The general geology and geomorphology of the Appalachians is summarized. Geological features and the subdued relief of the topography indicate up to 6.5 km of erosion. Erosion can also be estimated by the amount of sedimentary rocks on the offshore continental margin sourced from the west. Assuming that this erosion came from the Appalachians east of the divide, the amount of sediment matches the estimate based on coal rank fairly well. Erosion of the Appalachians and deposition of the continental margin can readily be explained by sheet flow early in the retreating stage of the Genesis Flood, as the land rose up and the continental margin subsided. This is a pattern seen worldwide and is inexplicable by uniformitarianism. This places the Flood/post-Flood boundary in the very late Cenozoic in this region.