There is reasonable doubt that a collection of vertebrate fossils listed by Dumble and quoted by later authors came from the Oakville formation in southwest Texas. Vertebrate fossils low in the Fleming formation have been collected between Burkeville and George West, Texas, extending the Fleming formation vertebrate faunas into the upper Oakville of Renick and the emended Lagarto of Plummer. It is recommended that both be included in the Fleming formation, and the Oakville sandstone be restricted to beds from the top of the Catahoula to the top of the Moulton sandstone member, Oakville formation of Renick.

The vertebrate fauna found at Cold Spring is appreciably younger than that found at Navasota. The former is in the Fleming formation and the latter in the Oakville formation.

Vertebrate remains of the same age as those found at Cold Spring within the Fleming formation are also found at the type section of the emended Lagarto formation (Plummer, 1933).

Traceable biostratigraphic units herein called faunas, are used to correlate and identify Miocene formations along the Texas Coastal Plain. Arikareean, Hemingfordian, Barstovian, and Pliocene biostratigraphic units are recognized.