356 SEE— THE CAUSE OF EARTHQUAKES. [October 19, 



such islands as Cyprus, Crete, and others in the Mediterranean, 

 Saghallien, Formosa, Sumatra, Java, and others in the East Indies. 

 The regular symmetry of the mountains makes them in all cases the 

 backbones of the islands, and this can only mean that they were 

 formed in their present position by injections from the ocean on 

 both sides; in no other way could such a symmetrical arrangement 

 arise. The universality of this law shows that the mountains depend 

 on the sea, and not at all on the shrinkage of the globe. The same 

 symmetrical arrangement is shown in numerous peninsulas through- 

 out the world. 



§ 35- ^hy all upheavals do not produce volcanoes. 



It is not necessary for the subterranean forces to break through 

 and form volcanoes — the movement often becomes so deep-seated 

 or feeble with the raising of the mountains that outbreaks do not 

 occur. What takes place in this respect depends on the depth and 

 recession of the sea and the suddenness and violence with which the 

 upheaving pressure is exerted. Thus, along the east coast of South 

 America no large volcanoes were formed, and such small ones as 

 may have once existed have now lost all trace of a volcanic aspect, 

 because the sea was shallow and kept retreating. On the northeast 

 of South America, however, the Lesser Antilles are in deeper water, 

 and when they rise to full growth may form a somewhat imposing 

 chain of mountains, exhibiting volcanic violence depending on the 

 depth of the sea. 



In the case of the Alps the development was arrested by the rise 

 of Italy from the Mediterranean, which stopped the sinking of the 

 deep trough which has since become Lombardy. This was formerly 

 the Alpine trough, and it is now so filled up by erosion that the 

 Adriatic is the nearest sea, the recognized recession of which con- 

 firms the law. 



In the case of the Himalayas also the development was arrested 

 by the rise of the vast plain of India. And while the resulting moun- 

 tain range became high, volcanic force was at length enfeebled by 

 the shallowness of the troughs where the Indus and the Ganges now 

 flow, and thus it is supposed that no active volcanoes broke forth 

 on the tops of these mighty mountains. If the adjacent water had 

 remained deep, as off the west coast of South America, the Hima- 



