|Geologic age||Early Cretaceous|
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Carbonate > Dolostone (Bed)
Sedimentary > Chemical > Chert (Bed)
|Comments||In Eastern part of Trans-Pecos and High Plains- Limestone, dolostone, and chert; ls. aphanitic to fine grained, massive to thin-bedded, hard, brittle, in part rudistid biostromes, much miliolid biosparite; dolostone fine to v. fine grained, porous, chert nodules common. important aquifer. 350-400 ft thick. In North, central, and south Texas including Quaternary for all of west Texas- Limestone, dolostone, and chert; Upper part--mostly ls, argillaceous, beds of even thickness, some nodular; alternating hard and soft units, Exogyra texana and miliolids locally abdt; thickness 40 ft. Lower part--ls., dolostone, and chert; ls. aphanitic to fine grained, argill., locally siliceous, thin beds to nodular and massive, hard, gray to lt brn, miliolids, gastropods, and rudistids, chert nodules and plates common; dolostone fine to v. fine grained, porous, chert nodules common. important aquifer. Lower part up to 100 ft thick. Total thickness of Edwards in Brownwood Sheet as much as 140 ft.|
|Stratigraphic units||bott to top: Bee Cave Marl Member, Cedar Park Limestone Member, Port Terrett Member, Segovia Member contains Kirschberg evaporite|
Bureau of Economic Geology, 1981, Llano sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, scale 1:250,000.
Bureau of Economic Geology, 1974, San Angelo Sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, scale 1:250,000.
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.
|Counties||Andrews - Bandera - Bexar - Blanco - Brewster - Brown - Caldwell - Callahan - Coke - Coleman - Comal - Comanche - Concho - Crockett - Ector - Edwards - Floyd - Gaines - Gillespie - Glasscock - Guadalupe - Hays - Howard - Irion - Kendall - Kent - Kerr - Kimble - McCulloch - Martin - Mason - Medina - Menard - Midland - Mitchell - Nolan - Pecos - Reagan - Real - Runnels - San Saba - Schleicher - Sterling - Sutton - Taylor - Terrell - Terry - Tom Green - Travis - Upton - Val Verde|