Fossils of Juvenile Crinoid Holdfasts (IMAGE) Ohio State University Caption Holdfasts from very young crinoids that lived 450 million years ago, fossilized in iron oxide. An international team of researchers discovered the tiny fossils, measuring one to four millimeters across, in rock exposed by World War I trenches dug in the Alps. Credit Image courtesy of The Ohio State University. 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.