[My2Cents]

You're ignoring the possibility that humans are probably better swimmers than velociraptors.

[Junior]

But ichthyosaurs are better swimmers than human beings and many species were of comparable size to the latter. However, they don't appear above humanity in the fossil record, either.

Oddly enough, insects, arachnids, and other similarly teeny critters, have a tendency to float because they don't break the surface tension of the water, yet some of their remains are found far below those of later, larger critters.

In other words, hydrographic sorting makes absolutely no sense as an explanation for the fossil record.

[Havoc]

That was a good one.. LOL.