@misc{indiciae806729fb4295, title = {Preliminary geologic map of [NW] part of the Flint Hill quadrangle, Fall River County, South Dakota, figure 5}, author = {Henry Bell and Edwin Van Horn Post}, year = {1955}, doi = {10.3133/ofr559}, url = {https://pubs.usgs.gov/publication/ofr559}, note = {Source identifier: ofr559} }