@misc{indiciae52eb7c8d3a42,
  title = {Geologic map of the Ashland quadrangle, Columbia and Schuylkill Counties, Pennsylvania},
  author = {Harold H. Arndt},
  year = {1971},
  doi = {10.3133/gq918},
  url = {https://pubs.usgs.gov/publication/gq918},
  note = {Source identifier: gq918}
}