@misc{indiciae13661efe86ec,
  title = {Preliminary geologic map of the Craig 1 degree by 2 degrees Quadrangle, northwestern Colorado},
  author = {Ogden Tweto},
  year = {1975},
  doi = {10.3133/mf666},
  url = {https://pubs.usgs.gov/publication/mf666},
  note = {Source identifier: mf666}
}