@misc{indiciae0496197d2463,
  title = {Geologic map of the Topton quadrangle, Lehigh and Berks Counties, Pennsylvania},
  author = {Avery Ala Drake},
  year = {1987},
  doi = {10.3133/gq1609},
  url = {https://pubs.usgs.gov/publication/gq1609},
  note = {Source identifier: gq1609}
}