@misc{indiciae0fd48d941e89,
  title = {Bedrock geologic map of the Ipswich quadrangle, Essex County, Massachusetts},
  author = {William H. Dennen},
  year = {1991},
  doi = {10.3133/gq1698},
  url = {https://pubs.usgs.gov/publication/gq1698},
  note = {Source identifier: gq1698}
}