UNITED STATES (PHYSICAL GEOGRAPHY). 



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and west by the Pacific ocean. The boundary be- 

 tween the United States and the British dominions 

 begins at the entrance of the St Croix into the 

 Atlantic, proceeding up that river to its source; 

 thence due north to the high lands which separate 

 the waters falling into the Atlantic from those fall- 

 ing into the St Lawrence; thence along those high 

 lands, in a south-west direction, to the parallel of 

 lat. 45 N. ; thence along that parallel to the river 

 St Lawrence ; thence up that river, and through 

 the middle of the great lakes Ontario, Erie, Huron 

 and Superior, to the north-west extremity of the 

 lake of the Woods ; thence, on the meridian line, 

 to the parallel of lat. 49 N. ; thence along that 

 parallel to the Rocky mountains. The north-east- 

 ern boundary was long in dispute. The words ofthe 

 treaty of 1783 (art. 2) are as follows: "From 

 the north-west angle of Nova Scotia, viz. that 

 angle which is formed by a line drawn due north 

 from the source of St Croix river to the high 

 lands, along said high lands which divide those 

 rivers that empty themselves into the river St 

 Lawrence from those which fall into the Atlantic 

 ocean, to the north-westernmost head of Connecti- 

 cut river." This part of the country was but im- 

 perfectly known at the time of making the treaty, 

 and the dividing ridge of high lands is by the 

 Americans assumed to be in lat. 48, while, by the 

 English construction, it is placed in lat. 46 30'. 

 The question in dispute was referred to the arbi- 

 tration of the king of the Netherlands, whose de- 

 cision has been rejected by the United States on 

 the ground that, instead of deciding upon the 

 claims of the two parties, he has attempted to 

 establish a new line of his own, as a matter of ex- 

 pediency and convenience. (The question is fully 

 treated in vols. 26 and 34 of the North American 

 Review.) Between the Rocky mountains and the 

 Pacific ocean, the boundary was lately settled. The 

 country west of tha Rocky mountains was claimed 

 by Great Britain ; and, by the convention, for ten 

 years, made in 1818 and renewed in 1827, it was 

 agreed, between the United States and that power, 

 that the country should remain open to both. By 

 the convention of 1824, between Russia and the 

 United States, it was agreed that the Russians 

 should make no settlements to the south, nor the 

 Americans to the north, of 54 40' N. latitude. 

 The boundary on the side of Mexico, as ratified by 

 a treaty with Spain, in 1821, begins on the gulf of 

 Mexico, at the mouth of Sabine river, proceeding 

 along the west bank of that river to lat. 32 N. ; 

 thence by a line due north to Red river ; thence 

 up that river to the meridian of Ion. 100 W. ; 

 thence due north along that meridian to the river 

 Arkansas ; thence along the south bank of the Ar- 

 kansas to its source ; thence due north to the 

 parallel of lat. 42 N. ; and thence along that 

 parallel to the Pacific ocean. Lon. 66 49' to 

 125 W. ; lat. 25 to 49 N. ; square miles, esti- 

 mated at upwards of 2,000,000. More than half 

 of the territory included within these limits con- 

 tains few or no settlers, and is not yet formed into 

 states. If a line were drawn from the mouth of 

 the Sabine due north to the Missouri ; thence in a 

 north-easterly direction to the south end of lake 

 Michigan, the eastern division would include nearly 

 all the population, though less than half of the 

 territory. The other division is almost wholly in 

 the possession of the Indians. The line of fron- 

 tier, taken according to the claims of the United 

 States, was estimated by Darby as follows : Fron- 



tier in common with British America, from the 

 mouth of the St Croix to the Rocky mountains, 

 3000 miles, of which a considerable portion is a 

 natural water boundary ; west of the Rocky moun- 

 tains, northern boundary in common with the Rus- 

 sian settlements, 600 miles ; western frontier, along 

 the Pacific ocean, from .54 to 42 N. lat., 800 

 miles (Darby estimated it from 42 to 51, 560 

 miles) ; in common with Mexico, along the parallel 

 of lat. 42 to the Rocky mountains, and thence, as 

 above described, to the mouth of the Sabine, 2300 

 miles ; along the gulf of Mexico to Florida point, 

 1000 miles ; along the Atlantic ocean to the mouth 

 of the St Croix, 1850 miles. According to this 

 estimate, the whole line of frontier amounts to 

 about 9550 miles, of which 3650 are sea coast. 

 This vast extent of country, comprising one twen- 

 tieth of the habitable land of the globe, is divided, 

 by two ranges of mountains, into three great na- 

 tural sections, the Atlantic slope, the Mississippi 

 valley, and the Pacific slope. The Alleghany 

 chain is more remarkable for its length than its 

 height. Perhaps there is no tract of country in 

 the world that preserves the mountain character 

 over so great a space with so little elevation. The 

 mean height of the Alleghanies is only from 2000 

 to 3000 feet, about one half of which consists of 

 the elevation of the mountains above their base, 

 and the other of the elevation of the adjoining 

 country above the sea. To this height the country 

 rises, by an almost imperceptible acclivity, from 

 the ocean, at the distance of 200 or 300 miles on 

 the one side, and from the channel of the Missis- 

 sippi, at an equal distance, on the other. A gra- 

 dual elevation of 1000 or 1200 feet upon a horizon- 

 tal surface of 200 or 300 miles, would give the 

 surface of the country, on the eastern side, an 

 average rise of from three to four feet in the mile, 

 and from two or three feet on the western side, 

 allowing for the height of the channel of the Mis- 

 sissippi above the sea. This small degree of in- 

 clination accounts for the great extent of inland 

 navigation which the United States enjoy. By 

 the course of the Mississippi, Ohio and Alleghany 

 rivers, vessels ascend over an inclined plane of 2400 

 miles in extent, to an elevation of perhaps 1200 or 

 1400 feet, without the help of canals or locks. 

 The second great mountainous range which tra- 

 verses the United States is the Rocky mountains. 

 This ridge is more elevated than the former, but 

 is also more distant from the Pacific ocean on the 

 one side and the Mississippi on the other. From 

 the Mississippi to the Pacific, in lat. 40, is about 

 1500 miles ; and the Rocky mountains, which 

 crown this gradually-swelling surface, rise, with 

 the exception of some insulated peaks, to a height 

 of about 9000 feet. This elevation is about three 

 times as great as that of the Alleghanies ; and it 

 is remarkable that the Mississippi, which is the com- 

 mon reservoir of the streams descending from both, 

 is about three times farther from the higher chain 

 than from the lower, so that the declivity on both 

 sides of the immense basin included between these 

 mountains, is nearly the same ; and the streams 

 flowing from the Rocky mountains are as suscepti- 

 ble of navigation as those from the Alleghanies. 

 The Mississippi valley also presents a southern 

 declivity, by which it gradually sinks from the 

 high table land of the centre of the continent to 

 the level of the ocean on the gulf of Mexico. 

 From this table land, which is estimated to have an 

 elevation of not more than 1500 feet above the sea, 



