@misc{indiciaeb683d668e53b,
  title = {The glacial boundary in western Pennsylvania, Ohio, Kentucky, Indiana, and Illinois},
  author = {G. Frederick Wright and Thomas C. Chamberlin},
  year = {1890},
  doi = {10.3133/b58},
  url = {https://pubs.usgs.gov/publication/b58},
  note = {Source identifier: b58}
}