@misc{indiciae662563237589,
  title = {Geology of the Brandywine area and origin of the upland of southern Maryland},
  author = {J.T. Hack},
  year = {1955},
  doi = {10.3133/pp267a},
  url = {https://pubs.usgs.gov/publication/pp267A},
  note = {Source identifier: pp267A}
}