termination of inclined strata (clinoforms) against overlying lower angle surface, mainly as a result of nondeposition (sediment bypass),
minor erosion. Strata lap out in a landward direction at the top of the unit, but the successive terminations lie progressively seaward. The toplap surface represents the proximal depositional limit of the sedimetary unit, in seismic stratigraphy, the topset of a deltaic system (delta plain deposits) may be too thin to be "seen" on the seismic profiles as a separate unit (thickness below the seismic resolution). In this case, the topset may be confused with the toplap (i.e., apparent toplap).