@misc{indiciae74d147141b2e,
  title = {Base of saprolite map, Fairfax Quadrangle, Virginia},
  author = {Arthur E. Nelson},
  year = {1976},
  doi = {10.3133/ofr76621},
  url = {https://pubs.usgs.gov/publication/ofr76621},
  note = {Source identifier: ofr76621}
}