2016. Centre County Government. Geology layer showing the short and long names of the geologic formation.
2020. U.S. Geological Survey, Southwest Region. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States (https://doi.org/10.5066/F7WH2N65) represents a seamless, s...
2018. York County, Pennsylvania. York County Geology; Intended for illustration and demonstration purposes only.