Coated with snow and illuminated with the warm light of sunset, Amphitheater Mountain glows with a wonderful golden color. Amphitheater Mountain and Abiathar Peak command the view from Round Prairie. They were formed during the Eocene, 30 to 58 million years ago, from volcanic ash deposits and mudflows. These deposits are rugged, unstable, fractured rocks. Few people have climbed the peaks, and no one casually scrambles on these cliffs but there is a new sport, climbing the ice falls in the neighborhood in the winter. Abiathar Peak was named after a paleontologist who worked for the U.S. Geological Survey in 1885, but who apparently never visited Yellowstone. Sunset light shining through scattered clouds, created spots of gold light sweeping across these wild, untouched cliffs.