AGASSIZ: FIJI ISLANDS AND CORAL KEEFS. 129 



merely been denuded so as to be just awash; the scouring of the sea on 

 the diminutive phUforui 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, 

 Xnku 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 Xuku 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 (P*iates 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 

 Knmbalau 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, Xamena 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 atod 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 Yatu 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 :\Ibua 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. XXXIII. 9 



