@misc{indiciae40ad11cd31ca,
  title = {The pre-Cambrian igneous rocks of eastern Pennsylvania and Maryland},
  author = {Florence Bascom},
  year = {2014},
  doi = {10.1029/tr016i001p00328},
  url = {https://pubs.usgs.gov/publication/70241315},
  note = {Source identifier: 70241315}
}