Chert Crescent from San Miguel Island (IMAGE) University of Oregon Caption A three-view look at a chert crescent dating to ancient seafarers on San Miguel Island. Credit Courtesy of Jon Erlandson 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.