@misc{indiciaec1819a0699b1,
  title = {Geology of the Penawawa quadrangle, Washington},
  author = {Howard Hamilton Waldron and Leonard Meade Gard},
  year = {1955},
  doi = {10.3133/gq56},
  url = {https://pubs.usgs.gov/publication/gq56},
  note = {Source identifier: gq56}
}