@misc{indiciae08ed89f652a4,
  title = {Geologic field compilation map of the northern Black Hills, South Dakota},
  author = {R. W. Bayley},
  year = {1972},
  doi = {10.3133/ofr7229},
  url = {https://pubs.usgs.gov/publication/ofr7229},
  note = {Source identifier: ofr7229}
}