the dimensions are measured by rods and furlongs and the displacements by tens and hundreds of feet. Looking eastward he sees the region of the great flexures spread out before him like a map. The Waterpocket flexure starts from the very mountain beneath him, and curving to the right, runs far to the south and is lost in the distance. Beyond it are the Henry Mountains springing abruptly from the desert; and against the horizon are outlined other island mountains, gray in the distance. To the left is the San Rafael Fold, the rival of the Waterpocket in grandeur; and all about are tables and cliffs. The vivid hues of the naked rocks are obscured only by the desert haze, and the whole structure is pictured forth by form and color. [Illustration: FIG. 6.—The Unconformity of the lower cañon of Salina Creek. The horizontal strata are Tertiary; the inclined, Cretaceous. ] To reach the Henry Mountains from Rabbit Valley, he must cross the Waterpocket flexure; and so continuous and steep are the monoclinal ridges which follow the line of flexure, that there are but four points known where he can effect a passage. Except at these points, the barrier is impassable from Thousand Lake Mountain to the Colorado River, a distance of eighty miles. The most difficult and circuitous route I will not describe. The remaining three diverge but slightly from each other. Starting from Rabbit Valley he follows for a few miles the valley of the Dirty Devil, which here, through the “Red Gate”, passes from the trachyte plateaus and enters the land of cañons. He does not follow it far, but where the river enters a cañon in the Aubrey Sandstone, bears to the left, and by the aid of a trail which Indians have made finds a sinuous but easy pathway along a monoclinal valley, following the outcrop of the lower Shinarump. At his right the Aubrey Sandstone rises to form the plateau through which the river defiles. At his left the Vermilion Sandstone stands in a vertical wall. Beneath his feet are the shaly sandstones of the Shinarump Group, bare of vegetation and displaying a profusion of ripple-marks, such as is rarely if ever equaled. A ride of twelve miles brings him once more to the Dirty Devil River, which emerging from its Carboniferous cañon dives at once into a still deeper cañon through the Vermilion and Gray Cliff Sandstones. He can follow the river if he tries, and emerge with it beyond the flexure; but the way is difficult and the Indian trail he has followed thus far leads on to another cañon. The monoclinal valley which has opened so easy a way continues for fifteen miles farther, and in that distance is crossed by four waterways, each of which leads by a narrow cañon through the great sandstones. The first and fourth are impassable. The second carries no permanent stream, and is called the “Capitol Cañon”. The third affords passage to Temple Creek. The smoothest road lies through Capitol Cañon, but the Temple Creek Cañon has an advantage in the