@misc{indiciae3d914b9df4ea,
  title = {Twentieth annual report of the United States Geological Survey, 1898-1899: Part I - Director's report including triangulation and spirit leveling},
  author = {Charles D. Walcott},
  year = {1899},
  doi = {10.3133/ar20\_1},
  url = {https://pubs.usgs.gov/publication/ar20\_1},
  note = {Source identifier: ar20\_1}
}