The pyramidal form of these rock-masses is accounted for by the fact that they were carved out from the top downward, and that each successive story is vastly older than the one immediately beneath it. The erosive forces have been working whole geologic ages longer on the top layer of rock than on the bottom layer; hence the topmost ones are entirely gone or else reduced to small dimensions. But what feature or quality of the rock it is that lends itself so readily or so inevitably to these architectural forms—the four square foundations, the end pilasters and balustrades, and so on—is to me not so clear. The peculiar rectangular jointings, the alternation of soft and hard layers, the nearly horizontal strata, and other things, no doubt, enter into the problem. Many of these features are found in our older geology of the East, as in the Catskills —horizontal strata, hard and soft layers alternating, but with the vertical jointing less pronounced; hence the Catskills have few canon-like valleys, though there are here and there huge gashes through the mountains that give a canon effect, and there are gigantic walls high up on the face of some of the mountains that suggest one side of a mighty canon. In the climate of the Catskills the rock-masses of the Colorado would crumble much more rapidly than they do here. The lines of many of these natural temples or fortresses are still more lengthened and attenuated than those of the Temple of Isis, appearing like mere skeletons of their former selves. The forms that weather out the formation above this, the Permian, appear to be more rotund, and tend more to domes and rounded hills.

One of the most surprising features of the Grand canon is its cleanness—its freedom from debris. It is a home of the gods, swept and garnished; no litter or confusion or fragments of fallen and broken rocky walls anywhere. Those vast sloping taluses are as clean as a meadow; rarely at the foot of the huge vertical walls do you see a fragment of fallen rock. It is as if the processes of erosion and degradation were as gentle as the dews and the snows, and carved out this mighty abyss grain by grain, which has probably been the case. That much of this red sandstone, from the amount of iron it contains, or from some other cause, disintegrates easily and rapidly, is very obvious. Looking down from Hopi Point upon a vast ridge called the "Man-of-War," one sees on the top, where once there must have been a huge wall of rock, a long level area of red soil that suggests a garden, the more so because it is regularly divided up into sections by straight lines of huge stone placed as if by the hands of man.

One's sense of the depths of the canyon is so great that it almost makes one dizzy to see the little birds fly out over it, or plunge down into it. One seems to fear that they too will get dizzy and fall to the bottom. We watched a line of tourists on mules creeping along the trail across the inner plateau, and the unaided eye had trouble to hold them; they looked like little red ants. The eye has more difficulty in estimating sizes and distances beneath it than when they are above or on a level with it, because it is so much less familiar with depth than with height or lateral dimensions.

Another remarkable and unexpected feature of the canyon is its look of ordered strength. Nearly all the lines are lines of greatest strength. The prevailing profile line everywhere is that shown herewith. The upright lines represent lines of cyclopean masonry, and the slant is the talus that connects them, covered with a short, sage-colored growth of some kind, and as soft to the eye as the turf of our fields. The simple, strong structural lines assert themselves everywhere, and give that look of repose and security characteristic of the scene. The rocky forces always seem to retreat in good order before the onslaught of time; there is neither rout nor confusion; everywhere they present a calm upright front to the foe. And the fallen from their ranks, where are they? A cleaner battlefield between the forces of nature one rarely sees.

The weaker portions are, of course, constantly giving way. The elements incessantly lay siege to these fortresses and take advantage of every flaw or unguarded point, so that what stands has been seven times, yea, seventy times seven times tested, and hence gives the impression of impregnable strength. The angles and curves, the terraces and foundations, seem to be the work of some master engineer, with only here and there a toppling rock.

I was puzzled to explain to myself the reason of a certain friendly and familiar look which the great abyss had for me. One sees or feels at a glance that it was not born of the throes and convulsions of nature—of earthquake shock or volcanic explosion. It does not suggest the crush of matter and the wreck of worlds. Clearly it is the work of the more gentle and beneficent forces. This probably accounts for the friendly look. Some of the inner slopes and plateaus seemed like familiar ground to me: I must have played upon them when a school-boy. Bright Angel Creek, for some inexplicable reason, recalled a favorite trout-stream of my native hills, and the old Cambrian plateau that edges the inner chasm, as we looked down upon it from nearly four thousand feet above, looked like the brown meadow where we played ball in the old school-days, friendly, tender, familiar, in its slopes and terraces, in its tints and basking sunshine, but grand and awe-inspiring in its depths, its huge walls, and its terrific precipices.

The geologists are agreed that the canyon is only of yesterday in geologic time,—the Middle Tertiary,—and yet behold the duration of that yesterday as here revealed, probably a million years or more! We can no more form any conception of such time than we can of the size of the sun or of the distance of the fixed stars.

The forces that did all this vast delving and sculpturing—the air, the rains, the frost, the sunshine—are as active now as they ever were; but their activity is a kind of slumbering that rarely makes a sign. Only at long intervals is the silence of any part of the profound abyss broken by the fall of loosened rocks or sliding talus. We ourselves saw where a huge splinter of rock had recently dropped from the face of the cliff. In time these loosened masses disappear, as if they melted like ice. A city not made with hands, but as surely not eternal in the earth! In our humid and severe Eastern climate, frost and ice and heavyrains working together, all these architectural forms would have crumbled long ago, and fertile fields or hill-slopes would have taken their place. In the older Hawaiian Islands, which probably also date from Tertiary times, the rains have carved enormous canons and amphitheatres out of the hard volcanic rock, in some places grinding the mountains to such a thin edge that a man may literally sit astride them, each leg pointing into opposite valleys. In the next geologic age, the temples and monuments of the Grand Canon will have largely disappeared, and the stupendous spectacle will be mainly a thing of the past.

It seems to take millions of years to tame a mountain, to curb its rude, savage power, to soften its outlines, and bring fertility out of the elemental crudeness and barrenness. But time and the gentle rains of heaven will do it, as they have done it in the East, and as they are fast doing it in the West.

An old guide with whom I talked, who had lived in and about the canon for twenty-six years, said, "While we have been sitting here, the canon has widened and deepened"; which was, of course, the literal truth, the mathematical truth, but the widening and deepening could not have been apprehended by human sense.