24S FORMATION OF CORAL REEFS AND ISLANDS. 
e. The following figure of the harbor of Falita, Upolu, 
represents another coral harbor, as surveyed by Lieutenant 
Emmons. At its head there is a stream twenty-five or thirty 
yards wide and three feet deep. Notwithstanding the unusual 
size of the river, the coral reef lies near its mouth, and pro- 

HARBOR OF FALIFA, 
jects some distance in front of it. Its surface is dead, but 
corals are growing upon its outer slope. 
yj. The harbor of Rewa, in the Feejees, may be again al- 
luded to. ‘The waters received by the bay amount to at least 
500,000 cubic feet a minute. Yet there is an extensive reef 
enclosing the bay, lying but three miles from the shores, and 
with only two narrow openings for ships. The case is so re- 
markable that we can hardly account for the facts without 
supposing the river’s mouth to have neared the reef by depo- 
sitions of detritus since the inner parts of the reef were formed ; 
and there is some evidence that this was the case, though to 
what distance we cannot definitely state. With this admis- 
sion, the facts may still surprise us; yet they are explained on 
the principle that fresh water does not sink in the ocean, but 
is superficial, and runs on in a distinct channel; its effect is al- 
most wholly through hydrostatic pressure, increasing the force 
of the underwater currents, and through their depositions of. 
detritus Besides these instances, there are many others in 
the Feejees, as will be observed on the chart at the end of 
this volume. Mokungai has a large harbor, without a 
stream of fresh water ;—so also Vakea and Direction Island. 
