Figure F7. The sharp boundary between Units II and III (at 60 cm), which represents a major hiatus between the lower-middle Miocene and upper Pliocene (interval 182-1129D-22R-1, 46-75 cm). The over-lying bryozoan grainstone to rudstone is 3 cm thick and grades upward. The underlying partially dolomitized bioclastic packstone to grainstone is well lithified.