@misc{indiciaed871f89256dc,
  title = {Geologic map of the national parks in the National Capital region, Washington, D.C., Virginia, Maryland, and West Virginia},
  author = {Scott Southworth and Danielle Denenny},
  year = {2006},
  doi = {10.3133/ofr20051331},
  url = {https://pubs.usgs.gov/publication/ofr20051331},
  note = {Source identifier: ofr20051331}
}