Figure 4. Generalized stratigraphic section of the northern Gulf of Mexico coastal plain showing gas (triangles) and oil (circles) occurrences and potential source rocks (boxes and stars). Arrows along the right side indicate major source rock intervals. L. = Lower; Mid. = Middle; Up. = Upper; Tria. = Triassic; Pal. = Paleocene; Plei. = Pleistocene; Holo. = Holocene; Quat. = Quaternary; vertical lines = unconformity; wavy line = disconformity; jagged line = interfingering; dashed line = uncertain (modified after Salvador and Quezada Muneton, 1991; Nehring, 1991; Palmer and Geissman, 1999; Humble Geochemical Services et al., 2002; and Warwick et al., 2007a).