334 On the Geology of the Northwestern Regions of America. 
sandstones are <9 6 eed of small extent.” This remark, 
which I quote from the learned and beautiful work of Professor 
Dana, ‘ The Geology of the United States Exploring Expedition 
under Commodore Wilkes,’ will prepare the reader for the exami- 
nation of a country of a different character from what has above 
formed the subject of investigation 
The grand features of the country on the Pacific side of the 
Rocky Mountains arise from the development of three ranges of 
mountains, intersecting the country in a direction parallel with 
the general course of the coast-line. Three of these are north 
and south ranges,—the Coast Range, the Cascade Range, and 
the Blue Mountain Range. The first lies near the coast, the 
second 130 miles inland, and the third 350 miles from the sea. 
The Cascade Range is much the most extensive of the three, 
and even rivals the Rocky Mountains in the height of some of its 
peaks. It may be traced, according to Professor Dana, far into 
California, and northward into Russian America; retaining 
throughout a direction nearly parallel with the coast. It termi- 
nates northward, according to Grewingk, in the lofty voleano of 
Mount Wrangell, in lat. 62° N, where it blends with the lateral 
volcanic range, forming the remarkable promontory of Aliaska. 
The main body of the Cascade range, in Oregon, is seldom over 
5000 or 6000 feet in elevation. [The Sierra Nevada is a con- 
tinuation of the chain; south it becomes the range of the Cali- 
ornia Peninsula. | 
The Blue Monntains form the western boundary of the Valley 
of the Snake River (of Lewis and Clarke), flowing into ed 
Columbia. Immediately to the north of this river, as far as For 
Colville, they are interrupted by an extensive level tract; but > 
the North of Fort Colville there is a range of heights which ex- 
tends along the north branch of the Columbia River, and may 
be considered a part of the same general ¢ 
e short western slope of the ecutiaied: from the Rocky 
Mountains to the Pacific differs from the eastern in its river-valleys 
being all more or less transverse,—the rivers flowing through 
passes or gorges of the intersecting ranges. ‘The peculiar wing- 
like projection in the north, towards Asia, is evidently due to the 
voleanic chain of Aliaska, which runs at right angles to the 
ocky Mountains. The great transverse valley of the Yukon 
their summits rise into the region of perpetual snow. The line in which the volcanic 
peaks of Aliaska lie when prolonged to the anboestl strikes the Big Reaver Moun- 
tains on the Yukon. On the side of the Atlantic, modern volean a 
Jan se ois Island only, whose principal mountain, Beerenberg, al 6870 feet 
I have] are recent] i he south of 
Cumberland House, ni edcbniioionten rege bre vleanie, an th that an eruption 
has observed there within last year. 
been year. report requi 
Mo cthet ¢aamelete ‘now of the existence of a volcano in any part of America 
Rocky Mountains. 
