@misc{indiciae1641acfcdb75,
  title = {Geology of the Boltsfork quadrangle and part of the Burnaugh quadrangle, Kentucky},
  author = {Frank Darwyn Spencer},
  year = {1964},
  doi = {10.3133/gq316},
  url = {https://pubs.usgs.gov/publication/gq316},
  note = {Source identifier: gq316}
}