One must not think of a mountain range as a line of peaks standing on a
plain, but as a broad platform many miles wide from which mountains have
been carved by the waters. One must conceive, too, that this plateau is
cut by gulches and canyons in many directions and that beautiful valleys
are scattered about at different altitudes. The first series of canyons
we are about to explore constitutes a river channel through such a range
of mountains. The canyon is cut nearly halfway through the range, then
turns to the east and is cut along the central line, or axis, gradually
crossing it to the south. Keeping this direction for more than 50 miles,
it then turns abruptly to a southwest course, and goes diagonally
through the southern slope of the range.

This much we know before entering, as we made a partial exploration of
the region last fall, climbing many of its peaks, and in a few places
reaching the brink of the canyon walls and looking over precipices many
hundreds of feet high to the water below.

Here and there the walls are broken by lateral canyons, the channels of
little streams entering the river. Through two or three of these we
found our way down to the Green in early winter and walked along the low
water-beach at the foot of the cliffs for several miles. Where the river
has this general easterly direction the western part only has cut for
itself a canyon, while the eastern has formed a broad valley, called, in
honor of an old-time trapper, Brown's Park, and long known as a favorite
winter resort for mountain men and Indians.

_May 30.--_This morning we are ready to enter the mysterious canyon, and
start with some anxiety. The old mountaineers tell us that it cannot be
run; the Indians say, "Water heap catch 'em"; but all are eager for the
trial, and off we go.