The antithesis of the Masuk Plateau is to be seen in the Circle Cliffs, on the summit of the Waterpocket fold. At the lowest point of the Masuk synclinal a circling cliff has been formed, which facing outward surrounds a plateau. At the highest point of the Waterpocket fold, which is in a certain sense anticlinal, a circling cliff has been formed which, facing inward, surrounds a valley. The two phenomena are alike illustrations of the law that in regions of inclined strata cliffs face toward districts of elevation and away from districts of depression. HOW TO REACH THE HENRY MOUNTAINS. [Illustration: FIG. 5.—Ways and Means. ] No one but a geologist will ever profitably seek out the Henry Mountains, and I will therefore, in marking out a route by which they may be reached, select whenever there is option those paths which will give him the best introduction to this wonderful land. There is no wagon-road to the mountains, and although a wagon might carry his baggage the greater part of the way, he must provide himself with other means of transportation. At Salt Lake City he can procure pack-mules and pack-saddles, or _apparajos_, and everything necessary for a mountain “outfit”. His route southward follows the line of the Utah Southern Railway to Juab Valley, and then touches the Mormon towns of Nephi, Gunnison, and Salina. At Salina he halts his train for a day while he rides a few miles up the creek to see the unconformity between the Tertiary above, and the Jura-Trias and Cretaceous below. This is at present the last settlement on the route, but there are “ranches” as far as Rabbit Valley, and if he delays a few years he will find a town there. By way of the “Twist” road and King’s Meadows he goes to Grass Valley, and thence to Fish Lake. The lake lies between two upheaved blocks of trachyte, and covers one which is relatively depressed, and tilted to the north. At the south end of the lake he stands on the higher end of the depressed block, and if he follows the shore to the outlet at the north he will find that the water is contained by a moraine, which has been thrown across the valley by an ancient glacier, descending from the mountain at the west. From Fish Lake he goes to Rabbit Valley, and there delays a day or two to climb Thousand Lake Mountain. Looking west from the summit he sees the lava-capped plateaus of the faulted district among which he has journeyed since he left the “Twist”—huge tables of trachyte bounded by cliffs of displacement, of which only the sharpest edges have been worn away; and when his eye has become accustomed to the _facies_ of the faults, he perceives that there is an identity in structure between the great and the small features. Just as the whole district is divided into blocks, of which the dimensions are measured by miles, and the displacements by thousands of feet, so the greater blocks are sometimes divided into smaller, of which