Colorado. Between the Grand River and the foot of this plateau there is
a low, narrow valley with mesas and buttes. Then the country suddenly
rises by a stupendous line of cliffs 2,000 or 3,000 feet high. These
cliffs are composed of sand stones, limestones, and shales, of many
colors. The stratification in many places is minute, so that they have
been called the Book Cliffs.

From the cliffs many salients are projected into the valleys, and within
deep re-entering angles vast amphitheaters appear. About the projected
salients many towering buttes, with pinnacles and minarets, are found.
The long, narrow plateau is covered with a forest along its summit, and,
though it rises abruptly on the south side from Grand River Valley, it
descends more gently toward the White River, and on this slope many
canyons of rare beauty are seen. Plateaus and mesas and canyons and
buttes characterize the region north of White River and stretch out to
the Yampa. The Yampa itself has an important tributary from the
northwest, known as Snake River. Just below the affluence of the Snake
with the Yampa a strange phenomenon is observed. Right athwart the
course of the river rises a great dome-shaped mountain, with valley
stretches on every side, and through this mountain the river runs,
dividing it by a beautiful canyon, through which it flows to its
junction with the Green. This canyon is in soft, white sandstone,
usually with vertical walls varying from 500 to 2,000 feet in height,
and the river flows in a gentle winding way through all this stretch. To
the east of this plateau region, with its mesas and buttes and its
volcanic mountains, stand the southern Rocky Mountains, or Park
Mountains, a system of north-and-south ranges. These ranges are huge
billows in the crust of the earth out of which mountains have been
carved. The parks of Colorado are great valley basins enclosed by these
ranges, and over their surfaces moss agates are scattered. The mountains