@misc{indiciaea41d027a6f8b,
  title = {Thirty-ninth annual report of the Director of the United States Geological Survey},
  author = {George Otis Smith},
  year = {1918},
  doi = {10.3133/ar39},
  url = {https://pubs.usgs.gov/publication/ar39},
  note = {Source identifier: ar39}
}