@misc{indiciae6a4628e3eeec,
  title = {Geologic map showing occurrence of diabase in Somerset County, Maine},
  author = {A. J. Boucot},
  year = {1952},
  doi = {10.3133/ofr5216},
  url = {https://pubs.usgs.gov/publication/ofr5216},
  note = {Source identifier: ofr5216}
}