202 



SEA AND LAND 



world lie alon^- the coast-lines of the continents or upon the 

 islands which border the shores of the mainland and are scat- 

 tered over the wide seas. On account of their position with 

 reference to the ocean level, it not infrequently occurs that the 

 sea enters an inactive crater through a relatively narrow breach 

 and forms a large and well-sheltered basin in the middle of 

 the cone. If such havens occurred in convenient positions 



.--"S'?*^'-- 



Volcanic Harbor 



for commerce and if their bottoms afforded good anchorage 

 grounds, they might have great economic value; but occur- 

 ring, as they almost invariably do, on small and desolate 

 islands, they have no other than a scientific interest. They 

 may be compared to the interesting lakes which frequently 

 form in the cups of long-inactive volcanoes, such as those 

 found in the region north and south of Rome, which are 

 very striking and beautiful features in the landscape, but 



