s of the future. The
entire west side is another, for, except for the lively settlement at
Grand Lake, its peaks and canyons, meadows, lakes, and valleys are
seldom visited. It is natural that the east side, with its broader
plateaus and showier range, should have the first development, but no
accessible country of the splendid beauty of the west side can long
remain neglected. Its unique feature is the broad and beautiful valley
of the North Fork of the Grand River, here starting for its great
adventure in the Grand Canyon of the Colorado.

[Illustration: _From a photograph by Wiswall Brothers_

SUMMIT OF LONGS PEAK, ROCKY MOUNTAIN NATIONAL PARK

Twenty-four hundred feet from water to peak, a mighty chasm carved by an
ancient glacier]

V

The Rockies are a masterpiece of erosion. When forces below the surface
began to push them high in air, their granite cores were covered
thousands of feet deep with the sediments of the great sea of whose
bottom once they were a part. The higher they rose the more insistently
frosts and rains concentrated upon their uplifting summits; in time all
sedimentary rocks were washed away, and the granite beneath exposed.

Then the frosts and rains, and later the glaciers, attacked the granite,
and carved it into the jagged forms of to-day. The glaciers moulded the
gorges which the streams had cut. The glaciers have passed, but still
the work goes on. Slowly the mountains rise, and slowly, but not so
slowly, the frosts chisel and the rains carry away. If conditions remain
as now, history will again repeat itself, and the gorgeous peaks of
to-day will decline, a million years or more from now, into the low
rounded summits of our eastern Appalachians, and later into the flat,
soil-hidden granites of Canada.

These processes may be seen in practical example. Ascend the precipitous
east side by the Flattop Trail, for instance, and notice particularly
the broad, rolling level of the continental divide. For many miles it
is nothing but a lofty, bare, undulating plain, interspersed with
summits, but easy to travel except for its accumulation of immense loose
boulders. This plain slopes gently toward the west, and presently
breaks, as on the east, into cliffs and canyons. It is a stage in the
reduction by erosion of mountains which, except for erosion, might have
risen many thousands of feet higher. Geologists call it a peneplain,
which means nearly-a-plain; it is from fragmentary remains o