AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 129 
merely been denuded so as to be just awash; the scouring of the sea on 
the diminutive platform of submarine erosion having formed a shallow 
lagoon in the first instances mentioned, or a series of disconnected pools. 
These flats and atolls are in every way identical with similar reef flats or 
atolls formed from peaks or islands rising from great depths; Na Ndongu, 
Nuku i ra, Thakau Moi, Laukoto, and Thakau Levu Reefs (Plates 3, 4, 
23°, Figs. 8-19). See the similar structures of Thakau Nalolo, Thakau 
Utulei, and Nuku i ra, on the eastern part of the north shore of Vanua 
Levu (Plate 4, Figs. 8-12). 
From the eastern point of Savu Savu Bay and the western point of 
Vanua Levu the island is bordered by a fringing reef (Plates 3*, 14). 
Savu Savu Bay is protected by an extensive fringing reef off Savu Savu 
Point on the east, and by a series of wide barrier reef patches lying off 
Kumbalau Point on the west, and stretching in smaller disconnected 
patches across the southern face of the opening of the bay. To the west 
of Kumbalau Point runs an extensive plateau, the outer edge of which 
is from ten to twenty miles off shore, and varying in depth up to about 
thirty fathoms. On the outer edge of the plateau are narrow discon- 
nected patches of corals and islets and rocks (Plates 3*, 4). The plateau 
makes out in two prominent points, one, Namena Reef, elliptical in 
shape, about twelve miles long and three miles wide, to the south of 
Kumbalau Point. The reef patches enclose an irregular lagoon, in the 
southern horn of which lies the island of Namena, about 320 feet in 
height (Plate 3*). The other spit of the plateau is triangular in shape, 
and extends towards Makongai, from which it is separated by a channel 
140 fathoms in depth. The western face of the plateau is bordered 
by a line of rocks and narrow coral patches, often widely separated, 
and extending in an undulating line. 
The outline of the plateau as it forms the eastern side of Vatu i ra 
Channel is rounded, forming a deep bight off Solevu Point, and extending 
in a northeasterly direction towards Yendua Island. North of Passage 
Island (Plate 3), 104 feet high, the coral patches lose their character of 
barrier reef flats; they become small, and are often very widely separated. 
The edge of the plateau is bordered with rocks, and the slope as we go 
north becomes less steep, passing off Solevu Point gradually into the 
deeper waters north of Vatu i ra Channel. But south of Nai Thombo 
thombo Point there are extensive reef flats, probably formed upon eroded 
flats of such detached spits as Lecupi Point on the south of Mbua Bay, 
and Lamut Islet north of Solevu Point. The principal one of these reef 
flats is Thakau Levu, on which some rocks are still awash at high water. 
VOL, XXXIIL. 9 
