erc:
who: Geological Survey (U.S.)
what: Brackett Sheet
when: 1897
where: https://texashistory.unt.edu/ark:/67531/metapth450440/
erc-support:
who: University of North Texas Libraries
what: Permanent: Stable Content:
when: 20081203
where: https://texashistory.unt.edu/ark:/67531/