@misc{indiciae9f9a9581ea43,
  title = {Fortieth annual report of the Director of the United States Geological Survey},
  author = {George Otis Smith},
  year = {1919},
  doi = {10.3133/ar40},
  url = {https://pubs.usgs.gov/publication/ar40},
  note = {Source identifier: ar40}
}