@misc{indiciae07acae41fe5f,
  title = {Geologic map of the Round Hill quadrangle, Clarke and Loudoun Counties, Virginia, and Jefferson County, West Virginia},
  author = {Robert C. McDowell and Daniel J. Milton},
  year = {1992},
  doi = {10.3133/gq1702},
  url = {https://pubs.usgs.gov/publication/gq1702},
  note = {Source identifier: gq1702}
}