Visible in this south-southeast-looking, low-oblique photograph are the forested Bighorn Mountains, which began to form approximately 60 million years ago and extend almost 120 miles (195 kilometers) southeast from the Montana-Wyoming border into central Wyoming. Cloud Peak, the highest point in the glacier-carved range at 13 175 feet (4018 meters), consists mostly of Precambrian basement rocks. East of the mountain range is the western portion of the Power River Basin; to the west is the eastern portion of the Bighorn Basin with its irrigated farmland along the Bighorn, Shoshone, and Greybull Rivers.