Red Mesa! Red Mesa! Red Mesa!--The certainty of its being the lost mesa kept singing in Sid’s ears as they descended. No such geologic formation as this could exist anywhere around Pinacate and not have been discovered before. Those ancient Papagoes who had reported it to Fra Pedro of 1680 no doubt had called it a mesa by reason of its resemblance to the true mesa formation. But, unlike the mesas of the north which are formed by water scouring and erosion, the walls of this one had been cast up bodily by the explosive force of pent-up lava. Still, there was resemblance enough to have given the place its name, Red Mesa, Sid was certain. The young Apache kept behind Sid as he prodded him on downward. There was no trail. His savage guide avoided choyas and chose the best possible routes for descent, that was all, while steadily the giant wall of Red Mesa frowned higher and nearer above them. Sid looked up as they approached the base of the west wall. Flat slabs of bare, smooth granite went up at a steep slope for perhaps a hundred feet. Above that the red wall rose sheer to fissured and turreted pinnacles three hundred feet above the top of that awful slope. Inaccessible from anywhere below was Red Mesa! After more rocky descent they came around the great tower at the lower end. Mighty and majestic, like the belfry of some huge cathedral, it rose out of the depths of the valley. A great smooth slope of black lava, shiny and slippery as glass, formed a slanting apron here, spanning the gap from tower to tower. But what an apron! Like the face of a dam, it spread across from one wall to the other, closing a gap three hundred feet wide and itself at least four hundred feet up to its edge, the towers of the two walls rising for half their height above it still. Geologically it was an imposing instance of the unlimited power of Nature. When that mountain side had burst, the whole round world must have shaken like a leaf and all the marine creatures in the great seas to the north have been swept over by a tidal wave of unexampled proportions! The lava had flowed out and downward, cooling slowly until this dam--for a cataract of fire--had formed and remained as a grim witness to the stupendous natural event that had once taken place here.