UNITED STATES OF AMERICA 



5947 



UNITED STATES OF AMERICA 



COMPARISON OF AREAS OF THE UNITED STATES AND EUROPE 



underlying rocks, and partly brought down 

 from the hills by the streams. In either case it 

 is as a rule very fertile, with the result that the 

 Great Valley is occupied by prosperous farms, 

 and contains many important towns. 



West of the Great Valley rises what appears, 

 as seen from the valley, to be another mountain 

 range, but is in fact merely the abrupt edge of 

 a great plateau which slopes down gradually 

 westward toward the Mississippi Valley. This 

 plateau, called the Catskills in N. \\ York, tin- 



.:hany in Pennsylvania and the Cumberland 

 Mountains in the South, has been deeply cut 



> by numerous rivers, giving much of it a 

 very rugged surface and rendering good wagon 

 roads difficult to build and to maintain. A 

 portion of it is also covered with thin, 



ly soil, which washes away as soon as the 

 frost leaves the ground and in any case repays 

 but scantily the fanner's toil. For all these 

 reasons population is sparse throughout most 

 of the Alleghany- Cumberland belt, except 

 where minerals are worked or factories have 

 been established. Only in a few of the valleys 



and in certain areas where the soil is underlaid 

 by limestone is there any considerable number 

 of prosperous farms. In fact, this district, away 

 from the large towns, is one of the least ad- 

 vanced in the country. 



The interior plain extends from the Alle- 

 ghany -Cumberland plateau to the Rocky 

 Mountains and from the Gulf of Mexico to the 

 Arctic Ocean, thus including, as here defined, 

 tin- westward extension of the coastal plain. 

 Only low divides separate the waters flowing 

 south from those flowing north, hence this in- 

 terior part of the continent offers no serious 

 obstacles to transportation. There are, h<>\\- 

 r, several smaller highland areas. The most 

 important arc (1) the uplands on both shores 

 of Lake Superior, which are a continuation of 

 the Laurcntian highlands of Canada; (2) th< 

 Ozark plateau in Missouri and Arkansas, which 

 is of much the same age and character as tin- 

 Cumberland plateau, and (3) the Black Hills, 

 an outlying portion of the Rocky Mountains. 



Aside from these highlands, the interior plain 

 has in general a fertile soil. In the south this 



