Cool post! The upshot: during the Cretaceous, an arc of what is now the Deep South was the shore of a warm, shallow sea, and plankton died there for millions of years, settled to the bottom, and became chalk. The result: some of the most fertile soil in North America. So fertile that cotton yields were enormous, so plantation owners needed a lot of slaves to harvest it. And their descendants are still there, and voted Obama this week.
I love this kind of analysis.