Why was a flood needed?

Mike, you're taking an over-simplified view.Rapid burial can happen in other circumstances than a flood - and even if all fossils were formed by floods you would need a far more detailed look at the geological record to conclude that it was ONE big flood.So, some fossils are buried by sandstorms - rapid burial, but no flood. Some are buried by underwater mudslides - that can easily happen with no flood. The Burgess Shale fossils were swept off an underwater cliff and were slowly buried by fine sediment. And while similar fossils are found in other places - including Chengjiang in China you won't find any living examples of these animals today. Why not ?And this brings us to another point. The vast majority of fossils are marine - sea life. What does that have to do with a flood ? Surely with the Biblical flood it is the land animals that are supposed to have died - no sea life is taken on board the ark.If I was really looking to explain a large part of the geological record by a flood in the recent past, I would be looking for a large volume of rock that had clearly been laid down rapidly. It should show signs of hydrodynamic sorting with very coarse-grained sediments at the bottom grading upwards to finer sediments. The fossils too should be hydrodynamically sorted with modern mammals appearing with dinosaurs and amphibians of similar size. This unit should be quite distinct from the lower strata and distinct from the post-flood sediments being laid on top.