"Horseshoe Canyon contains what is probably the finest display of prehistoric Indian rock art in the United States. The famous Great Gallery, largest of several Horseshoe Canyon sites, is 200 feet long, 15 feet high, and contains dozens of intriguing red, brown and white pictographs. The paintings are at least 2,000 years old, and possibly as old as 8,000 years.
As you approach Water Canyon be sure to watch for the first two pictograph sites, one on each side of the canyon. The trail passes right by them. These sites, like the other two that you will see later, were painted by the Archaic People between 2,000 and 8,000 years ago. The third site is situated in a huge alcove on the west side of the stream, about 0.6 mile up-canyon from the first two. Unfortunately the alcove site has sustained substantial damage, both natural and man-caused, and it is not as impressive as the others. Finally, 1.3 miles from the alcove site, or 3.7 miles from the beginning of the trail, you will come to the Great Gallery."