GEOLOGICAL OBSERVATIONS I\ FI.H. 



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Ono-i-lau (Figure 28). 



The accompanying chart presents the main features of the Ono-i- 

 lau group. Near the center of the circuhir higoon, about G miles 

 wide, he three harge isUmds. These are arranged about a central 

 depression which represents an eroded crater. The crater walls have 





O Vz I 



Figure 28. Sketch Map of Ono-i-Iau. 



Black — elevated coral reef. White — volcanic rocks. 



been breached and dissected, their remnants being the islands, Ono 

 Levu, Ndavura, and Ndoi. They are composed of interbedded 

 andesitic ash, agglomerates, and flows. 



About the border of the lagoon, close to the edge of the present 

 reef, are groups of elevated limestone islets. The group at the north- 

 ern border is known as the Yanuia islands; that at the eastern border, 



