How an Ancient Sea Built the American Midwest

The Western Interior Seaway is why the Midwest is so fertile. This film explains how an 83-million-year-old sea that split North America for 34 million years left 650 feet of Niobrara Chalk and 3,000 feet of Pierre Shale beneath Kansas and the Dakotas, and how that chalk still buffers Iowa and Illinois mollisols. It covers coccolithophores, loess and glacial till, why Canada can't farm like Iowa at 206 bushels per acre, and why that ancient deposit is finite.