@misc{indiciae48a4c8a223f8,
  title = {Gravel and sand deposits of eastern Maryland, adjacent to Washington and Baltimore},
  author = {Nelson Horatio Darton},
  year = {1939},
  doi = {10.3133/b906a},
  url = {https://pubs.usgs.gov/publication/b906A},
  note = {Source identifier: b906A}
}