@misc{indiciae600503659449,
  title = {The Chopawamsic Formation — A new stratigraphic unit in the Piedmont of northeastern Virginia},
  author = {D. L. Southwick and John Calvin Reed and Robert B. Mixon},
  year = {1971},
  doi = {10.3133/b1324d},
  url = {https://pubs.usgs.gov/publication/b1324D},
  note = {Source identifier: b1324D}
}