The time spent in this voyage was ninety-eight days, and the distance travelled was upward of one thousand miles. Four of his men left him when the voyage was but partly finished, being frightened by the perils that beset them. They were killed by Indians. The others, after many accidents and hair-breadth escapes, succeeded in getting through in safety. In addition to the rapidity of the current the river has many rapids and water-falls with jagged projecting rocks which make boating extremely hazardous. All these perils were conjectured but unknown to Major Powell's party, and every new bend of the river was liable to disclose a cataract more dangerous than any encountered before. Then the reverberating sound of the roaring river as it struck the sides of its lofty prison walls together with the deep gloom of the mighty abyss was calculated to terrify the bravest. Thus, facing death at every turn of the stream, the men were kept constantly in a tense state of excitement. A wealth of adjectives has been expended in attempting properly to describe the immensity of this great handiwork of nature, and scores of persons have produced fascinating word-paintings of its awe-inspiring grandeur. Leading back from the river the canyon walls are made up in part of shelving rocks and terraces. These, with peaks, buttes, and myriads of other structures arising from the great gulf, show plainly the different strata of rocks of which they are composed. Many of these rocks are richly colored; the tints as a rule result from the salts of iron and other mineral matter disseminated through them. In some instances the coloring material of the upper strata has been washed down by the storms and has stained the rock of the walls below. This is the case in the Grand Canyon, where the limestone wall is colored red by the iron in an overlying stratum. When the gigantic forms partly filling the chasm, yet standing apart from each other, are seen near sunrise or sunset with their shifting shadows, they leave on the mind remembrances that will never fade. To appreciate properly the magnitude and height of these towering masses one should examine them not only by travelling along the brink, but by descending to the river level in order to examine them from below. Then only will the awful grandeur and immensity of this monumental architecture of nature begin to dawn upon the understanding. To the geologist this chasm is an intensely interesting book which reveals much of the history of the past in world-building.