G. K. Gilbert— The Oolorado Plateau Province. 17 
ern portions with the southern, was Professor W. P. Blake (Pac. 
R. Repts., vol. iii, part Iv, pp. 8 and 42, 1856.) The title of 
“Colorado Plateau” first appeared in the map of Ives’ Colorado 
River Report in 1861, and was written between San Francisco 
mountains and the Grand Cafion. Later usage extended the 
term to include the broad upland through which the Colorado 
has excavated its deep channel; and finally, as the minor pla- 
teaus of which the great one is composed began, in the progress 
of geographical knowledge, to be discriminated and named, the 
comprehensive title of the whole became the Colorado Plateaus 
or the Colorado Plateau Province. Portions of the region have 
been studied, described, and mapped by numerous geologists 
and geographers, but the chief contributions to our knowledge 
of the Province as a whole, and of its limits, have come from the 
surveys conducted by Major Powell and Lieutenant Wheeler.* 
t would avail little to describe in detail the boundaries of the 
province without the aid of a map. On the east it is separated 
by mountains for which there is no comprehensive title. Its 
or one-twenty-fourth part of the territory of the United States. 
It is drained chiefly by the Colorado of the West and its tribu- 
n, and 
the Puerco of the East in its eastern, and the North Platte drains 
its northeastern angle. The plateaus which compose it range 
In altitude from 5,000 to 11,000 feet above the sea, but the 
lines of drainage are much lower, and the streams run at the 
bottoms of deep gorges or cafions. The plateaus are terminated 
mn vet by cliffs, and the cafion walls are cliffs. Plateaus, cafions, 
and cliffs are the characteristic features. The chief mountains 
are of volcanic origin, and they are doubly conspicuous, since 
PowegPloration of the Colorado River of the West and its tributaries; by J. W. 
n. 7 
In defining the province in my report to Lieut. Wheeler (see U. S. Eng. Expl. 
the Sur. W. of the 100th mer., =. ii, Geology, pp. 43 and 542) I have not included 
;_. Portion south of the Uinta mountains. 1 was not aware, at the time of writ- 
the that the plateaus south of the Uintas were continuous with those of Wyoming, 
Uinta uplift not in, to the Park Mountains. 
AM. Jour. 8ct.—Turrp Series, Vou. XII, No. 67.—JuLy, 1876. 
2 
