@misc{indiciae0730ae473dff,
  title = {Stratigraphy of the Cretaceous Hornbrook Formation, southern Oregon and Northern California},
  author = {T. H. Nilsen},
  year = {1993},
  doi = {10.3133/pp1521},
  url = {https://pubs.usgs.gov/publication/pp1521},
  note = {Source identifier: pp1521}
}