AGASSIZ: FIJI ISLANDS AND CORAL REEFS. aL 
for instance, as is done by Dana and Darwin, as the single cause for 
the formation of the many different kinds of atolls and of barrier reef 
islands to be found in the Fijis. 
THE TERTIARY ELEVATED LIMESTONES OF FIJI. 
The existence throughout Fiji of numerous platforms of submarine 
erosion at average depths varying within very moderate limits seems to 
indicate a condition of approximate equilibrium as far as either elevation 
or subsidence is concerned. The elevation of the limestones of late 
tertiary age clearly indicates that the origin of the greater number of 
the Fiji Islands dates back approximately to that period. This is un- 
doubtedly the case with the range of islands known as the Lau or Eastern 
Archipelago of Fiji. With them we should include the more northerly 
islands, the group to the east of Ngamia, and of Budd Reef, including 
Thikombia. 
It is more difficult to determine the age of the larger islands, Viti Levu 
and Vanua Levu, as well as Taviuni, Kandavu, and the voleanic islands 
of the Koro Sea. We may assume with a certain degree of probability 
that the age of such islands as Nairai and Ngau corresponds with the 
age of the volcanic rocks which have lifted the islands of the Lau group 
to their present altitude. But in Viti Levu and Vanua Levu the 
problem is more complicated. While elevated coralliferous limestones 
of late tertiary age occur along the shores of Viti Levu evidently of the 
same age as the limestones of Lau,’ yet there is evidence of the existence 
of older rocks as a nucleus of the larger Fiji Islands. So that until the 
geology of Viti Levu and of Vanua Levu has been more accurately 
studied, we must leave their age undetermined ; but enough is known 
of the geology of the shore line to show that the existence of the great 
barrier and fringing reefs along the shores of Viti Levu and of Vanua 
Levu gives no evidence that the great barrier reefs of these islands owe 
their origin to the gradual subsidence, during our epoch, of the islands 
themselves. 
The existence of the tertiary elevated coralliferous limestone at so 
many points in the Fiji Archipelago (Plate 2) seems to indicate a huge 
limestone bed of great thickness and extent, formed during tertiary times, 
along the flanks of ancient volcanic islands, and elevated by subsequent 
intermittent volcanic action during more recent times over areas of 
1 Horne (A Year in Fiji, London, 1881, p. 165) says that in Viti Levu and Vanua 
Levu sedimentary or limestone rocks are found on all mountains. 
