The Sabine uplift, the most prominent structural feature of the Gulf Embayment region, centers in northwestern Louisiana. This area of structural unrest underwent a long and complicated history in Mesozoic time, but its present characteristics were not completed until the end of Miocene deposition. The dawn of Tertiary time showed a widespread advance of the waters of the Midway sea. Remarkably stable conditions of the earth's crust prevailed during the deposition of 600 feet of black shaly clay on a heterogeneous Cretaceous floor. Subsequent depositional history is traced in continual and widespread advances and retreats of the gulf waters. During the deposition of the beds of the Wilcox group the Sabine uplift region was slowly rising. Twice during Claiborne time the gu f withdrew almost to its present limits. Eocene deposition closed with the withdrawal of the extensive Jackson sea. Oligocene deposits were laid down in a contracting gulf and the succeeding Miocene beds are largely continental in character.

The existing folds, faults, and salt domes were formed immediately following the completion of Miocene deposition. The gulf then receded far beyond the present shore line, erosion became active, and the Tertiary period closed with the entire region deeply covered with a mantle of Pliocene sand and gravel. Quaternary time has been largely consumed in the removal of this debris.

It is suggested that the origin of the disturbance is related to the development of the ocean deep now occupied by the Gulf of Mexico and that its details are the result of the lateral migration of molten material deep in the underlying crust of the earth.