@misc{indiciaeb8429ab416fb,
  title = {Map showing depth to bedrock, Williamsburg Quadrangle, Massachusetts},
  author = {C.J. Londquist},
  year = {1974},
  doi = {10.3133/mf589a},
  url = {https://pubs.usgs.gov/publication/mf589A},
  note = {Source identifier: mf589A}
}