The erosion represented in the canyons, although vast, is but a small
part of the great erosion of the region, for between the cliffs blocks
have been carried away far superior in magnitude to those necessary to
fill the canyons. Probably there is no portion of the whole region from
which there have not been more than a thousand feet degraded, and there
are districts from which more than 30,000 feet of rock have been carried
away; altogether there is a district of country more than 200,000 square
miles in extent, from which, on the average, more than 6,000 feet have
been eroded. Consider a rock 200,000 square miles in extent and a mile
in thickness, against which the clouds have hurled their storms, and
beat it into sands, and the rills have carried the sands into the
creeks, and the creeks have carried them into the rivers, and the
Colorado has carried them into the sea.
We think of the mountains as forming clouds about their brows, but the
clouds have formed the mountains. Great continental blocks are upheaved
from beneath the sea by internal geologic forces that fashion the earth.
Then the wandering clouds, the tempest-bearing clouds, the
rainbow-decked clouds, with mighty power and with wonderful skill, carve
out valleys and canyons and fashion hills and cliffs and mountains. The
clouds are the artists sublime.