The prevailing winds of this region are from the west, northwest, and southwest, and are a portion of the more general movement of the atmospheric ocean which moves bodily from the Pacific to the heart of the continent. In crossing the Sierra Nevada a large portion of its moisture is wrung from the air, which blows hot and arid across the Great Basin. Notwithstanding the aridity of the basin area, the air gains about as much moisture as it loses in crossing it, until it strikes the great barriers on the east side of the basin--the Wasatch and the chain of high plateaus which are mapped as its southerly continuation. Here the winds are projected by the bold fronts several thousands of feet upward. The consequent cooling and rarefaction condense from them an amount of moisture which, relatively to that arid country, may be called large, though far less than that of more favored regions. In the valleys the rainfall is exceedingly small; almost the whole of the precipitation is in the high altitudes. It is no uncommon thing to see the heavy masses of the cumulus clouds enveloping the summits of all the plateaus while the valleys lie under a sky but little obscured. The plateaus, then, are the reservoirs where the waters accumulate, and from which they descend in many rivulets and rills, while around their bases are copious springs fed by the waters which fall above. The rainfall in the valleys is very small, as compared with that upon the plateaus, and it is also highly variable. No record has been kept of the precipitation within the drainage system of the Sevier, and the nearest point where such a record has been kept is at Fort Cameron, near Beaver, at the western base of the Tushar Mountains. These observations cover but a brief period, and no doubt represent a much larger precipitation than that which occurs in the valleys and plains generally, because the situation of the point of observation is just at the base of the loftiest range in southern Utah, where the air currents from the west first strike it. Moreover, these observations are not yet published, and are not at present available. In the narrow valleys between closely approximated and lofty mountain walls, like the valley of the Sevier at Marysvale, the rainfall is greater than where the valley is wider, with lower walls, as at Panguitch, Richfield, and Gunnison. An estimate of the amount would be very hazardous; but, judging from what is known of similar localities, the amount in the wider valleys may be as low as 7 or 8 inches, or as high as 10 or 11. In the narrower and deeper valleys it may be between 10 and 12 inches. Upon the plateaus it may be as large as 30 to 35 inches. The principal fall is in the winter and spring months, from the middle of November to the first of June; and in this period at least seven-eighths of the precipitation must be accomplished in the valleys and three-fourths upon the plateaus. There