AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 61 
end of Ongea Levu the lagoon expands, and attains a width of nearly 
six miles. The outer reef flat is narrow, but expands to a width of 
three quarters of a mile off the southern face of Ongea Ndriti, where 
it becomes a fringing reef. Ongea Ndriti is nearly two miles long 
and one mile broad, and rises to a height of 300 feet. The Barracouta 
Passage is the only ship channel leading into the lagoon. It opens 
through the western reef flat into the widest part of the pear-shaped 
lagoon, a little south of the extremity of Ongea Levu. The greatest 
length of the lagoon is about eight miles. 
The Ongea Islands consist of elevated limestone, rising in nearly verti- 
cal cliffs along the shore line. This is deeply indented by broad and deep 
bays, forming small irregularly shaped sounds, which in the case of Ongea 
Levu have nearly cut that island into two (Plate 22). The openings of 
the bays and the shores of the islands themselves on the western and 
a N.W 
SOUTIIWEST POINT OF ONGEA LEVU. 
southern faces of Ongea Levu are studded with islets and rocks, which, 
like the ridges of the islands, consist of elevated limestone. They are 
most numerous off the wide and deep bay on the southern face of ihe 
larger island, and extend across the channel separating Ongea Levu and 
Ongea Ndriti (Plate 94). The outliers extending south from the former 
island connect with those stretching north from the opposite face of the 
smaller island. 
The mushroom-shaped rocks and islets also extend along the western 
face of Ongea Ndriti, but they are not as numerous as on the northern 
face. On many of the islets are found a few straggling palmettos, iden- 
tical with those growing on the principal island. The islets and rocks 
as well as the shore cliffs are deeply underent, and the surface is deeply 
pitted, honeycombed, and full of potholes and eaverns, and presenting 
the appearance so characteristic of the weathered coralliferous limestone 
wherever we have found it in Fiji. It seems, however, as if the erosion 
