Hiking down into the Calf Creek Canyon of Escalante-Grand Staircase National Monument, we stumbled upon these dark basalt boulders. They were a stark contrast from the white Navajo Sandstone landscape that spreads out in all directions. While they may look like unusual dinosaur eggs, they are actually from an eruption that occurred 20 million years ago from nearby volcanic activity. Thankfully those volcanos are no longer active, since hiking in a rain of smoldering hot boulders would make for a terrible day.