Brasier, University of Oxford 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.