4.
Take a break here and look at the valley between the multicolored mesa and the higher parts of the Zuñi Mountains. This valley was formed by water gradually wearing away the softer rocks of the Chinle formation. The harder sandstones of El Morro and the adjacent mesa on the southwest and the sandstones and limestones of the higher slopes resisted such erosion.
During the last few million years, while the Zuñi Mountains were being gradually pushed up to their present height, more than 10,000 feet of sedimentary rocks have been removed from what you see. This has been done by running water and wind, carrying away the rocks a few particles at a time. Before that, about 100 million years ago, this entire area, as far as you can see in any direction, was under the water of an ancient ocean. Forty million years before that, the sands of El Morro were accumulating on a broad, desert-like plain, built up by sand deposition of sluggish, wandering streams, and re-sorted by wind into large dunes.
Before continuing along the trail, you will notice many small trees around you which are called pinyon (Pinus edulis). These pine trees have two needles to a cluster and are never tall like the ponderosa pine. They are usually less than 35 feet in height, and have a rounded, compact crown. Pinyons are seldom found growing in pure stands but are associated with various kinds of juniper. Because of the nature of their growth, heavy stands of pinyon and juniper are often called pigmy forests. The pinyon produces edible nuts which are abundantly used by local residents as well as marketed commercially elsewhere in the United States.