@misc{indiciae15e046f22907,
  title = {Contributions to the mineralogy of the Rocky Mountains},
  author = {Whitman Cross and W. F. Hillebrand},
  year = {1885},
  doi = {10.3133/b20},
  url = {https://pubs.usgs.gov/publication/b20},
  note = {Source identifier: b20}
}