@misc{indiciae2f350ec04ade,
  title = {Preliminary geologic map of [east-central] part of the Flint Hill quadrangle, Fall River County, South Dakota, figure 7},
  author = {Henry Bell and Edwin Van Horn Post},
  year = {1955},
  doi = {10.3133/ofr558},
  url = {https://pubs.usgs.gov/publication/ofr558},
  note = {Source identifier: ofr558}
}