@misc{indiciae940ff2ae964b,
  title = {Quaternary geology of Alameda County, and parts of Contra Costa, Santa Clara, San Mateo, San Francisco, Stanislaus, and San Joaquin Counties, California: A digital database},
  author = {E. J. Helley and R. W. Graymer},
  year = {1997},
  doi = {10.3133/ofr9797},
  url = {https://pubs.usgs.gov/publication/ofr9797},
  note = {Source identifier: ofr9797}
}