This scripture alone should make it obvious to everyone that the flood covered the WHOLE earth:
Genesis 7:19 And the waters prevailed exceedingly upon the earth; and all the high hills, that were under the whole heaven, were covered. 20 Fifteen cubits upward did the waters prevail; and the mountains were covered. 21 And all flesh died that moved upon the earth, both of fowl, and of cattle, and of beast, and of every creeping thing that creepeth upon the earth, and every man: 22 all in whose nostrils was the breath of life, of all that was in the dry land, died.If the flood was only local, there would have been no need for Noah to take two of every kind of animal on board the ark to preserve them. I could be wrong, but I also believe there was only one continent/land mass before the flood, and that it was the seismic/tectonic activity which broke this up into multiple land masses, such as when Genesis describes 'the fountains of the great deep (were) opened up' (Genesis 7:11)
I also believe that the descriptions of behemoth and leviathan in Job are talking about dinosaurs. There are many other pieces of evidence that man co-existed with dinosaurs, both before and after the flood. Ancient peoples called these creatures dragons. The Native American thunderbird could have been based on the pterodactyl.
Chris wrote an article about what he thinks the pre-flood world could have been like, but of course, as with any piece of literature describing that world, it is all conjecture.
http://creationliberty.com/articles/preflood.php