Fossils from the Flood

Lately, I’ve been stumbling on many articles and videos wherein young world creationists try to explain the source of fossils. This is what I call willful ignorance. They can sum up the source in one sentence; these are all the things that died in Noah’s flood.
The articles assure us that the flood is the most logical explanation for fossils. We all have seen dead animals on the side of the road, or on the sacrificial alter, or from an aircraft as we gun them down in Alaska. Those animals don’t become fossils; they just rot away. But if they were underwater with sediment settling atop them, like might happen in a really big flood, then fossils would be formed all over the world. So there.
All the layers of sedimentary rock were laid down during the flood. As proof that this could occur they point out that in events, like the Mount Saint Helen eruption for example, sediments settle in alternating light and dark layers. The creationist writers don’t seem concerned that real sedimentary layers have sandstone below limestone below shale and so on and so forth. Furthermore, they don’t seem to notice that geologist don’t have any trouble distinguishing between a single volcanic event and several layers of rock.
The writers demonstrate an equal lack of concern about the fact that specific species can only be found in certain layers. In fact they assure us that although marker fossils are found in the layer they are used to identify, they may also be found in other layers. So don’t be surprised if you find a trilobite lodged in the throat of an Australopithecine. Actually the creationists never seem to notice that life forms are not spread evenly though all strata or that the layers higher up always contain the more advanced species. Were mammals more buoyant than amphibians?
I know creationists have no respect for those imprecise wishy-washy scientific theories. But shouldn’t the law of superposition receive more respect? I suppose, if someone pointed out that older strata underlie younger, they would merely say that Cambrian fossils sank on the first day and Pleistocene fossils settled to the bottom near the end. Maybe more advanced animals could climb up the mountains and hang on the longest. Whatever their motivation, I think what will always amaze me is that people will invest so much mental energy to invent a spurious explanation for what would be obvious if they stopped working so hard.