Goliad Formation

The Goliad Formation (Tg) is a geologic formation in Texas. It preserves fossils dating back to the Serravallian to earliest Pliocene stages (Clarendonian, Hemphillian and earliest Blancan in the NALMA classification) of the Neogene period, including the gomphothere Blancotherium among many other fossil mammals, reptiles, birds and fish.

The formation hosts uranium deposits and forms the Evangeline aquifer underneath the city of Houston.

Description
The Goliad Formation was described by Plummer in 1933, as consisting of three members; the Lapara Sand, overlain by the Lagarto Creek Beds, in turn overlain by the Labahia Beds with outcrop thicknesses ranging from 35 to 200 ft. The Goliad Formation comprises claystone, sand, sandstone, marl, caliche, limestone, and conglomerates and reaches in certain areas a thickness of 180 m. The formation overlies the Fleming Formation and dates from the Clarendonian to the earliest Blancan. In the southwest of its range, the formation overlies the Catahoula and Gueydan Formations. The Goliad Formation is recognized regionally across the Texas coastal plain as an interval of dominantly fluvial siliciclastic strata that overlies the Miocene Fleming Formation and underlies Pleistocene terrace deposits. The formation is now interpreted as a basinward-thickening progradational wedge of Middle and Late Miocene age. Stratigraphic thicknesses in outcrop range from 60 to 120 m, but offshore the interval thickens to as much as 365 to 425 m.

Together with the Catahoula, Fleming and Oakville Formation, the Goliad Formation is part of the Gulf Coast aquifer, an extensive artesian aquifer that produces water primarily for irrigation and municipalities. The Evangeline aquifer is hosted by the Goliad Formation underlying the city of Houston. The formation hosts uranium deposits in the South Texas Uranium Province and is mined for caliche in Hidalgo County, Texas.

Fossil content
Tertiary mammal fossils from South Texas were first reported by Dumble (1894) as coming from the Lapara division, later the Lapara Beds (Dumble, 1903).

The following fossils have been reported from the formation: