@misc{indiciae9c9bc0e2df4e,
  title = {Geologic map of the Rapid City NW quadrangle, Meade and Pennington Counties, South Dakota},
  author = {Edward E. McGregor and John Mark Cattermole},
  year = {1973},
  doi = {10.3133/gq1093},
  url = {https://pubs.usgs.gov/publication/gq1093},
  note = {Source identifier: gq1093}
}