|Geologic age||Phanerozoic | Mesozoic | Cretaceous-Late [Gulfian]|
|Comments||Basal unit in Austin Group in northeast Texas, 10 mi SE of Denison in Grayson and Fannin Cos. Chalk, argillaceous, brittle, light gray; weathers white; thickness 35 ft. feathers out eastward in Fannin County.|
|Primary rock type||limestone|
|Secondary rock type|
|Other rock types|
Sedimentary > Carbonate > Limestone > Chalk (Bed)Chalk.
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, 1967, Sherman Sheet, Geologic Atlas of Texas: University of Texas at Austin, Bureau of Economic Geology, scale 1:250,000.
|Counties||Fannin - Grayson|