@misc{indiciae4769b7cea8c3,
  title = {Geologic map of the Boulder-Fort Collins-Greeley area, Colorado},
  author = {Roger B. Colton},
  year = {1978},
  doi = {10.3133/i855g},
  url = {https://pubs.usgs.gov/publication/i855G},
  note = {Source identifier: i855G}
}