Inside the Subway - the Pools
The floor of this canyon is fairly level left to right but slopes down steeply in the direction of the water flow. However, it is pock-marked with a series of 6 or 8 of these remarkable round-ish pools. They have abruptly vertical sides and flat bottoms. There must be some anomalies in the composition of the sandstone that causes it to fracture only in certain spots. It makes for a unique series of miniature waterfalls.
The SubwayUtahZion National Parkcanyonwaterfall