118 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
The coral patches now thriving on the slopes of the reef are growing 
on the slopes of the former elevated reef, which from its disintegration 
has formed the extensive reef flats covered with dead corals and flanked 
with negro heads.” The patches of living coral and the heads do not 
extend to a greater depth than six to seven fathoms. Nowhere at ten 
fathoms have we found any isolated heads ; the bottom at that depth 
near a coral reef being invariably clean coral sand, with fragments of dead 
coral. A similar bottom extended into deeper water, and characterized 
the coral sand lanes separating the coral heads, So that the present reof 
corals may be said in the upper part of the reef to form a crust over the 
1 Т cannot forbear quoting Jukes again at length (Voyage of the * Fly," Vol. I. 
pp. 340, 341) regarding the negro heads, to show how accurately he noted the existing 
'state of things on one of the great reef flats we have just described. Jukes, in 
fact, all but named the existence of a former elevated reef as the source from which 
the negro heads were derived. Не writes: “Опа reef, forming part of the Great 
Barrier, about twelve miles south west of Raine's Islet, I observed a very remark- 
able, and as far as I know unique fact, which seems to favor the idea of the reef 
having been slightly elevated in that locality. 'The mass of reef alluded to is two 
or three miles long, and from a quarter to half a mile in width. Near its southern 
extremity, and about fifty yards from its inner edge, there is a range of large coral 
blocks permanently above water. Immediately to the south of them is a gap or 
channel of deep water, about a quarter of a mile wide, to the south of which another 
reef sets on. These blocks are full two hundred yards from the outer edge of the 
reef, and protected by it from heavy breakers, and it is only at high water that the 
last curl of. surf reaches them through the gap to the southward. No conceivable 
storm could lift them into their present condition, with the reef around having its 
present extension. They not only rested on the reef, but appeared to pass down- 
wards into it, as if forming part of its mass. They were composed wholly of a 
species of Porites, very solid and massive, with comparatively small cells. They 
seemed to be in the position of growth, with the cells all pointing upwards. ‘The 
blocks were often as much as twenty or twenty-five feet in length, and rose from 
the reef to a height of ten or twelve feet; they were very rugged, and apparently 
much worn, the cells being apparent at the surface in the more sheltered hollows 
only of the masses. They ran along a line parallel to the inner edge of the reef, 
for three or four hundred yards. High-water mark was very apparent on them, 
forming a horizontal line, below which they were much smoother than above it. 
They ended upwards in sharp points and crags, much honeycombed and excessively 
rugged. From high-water mark to some of their summits was about eight feet 
and a sufficiently large mass of them was visible at high water to show like a line 
of large black rocks, at a distance of two miles. I examined them attentively, and 
walked about them at low water, and could form no other conjecture respecting 
them than that they had been produced under water, and raised above it by the 
elevation of the mass on which they reposed. They looked exactly like the rem- 
nants of a much larger mass that had been gradually caten away and destroyed by 
the action of the sea and weather.” 
