The lower forty-eight United States showing locations discussed in this book.North Amer i ca showing the extent of the Mississippi-Missouri and the Colorado river drainages, and the areas of the Corn Belt and dead zone in the Gulf of Mexico.Also indicated are the paths of Hurricanes Katrina, Sandy, Harvey, Irma, and Maria; the course of the Gulf Stream; and locations beyond the lower forty-eight states that are referred to in this book.