About a mile away along the bank there was a deep fault which could be entered a few hundred yards back on the plateau. The lad knew about this, for the spring whence the camp got its water was close by. Into this Roger turned with his burro, casting one long glance at the camp just visible in the distance, before he took his courage in both hands and plunged into the almost inaccessible ravine. "They call this Bright Angel Canyon, Jack," he said aloud. "I'd like to have a pair of their wings right now." The little gray burro looked at him for a moment, then went on picking his steps carefully. It was rough but not perilous for a few hundred yards and the boy's spirits rose until in an hour or so he came to an obstruction about ten feet high, but this puny ten feet, which had looked simply like a little ridge of dirt, baffled him for hours. He traveled up and down, but found the terrace continuous, and it seemed as though his quest would fail almost before it had well begun. Suddenly there flashed into the boy's mind one of the old fables, and, as before, he took his rough-haired friend into his confidence. "We can't jump it or knock it down, Jack, old boy," he said. "It's up to us to climb it some way." With immense toil and labor he carried stone and rock and bits of boulders, and though hours were spent on the task he built up a kind of shaky and insecure pile up which the burro, following him patiently, reached the top. There luck was with him, for, by picking his steps carefully for twenty yards or so, he was enabled to reach a newly fallen piece of cliff, by which he got to firm ground on the other side. Stopping to rest, this obstacle over, the boy's ears were greeted by the musical and grateful sound of falling water, and hurrying to the place, he found a little stream fed by springs and gurgling merrily in tiny cascades to the river. Although he knew but little of geology, Roger's sense speedily showed him that, by following this little tributary, he probably would have a fair path down to the river, or at least, while he would probably find many drops downward, there would be no walls across his path unless it were one through which the little creek had tunneled. So, ankle deep in the grooved bed, they started down the streamlet on its way to the bottom of the valley.