The Cretaceous Area North of the Colorado River, map, Date Unknown; (https://texashistory.unt.edu/ark:/67531/metapth493231/m1/1/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .
The Cretaceous Area North of the Colorado River, map, Date Unknown; (https://texashistory.unt.edu/ark:/67531/metapth493231/m1/1/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .