MOUNTAINS AND PLATEAUS 



357 



Mountains of Switzerland present a classic example of gently folded 

 strata ; here one finds, in certain places across the system, a series 



Fig. 344. — Section through the Juras, showing mountain ridges produced by 

 several open folds, like great earth waves. 



of simple anticlines and synclines (Fig. 344). A portion of the 

 Appalachian Mountains in Pennsylvania also presents a similar sim- 

 ple structure (Fig. 345). In the Alps, however, the folds are much 



Fig. 345. — Relief map of the Appalachian Mountains. 

 (See Figs. 244 and 245, p. 255.) 



more pronounced and complicated, and it is often extremely difficult 

 to determine the structure of the strata (Fig. 346). 



