Basalt Flows (IMAGE) Princeton University Caption The well-exposed layering of basalt flows in formations near Lake Superior is aiding scientific understanding of the geomagnetic field in ancient times. Nicholas Swanson-Hysell, a Princeton graduate student, examines the details of the top of a lava flow. Credit Catherine Rose 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.