First, they are not millions of years old.
Wow, how lame -- you completely dodged the part where I specifically asked you to answer the above question in a way that doesn't fly in the face of the known evidence. I'm afraid that snipping that part out and then just stamping your feet and declaring "they aren't that old" doesn't cut it.
Second, a worldwide flood could and would leave millions and millions of dead things laying around in hundreds of feet of mud worldwide.
...in many characteristic ways, which unfortunately for your thesis is NOT how "dead things" are actually configured in the Earth. Geology 1, newsgatherer's fantasies 0. For example:
Problems with a Global FloodReview of John Woodmorappe's "Noah's Ark: A Feasibility Study"
The Geologic Column and its Implications for the Flood
Is the Devonian Chattanooga Shale Really a Volcanic Ash-Fall Deposit?
Geology in Error?: The Lewis Thrust
Thrust Faults and the Lewis Overthrust
What Would We Expect to Find if the World had Flooded?
Problems with Walter Brown's Hydroplate Theory
Burrows in the Orkney Islands contradict the Global Flood
The Fish is Served With a Delicate Creamy Mercury Sauce
The Letter The Creation Research Society Quarterly Didn't Want You to See
Microfossil Stratigraphy Presents Problems for the Flood
Why Would the Flood Sort Animals by Cell Type?
Isotopic Sorting and the Noah's Flood Model
Evidence from the Orkney Islands Against a Global Flood
While the Flood Rages, Termites Dig, Dinosaurs Dance and Cicadas Sing
More Nonsense on "TRUE.ORIGINS": Jonathan Sarfati's Support Of Flood Geology
Why Geology Shows Sedimentation to Be too Slow for a Global Flood
Which, I might add is exactly what we have, millions and millions of dead things trapped in hundreds of feet of mud worldwide.
I see... So it is actually your contention that fossils are found in "hundreds of feet of mud"?
Fascinating. So what about those that are found in *thousands* of feet of *rock*? Or do those actually not exist either?
(Folks, this is your brain on too many creationist pamphlets and not enough science books...)