AGASSIZ: FIJI ISLANDS AND CORAL REEFS. £35 
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which however he considers as belonging to the present epoch. Elevated 
coralliferous limestones also exist in the New Hebrides as well as on the 
southern shore of New Guinea. 
The time of this Fijian elevation we cannot at present ascertain. It is 
not unnatural to assume that it was coincident with the elevation of 
Northern Queensland, and that the area of elevation included New 
Guinea, the islands to the east of it as far south as New Caledonia, and 
as far east as the most distant of the Paumcotus (Gambier Islands), 
and extended northward of that line to include the Gilbert, Ellice, 
Marshall, and Caroline Islands; and that since this epoch of elevation 
the islands within that area have been, like Northern Australia, subject 
to an extensive denudation and erosion, many of them being reduced to 
-mere flats but a few feet above the surface of the sea, others worn away 
to represent to-day but a small portion of their former extent. It is 
upon the reef flats thus eroded, or around the islands and islets which 
are the remnants of a former period, that the corals of to-day have ob- 
tained a foothold. And further, by the mechanical action of the sea 
combined with that of the trade winds, channels have been excavated out 
of the substratum underlying the coral reefs to form the lagoons of the 
barrier reefs and atolls of Fiji. 
So that, as far as we can judge from the case of the Fiji Islands, the 
shape of the atolls and of the barrier reefs is due to causes which have 
acted during a period preceding our own. The islands of the whole 
group have been elevated, and since their elevation have, like the 
northern part of Queensland, remained nearly stationary, and exposed 
to a great and prolonged process of denudation and of aerial and sub- 
marine erosion, which has reduced them to their present height. The 
submarine platforms upon which the barrier reefs have grown being 
merely the flats left by the denudation and erosion of the central island, 
while the atolls are similar flats from the surface of which the islands 
have at first disappeared and the interior parts of which have next been 
removed by the incessant scouring of the action of the sea, the ceaseless 
rollers pouring a huge mass of water into the lagoon, which finds its 
way out of the passages leading into it or over the low outer edges of 
the jagoon. These atolls and islands, surrounded in part or wholly by 
encircling and barrier reefs, have not been built (as is claimed by Dana 
and Darwin) by the subsidence of the islands they enclose. They are 
not situated in an area of subsidence, but on the contrary in an area of 
elevation. The theory of Darwin and Dana is therefore not applicable 
to the Fiji Islands. 
