And the waters prevailed, and were increased greatly upon the earth... Genesis 7:18
"Evidence for the final receding phase of the global Flood involves the
presence of huge Cenozoic coal beds formed from mostly angiosperm
(flowering) plants.
Coal beds are formed by enormous amounts
of plant
material being ripped up,
transported en masse,
and then buried rapidly
before the material has a chance to decay—exactly the type of
catastrophic processes that occurred in the global Flood.
Compared to
the Carboniferous coal beds formed earlier in the Flood that contained
tropical coastal vegetation, the larger Cenozoic coal 
layers were formed
from plants and trees growing at higher elevations in the pre-Flood
world.
Like the many other Cenozoic fossils, these coal beds had a
propensity to form in large sedimentary basins that formed late in the
Flood year where the plant material would have been easily trapped and
buried." ICR