SUMMARY 311 



felt the enticing allurement of a captive sea waiting in 

 their harbors like a steed for them to mount and ride 

 away in quest of the world's best. Thus they have ex- 

 tended their conquest and influence far beyond the home- 

 land. From the time of Peter the Great, the efforts of 

 Russia to gain suitable outlet to the sea show the impor- 

 tance placed by progressive communities upon ocean 

 traffic. The struggle of all the great world powers to 

 strengthen their navies, no matter what the cost, shows 

 with what jealousy the products of their ports are 

 guarded. 



Coasts with harbors give their people the facilities and 

 inducements for seeking the unknown, while the harbor- 

 less coasts confine the aspirations of their inhabitants to 

 the products immediately around them. A glance at the 

 coast line and harbors of Greece shows one cause of its 

 ancient civilization and a reason why the Greeks were 

 " always seeking some new thing." 



Summary. A glance at a map shows the great variety 

 of coast lines. The waves and tides are constantly cutting 

 and wearing the coast. The material thus cut away is 

 ground fine and spread out by the currents in bars and 

 beaches, filling up coves and straightening the coast. 

 Thus one of the results of these erosive forces is to make 

 the coastline more regular. 



Coastlines are affected not only by wind and water 

 erosion, but by elevation and depression. When the 

 shore rises, or is elevated, part of the comparatively even 

 level of the continental shelf becomes the coastline. Thus 

 elevated coasts are usually regular. But when the shore 

 is depressed, the irregularities caused by the surface 

 erosion on land make bays and estuaries. Thus depressed 

 coasts are usually irregular and offer the best harbors. 



