@misc{indiciae924757d1728f,
  title = {Preliminary geologic map of part of the Edgemont quadrangle, Fall River County, South Dakota, figure 8},
  author = {John Donald Ryan and Roy E. Roadifer},
  year = {1955},
  doi = {10.3133/ofr55156},
  url = {https://pubs.usgs.gov/publication/ofr55156},
  note = {Source identifier: ofr55156}
}