GENERAL FEATURES. 617 
course, west of the longitude of the Blue Range, but turns east near 
Okanagan, and having crossed this longitude, it forks again just 
beyond Fort Colville, one affluent coming from the north in latitude 
52°, and the other from the southeast. Fraser’s River, which empties 
north of latitude 49°, has a nearly parallel course with the north 
branch of the Columbia, and flows from the Rocky Mountains, rising 
in latitude 54°. The mountain range north of Fort Colville forms the 
boundary between the two great river depressions, Fraser’s and the 
North Columbia. 
We observe therefore that the arrangement of the mountains has 
given the remarkable expansion and length to the Oregon rivers. In- 
stead of many small streams flowing direct from the mountains to the 
sea over the narrow western slopes of the Rocky Mountains, the 
waters of the great interior section are gathered along the range for 
seven hundred miles from north to south, into a common channel, 
and this channel has found a passage through the great barrier, the 
Cascade Range. Fraser’s River, to the north, is the only other river 
which intersects this range, and this is north of the parallel of 
forty-nine. So the Cascade Range, without the Coast Mountains, 
would have given rise to a number of little streams, with small and 
narrow alluvial flats, flowing with few turns to the coast. But with 
the existing features of the surface, the streamlets collect into the 
larger rivers; and these flow long distances north or south, to find 
their exit either into the Columbia or the Bay of San Francisco. They 
flow, too, in consequence of this arrangement, notwithstanding the 
general slopes of the country, over a nearly level tract, lying at almost 
a uniform distance from the ocean, and they there spread their allu- 
vial plains to the great improvement of the country. The Willammet 
Valley is a striking example of this, and the Sacramento and Joaquin, 
with their broad alluvial lands, are others. Between the head waters 
of the Sacramento and Willammet there are the Umpqua and Clammat 
rivers, crossing the Coast Range to the sea, and illustrating, by their 
small bottom plains, the principles here explained. 
South of the region drained by the Columbia, spurs from the Blue 
Mountains stretch along to the east, parallel with the Salmon River 
Range. These form the northern boundary of the great Colorado 
territory, which hes between the summit of the Rocky Mountains, (or 
the Anahuac Range, as they have been called,) and the Californian 
portion of the Cascade Range, or the Sierra Nevada. The Colorado 
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