We were glad to turn from sight of this place and press onward into the cañon, for such the valley now had become; and we found in the dark shadows which enveloped us in this deep cleft between the mountains a sombreness in keeping with the feelings in our hearts. So high above us towered the cliffs that at their top they seemed almost to meet, showing between them only a narrow ribbon of bright blue sky, and below us the chasm went down sheer for a thousand feet; a gloomy depth that our eyes could not have penetrated had there not gleamed at the bottom of it the foam and sparkle of a little stream. Here the path was hewn almost continuously out of the solid rock; and we could see that a like path was cut in the rock on the other side. That so prodigious a piece of work should be thus duplicated seemed to us a very astonishing waste of energy; for even Young did not have much faith in his own suggestion that two prehistoric railway companies had secured rights of way along the opposite sides of the cañon, and had begun the building there of rival lines.
But the matter was explained, presently, by our finding that this other path was but a doubling of the path that we were on. As we rounded a turn in the cañon we came suddenly to a broad natural ledge in the rock, over which hung a great projection of the cliff so that the sky above was hid from us. Here our path went off into the air, and began again on the other side of the vastly deep chasm, a good sixty feet away. "Rather long for a jump," was Rayburn's curt comment as we pulled up on the edge of the precipice and looked at each other blankly. Yet it was evident that those who had made with such great expense of toil and time these path-ways on the opposite sides of the cañon had crossed in some way from the one to the other at this point, and the only surmise that seemed to fit the facts of the case was that there had been stretched across the chasm a swinging bridge of _lianas_--such as still are to be found spanning streams in the hot lands of Mexico--and that in the course of ages this had rotted entirely away. But as this bridge, if ever there had been one here, was absolutely gone, we found ourselves in as shrewdly strait a place as men well could be in. To go ahead was as clearly impossible as was the hopelessness of turning back upon our path. At the most, we could only return to the valley out of which we had climbed with such thankfulness; and rather than go back to die of starvation in that place, so beautiful and so desolate, there was not one of us but would have chosen to end all quickly by springing into the gulf above which we stood.