@misc{indiciae186f714d13b4,
  title = {Ordovician and Silurian graptolite succession in the Trail Creek area, central Idaho; a graptolite zone reference section},
  author = {Claire Carter and Michael Churkin},
  year = {1977},
  doi = {10.3133/pp1020},
  url = {https://pubs.usgs.gov/publication/pp1020},
  note = {Source identifier: pp1020}
}