@misc{indiciae497e7c5fe8c5,
  title = {La Plata folio, Colorado},
  author = {Whitman Cross and Arthur Coe Spencer and Chester Wells Purington},
  year = {1899},
  doi = {10.3133/gf60},
  url = {https://pubs.usgs.gov/publication/gf60},
  note = {Source identifier: gf60}
}