Since 1947, the Morton Salt Company's Kleer mine in the Grand Saline salt dome has more than doubled in size. Balk's mapping of the salt structures in the pre-1947 workings showed that (1) the layers of salt near the southeastern border of the dome dip steeply southeast and south, presumably parallel with the dome border. Elsewhere the layers form intricate systems of folds. (2) The axes of all folds plunge nearly vertically. (3) Anhydrite and halite are elongated parallel to the nearest fold axis.

The Ogallala formation extends from the north side of the Pecos Valley northward across western Texas, Oklahoma, Kansas, and Nebraska into southern South Dakota. With its southern limit within the Edwards Plateau, it underlies the upland surface of much of the High Plains section of the Great Plains Province. The extensive fluvial deposits of Neogene age are widely exposed throughout the dissected plateau region that flanks the Rocky Mountains on the east. The deposits have yielded large faunas of fossil vertebrates and mollusks and an abundance and variety of fossil plant seeds.

Vermiculite deposits in the Central Mineral region of Texas, chiefly in Precambrian metamorphic rocks, are situated in Llano County and adjacent parts of Mason, Gillespie, and Burnet counties with minor occurrences in Blanco and San Saba counties. All of the known deposits contain a lesser percentage of vermiculite than the deposits now being exploited in South Carolina and Montana; however, the deposits are substantial in size and will probably be mined when the richer domestic and foreign sources are exhausted.