AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 127 



haps assume from the iuformatiou I have gathered and from an exami- 

 nation of the charts, that neither they nor the smaller islands and reefs 

 in the Lau Archipelago, which have been passed by, present any features 

 which are likely to throw much additional light on the results obtained 

 from the examination made by the " Yaralla." The ai'ea between the 

 Yasawa group and the north shore of Viti Levu (Plate 3) has not been 

 systematically surveyed. All we know is that it is full of coral patches, 

 undoubtedly the eastern extension of the patches to the northwest of 

 Nandi waters towards the Yasawa group. How far west of Charybdis 

 Reef the extension of the deep water bay north of A^atu i ra Channel 

 reaches is not known. Its northern and eastern limits off Yanua Levu 

 are well defined on the charts (Plate 3). It is interesting to note that 

 a very steep slope — fully as steep as any of the sea faces off the reefs or 

 smaller islands of Fiji, or as steep as the sea faces of the great barrier 

 reef oflf the south coast of Yiti Levu — runs ofl* the west side of Yanua 

 Levu from the Makougai Channel beyond Yendua Island (Plate 3), and 

 off the east side of Yiti Levu from the horn of the reef north of Ovalau 

 to opposite Charybdis Eeef. Yet on this steep ftice the corals form 

 only scattered patches over the surface of the flats, extending between 

 the shore lines towai'd the 100 fathom line, — patches and stretches 

 which are separated by wide areas in which the bottom is full of heads 

 of rocks similar to those of the adjoining shores. 



Charybdis Reef and the extensive reef on the southwest side of Yatu 

 i ra Channel (Yatu i ra Reef), represent probably the eroded summits of 

 a more or less circular island and of an elongated ridge, on the outer 

 edges of which coral patches have found a footing, and of which Yatu i ra 

 Islet (one hundred feet high) is the only remnant. The lagoon varies in 

 depth from twenty-two to twenty-seven fathoms, " with several passages 

 into it through which the tide runs strongly." Charybdis Lagoon is 

 full of rocks and patches its average depth is about twenty fathoms ; 

 its western edge is open, with rocks scattered along its face. 



An extensive frino^ins; reef skirts the north shore of Yiti Levu, which 

 disappears within reach of the influence of Ba River. There is a 

 wide navigable channel between it and the broad outer barrier reef 

 patches, which resemble those off the east coast of Yiti Levu, south of 

 Moturiki Channel. 



I have not examined the shores of Yanua Levu, but according to 

 Horne^ and from some verbal information relating to the barrier 



1 John Home, " A Year in Fiji," London, 1881, pp. 167, 168. Home says that 

 on the southwest side of Rambe a reef has been elevated twenty feet, and that the 



