to it, its character became somewhat altered; the
square box-like form appeared less regular, and it was then perceived
that the parallelopipedon was not perfect. Slight ledges could be
traced traversing the face of its cliffs, and here and there the
rectangular lines were broken to the eye. Nature, after all, had not
been so exact in her architecture.

Yet, with every deduction, it was a singular structure to look upon, not
the less so that its summit was inaccessible to human foot. A precipice
fifty yards sheer fronted outward on all sides. No one had ever scaled
this precipice--so alleged my companions, who were well acquainted with
the locality.

We had approached within less than a mile of its base; our conversation
had dropped--at least so far as I was concerned; my thoughts were
occupied with the mound, and my eyes wandering over its outlines.

I was endeavouring to make out the character of the vegetation which
seemed to flourish luxuriantly on its summit. The dark foliage was
evidently that of some species of acicular trees, perhaps the common red
cedar (_Juniperus Virginiana_), but there were others of lighter hue--in
all likelihood _pinons_, the pines with edible cones, peculiar to this
region. I noticed, also, growing upon the very edge of the cliff,
yuccas and aloes, whose radiating blades, stretching out, curved
gracefully over the white rock. Forms of cactus, too, were apparent,
and several plants of the great _pitahaya_ rose high above the cliff,
like gigantic candelabra--strange objects in such a situation.

My companions seemed to have no eyes for these rare vegetable beauties;
I could hear them at intervals engaged in conversation; but the subject
had no reference to the scene, and I paid little attention to what they
were saying.

All at once I was startled by the voice of Garey, giving utterance to
the emphatic announcement--

"Injuns, by God!"

"Indians!--where?"

The interrogation as it escaped my lips, was half involuntary, and
needed no reply. Garey's glance guided me; and following its direction,
I observed a string of horsemen just debouching from behind the mesa,
and spurring forward upon the plain.

Both my companions had drawn bridle, and halted. I followed their
example; and all three of us sat in our saddles, scanning this sudden
apparition of mounted men. A dozen had now cleared themselves from
behind the mesa, and were riding towards us.

We were yet nearly a mile