Near Burkeville, Newton County, Texas, the Potamides matsoni subsurface zone of southeastern Texas and adjoining Louisiana reaches the surface. There it is possible to tie together stratigraphically subsurface and surface strata, marine and non-marine facies, and vertebrate and invertebrate faunas. Recent discoveries of fossils near Burkeville include several vertebrates, such as horse, rhinoceros, camel, deer, horned ruminant, primitive beaver, and sea cow. These newly discovered vertebrates and the reidentified invertebrates determine the age of the Burkeville fauna and the Potamides matsoni zone as upper Miocene (Barstovian). The relationship to other vertebrate faunas from the west coast and the interior of the continent is discussed as is the relationship of the invertebrates to other Gulf Coast faunas. The Burkeville exposures are part of the Fleming formation which is widespread in East Texas and Louisiana.The use of Lagarto formation for this unit is declined by the writers.
The Burkeville fauna is a mingled assembly of forms some of which lived on firm land, while others lived in fresh flowing river water and others in brackish coastal waters. The locale was probably near the mouth of a Miocene river. A detailed description of the localities and the sections exposed is given. The environmental conditions are evaluated.