hern extremity dips in the Arctic Sea in
latitude 70 degrees north, and longitude 135 degrees west, running
nearly south-east, and begins to be parallel to the coast of the Pacific
ocean from Cook's inlet, and so onwards to the Columbia. From thence it
appears to quit the coast, but still continuing with less elevation to
divide the waters of the Atlantic from those of the Pacific. In these
snow-clad mountains rises the Mississippi, if we admit the Missouri to
be its source, which flows into the Gulph of Mexico; the river Nelson
which is lost in Hudson's Bay; Mackenzie's river that discharges itself
into the North Sea, and the Columbia emptying itself into the Pacific
Ocean. The breadth of the mountains from Cook's inlet to the Columbia is
from four to eight degrees easterly." I may add, that the great rivers
mentioned by Mackenzie not only take their origin from the same range of
mountains, but almost from the same hill; the head waters of the
Columbia and Mackenzie being only about two hundred yards apart in
latitude 54-1/2 degrees. Mr. Drummond, who crossed the mountains at that
place, informs me, that the Eastern side of the range consists of
conglomerate and sandstone, to which succeed limestone hills exceedingly
barren, and afterwards clay-slate and granite.

James, the intelligent naturalist, who accompanied Major Long on his
first expedition, says of the Rocky Mountains to the southward of the
Missouri, "They rise abruptly out of the plains which lie extended at
their base on the east side, towering into peaks of great height, which
renders them visible at the distance of more than one hundred miles from
their base. They consist of ridges, knobs, and peaks, variously
disposed, among which are interspersed many broad and fertile valleys.
James's peak, one of the more elevated, was ascertained by
trigonometrical measurement to rise 8500 feet above the common level.
The rocky formations are uniformly of a primitive character, but a deep
crust of secondary rocks appears to recline on the east side of the
mountains, extending upwards from their base many hundred feet." In
another place, he says, "The woodless plain is terminated by a range of
naked and almost perpendicular rocks, visible at the distance of several
miles, and resembling a vast wall parallel to the base of the mountain.
These rocks are sandstone, and rise abruptly to an elevation of one
hundred and fifty or two hundred feet." The sandstone walls seem to