“It’s narrow,” finished the physician. “I wouldn’t care to meet that bear down there, and find it necessary to argue the right of way with him with this .22.” “We won’t argue,” said Charmian. “It isn’t polite. We’ll excuse ourselves and go back. It’s his trail, anyway. Let’s try it. But I wish I hadn’t crowed so loudly when I outcrawled you in the chaparral. I feel sick and dizzy every time I look over the edge. And on a narrow trail, with that chasm grinning up at me--_whew_! Don’t you remember the iron rail at the edge of the great boulder overlooking the forest at El Trono de Tolerancia? I had to have it there. I never dared to stand and look without the feel of that iron pipe in my hands.” “Don’t let that worry you,” he cheered her. “Try to make it. Don’t think of the chasm. Don’t look at it. Keep your eyes on the trail. But if you get dizzy and nauseated let me know. I’ll fix you up. Don’t want to do it, though, unless it becomes necessary. But, being a doctor, I realize what a terrible sensation it is for one who suffers that way. It’s dangerous, too. I never feel it myself. I would have made a wonderful mechanic at erecting the framework of skyscrapers.” He smiled at her encouragingly. “I’ll go ahead,” he said. “Keep close to me and think of something pleasant.” With a brave but wan little smile she fell in behind him, and he started along the descending shelf that followed the wall of the cavern. It was dangerously narrow, a ticklish piece of business to follow it. Above them rose a craggy wall, growing in height as they progressed slowly downward. Occasionally the trail grew wider, but this usually occurred above a slope that was less precipitous. They wound in and out as the trail rounded gashes that extended from the lip above to the valley’s floor. “I’ll tell you what,” said Shonto, stopping suddenly and facing her: “This is not a natural trail, by any means. Though it’s ages old, there are evidences left of the work of man. This shelf has been hacked in the cañon wall by somebody. It’s preposterous to believe that animals--even wild goats or bighorn sheep--could have climbed up and down along this wall and eventually worn a level trail. They can go almost where a fly can, but they never could have struggled along this wall in its natural state.” “But who could have built it?” asked Charmian. “I’m only too eager to find out,” returned the doctor. “We may discover something mighty valuable down there on the floor. And I’m convinced that the trail extends entirely down. I’ve seen deer tracks. I don’t believe deer would travel this trail, where there is not a blade for them to nibble, unless they were bound for the grass and the water down below. I’ve noticed ’coon tracks and skunk tracks and coyote tracks, too--but no sign of a man track. Yet men built this trail--hacked it in the side of this stone wall. I’ll show you the next time I see a place where this is evident.”