Neither a meteor nor a tsunami equate to 40 days and nights of rain to the point of covering the entire world, inluding Mt Everest, with 15 cubits of water. Glaciers melt as they recede causing flooding in local area. Just because it's evidence of a
flood, doesn't mean it's talking about that
flood. Floods happen every year.
Seashells at the top of mountains is explained by the "just a theory
" known as Plate Tectonics. This explains Earthquakes, Volcanoes, Mountains, Valleys like Rift Valley/Death Valley, Tsunamis, why certain geographic features over vast oceans resemble each other
, AND why seashells are at the top of mountains.
You see, you're putting the cart before the horse. Ancient man found shells in places far from water and tried to explain 'why' to thier fellows. If you pretend to know the answers, you become king of your tribe. If you say, "I don't know," people will ignore you and go to the next person hoping that person will pull something out of thier *** and follow them. Like Mohammed and why children sometimes look like the mother and other times like the father. The only wrong answer in these situations was to say, "I don't know." You make up any other kind of BS and people will believe it for thousands of years, regardless to how wrong you were.