@misc{indiciae495b34221139,
  title = {Geologic map of the Ennis 30' x 60' quadrangle, Gallatin and Madison Counties, Montana},
  author = {Karl S. Kellogg and Van S. Williams},
  year = {1998},
  doi = {10.3133/ofr97851},
  url = {https://pubs.usgs.gov/publication/ofr97851},
  note = {Source identifier: ofr97851}
}