@misc{indiciae2f4d8e8df643,
  title = {Thirtieth annual report of the Director of the United States Geological Survey},
  author = {George Otis Smith},
  year = {1909},
  doi = {10.3133/ar30},
  url = {https://pubs.usgs.gov/publication/ar30},
  note = {Source identifier: ar30}
}