602 GEOLOGY. 



segments. The Antillean and Central American volcanic region, that 

 has recently been so demonstrative, lies where the southern angle of 

 the North American continental block joins the northern angle of the 

 South American continental block, and where the western angle of 





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Fig. 462. — Active volcanic area at the junction of the continental segments of Asia 

 and Australia, and the abysmal segments of the Pacific and Indian oceans. Jones 

 Relief Globe. (Photo. by"^R. T. Chamberlin.) 



the North Atlantic abysmal segment closely approaches one of the 

 eastern angles of the great Pacific abysmal segment. The complex 

 and very active Java-Philippine volcanic region lies where the south- 

 eastern angle of the great Asian segment projects toward the Australian 

 block, and where the western angle of the Pacific block approaches the 

 northeastern angle of the Indian oceanic segment. The active Alaskan 

 volcanic area hes at the angles of the North American, Asian, Pacific, 

 and Arctic segments. The Mediterranean volcanic area falls less no- 

 tably under this generahzation, but it hes where the continental blocks 

 of Europe and Africa come into peculiar relations to each other on 

 either side of the remarkable Mediterranean trough. The eastern 

 angle of the North Atlantic segment is near by, but not in very close 

 relations. The Icelandic region, small but vigorous, hes near the junc- 



