working on a core sample (IMAGE) Penn State Caption Victoria Fortiz (right), then a graduate student at Penn State, and Jean Self-Trail, a research geologist at the U.S. Geological Survey, work on a core sample from the Howards Tract site in Maryland Credit Penn State Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. No derivatives or adaptations of the work are permitted. License CC BY-NC-ND 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.