In describing those subdivisions of the Grand Cañon district which are of greatest moment to the present discussion, I shall begin with the terraces terminating the High Plateaus.

Before the observer who stands upon a southern salient of the Markí gunt Plateau is spread out a magnificent spectacle. The altitude is nearly 11000 feet above the sea, and the radius of vision reaches to the southward nearly a hundred miles. In the extreme distance is the calm of the desert platform, its surface mottled with indistinct lights and shades, too remote to disclose their meaning. Against the southeastern horizon is projected the pale-blue escarpment of the Kaibab, which stretches away to the south until the curvature of the earth carries it out of sight. The southward rise in merest outline, and devoid of all visible details, the dark mass of Mount Trumbull and the waving cones of Uinkaret. Between these and the Kaibab the limit of the prospect is a horizontal line, like that which separates the sea from the sky. To the southwestward are the Sierras of the Basin Province, and quite near us there rises a short but quite lofty range of veritable mountains, contrasting powerfully with the flat crestlines and mesas which lie to the south and east. It is the Pine Valley range, and though its absolute altitude above the sea is smaller than many other ranges of the West, yet since their are comparatively low (3,000 to 3,500 feet above the sea), the mountain masses themselves are very high.