@misc{indiciae94569ab9fc4c,
  title = {Preliminary geologic map of Portage quadrangle, Montana, surficial geology},
  author = {Richard Walter Lemke and Edwin K. Maughan},
  year = {1954},
  doi = {10.3133/ofr54166},
  url = {https://pubs.usgs.gov/publication/ofr54166},
  note = {Source identifier: ofr54166}
}