This system will be unavailable from 7pm CST Friday, December 13th until 7am CST Monday, December 16th.

Geological Survey (U.S.). Amarillo, map, 1976; (https://texashistory.unt.edu/ark:/67531/metapth455412/m1/1/: accessed December 10, 2019), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .