@misc{indiciaebbeec9effecc,
  title = {Sections and maps of Lower Ordovician and Cambrian rocks in the Michigan basin, Michigan and adjoining areas},
  author = {G. V. Cohee},
  year = {1945},
  doi = {10.3133/oc9},
  url = {https://pubs.usgs.gov/publication/oc9},
  note = {Source identifier: oc9}
}