@misc{indiciae3bb6f8439bea,
  title = {Upper Mississippian rocks of southwestern Virginia, southern West Virginia, and eastern Kentucky},
  author = {Ralph H. Wilpolt and Douglas W. Marden},
  year = {1949},
  doi = {10.3133/oc38},
  url = {https://pubs.usgs.gov/publication/oc38},
  note = {Source identifier: oc38}
}