@misc{indiciaeca8c07a7406e,
  title = {Geologic map of northern part of Ruby Range, Madison County, Montana},
  author = {R. G. Tysdal},
  year = {1976},
  doi = {10.3133/i951},
  url = {https://pubs.usgs.gov/publication/i951},
  note = {Source identifier: i951}
}