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A The Monument landscape is typified by hundreds of ledges and shelves separating the cliffs. Nearly all the canyon walls are lined with such ledges. That is because the rather hard Cedar Mesa sandstone is seamed with many thin layers of relatively soft rock. The softer material erodes very much faster, and as it wears away, the rock above and below it is also exposed to the elements. As a deep horizontal crevice develops, support for the rock above it is removed and chunks eventually fall out. In time, a wide ledge (or shelf, or bench, or whatever) forms.
All of the above is happening here, right in front of you. This isn’t just an interesting formation, it’s a dynamic, continuing process that is changing the landscape.
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B The canyon coming around the corner on your left is Armstrong Canyon. It joins White Canyon on your right. In front of you is a waterfall (or it would be there if any water was flowing) above a deep, narrow plunge pool. This type of thing is often called a “nick point,” and it is evidence of some abrupt change in the canyon’s development. In this case, that change was probably formation of Kachina Bridge, which changed the gradient, or steepness, of the stream. The water, rushing over the lip and plunging into the pool, quarries out a hollow under the lip. In time the lip breaks off, the waterfall moves back a few feet, and the process goes on. A similar, but somewhat larger nick point is Niagara Falls.
If the canyon is dry today, it may be a little difficult to believe the explanation. If you could be here just after a heavy rain, when the flood thunders over the rocks at a rate of thousands of gallons each second, you would find the whole thing more believable.
Nick Point
Little Arch
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C This little arch (it’s not a bridge) may not win prizes for size, but it is very handy for helping explain bridge or arch growth. A bridge is first formed by the action of running water, but much of its subsequent growth is like development of an arch. Water seeps into tiny cracks, freezes in winter, and pries flakes or blocks of stone loose. Alternate heat and cold causes rock to expand and contract and that opens little cracks, causes tension, etc. If the rock has natural planes in it, it may break away along those lines.
If you look at the underside and sides of this little arch, you can see evidence of these processes. Please don’t “help nature along” by prying pieces loose.