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POOR ON MAP OF THE UNITED STATES [June 14, 1858. 
The Papers read were — 
1. Notes on a Map of the United States and the adjacent Countries. 
By Henry V. Poor, Esq., of New York. 
The best route of commerce across the continent seems to he 
indicated by the direction in which its great rivers run. The St. 
Lawrence, running very nearly east, carries a navigable water line 
into the heart of the continent, a distance of 2500 miles from 
the Atlantic Ocean. The Upper Missouri, very nearly upon the 
same parallel with Lake Superior, runs almost due east for 600 or 
700 miles, after issuing from the Eocky Mountains. The waters 
of this river interlock with those of the Columbia, the great river 
of the Pacific slope of the continent. The directions of these great 
rivers indicate a deep depression in the continent, extending from 
ocean to ocean, and a favourable route for a great highway to con- 
nect them. 
But upon going north, we find a much lower depression than 
that occupied by the valley of the Missouri Eiver. Lake Winnipeg 
is only slightly elevated above Lake Superior ; the surface of the 
latter being about 590 feet above the sea, while that of the former 
is about 850 feet. The rivers that flow into this lake from the 
south and west have very gentle and uniform currents. The Eed 
Eiver of the North has an inclination of only two or three inches to 
the mile, and is navigable nearly to its source, by large class steam- 
boats, at all periods of the year when not obstructed by ice. The 
Saskatchawan, which flows from the west, is one of the great rivers 
of the continent. Near its entrance into the lake it is for a short 
distance obstructed by rapids. From the head of these to the Eocky 
Mountains there is no obstruction to the navigation of the river. 
The valley through which it runs is depressed from 1000 to 1200 
feet lower than that occupied by the Missouri Eiver upon similar 
meridians. At the mouth of the Yellow Stone Eiver, 102^-° west 
from Greenwich, the surface of the Missouri Eiver is about 2180 feet 
above the level of the sea. Fort Cumberland, on the Saskatchawan, 
and very nearly on the same meridian, is only about 900 feet above 
the sea. Both rivers have, probably, very nearly the same rate of 
fall. The eastern slope of the Eocky Mountains at the source of 
the Saskatchawan is, consequently, much more depressed than at the 
source of the Missouri. This fact would indicate, that after leaving 
Lake Superior, the best route for a railroad across the continent 
deflects, northerly, into the basin of Lake Winnipeg and its tribu- 
taries, assuming that the mountains can be passed at the head of 
the Saskatchawan as well as at the head of the Missouri Eiver. 
