@misc{indiciae83952695cb00,
  title = {Preliminary geologic map of the Roc Creek quadrangle, Colorado},
  author = {E.M. Shoemaker},
  year = {1955},
  doi = {10.3133/mf23},
  url = {https://pubs.usgs.gov/publication/mf23},
  note = {Source identifier: mf23}
}