Figure 1 (IMAGE) Nagoya University Caption An example of concretion formed around a tusk shell. Fossils in concretions are remarkably resilient. Credit Hidekazu Yoshida Usage Restrictions Credit must be given where image is used License Original 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.