@misc{indiciae29fba34bc031,
  title = {Contributions to the stratigraphy of southwestern Colorado},
  author = {Whitman Cross and E. S. Larsen},
  year = {1915},
  doi = {10.3133/pp90e},
  url = {https://pubs.usgs.gov/publication/pp90E},
  note = {Source identifier: pp90E}
}