68 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
varying in width from a few yards te 300 or 500 yards, or even disap- 
pearing entirely along some of the beaches, with many areas of smooth 
impounded water within the fringing reef flats. The north side of the 
lagoon is protected by an outer reef flat fully half a mile wide in some 
places. On it corals are flourishing. There are two passages into the 
lagoon, with about ten feet of water in the channel. On the eastern 
side the outer reef runs parallel with the coast, gradually becoming wider 
towards the south, where it forms a wide coral flat connecting as a frin- 
ging reef the outer reef with the low southern part of the island. 
To the west of the lee passage are the small island of Vatu Savu 
(Plate 101), consisting of a larger low rock of elevated limestone deeply 
undercut and pitted and honeycombed, and of three other mushroom- 
shaped rocks of the same structure. Between the lee and the weather 
passage are the islands of Vatu Levu and the cluster of rocks Vatu 
lai lai (Plate 102), similar in structure and in appearance to Vatu Savu. 
These islands and islets are all situated upon the flat of the outer reef. 
The whole reef flat is further studded with negro-heads, the remnants of 
former islands and islets of elevated limestone. 
The presence of these islands, islets, and rocks, as well as the existence 
of the extensive flats off the east coast, clearly indicate the manner in 
which denudation and erosion have transformed the greater Vatu Leile 
which once may have covered the whole area of the lagoon, leaving only 
a part of the main island, with the islands and islets on the outer reef 
flats and the innumerable patches of corals flanking the inner edge of the 
outer reef. There is a strong current flowing out through the passages 
of the northern line of the outer reef. 
THE SOUNDS OF FIJI. 
Plate 22. f 
Fulanga is also interesting as illustrating the formation of an atoll by 
the same causes which have produced the Sounds in the Bermudas.’ 
In the case of Fulanga we have a ring of elevated coralliferous lime- 
stone raised by volcanic agencies to a height of nearly two hundred feet. 
The whole area of Fulanga was probably once covered by coralliferous 
limestone, forming an island resembling Kambara or Mango. The island 
was, judging from its present condition, highest on the northern side, with 
1 Bull. Mus. Comp. Zoél., Vol. XX VI. No. 2, 1895, p. 231; also Bull. Mus. Comp. 
Zobl., Vol. XX VIIL. No. 2, 1896, p. 29. 
