The Plio-Pleistocene hydrocarbon fairway of offshore western Louisiana is restricted to the outer continental shelf and upper continental slope where a thick wedge of nearshore and deep-marine sediments was deposited.

Plio-Pleistocene strata of offshore Texas having hydrocarbon exploration potential are restricted to the southeastern continental shelf and upper continental slope. This thick wedge of nearshore and deep-marine sediments firms the west margin of a late Neogene and Quaternary depocenter.

Middle-upper Miocene depositional sequences of offshore Texas represent the last regionally significant influx of terrigenous elastic sediments into the western Gulf Coast Basin.

The Fleming Group and its basinward equivalents constitute the stratigraphic record of one of the major Cenozoic depositional episodes of the northern Gulf Coast Basin. The depositional sequence representing the episode is bounded above by the Amphistegina B shale and below by the Anahuac shale.