@misc{indiciae5e04739e7702,
  title = {The river and the rocks : the geologic story of Great Falls and the Potomac River Gorge},
  year = {1970},
  doi = {10.3133/70007449},
  url = {https://pubs.usgs.gov/publication/70007449},
  note = {Source identifier: 70007449}
}