The wild heart of the Escalante River drainage spreads out as a labyrinth of canyons, mesas, and rolling slickrock, with remote peaks on the horizon including the Henry Mountains on the far left, the last-named mountain range in the continental United States and home to one of the country’s few free-roaming bison herds, and, farther south, the rounded dome of Navajo Mountain on the Utah-Arizona border. The 100-mile-long Waterpocket Fold forms the backbone of Capitol Reef National Park, where geologic rock layers drape over a steeply dipping fault plane and, over millennia, water and wind have eroded the soft layers to sculpt intricate contours, while water collects in sandstone basins along the fold to form waterpockets. In the Circle Cliffs section of Grand Staircase-Escalante National Monument, huge petrified wood logs, some nearly 90 feet long, formed from trees that grew some 210 million years ago, were buried in river sediments, and became petrified as silica from volcanic ash gradually replaced organic cell tissue.