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... Montgomery County, Pennsylvania.
2018. York County, Pennsylvania. York County Geology; Intended for illustration and demonstration purposes only. York County, Pennsylvania.
2016. Centre County Government. Geology layer showing the short and long names of the geologic formation. Centre County, Pennsylvania.
2018. Digitized regional surficial geology map for northwestern Pennsylvania. The complete citation for the paper map is: Map of the Glacial Deposits of ... Allegheny College.