Geology of the forty-ninth parallel sheet no. 6, map 79 A.
Geology of the forty-ninth parallel sheet no. 6, map 79 A., map, 1913; [Ottawa, Ontario, Canada]. (texashistory.unt.edu/ark:/67531/metapth187400/: accessed March 21, 2018), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; crediting University of Texas at Arlington Library.