The atmosphere contained twice the amount of oxygen prior to the Noahic flood which would answer the question of how dinosaurs or dragons as they were called prior to the 1800s would have been able to breathe enough oxygen through their small nostrils.
In Genesis the Bible speaks of a firmament which is described as a layer of water surrounding the earth several miles thick which would have made the air pressure much greater creating the same atmosphere that we use today in medical treatment, (the hyperbaric chamber), hyperbaric meaning high pressure, the oxygen would have been about twice that of today 42 percent, according to samples of air bubbles they have found, and the water that was in the firmament would have block out the X-rays which does tremendous damage to our skin, people would have lived longer, such as Methuselah who lived to be 969 years old.

If you were to take out the water from the ocean you would notice that the continents are still connected. Most of the ocean probably came from the firmament and the waters underneath of the earth which were described as the fountain of the deep.

If you look at the fault lines within the ocean floor they would have been where the fountains of the deep broke forth and the continents would have moved some which is evident by the zipper pattern along the fault line much as claw marks are formed when someone is being dragged by force.

Also the mountains were probably formed at the time of the flood because the fault lines are directly proportional to the location of the mountain ranges.