@misc{indiciae338092ad3910,
  title = {Map showing contours on top of the upper Cretaceous Mowry Shale, Powder River basin, Wyoming and Montana},
  author = {B.L. Crysdale},
  year = {1991},
  doi = {10.3133/mf2140d},
  url = {https://pubs.usgs.gov/publication/mf2140D},
  note = {Source identifier: mf2140D}
}