@misc{indiciae570e25cca6b7,
  title = {Geology of some dam sites on Little Colorado and its tributaries, Arizona},
  author = {Edwin B. Eckel},
  year = {1939},
  doi = {10.3133/ofr405},
  url = {https://pubs.usgs.gov/publication/ofr405},
  note = {Source identifier: ofr405}
}