It is a double cañon, i. e. a cañon within a cañon.
The outer cañon is from 2,000 to 3,000 feet deep, and from five to twelve miles wide.
Its general direction is east and west, but the mighty river, which in ancient geologic ages eroded this vast abyss, curved, like all rivers, now this way and now that, so that each wall is recessed in mighty amphitheaters, between which comparatively narrow promontories or points run out from one to six miles into the cañon.
From the base of the mighty palisade which forms the walls of the outer cañon stretches a plateau 5, 8, 10, or 12 miles wide, to the equally lofty palisade which forms the opposite wall of the outer cañon, and somewhere near the middle of this plateau is sunk the inner cañon, another 2,000 to 3,000 feet deep, with a width at the top varying from one-half to three-fourths of a mile, and in its somber depths rolls the ever turbid Colorado, ceaselessly at its endless labor of cutting down the mountains and sweeping their ruins to the sea.
Scattered all over this plateau are the remains of what were once long promontories like the points on which we now walk or ride far out towards the middle of the cañon, but which have weathered so that they are now lines of hills and mountains.
Real mountains many of them are, for from their bases on the plateau, 2,000 to 3,000 feet above the bottom of the inner cañon, they rise 1,500 to 2,500 feet, nearly or quite to the level of the tops of the cliffs bounding the outer cañon.
Nearly all the length of the cañon is through sandstones, and limestones, and shales, resplendent with the colors which add so much to the beauty of Rocky Mountain scenery.
The almost uniform horizontality of stratification of these rocks demonstrates that the erosion of the cañon was little aided or affected by any violent upheavals or disturbances of the rocks.
We see clearly about twenty-five miles each way along the cañon, and somewhat indistinctly probably another twenty-five or thirty miles each way, and everywhere is the same indescribable splendor of color and of beauty of form.
It is a new "Holy City," and whether viewed from above, by a ride or walk along the edge of the cañon, or from the multitudinous turns and loops of the trail by which one can descend on horseback to the plateau and ride across to the edge of the inner cañon, whence a path enables us to safely climb on foot down to the river's edge, everywhere we seem to be gazing on the ruins of cities, palaces, towers, and temples, such as might have been builded by the gnomes and genii of the "Arabian Nights."