AGASSIZ: FIJI ISLANDS AND CORAL REEFS. 59 
The little bay was studded with mushroom-shaped and conical islets 
and rocks, all deeply undercut (Plates 91, 93), and the bottom in from 
two to four fathoms was covered with sunken coral patches and heads 
rising at all depths. 
Some of the islets were covered with bushes and cocoanut trees, like 
the main island. The highest point of Navutuiloma is 210 feet; it is a 
little over one mile in length, and is larger than Navutuira. The shape 
of the outer reef flats enclosing the lagoon of Yangasa (Plate 22) is ir- 
regularly rectangular, with rounded angles; the faces are each about 
five miles long, the western face being the longer. On the eastern and 
northeastern side, the reef flat is quite narrow, but it is studded along 
the inner edge with a belt of heads and coral patches and negro-heads. 
Off the southeastern horn, the reef flat becomes very wide, projecting in 
a point fully two miles beyond its general line. The reef flats of the 
southern and western faces are also broad, fully a mile in width in some 
places, and at the northwestern horn the reef flat is more than a mile 
and a quarter wide. , 
On the northern face of the lagoon a tongue of deep water (145 fath- 
oms) fully a mile wide runs towards the centre of the lagoon ; this is the 
passage used for entering the lagoon. The slope of this part of the lagoon 
is very steep, and it is studded with coral patches and heads growing 
upon the remnants of the former island of Yangasé. This narrow and 
deep tongue of the ocean represents probably an original valley formed 
in the uplifting of the island, and has no connection with a subsidence 
of the island during the formation of the encircling reef, which has 
grown subsequently upon the platform of submarine erosion formed by 
the wearing away of the original land mass. The average depth of the 
northern part of the lagoon is from 14 to 19 fathoms. The southern 
part, between Yangasé Levu and Navutuiloma and the reef flat, is shal- 
lower, from six to twelve fathoms, with a still shallower belt along the 
inner edge of the southern reef flat. 
Off the southeastern extremity of Navutuiloma extend a number of 
mushroom-shaped rocks and islets, deeply undercut and eroded into fan- 
tastic crests, pinnacles, and summits. The reef flat of the western face 
of the Yangas4 lagoon is full of thriving coral patches, which extend 
along the inner edge, between and upon the negro-heads, down to seven 
or eight fathoms. The formation, by erosion and denudation, of diminu- 
tive or incipient sounds, as in the bay of Navutuiloma, is interesting as 
representing one stage in the action of such processes, of which others 
can be followed in the conditions which have been reached by such 
