8 
C. F. Oldham —Physical Features of the Laccadives. 
[No. 1, 
part is a,n iron band boiler which must have been part of a wreck ; 
it is embedded about one foot and lies completely on the reef, so that 
at low water I was able to walk round it. Two clumps of coral about 
one foot in diameter were growing on its outside, and several smaller 
inside. 
The reef here dries about one foot at low water and is covered 
with live coral. Of the latter the branching Madrepores were the most 
common, but a Porites and Brain-coral were also numerous. 
The north side of the reef is the narrowest; it dries 3 feet at low 
water, is about 100 yards broad, and is composed of piled up coral, broken 
off the growing edge. 
Inside the lagoon the average depth is from 3 to 4 fathoms. Here 
are numerous coral clumps awash or dry at low water. I examined two 
of them and found that coral was growing on the sides, but the top was 
dead, and covered with Nullipore. 
Inside the reef, from the islet round the western side to the sand 
cays on the south side, is a remarkable broad shelf with about half a 
fathom water over it, formed of dead coral and sand, the coral being in a 
state of decomposition. 
This shelf is about half a mile broad on the north-west part, increas¬ 
ing as the width of the growing reef increases, and reaching a width of one 
mile to the southward. On its inner side it drops suddenly into the 
general depths of the lagoon which I have already mentioned as being 
from 3 to 4 fathoms. 
I think that this shelf may be accounted for on the supposition 
that the coral reef commenced to grow at the inner edge of the shelf, 
and has worked seaward, leaving behind it a reef-flat, which is kept at its 
present level by sand and debris being washed in from the outer edge, 
and by the solvent action of the sea-water. The eastern side of the atoll, 
not being so favourably situated as regards the currents and tides, has 
not grown seaward sufficiently and rapidly to leave a reef-flat behind ; it 
is here also that sand and debris collect which would also assist in 
retarding the growth of the coral. 
The soundings shew a fairly corresponding slope on all sides, from 
the edge of the reef out into deep water. 
Peri Mul Par. This reef, which only dries at low-water springs, is 
somewhat crescent shaped, the concave side being open to the northwest. 
Its longest diameter is seven miles, and its width four miles. The edge of 
the reef shews at low water, but at high water and in smooth weather it 
is difficult to distinguish, and in many places does not break. The encir¬ 
cling reef is very narrow, and I am informed by the officers who examin¬ 
ed it that it is only growing at the outer edge. 
