@misc{indiciaecf3601f7a6e1,
  title = {Geologic map of the Hayfield quadrangle, Frederick County, Virginia},
  author = {Daniel H. Doctor and Ronald A. Parker},
  year = {2018},
  doi = {10.3133/sim3407},
  url = {https://pubs.usgs.gov/publication/sim3407},
  note = {Source identifier: sim3407}
}