Fossil-Containing Spherical Concretion (IMAGE) Nagoya University Caption Concretion formed by very rapid reaction of carbon from the fossilized organism (ghost shrimp: ca. 16 million years old) with calcium ions of the surrounding seawater. Credit Hidekazu Yoshida Usage Restrictions with credit 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.