The oldest rocks you will see at Alta form the dramatic outcrops on the southeast flank of Mount Superior on the north side of Little Cottonwood Canyon. These are extremely old rocks (Upper Proterozoic Era, + 800 million years). The lighter brown rocks to the west consist of the Little Cottonwood Formation. The dark brown rocks to the east are the Little Cottonwood Tillite formed by an ancient glacial event. You can see folded beds in the Tillite near the summit of Mount Superior formed by a mountain building event that preceded the formation of the Wasatch Mountains by hundreds of millions of years.

Mount Superior.