IRRIGABLE LANDS OF THE COLORADO DRAINAGE. 157 
THE FREMONT RIVER. 
The largest branch of this stream rises in the Un-ca-pa-ga Mountains, 
and after flowing in an easterly direction for 125 miles enters the Colo- 
‘ado about 40 miles below the junction of the Grand and Green. It is 
joined by one considerable tributary, Curtis Creek, from the north, and 
another smaller, Tantalus Creek, from the south. The lower half of its 
course is through two deep canons, separated by an intervening valley called 
Graves Valley, in which is an area of 10 square miles of arable land, 
with an altitude of 4,500 feet above sea level. On the upper waters of 
the main river, in what is known as Rabbit Valley, and at an altitude of 
nearly 7,000 feet, are 25 square miles of arable land of good quality. This 
area, from its altitude, should be subject to late and early frosts, but the 
warm sandy soil and southeastern slope of the whole valley will probably 
prevent much damage from this cause. The valley is now used as a herd 
ground for cattle belonging to the settlements in Sevier Valley, and the few 
experiments made by the herdsmen in cultivating the soil also indicate that 
the danger to be apprehended is slight. The volume of water flowing 
through Rabbit Valley in July, 1875, was 175 cubic feet per second. 
Tantalus Creek drains the northern portion of the eastern slope of the 
Aquarius Plateau. It enters a close canon at 8,000 feet altitude, and 
continues in canons until it has passed through Water Pocket Fold. It 
then flows along a desolate valley at the foot of the fold until it joins the 
Fremont River. During the warmer months the water in this creek is 
usually absorbed and evaporated before reaching its mouth. In the valley 
at the foot of Water Pocket Fold are about 10 square miles of arable land ; 
but the almost inaccessible situation of the valley and the desolation and 
ruggedness of the surrounding country may present insurmountable obsta- 
cles to its settlement. 
Curtis Creek, the northern tributary of Fremont River, is formed by 
the union of several smaller streams that rise in the Wasatch Plateau. 
Debouching from the plateau, these branches flow across what is known 
as Castle Valley, and here, at an altitude of 6,000 feet, are 25 square 
miles of good arable land. They were measured in September, 1876, and 
