@misc{indiciae64d4c2c023ec,
  title = {Contour map of the bedrock surface, Hampden quadrangle, Massachusetts–Connecticut},
  author = {C.J. Londquist},
  year = {1973},
  doi = {10.3133/mf486a},
  url = {https://pubs.usgs.gov/publication/mf486A},
  note = {Source identifier: mf486A}
}