OK, so "We do not find fossils of marine mammals in the layers where we find marine dinosaurs. Never. Nyet. Nada. Nowhere.
And we never find marine dinosaurs in the layers with marine mammals. Never. Nyet. Nada. Nowhere." (post 76 in fossil sorting in the great flood 2- by 'jar') must be wrong.
No, that's still a true statement. No marine mammals are found in layers with marine dinosaurs.
Mammals existed during the time of the dinosaurs, sure, but there were no
marine mammals at that time.
Get it, yet? Both statements are true - there were mammals alive at the time of the dinosaurs; no marine mammals were alive during the time of the dinosaurs.