@misc{indiciae3732172c852b,
  title = {Geologic map of the Purcellville quadrangle, Loudoun County, Virginia},
  author = {Scott Southworth},
  year = {1995},
  doi = {10.3133/gq1755},
  url = {https://pubs.usgs.gov/publication/gq1755},
  note = {Source identifier: gq1755}
}