@misc{indiciae992fb19e2ffa,
  title = {Sixteenth Annual report of the United States Geological Survey to the Secretary of the Interior, 1894-1895: Part 4 -- Mineral Resources of the United States, 1894, Nonmetallic Products},
  author = {Charles D. Walcott},
  year = {1896},
  doi = {10.3133/ar16},
  url = {https://pubs.usgs.gov/publication/ar16},
  note = {Source identifier: ar16}
}