AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 27 
CLASSIFICATION OF THE ISLANDS OF FUT, 
It will greatly facilitate understanding the relations of the islands 
and coral reefs of Fiji, if we follow in their description a classification 
which will bring together islands and reefs of identical or similar geo- 
logical structure. 
We may take at first such volcanic islands as Koro, Ngau, and pass 
to the larger islands like Taviuni-and Kandavu, finishing that class of 
islands with descriptions of Mbengha, Komo, and the like. We will 
take up next islands and reefs composed wholly of elevated coralliferous 
limestones like Marambo, passing to such islands as Namuka, Ongea, 
Fulanga, and to such reefs as Wailangilala and Ngele Levu. Next the 
island groups in which we find both volcanic and coralliferous limestones, 
such as Lakemba, Mothe, Vanua Mbalavu, Kimbombo, and the like, 
the two large islands of Viti Levu and Vanua Levu being treated sepa- 
rately. This will be followed by an account of the islands and reefs we 
did not examine, and finally by a sketch of the atolls, the geological 
structure of which could not be determined, and which might owe 
their origin to banks of submarine erosion, derived either from volcanic 
or from elevated coralliferous limestone islands. 
Undoubtedly the islands of Fiji, whether of volcanic origin or of 
limestone, would vary greatly in the height to which they had been 
elevated. Naturally, the volcanic islands would be denuded and eroded 
to a less extent than the limestone islands, and the comparison of the 
islands in Lau might give us some idea of the extent of this erosion 
and denudation. The volcanic islands, consisting mainly of breccia, 
are of course far more rapidly eroded than if they consisted of compact 
voleanic rocks. 
Of course some of the islands which have been named here as vol- 
canic or as composed of tertiary limestones may prove on more extended 
examination to be composite islands, and in the rapid visit made to some 
of the islands we may not always have discerned their most character- 
istic features. Yet in a general way steaming between the islands, one 
cannot fail to be struck with the totally different aspect of the volcanic 
islands and of the islands composed of elevated limestone. A mere 
glance is sufficient to distinguish the rounded and gradual voleanic slopes 
(Plates 46, 51, 57, 58) from the flat-topped summits and precipitous 
cliffs characterizing the limestone islands (Plates 75, 76, 79, 86, 88, 90). 
Gardiner has, as we have, classified the islands of Fiji into elevated 
limestone islands, into elevated limestone and partly volcanic, and into 
VOL. XXXIIT. 2 
