1. Earth Science Excursions, LLC, 1 Trimont Lane, Unit 1020-B, Pittsburgh, Pennsylvania 15211, USA
2. Pennsylvania Geological Survey (Retired), 1633 Walnut Bottom Road, Carlisle, Pennsylvania 17015, USA
3. Department of Earth and Environmental Sciences, Dalhousie University, 1459 Oxford Street, Halifax, Nova Scotia B3H 4R2, Canada