Some might think I'm cooky, but I believe in the Bible. The earth is the supernatural product of a supernatural Creator. That means that many things would have an appearance of age, all the way down to the molecular level. In addition, we know nothing regarding the matter God used to create man and beast. God formed man and beast out of the earth. What if the earth God used was created with an appearance of millions of years? There are just so many variables that would throw modern dating methods way off for me to put 100% trust in them.
I personally believe that God created the heavens and the earth we know in 6 literal days and rested on the 7th. I believe that this world was much different from the world we know. It was filled with a wide variety of species that are currently extinct. It was a single continent. And yes, I believe that many species are extinct today on account of the flood, primarily what we call "prehistoric" creatures. I believe that the flood produced massive global sedimentation, geological disturbances, and fossilization. You know, the whole "Young Earth" theory. I believe that the flood was such a massive geological event that it broke up the single continent into what we essentially know today as 7 continents.
The flood lasted roughly a year. Much, if not most, of the water at the poles would have been frozen into massive sheets of polar ice. As the flood waters receded these massive ice caps would have remained, locking up a significant amount of flood water. While the waters that were not frozen in the poles receded, land bridges would have been exposed throughout the world. These land bridges would have provided ample clearance for human beings (and animals) to settle distant lands such as Australia.
Throughout the Northern hemisphere, this would have been a period best described as an Ice Age. However, in time the earth's temperature no doubt began to stabilize and warm. A significant amount of the waters locked up and frozen in the polar ice cap would have melted, leading to raging rivers and rising sea levels. These rising sea levels would have covered over many of the land bridges connecting the continents, leaving mankind separated. This rise in sea level would have trapped mankind as we were scattered among the 7 continents. And it was at this time that we can say that the world was "divided".
In Genesis we read...
Genesis 10:25 (ESV)
"To Eber were born two sons: the name of the one was Peleg, for in his days the earth was divided, and his brother's name was Joktan."
The earth was sufficiently and completely divided once these land bridges were covered by the melting ice from the ice caps. The name Peleg is a clue. The name Peleg means: pe'-leg (pelegh, 'watercourse,' 'division'). Peleg's name hails back to a time when the earth was divided by a significant increase in flowing waters (flooding rivers) and rising sea levels (covering land bridges). Peleg's name points to a time marked by waters dividing the land as they covered they previously exposed land bridges.
And so we have the world that we know today.