ards noon that he came softly back to us and bade us lay down our
packs and advance silently with him, carrying only our arms. "There's
something queer ahead; and I thought that I heard voices," he explained.
"But there must be no shooting unless we are shot at. Some of these
Indians are friendly, and we don't want to start a row with them if they
are willing not to row with us."

The canon was very narrow at this point, and high above us its walls
drew so closely together that the shadows about us were deep. As we
rounded a bend in it, the rock closed above our heads in a great arch,
so that we were in a sort of natural tunnel; at the far end of which was
a bright spot showing that a wide and sunny open space was beyond. But
over this opening were bars which cut sharply against the light, as
though a gigantic spider had spun there a massive web; and as we drew
nearer to this curious barrier we saw beyond it a broad and glorious
valley, rich with all manner of luxuriant tropical growth and flooded
everywhere with the warm light of the sun.

We approached the strange barrier cautiously, and our wonder at it was
increased as we found that it was made of the bright metal of which we
had found so many specimens; and still more we wondered as we found that
the bars were fastened on the side from which we approached, so that we
could remove them easily, while from the side of the valley they
presented an impassable barrier. In strong excitement we drew out the
metal pins which dropped into slots cut in the rock and so held the bars
fast, and in a few minutes we had cleared the way for our advance. Just
as we were making ready to pass through the opening we heard the sound
of voices; and as we quickly drew back into the shadows two men sprang
up suddenly before us, and cried in wonder as they saw that the lower
bars across the opening were gone. Yet the expression upon their faces
was not that of anger; rather did they seem to be stirred by a strong
feeling of joy with which was also awe. Both men were accoutred in the
fashion which the pictured records show was usual with the Aztec
warriors, and one of them--as was indicated by his head-dress and by the
metal corselet that he wore--was a chief; and they challenged us
sharply, yet with gladness in their tones, in the Aztec tongue.

So sudden and so ringing was this challenge, and so startling was the
uprising of the men before us, that as we sprang back into the shadow we
in