Using measured sections, sedimentological descriptions, photomosaics, thin sections and gamma-ray logs, this study characterizes scales of lithological heterogeneity in the deposits of the Eagle Ford Fm., which is a cropping out formation analog for producing shale-gas reservoirs in the adjacent Maverick Basin. In recent years the Maverick Basin has become a target for unconventional shale-gas production in Cretaceous carbonate and clastic deposits, including the Eagle Ford shale. In SW Texas, the Eagle Ford shale is ca. 70 m (230 ft) thick and, along fresh road cuts, is exposed in outcrops up to 500 m (1640 ft) long that allow stratigraphic correlations for 320 km (200 mi). Large-scale vertical heterogeneity is associated with alternating clay-rich mudstones, carbonate-rich mudstones and limestones. Each of these facies record considerable small-scale heterogeneity. Some reddish clayrich mudstones present milimeter-scale laminations and/or interbedded layers of white chalk. Specific units of the carbonaterich mudstones include in-situ Inoceramus shells, limestones have nodular or tabular aspects, and exhibit massive, plane-parallel or cross-bedding laminations. Further depositional features generate high vertical variability and constitute markers for stratigraphic correlations: i.e., mass-transport deposits, fossil-rich units and volcaniclastic beds. Overall the stratigraphy of the Eagle Ford suggests an environment of deposition subject to intense variations in quantity and composition of sediment delivery, depositional processes, fauna colonization and organic content. The observations of bed-scale facies variability in the outcrop help in the understanding of correlative facies that are producing gas in the subsurface and, as a result, may help define exploration strategies.