For the lack of something better to do while I wait for my 'trip' to start; Section scale is about 20 feet high by proportionately wide. Here's the story behind it; -- About 18.5 million years ago, a powerful volcanic eruption blasted outward from the nearby Woods Mountains. Propelled by the force of rapidly rising and expanding gasses, a ground-hugging cloud of ash and rock fragments spread out at near super-sonic speeds across the countryside. Some of the rocks thrown out by the blast are 14-20 meters (60 feet) across - the largest ever documented! Hot, suffocating ash buried every living thing in the path of the blast. An area of over 600 km2 was covered with ash and rock fragments so hot that they welded together after they reached the ground. The toasted and fossilized remains of birds, mammals, and plants lie entombed beneath the volcanic tuff that forms the colorful cliffs of Hole in the Wall. -- And then it happened again, and again, and again. This is the basaltic shell from the last explosion. The tuff from previous explosions eroded away over the last 17 million years. Inside looking out, so to speak. Pretty knarly- very abstract.