@misc{indiciae400bd7584abc,
  title = {General distribution of geologic materials in the southern San Francisco Bay Region, California: A digital map database},
  author = {Carl M. Wentworth},
  year = {1993},
  doi = {10.3133/ofr93693},
  url = {https://pubs.usgs.gov/publication/ofr93693},
  note = {Source identifier: ofr93693}
}