The Superstitions are...abrupt. The sheer cliffs are fascinating; they are composed of volcanic rocks that once made up the core of a vast caldera complex not unlike Yellowstone. Several massive explosions rocked the region, and so much ash was blasted out of the magma chamber that the chamber collapsed in on itself, forming a series of vast 'craters' 10-12 miles across. The calderas of the Superstitions are 15-25 million years older than Yellowstone, are extinct, and have been deeply eroded. The high peaks and spires were once part of the resurgent dome of the caldera.
As we drove east we reached the marginal area of the caldera, where vast blocks of tilted ash and tuff are exposed in deep rugged canyons. Highway 88, the Apache Trail, winds upwards from the Phoenix suburbs to a series of three reservoirs that were constructed a century ago to provide dependable water supplies for the vast city (it wasn't enough, though). The reservoir below is Canyon Lake, the lowest of the three. Thick rhyolite flows form the bold cliffs.