@misc{indiciaec8ff057425e5,
  title = {Geology of the Portland quadrangle, Oregon-Washington},
  author = {Donald E. Trimble},
  year = {1957},
  doi = {10.3133/gq104},
  url = {https://pubs.usgs.gov/publication/gq104},
  note = {Source identifier: gq104}
}