|Geologic age||Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]|
|Comments||Chalk, in part argillaceous and sandy, thickly bedded to massive, hard bluish white; weathers white; scattered marine megafossils; thickness 450 +_ ft, thins eastward.|
|Primary rock type||limestone|
|Secondary rock type|
|Other rock types|
Sedimentary > Carbonate > Limestone > Chalk (Bed)
Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000
Bureau of Economic Geology, 1966, Texarkana Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, scale 1:250,000.