This dramatic formation is called Balanced Rock. Carved by water and wind over millions of years, Colorado National Monument encompasses 32 square miles of red-rock canyons and sandstone monoliths, more than 1,000 feet above the Colorado River. A combination of upward lifts and erosion caused the chaos of formations here. Each layer visible in the striations of the canyon walls marks a time in the land's history. Fossils permit scientists to date these rocks back through the Mesozoic era of 225 million to 65 million years ago, and the Precambrian formation dates back 1.67 billion years..