RELIEF FEATURES 9 



first contour is nearly an inch from the coast. This shows that 

 north of Floras Lake the land does not rise to the height of 100 feet 

 for a distance of about two miles from the shore. South of Floras 

 Lake, on the other hand, the 100-foot contour line is close to the 

 shore, showing that there is a steep slope (cliff) more than 100 feet 

 high along this part of the shore. 



Cape Blanco has two contours, and is therefore more than 200 

 feet high. Gull Rock, Castle Rock, and Blacklock Point are more 

 than 100 feet high. At the western border of the high land, there 

 are steep slopes where six contours occur in the space of an eighth of 

 an inch (% mile) . This shows that the surface rises at least 500 feet 

 in a quarter of a mile in some places, and this makes a steep slope. 

 The principal wagon road of the region runs along the base of the 

 steep slopes, while less important roads (indicated by dotted lines) 

 branch from the main one. 



Interior plains are often higher, and sometimes much higher, 

 than coastal plains. A large part of the area between the Appala- 

 chian Mountains on the east, and the Rocky Mountains on the west, 

 is a great interior plain. Here and there mountains, such as the 

 Black Hills of South Dakota, and the Ouachita (pronounced Wash'- 

 i-ta) Mountains of Arkansas and Oklahoma, rise distinctly above 

 the general level of this plain. (PL III, Fig. 1, p. 6.) 



Extent and habitability. Plains are more extensive than pla- 

 teaus or mountains, and most of the people of the earth live upon 

 them. They are the chief sites of human activity, partly because 

 their climate is more favorable than that of higher regions, and 

 partly because there is a greater proportion of land which is flat 

 enough to be cultivated. Plains favor transportation and com- 

 merce, for (1) the building of roads, railways, and canals is much 

 easier in plains than in higher and rougher regions; and (2) the 

 streams of plains are more commonly navigable than those of moun- 

 tains and plateaus. For these reasons, and also because many of 

 the raw materials used in manufacturing are grown on plains, the 

 larger part of the manufacturing of the world is there. It is note- 

 worthy that the extensive plains most favored by climate and soil 

 border the Atlantic Ocean, and, largely for this reason, these plains 

 have been the theaters of the world's culture and trade. In 1900, 



