@misc{indiciae1d379c4b2a32,
  title = {Geologic map of the Black Butte Mountain Quadrangle, Meagher County, Montana},
  author = {L.W. McGrew},
  year = {1974},
  doi = {10.3133/ofr74106},
  url = {https://pubs.usgs.gov/publication/ofr74106},
  note = {Source identifier: ofr74106}
}