@misc{indiciae5f74cb0ef558,
  title = {Crystalline rocks of the Potomac River Gorge near Washington, D.C.},
  author = {John Calvin Reed and Janice Jolly},
  year = {1963},
  doi = {10.3133/pp414h},
  url = {https://pubs.usgs.gov/publication/pp414H},
  note = {Source identifier: pp414H}
}