Vol. S9 .] 



THE FIGTJKE OF THE EAKTH. 



183 



the way, but not those of the other festoon islands. In its further 

 progress it crosses the Mesozoic deposits of North America, along the 

 borders of the great chain of inland lakes, passes very close to the 

 Californian centre, cuts across the extremity of the Appalachians, 



Fig. 2. 



and leaves the continent along the middle line of Florida. It 

 extends through the middle of the Caribbean Sea, enters South 

 America, passes near to the South American centre, and runs out 

 to sea through the southernmost part of Brazil. It passes near the 

 Sandwich Isles, parallel with the coast of the Antarctic continent 

 near Enderby Land, but remote from it, and returns to the East 

 Indian centre without touching Australia, though it is almost 

 tangential with the Australian circle. 



Thus a great circle joining the East Indian and Aleutian centres 

 takes a course in remarkable correspondence with the general 

 trend of the great zone of Pacific weakness. Such a correspondence 

 can scarcely be a matter of mere accident. One pole of this great 



