On a main east-west trail, dating from antiquity, rises a great sandstone promontory with a pool of water at its base. Over the centuries those who traveled this trail stopped to camp at the shaded oasis under the cliffs. They left carved evidence of their passage: symbols, names, dates, and fragments of their stories that register the cultures and history intermingled on the rock. El Morro is a cuesta - a long formation with a gentle upward slope that drops off abruptly at one end. From National Park Service pamphlet. 10-08