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Show 258 GEOLOGY OP THE HIGH PLATEAUS. As we go southward from the Wasatch Plateau, crossing Salina Canon near its middle, we at once begin to ascend the northern slopes of the third chain. We are among the sedimentaries, which dip gently to the westward; and descending from the south, a noble valley opens into the middle of Salina Canon, with the edges of the lowest Tertiary beds walling it abruptly on the west and the surface of the Upper Cretaceous rising gradually on the east. This lateral valley is named, locally, Strawberry Valleyâ€"a name which recurs with great frequency throughout the mountain regions of the West. As we move upward towards the south the dip of the beds increases, and the very long and gentle inclination of the strata at length becomes wrinkled into a monoclinal of large proportions. We perceive this readily when, at a distance of 4 or 5 miles south of Salina Canon, we climb the western wall of Strawberry Valley, and see directly in front of us to the southward the Tertiary beds covered with immense sheets of old lava, but exposed beneath in a deep ravine. We see them rising monoclinally from the west and smoothing out eastwardly to a sensibly horizontal position at a high altitude. The underlying sedimentaries are well exposed, for erosion has carved away much of the country to the northward and given admirable sections transverse to the main structure lines and axes. Three days' inspection of these northern flanks will convey a full conception of the general features of the structure, for they are very easily read. Climbing the western wall of Strawberry Valley, we reach a platform about 2 miles wide, from which start the long slopes leading up to higher levels. Immediately in front is the Fish Lake Plateau, full 4,000 feet above us. To the south-southeast is an easy ramp leading up to Summit Valley, an elevated interspace between Fish Lake Plateau and Mount Marvine. As we ascend this grade, we have on the right a deep ravine carved into the general plateau mass, laying bare, in an admirable manner, the sweeping curves of the Tertiary beds, overlaid by trachyte, both being bent into typical monoclinal form. The strike of this monoclinal is visible, extending south-southwest nearly 15 miles, giving origin to a slope varying in inclination from 18° to 20°, and with no other ravines than the one just mentioned. It conveys to the eye an impression of singular smoothnessâ€"like a vast roof. The slope we are ascending is much more uneven; and, at an altitude of |