This river rises in the angle formed by the intersection of the Wasatch and Western Tavaputs Plateaus, receiving tributaries from both these table lands, and has a general easterly course for 100 miles. It crosses the northern end of Castle Valley, and then flows through a broken country near the foot of the escarpment called the Book Cliffs, forming the southern boundary of the Tavaputs Plateau, till within 20 miles of the Green River, when it cuts through this escarpment into the plateau and joins the Green a few miles above the foot of Gray Cañon. The arable lands along its course are mostly found in Castle Valley, where there are at least 50 square miles--a quantity considerably in excess of the irrigating capacity of the stream. The volume of water was measured in July, 1877, a few miles below where it debouches into Castle Valley, and found to be 189 cubic feet per second. It must suffer great loss from absorption, as the volume when leaving the cliffs is much greater, and the aggregated flow of the branches on the plateaus is at least twice as great. MINNIE MAUD CREEK. This stream rises in the broken country, where the Western Tavaputs and Wasatch Plateaus break into the Uinta Mountains. It has a general easterly course, and joins the Green midway in the Cañon of Desolation. For the greater part of its course it flows in a cañon that widens enough occasionally to give a small area of arable land. One such area, containing 6 square miles, occurs at an altitude of 5,500 feet. Here the volume of water was measured in July, 1877, and found to be 16 cubic feet per second. THE UINTA RIVER.