@misc{indiciae4a5142c02272,
  title = {Geological and Geographical Atlas of Colorado and portions of adjacent territory},
  author = {Ferdinand Vandeveer Hayden and Julius Bien},
  year = {1877},
  doi = {10.3133/70039832},
  url = {https://pubs.usgs.gov/publication/70039832},
  note = {Source identifier: 70039832}
}