@misc{indiciaec9d8a7e45417,
  title = {The Shawangunk Formation (Upper Ordovician(?) to Middle Silurian) in eastern Pennsylvania},
  author = {Jack Burton Epstein and Anita G. Epstein},
  year = {1972},
  doi = {10.3133/pp744},
  url = {https://pubs.usgs.gov/publication/pp744},
  note = {Source identifier: pp744}
}