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IRRIGABLE LANDS OF THAT PORTION OF UTAH 
DRAINED BY THE COLORADO RIVER AND ITS 
TRIBUTARIES. 
By A. H. THOMPSON. 
That portion of Utah drained by the Colorado River and its tributaries 
belongs to -a great basin limited on the north by the Uinta Mountains and 
on the west by the high plateaus that separate the drainage of the Colorado 
from that of the salt lakes of the interior, and extending beyond the limits 
of the Territory on the east and south. ‘The floor of this basin is extremely 
rough, being broken by isolated groups of rugged mountains, by plateaus 
encircled with cliffs of almost vertical rock, by mesas and amphitheaters, 
and huge monumental and castellated buttes. Everywhere the surface is 
cut and carved with a network of canons, hundreds and often thousands of 
feet in depth. 
The main channel through which its drainage passes to the sea is the 
Jolorado, and its proper upper continuation, the Green River. 
The principal tributaries to these streams from the east are the White, 
the Grand, and the San Juan Rivers—all rising in the high mountains east 
of the Territory and flowing in a general westerly course—the White enter- 
ing the Green River, the Grand uniting with the Green to form the Colorado, 
and the San Juan entering the latter about 125 miles below the junction 
of the Grand and the Green. The Virgin, the Kanab, the Paria, the 
Escalante, the Fremont, the San Rafael, the Price, the Minnie Maud, the 
Uinta, and Ashley Fork are the principal tributaries from the west. 
This portion of Utah is but sparsely settled by white people, the only 
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