If the present world contains sediments generated in the global Flood described in the Bible, we would expect a distinctive paleontological uniformity at both the beginning and the end of the Flood. Populations of organisms both before and after the Flood would be expected to persist at any particular locality for a significant period of time. Many of the same species would be expected to persist across every depositional time boundary at most localities in the world throughout both the pre-Flood and post-Flood worlds. During the Flood, of the species deposited in more than one depositional level, it would not be surprising to find many of them in both of two successive depositional units at a given locality. Across both the pre-Flood/Flood and Flood/post-Flood boundaries, however, it would be unlikely for the same species to be found both above and below a depositional boundary between successive units at the same locality. At the pre-Flood/Flood boundary, organisms were transported away from where they lived and deposited after some amount of transport. It seems unlikely that such transport would deposit them immediately above their pre-Flood ancestors at a given locality without something else from another locality having been deposited there in the meantime. Likewise, it seems unlikely that the last burial location of a particular Flood-deposited organism would happen to correspond to where that same species came to reside immediately after the Flood. This means that both the pre-Flood/Flood and Flood/post-Flood boundaries should be identifiable as a substantial paleontological unconformity. Two further notes: (a) slow recession of post-Flood waters might yield shallow marine species on both sides of the Flood/post-Flood boundary on low-lying continental shoulders, and (b) since biostratigraphic units are largely defined by their contained fossils, the anticipated paleontological unconformity will be found at a boundary between global stages, not within a global stage.
To identify the inter-stage boundaries that mark the beginning and end of the Flood, (1) the Paleobiology Database is queried to produce a complete species list for every stage, (2) each of those files are duplicated into two files (one for species below the stage’s upper boundary, and one for the species above the stage’s lower boundary), (3) in all files species are deleted that are not reported all the way to the associated boundary, (4) files on both sides of every boundary are combined and every species is dropped which is not found on both sides of the boundary, and (5) in each boundary file, every species occurrence is dropped which is not found within 2-3 longitude and latitude degrees of that species on the other side of the boundary. The boundary files with zero species are optimal candidates for the pre-Flood/Flood boundary. The boundary file(s) containing the fewest species and where all those species are marine species located in marine sediments on the shoulder of continents is(are) optimal candidates for the Flood/post-Flood boundary.