NORTH AMERICA 



4251 



NORTH AMERICA 



many of the greatest rivers in the world. 

 Though it possesses physical features of every 

 sort, their arrangement is simple. The greater 

 part of the continent is occupied by a central 

 plain, the largest in the world, stretching across 

 it from north to south and extending from the 

 Arctic Ocean to the Gulf of Mexico. This 



the whole area of the continent, with the re- 

 sult that the mean elevation of North America 

 is 2,300 feet above sea level, more than twice 

 as high as that of Europe. Many of the peaks 

 are more than 14,000 feet high, and one, Mount 

 McKinley in Alaska, rises 20,300 feet above the 

 ocean. 



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RTH 

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 IRICA 

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RELATIVE POSITIONS 



Almost the entire continent of South America 

 lies east of the longitude of New York City. Prac- 

 tically every portion of It Is east of the longitude 

 of Charleston. The above map will correct the 

 "mmon Impression that North America lies north 

 of South America. 



plain is walled in by two mountain systems: 

 on the east a shorter and smaller one, and on 

 tin- west a longer and higher one, which con- 

 tinues southward to Panama. 

 The mountains of the east, the Appalachians, 

 ;i near (he Gulf of Saint Lawrence as hills 

 and extend in a southwesterly direction, gradu- 

 ally increasing in height until within about 300 

 - of the Gulf of Mexico, where they ab- 

 ruptly end. East of them the surface slopes 

 ly to the Atlantic in a plain which varies 

 1th from fifty miles in the north to about 

 300 miles in the south. 



most prominent relief feature of both 



North and South America is the lofty we*t. in 



mount. mi system, known as the Cordillera 



). Its chief range in North America 



'>< Rocky Mountains. The system attains 



its greatest width m the United States, where 



ncloaes a plateau varying from 3,000 to 



,10,000 feet in height and from a f \\ miles in 



wi.lt h near its southern extremity to a breadth 



of over 1,000 miles in Utah and Colorado. Tin- 



western mountains cover about one-third of 



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0* 50 



SOUTH 



AMERICA 



dodeJaneirc 



ilparaiso- 



>s Aires 



Rivers, Lakes and Harbors. The early ex- 

 plorers of the eastern half of the United States 

 and Canada found tin ir work made easier by 

 nature's generous provision of lakes and rivers. 

 in 1534, discovered that th. broad Saint 

 Lawrence led into the heart of the con 

 :md l-'rench explorers of a later date found that 

 it was fed by five inland seas, the most ex- 



