GENERAL FEATURES OF THE EARTH. 33 



35. Pacific island-chains. — The groups of Pacific islands, with a 

 few exceptions, are not independent lines, but subordinate parts of 

 island-chains. There are three great island-chains in the ocean 

 which belong to the northwesterly system, — the Hawaian, the Poly- 

 nesian, and the Australasian, — and, excluding the Ladrones, which 

 belong to the western Pacific, one belonging to the northeasterly 

 system, viz. : the Tongan or New Zealand chain. 



(1.) Hawaian chain. — This chain has already been described. 



(2.) Polynesian chain. — This chain sweeps through the centre of 

 the ocean, and has a length of 5500 miles, or nearly one-fourth the 

 circumference of the globe. The Paumotu Archipelago and the 

 Tahitian and Hervey Islands are parallel lines in the chain, forming 

 its eastern extremity ; westward there are the Samoan and Tara- 

 wan groups and others intermediate ; still northwestward there 

 are the Eadack and Ealick groups, and in 20° N., on the same line, 

 Wakes Island. 



Fig. 27. 



1 



A 



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4 "'••. 



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\\ \ 10 





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9 \\ 









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\x 







h ' - "V 8 









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B 



1 to 10, the Polynesian chain : 1, Paumotu group ; 2, Tahitian ; 3, Rurutu group ; 4, Hervey 

 group ; 5, Samoan or Navigators' ; 6, Vakaafo group ; 7, Vaitupu group ; 8, Kingsmill group ; 

 9, Ralick ; 10, Radack ; 11, Carolines ; 12, Marquesas ; 13, Fanning group ; 14, Hawaian. 

 a to /i,part of the Australasian chain: a, New Caledonia; b, Loyalty group; c, New Hebri- 

 des; d, Santa Cruz group; e, Salomon Islands ; /, Louisiade group; g, New Ireland; h, Ad- 

 miralty group. 



In fig. 27 the positions and trends of the various groups in this 

 Polynesian chain are indicated by lines numbered from 1 to 10. 



