@misc{indiciae45f4194b318b,
  title = {Index to the stratigraphy of North America accompanied by a geologic map of North America},
  author = {Bailey Willis},
  year = {1912},
  doi = {10.3133/pp71},
  url = {https://pubs.usgs.gov/publication/pp71},
  note = {Source identifier: pp71}
}