@misc{indiciae0cb2eb7a15f9,
  title = {Twenty-seventh annual report of the Director of the United States Geological Survey},
  author = {Charles D. Walcott},
  year = {1906},
  doi = {10.3133/ar27},
  url = {https://pubs.usgs.gov/publication/ar27},
  note = {Source identifier: ar27}
}