Valley River View (IMAGE) Penn State Caption The Shale Hills Critical Zone Observatory, part of the Critical Zone Exploration Network, is a small watershed located in Huntingdon County, Pa. Credit Elizebeth Herndon Usage Restrictions Non-commercial use only. 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.