6 BULLETIN 50, U. S. DEPARTMENT OF AGRICULTURE. 
is by steamer from Seattle to St. Michael, at the mouth of the Yukon 
Kiver, then up this stream on the river boats; or, from Seattle to 
Skagway on deep-water boats via the inside passage, from Skagway 
to White Horse, Yukon Territory, on the White Pass Railroad, 110 
miles over the range, and then by Yukon River steamers. On the 
latter route 20 miles on the railroad carries one to the summit of the 
range that separates the coast from the interior and puts the traveler 
in the Yukon drainage area. White Horse is at the head of navi- 
gation on the Yukon, the White Horse Rapids being a bar to farther 
travel upstream. Downstream it is 560 miles to where the river 
crosses the international boundary near Eagle, Alaska, about 125 
miles south of the Arctic Circle, and it is 1,500 miles from Eagle 
to St. Michael. The Yukon, with its tributaries, has nearly 4,000 
miles of navigable water. It is the fifth in size of the rivers of 
North America, and it drains an area of 200,000 square miles. 
The great interior of Alaska is essentially a mountainous area, 
although the mountains between the Endicott Range on the north 
and the Alaskan Range on the south are more or less detached and 
of quite moderate altitude. 
Level areas in the interior are for the most part limited to the 
alluvial bottoms along the streams. The most pronounced exception 
to this is in the Yukon Flats. About 200 miles downstream from 
Eagle the river passes into an area 150 miles long and 50 to 75 miles 
wide that is quite level. The river banks are low and the stream 
divides into innumerable channels, thus forming a myriad of islands. 
Dense growths of spruce and poplar occupj^ the land, with occasional 
grass meadows. For the most part the bottom lands comprise a 
strip on one or both banks of the larger streams, rarely exceeding a 
couple of miles in width. Next to the bottoms there may be benches 
which merge into low hills, and these into the mountains that make 
up the larger proportion of the area. The bottom, bench, and low 
hill lands are, of course, those that are suitable for farming, the 
higher hills and mountains being more or less available for grazing. 
The low hills having a southern exposure, and particularly if cov- 
ered with a growth of birch, are the best suited to tillage. The 
benches with comparatively high banks above the streams and free 
from gravel banks are the next best. The low-lying bottom lands, 
lacking both water and air drainage, are the least desirable for farm- 
ing purposes. 
The largest area of tillable land thus far located in the interior is 
in the Tanana Valley, extending 20 to 30 miles above Fairbanks and 
downstream to the junction of the Tanana with the Yukon. The 
Kuskokwim River, which rises on the northwestern slope of the 
Alaskan Range and flows southwest into Bering Sea, occupies a 
