AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 31 
or eight fathoms to seventeen and eighteen fathoms, with a number of 
extensive patches, the remnants of former islands now covered with 
coral. (Plate 11.) 
Within the Great Astrolabe Reef are included a number of islands 
and islets. They are all volcanic in structure, and all bear signs of the 
great 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 Ndravuni, 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 AND YANU YANU ELOMA. 
Nmara 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 Yankuve 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 Astro- 
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 separate 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 fringing reefs. The eastern 
reef flat 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 progwess of the denndation 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 represent the 
fragments of the former northern extension of Kandavu itself, which 
