@misc{indiciaea6d91a55d36f,
  title = {Geologic map of the Niwot quadrangle, Boulder County, Colorado},
  author = {Donald E. Trimble},
  year = {1975},
  doi = {10.3133/gq1229},
  url = {https://pubs.usgs.gov/publication/gq1229},
  note = {Source identifier: gq1229}
}