ng just a bit choked up and tired, and, to crown a series of
petty misfortunes, the fire failed to respond to Black Sam's endeavours.
This made supper late.

Now at one time in this particular locality Arizona had not been dry and
full of alkali. A mighty river, so mighty that in its rolling flood no
animal that lives to-day would have had the slightest chance, surged
down from the sharp-pointed mountains on the north, pushed fiercely its
way through the southern plains, and finally seethed and boiled in
eddies of foam out into a southern sea which has long since disappeared.
On its banks grew strange, bulbous plants. Across its waters swam
uncouth monsters with snake-like necks. Over it alternated storms so
savage that they seemed to rend the world, and sunshine so hot that it
seemed that were it not for the bulbous plants all living things would
perish as in an oven.

In the course of time conditions changed, and the change brought the
Arizona of to-day. There are now no turbid waters, no bulbous plants, no
uncouth beasts, and, above all, no storms. Only the sun and one other
thing remain: that other thing is the bed of the ancient stream.

On one side--the concave of the curve--is a long easy slope, so gradual
that one hardly realises where it shades into the river-bottom itself.
On the other--the convex of the curve--where the swift waters were
turned aside to a new direction, is a high, perpendicular cliff running
in an almost unbroken breastwork for a great many miles, and baked as
hard as iron in this sunny and almost rainless climate. Occasional
showers have here and there started to eat out little transverse
gullies, but with a few exceptions have only gone so far as slightly to
nick the crest. The exceptions, reaching to the plain, afford steep and
perilous ascents to the level above. Anyone who wishes to pass the
barrier made by the primeval river must hunt out for himself one of
these narrow passages.

On the evening in question the cowmen had made camp in the hollow beyond
the easy slope. On the rise, sharply silhouetted against the west,
Alfred rode wrangler to the little herd of ponies. Still farther
westward across the plain was the clay-cliff barrier, looking under the
sunset like a narrow black ribbon. In the hollow itself was the camp,
giving impression in the background of a scattering of ghostly mules, a
half-circle of wagons, ill-defined forms of recumbent vaqueros, and then
in the foreground o