294 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
as being a very fine valley, with luxuriant grasses in the upper part, de- 
generating into Artemisia near Green River. 
The Grand River, alter emerging from the Middle Park. Hows through 
a region of high broken table lands, most of the way in a canon, only occa- 
sionally emerging into a narrow sage-brush valley, nearly to its point of 
junction with the Gunnison. The latter stream has a somewhat more 
open course, with several large valleys. The uppermost of these, Taylor's 
Park, near the head of the stream, is pretty well covered with forests. 
Then follows a short canon, from which the river emerges into the Gun- 
nison Valley, a meeting place of several considerable streams, and of a 
number of valleys of greater or less width. The lower part of this com- 
pound valley is sage-covered, while the upper parts and the plateaus in 
the neighborhood are covered with luxuriant grasses and cotton wood. 
Below this valley the river is in canon for a long distance, while the 
plateaus bordering it, which rise gradually on the north to the Elk 
Mountains and on the south to the San Juan Range, are grassy, with 
groves of quaking aspens. At the foot of this, the Grand Canon, the river 
emerges into daylight at the foot of the Uncompahgre Valley and flows 
across its lower end. This valley extends northward from the base of 
the San Juan Mountains, the Uncompahgre River flowing down its cen- 
ter. It is about 50 miles in length and 15 to 20 miles wide. It contains 
but little grass, except at its upper end. The growth is sage, the soil 
a heavy, cold clay. The bottom lands of the river are broad — one-half 
mile to a miie — and overgrown with bushes of various species, with 
quite an extensive growth of cotton wood and willow. At the foot of 
this valley it joins the Gunnison, which in the valley has bottom lands 
one to two miles in width, with a fine growth of willows. 
Below the mouth of the Uncompahgre the Gunnison flows in a canon 
on the left-hand side of a broad valley which produces but very little 
vegetable growth ; and the same remark holds good, in a still more 
marked degree, concerning the broad valley which extends down the 
Grand below their junction, lying at the south base of the Book Cliff's. 
It is an utter desert, without possibility of amelioration save by a change 
of climate. 
West of the Uncompahgre and Gunnison is a high plateau iuclining 
toward those valleys and breaking off abruptly toward the southwest. 
It has the form of an immense spur from the San Juan Mountains, 
trending to the northwest. Its crest has an elevation of 8,000 to 9,000 
feet; its higher part, near the crest, is well timbered, but contains many 
open grassy parks. Lower down on each slope the plateau is covered 
with sage, interspersed with piuon pine. 
Farther to the westward are lower plateaus falling oue below another 
and passing by gradations, according to altitude, into a more and more 
desert country. In the lowest and worst of this region the Grand and 
Green join, forming the Colorado. 
West of the San Juan Mountains stretches the Great Sage Plain, 
