PREVENTIVE MEASURES IN THE PLAINS AREA. 301 
breadth of more than a mile. These bottom lauds are fertile and, where 
not covered with cottonwood and willow timber, are clothed with luxu- 
riant grasses. The total area of the more fertile portions of Montana 
may be roughly estimated at 20,000 square miles. 
In Washington Territory, all of that portion represented on the map, 
with the exception of that occupied by forests, is covered by luxuriant 
grass. Its area may be set down at about 7,000 square miles. 
In the eastern part of Oregon the more fertile portions consist prin- 
cipally of comparatively small valleys in the Blue Mountains, such as 
the Grand Eonde. They sum up about 2,000 square miles. 
In Idaho the more fertile grass lands are very widely scattered, con- 
sisting mainly of more or less narrow belts about the bases of the Bit- 
terroot, Cceur d'Alene, and Salmon Mountains, and in the mountains in 
the southeast corner. Altogether they sum up about 10,000 square 
miles. 
In Western Dakota the most fertile grass regions are on the north, 
east, and south of the Black Hills. Luxuriant grass extends northward 
for many miles from their base, and eastward covers nearly all the 
country between the forks of the Cheyenne. The area may approxi- 
mately be estimated at about 5,000 square miles. 
In Wyoming the principal breeding grounds are probably the follow- 
ing localities: The plains east of the Laramie Range, the Laramie 
Plains, the country about the base of the Park Bange, the borders of 
the Wind Biver Valley and the Green Biver Basin, the valley of the 
Sweetwater and the Granite Hills just north of it, the eastern base of 
the Yellowstone Bange, and the Big Horn Mountains. The total area 
of the Territory may be roughly estimated at 12,000 square miles. 
In Colorado the following regions are the most fertile : The plains at 
the eastern base of the Front and Sangre de Cristo Banges — this fer- 
tile region extends eastward to a varying distance in different latitudes 
and altitudes ; the Parks, North, South, and Middle, with the northern 
end of San Luis Valley ; the plateaus about the canon of the Arkan- 
sas and the Gunnison Bivers, the Wet Mountain Valley and Huerfano 
Park, and also many small areas among the mountains, which cannot 
be specified, but which, in the aggregate, swell the total considerably. 
The total area is probably about 15,000 square miles. 
Proceeding southward, the area of luxuriant grasses becomes mark- 
edly less. In New Mexico it probably does not exceed 5,000 square 
miles, or about one-third that of Colorado. This is found at the east 
base of the Sangre de Cristo Range, and about the Baton Hills, along 
the Bios San Jose", Puerco, and Vaca, in the Valles Mountains, and on 
the plateaus about the head of the Colorado Chiquito. 
In Utah the area is about the same. It is located mainly in Cache 
Valley, on the narrow ranges of mountains west of it, in the narrow 
strip of land between the Wahsatch Mountains and Great Salt Lake, in 
the upper valleys of the Sevier Biver, the Uinta, Castle, and Grass Val- 
leys, and about the bases of the Henry Mountains and Sierra la Sal. 
