13 LANDS OF THE ARID REGION OF THE UNITED STATES. 
moreover, is coated with a thick layer of fine loam, and it is not until 
penetrated to a considerable depth that we come upon a coarser material. 
This portion of the valley of the Sevier has been under cultivation for more 
than eight years. he art of irrigation has also reached a certain stage of 
advancement, at which it can be studied with some interest. A canal of 
sufficient magnitude to carry the entire body of the water of the Sevier 
during the dry season has been run for a distance of 8 miles, and is 
used for irrigating the large grain fields which lie around Richfield ; and, as 
irrigation is now conducted, the entire flow of the stream is turned through 
this canal after having. been employed for irrigating the various fields, 
which extend for the distance of nearly 7 miles. The total amount of 
irrigable land which may be found between Joseph City on the south and 
the point where the Sevier leaves its proper valley, 65 miles to the north- 
yard, cannot be much less than 90,000 acres. The limit of irrigation 
throughout this entire valley is the limit of the water supply. 
There is one other valley to which we must advert, namely, the valley 
of the San Pete. his is fully equal in fertility and in the convenience of 
every element connected with irrigation to the best part of the main valley 
of the Sevier. The San Pete is a stream of considerable magnitude, and 
experience has shown that it is probably capable, under a more improved 
system of irrigation than that now in use, of watering the greater portion 
of its valley. The cultivable acreage of the San Pete Valley is about 
55,000 acres, provided the whole could be watered. 
The quantity of water carried by the Sevier will now be considered, 
This, of course, is highly variable from month to month. The time for 
measurement, if the true irrigating capacity of the stream is to be con- 
sidered, should be that time at which the ratio of water in the stream to 
the amount required is smallest. At different stages of growth of the crops 
the amount of water required differs considerably. The largest amount is 
needed about the time the seeds of the grain begin to fill out. Ordinarily 
this is in the latter part of July and early in August throughout the lower 
and most extensive portion of the valley, and a week later in the upper 
portions. At this season the water is not at its minimum. ‘There is a 
gradual diminution of the flow during July, but the great shrinkage of the 
