Dr. Andrew Leier, University of Calgary (IMAGE) University of Calgary Caption Dr. Andrew Leier researched the origin of individual sand grains that were deposited during the Cretaceous Period in western North America. Credit University of Calgary 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.