I live on a mountain that was once an island in a sea. In a city near here, there is a museum of the inland ocean with a great fossil record of it all. Deep ocean sea creatues in the midst of mainland USA. They apparently all got trapped in a valley between the mountain peaks as the waters receded, which is evidence even that the water was once higher than the peaks, which is how they all were able to swim here to begin with. But they didn't leave quickly enough... and died here. And we sit at a point higher than most of the rest of continental North America. So even if you want to argue that there never was a flood or that the land we now know of as America was not completely covered in water at some point in the not too distant historical past, even then you'll have a real problem. Because fossils prove otherwise.