14 
FAIRBANKS AND RAMPART QUADRANGLES. 
molted snow and rain, is not great. Observations taken at Xanana 
at intervals from 1882 to 1886 gave an annual average of 15.15 inches. 
The rainfall varies greatly in the different seasons; sometimes long 
continued drought lowers the quantity of water in the streams below 
the economic limit, while in other seasons water is almost constantly 
in excess of the amount required. A detailed statement of the water 
supply and rainfall, by C. C. Covert, is given on pages 51-59 of this 
report. 
The distribution of vegetation is shown in fig. 2. The high ridges 
are mostly Inure of trees and are covered only with the low vegetation 
Fig.^ 2. — Map showing distribution of timber in the Fairbanks and Rampart quadrangles. 
of the tundra. The lower ridges are largely covered with a dense 
growth of small spruce, accompanied by birch and poplar and in the 
larger valleys by a small proportion of tamarack. Willows and scrub 
alders grow abundantly near the streams. Good timber is confined to 
the larger valleys, where it is most thickly concentrated in scattering 
patches along the streams. Spruce is the most important tree and at- 
tains in many places a diameter of 2 or more feet. 
The valley sides and lower ridges of the Fairbanks region are cov- 
ered with a light growth of spruce and poplar, and fine patches of 
birch are common on the hillsides facing the Tanana. Good timber 
is reported from the lower valleys of the Chatanika and Tolovana. 
