So I have this idea for a story. Tribes of cavemen roamed Pangea with early, wacky dinosaurs and other flukes of nature. The tribes hated each other, and could be united by only one thing: their common hatred. Each tribe chooses its champion and the champions are given the task of finding a way to divide the landmass so the tribes can live in peace.
Here's a conceptual image for characters of a particular tribe...the one that becomes South America.