@misc{indiciae94985caf5885,
  title = {The river and the rocks: The geologic story of Great Falls and the Potomac River Gorge},
  author = {John Calvin Reed and Robert Sumner Sigafoos and George Wescott Fisher},
  year = {1980},
  doi = {10.3133/b1471},
  url = {https://pubs.usgs.gov/publication/b1471},
  note = {Source identifier: b1471}
}