AGASSIZ: FIJI ISLANDS AND CORAL EEEFS. 31 



or eight fathoms to seventeen and eighteen fiitlioms, with a number of 

 extensive patches, the remnants of former ishxuds now covered with 

 coral. (PLnte 11.) 



Within the Great Astrolabe Reef are included a number of islands 

 and islets. They are all volcanic in structure, and all Ijear signs of the 

 gi-eat denudation and erosion to which they have been subjected. Be- 

 ginning at the north there is Vanua Kula, about 250 feet in height, 

 covered by scanty vegetation ; next comes Xdravuni, a much larger 

 island, rising to a height of 350 feet. Yanu Yanu sau and Yanu Yanu 

 eloma are small islets upon a spit which must have formed a part of 



NMARA AXD YAXU TANU ELOMA 



iN'mara Island ; to the south of it is Ngasi Mbali. To the eastward 

 are Yaukuve and Yaukuve lai lai (Plate 52), 400 and 200 feet respect- 

 ively, connected by a spit, and off the south point of Yaukuve lai lai 

 extends a long sunken shallow rocky spit. Mbulia and Yambu are to 

 the north of Ono, the largest of the islands within the Great Asti'o- 

 labe Lagoon (Plate 51). It has two peaks of over 1,100 feet, and is 

 indented with deep bays forming finger-like spokes, which further dis- 

 integration would soon sepai'ate as distinct islands, similar to those of 

 Vuro and Vuro lai lai off the northeastern point of the island. Between 

 Ono and the eastern point of Kandavu Island the lagoon is dotted with 

 numerous rocky and coral patches. Ono, and most of the islands of 

 the Great Astrolabe Lagoon, are edged with frincring reefs. The eastern 

 reef fiat is quite broad (Plate 11) ; in some localities it is nearly a mile 

 wide, besides being fringed along the inner edge by nearly continuous 

 patches of rocks and corals. On the western face of Ono there are some 

 fine cliffs, interesting as showing the progress of tlie denudation and 

 erosion to which the island has been subjected. It seems comparatively 

 simple to follow with the chart the changes which must have taken place 

 in separating from Kandavu the islands enclosed within the Great As- 

 trolabe Lagoon north of that island. They undoubtedly I'epresent the 

 fragments of the former northern extension of Kandavu itself, which 



