Look at this–a crinoid stem. How can this be? A sea-floor fossil perched at 9000 feet in a volcanic field that stretches for miles in every direction?
Just north of Flagstaff, Mount Humphreys stands 12,633 feet above sea level, the highest summit in Arizona. Humphreys and the rest of the San Francisco Peaks are old volcanoes. Surrounding them is a necklace of dome-shaped mountains—Sugarloaf, O’Leary, Kendrick, the Dry Lake Hills, and Elden Mountain. They’re volcanic too, but they formed in a different way.