@misc{indiciaec71e73d59277,
  title = {Bundled slaty cleavage in laminated argillite, north-central Minnesota},
  author = {D. L. Southwick},
  year = {1987},
  doi = {10.1016/0191-8141(87)90006-x},
  url = {https://pubs.usgs.gov/publication/70014747},
  note = {Source identifier: 70014747}
}