@misc{indiciae93a2ffdd5654,
  title = {Reports and maps of the Geological Survey released only in the open files, 1970},
  author = {Betsy A. Weld and Margaret S. Griffin and George W. Brett},
  year = {1971},
  doi = {10.3133/cir638},
  url = {https://pubs.usgs.gov/publication/cir638},
  note = {Source identifier: cir638}
}