Above the Paria the great river runs down a canyon which it has cut
through one plateau. On its way it flows with comparative quiet through
beautiful scenery, with glens that are vast amphitheaters which often
overhang great springs and ponds of water deeply embosomed in the
cliffs. From the southern escarpment of this plateau the great Colorado
Plateau rises by a comparatively gentle acclivity, and Marble Canyon
starts with walls but a few score feet in height until they reach an
altitude of about 5,000 feet. On the way the channel is cut into beds of
rock of lower geologic horizon, or greater geologic age. These rocks are
sandstones and limestones. Some beds are very hard, others are soft and
friable. The friable rocks wash out and the harder rocks remain
projecting from the walls, so that every wall presents a set of stony
shelves. These shelves rise along the wall toward the south as new
shelves set in from below.
In addition to this shelving structure the walls are terraced and the
cliffs of the canyon are set back one upon the other. Then these canyon
walls are interrupted by side streams which themselves have carved
lateral canyons, some small, others large, but all deep. In these side
gorges the scenery is varied and picturesque; deep clefts are seen here
and there as you descend the river—clefts furnished with little streams
along which mosses and other plants grow. At low water the floor of the
great canyon is more or less exposed, and where it flows over limestone
rocks beautiful marbles are seen in many colors; saffron, pink, and blue
prevail. Sometimes a façade or wall appears rising vertically from the
water for thousands of feet. At last the canyon abruptly ends in a
confusion of hills beyond which rise towering cliffs, and the group of
hills are nestled in the bottom of a valley-like region which is
surrounded by cliffs more than a mile in altitude.