Carboniferous stratigraphy of the Brady area, McCulloch and San Saba counties, Texas

Every traceable interval with lithic or topographic distinction was mapped, and these were nomenclatorially arranged into genetically distinct units. Abnormally thick deposits of Chappel limestone occur in structural sinks, two of which have undergone post-Chappel collapse. Elsewhere the Chappel was probably reduced by pre-Barnett erosion, but removal of Chappel beds cannot be conclusively demonstrated. At the top of the Barnett Formation is an interval of glauconitic and phosphatic limestone that represents a retarded rate of sediment accumulation. No erosional vacuity can be shown, but it is... Mehr ...