AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 33 
of volcanic rocks, and has been very much eroded by the action of the 
sea (Plate 54). Corals grow upon its slopes, but they are not very 
flourishing, either there or upon the many patches found inside the 
lagoon, and which are separated by broad sand lanes, or by dark patches 
of nullipores and alge, with a few scattered coral heads. 
The reef enclosing the lagoon is continuous except on the north side, 
where there are two entrances into the lagoon, one with thirteen and the 
other with three fathoms in the channel. The inner side of the weather 
reef can be reached quite close to the breakers. There is from one and a 
half to two fathoms of water on the reef flat, which is covered by a great 
number of flourishing patches of coral, mainly Madrepores, Pociliopores, 
heads of Astreans and Meeandrinas, with a few Gorgonians. The patches 
are separated by wide areas of coral and coralline sand. Towards the 
inner part of the lagoon, as the water deepens, the coral patches are 
separated by masses of dead corals and of fragments. Dark patches of 
coralline Algze become more abundant, and the coral patches less fiour- 
ishing and more distant. On the outer edge of the reef, to the south 
of Beagle Passage, the reef flat is somewhat narrower than on the east- 
ern face, where it varies from 1,000 to 1,800 feet in width; it is coy- 
ered by one to two fathoms of water, and the coral patches appear to 
flourish upon its surface fully as luxuriantly as upon the eastern face. 
The corals descended in steps to ten or even eighteen fathoms, rising 
from the coral and coralline sand separating the heads. They were 
most flourishing in the belt of from six to ten fathoms in depth. The 
prevailing trades drive a strong current across the lagoon, and the 
water of the lagoon rushes out through the northern passages and over 
the western reef flats with considerable velocity. The bottom inside 
of the lagoon consists mainly of alge, of coralline alge, and of broken 
shells and fragments of coral. 
It is quite probable that the North Astrolabe Reef represents an 
eroded peak adjacent to the former greater Kandavu, of which Solo 
Rock is the only witness left (Plate 53). 
Budd Reef. 
Plates 4, 18, 70. 
Budd Reef (Plate 18) has a narrow outer reef of irregular shape, broken 
into many separate patches. These become quite distant on the south- 
ern side, leaving the outline of the reef indistinct. The lagoon, as 
well as the channels separating the islands enclosed within the outer 
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