@misc{indiciae93f446e03866,
  title = {Altitude of the top of the Madison Limestone in the Black Hills area, South Dakota},
  author = {Janet M. Carter and Jack A. Redden},
  year = {1999},
  doi = {10.3133/ha744d},
  url = {https://pubs.usgs.gov/publication/ha744D},
  note = {Source identifier: ha744D}
}