Igr0] ROBBINS—VEGETATION IN COLORADO 259 
mountainous. The lowest point in the state has an elevation of 3386 
feet; there are a number of peaks over 14,000 feet high; thus there is 
an altitudinal range considerably over 11, 500 feet. 
DRAINAGE SYSTEMS.—The general north and south direction of the 
mountains of Colorado determines the general east and west direction 
of the streams. In the mountainous country small streams are very 
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Fic. 3. Mean ammual eames the area along the eastern border of the 
state having 15~20 inches annually is called the “rainbelt”; dry farming is more 
Successful here than in the belt on A a of it 
abundant, and they usually have their head in a wet mountain 
meadow which is fed by water from melting snow. The prevalent 
€ast and west direction of the streams is a condition affecting the 
migration of riparian species. Generally speaking, the streamside 
flora and vegetation at any point is more like that east and west than 
that north and south. 
Lessthanl0 WtolS 
PRECIPITATION 
GENERAL account.—The precipitation amounts of Colorado are 
Shown in fig. 3. In making a rainfall map it is found difficult to 
