The Yellowstone eruption of two million years ago put out enough ash to bury New York State to a depth of sixty-seven feet of California to a depth of twenty. This was the ash that made Mike Voorhies’s fossil beds in eastern Nebraska. That blast occurred in what is now Idaho, but over millions of years, at a rate of about one inch a year, the Earth’s crust has traveled over it, so that today it is directly under northwest Wyoming. (The hot spot itself stays in one place, like an acetylene torch aimed at a ceiling.) In its wake it leaves the sort of rich volcanic plains that are ideal for growing potatoes, as Idaho’s farmers long ago discovered. In another two million years, geologists like to joke, Yellowstone will be producing French fries for McDonald’s, and the people of Billings, Montana, will be stepping around geysers.
—Bill Bryson, “Dangerous Beauty,” A Short History of Nearly Everything, p. 227, 2003.
