The lithology and succession of the component beds of the formations are described and the topographic expression of prominent members noted. Localities where individual members and contacts are typically exposed are mentioned.
The gravels and conglomerates of the several formations and zones are described. A caliche mantle is present, being thickest southwest of the town of Goliad. Chalcedony, forming knobs in the Lagarto outcrop area, is believed to have had its source in the Catahoula tuff. Chalcedony may have formed where underground water moved up fault planes to the surface, but it is not believed to indicate favorable structure for oil and gas production.