34 CORAL FORMATIONS. 
dangerous. Again, it is for miles in breadth an open sea, in which 
ships find room to beat against a head wind with a depth of twenty, 
thirty, or even fifty fathoms. Yet hidden reefs make caution neces- 
sary: Patches from a few square feet to many square miles in 
extent are met with over the broad area enclosed by these distant 
barriers. 
These varieties of form and position are well exemplified in a single 
group of islands—the Feejees; and we would refer the reader to a 
reduced copy of the excellent chart of the Expedition, in this volume, 
preceding the chapter on that group. 
Near the middle of the chart is the island Goro; its shores, 
excepting the western, are bordered by a fringing reef. ‘The island 
Angau, south of Goro, is encircled by a coral breakwater, which on 
the southern and western sides runs far from the shores, and is a 
proper barrier reef, while on the eastern side, the same reef is 
attached to the coast and is a fringing reef. From these examples 
it is perceived that there is no proper distinction as regards mode 
of formation between barrier and fringing reefs. It is also apparent 
that while a reef is sometimes quite encircling, in other instances 
it 1s interrupted along certain shores, or may be wanting along a 
large part of a line of coast: occasionally the reef may be confined 
to a single point of an island. 
Above Angau lies Nairaz; though a smaller island than Angau 
the barrier reef is of greater extent, and stretches off far from the 
shores. ‘To the eastward of Nairai.are Vatu Rera, Chichia, and 
Naiau, other examples of islands fringed around with narrow reefs. 
Lakemba, a little more to the southward, is also encircled with coral: 
but on the east side the reef is a distant barrier. In Azva, imme- 
diately south of Lakemba, the same structure is exemplified ; but the 
coral ring is singularly large for the little spots of land it encloses. 
The Argo Reef, east of Lakemba, is a still larger barrier, encircling 
two points of rock called Bacon’s Isles. It is actually a large lagoon 
island, twenty miles long, with some coral islets in the lagoon and 
two of basaltic constitution, the largest of which is only a mile in 
diameter. Aiva and Lakemba are in fact other lagoon islands, in 
which the rocky islands of the interior bear a larger proportion to 
the whole area. The same view is farther illustrated by comparing 
the Argo Reef with Nairai, Angau, or Moala: the only difference in 
these cases consists in the greater distance of the reef from the shores 
which it encircles, and the smaller extent of the enclosed land. 
