@misc{indiciae16abb5836d5c,
  title = {Preliminary geologic map of the Black Butte iron deposit, Madison County, Montana},
  author = {K. L. Wier},
  year = {1965},
  doi = {10.3133/ofr65174},
  url = {https://pubs.usgs.gov/publication/ofr65174},
  note = {Source identifier: ofr65174}
}