Geologic map that depicts surface geology of Tarrant, Dallas, Kaufman, Ellis, Johnson, Somervell, and Rockwall Counties and parts of Parker, Hood, Erath, Bosque, Hill, Navarro, Henderson, Van Zandt, and Hunt Counties, Texas.

Principal fault systems in the East Texas Basin were examined in terms of their distribution, geometry, displacement history, and possible origins.

Mobilization of the Louann Salt created the present structural configuration in the central part of the East Texas Basin and was the major control on hydrocarbon accumulation in the area. Salt-cored anticlines, turtle-structure anticlines, and salt diapirs were produced by flow of salt.

Correct interpretation of the effect of basin infilling on salt mobilization is critical to understanding salt dome growth and stability. The size of salt structures in the East Texas Basin is determined by the original thickness of the underlying Louann Salt (Middle Jurassic).

The Nacatoch Formation of the East Texas Basin is the middle formation of the Navarro Group and consists of marine sandstones and mudstones derived largely from source areas to the northwest, north, and northeast of the East Texas Embayment.