THE LACCADIVES AND THE WEST COAST. 431 
We anchored just off Betrapar about, 2 p.m. Betrapar 
is a small uninhabited island, nowhere more than 9 or 10 feet 
above high water level, about half-a-mile long, and perhaps a 
quarter of a mile in width at the broadest point, occupying 
the north-east corner of a large very regular oval atoll, some 
7 to 8 miles in length, and 4 to 5 broad in its broadest part. 
The island is the only part of the atoll above water at high tide, 
but the edge of the reef is well marked by high breakers all 
round, and the reef itself is more or less bare at low water, al- 
most throughout its entire length, except for about three-fourths 
of a mile on its eastern side, immediately south of the island 
where we found from 1 to 2 fathoms over the edge when the 
rest of the reef was uncovered. 
The Lagoon is very shallow at the northern end, and all 
along its western side, but throughout the middle and eastern 
half, carries from 3 to 6 fathoms, so dotted about, however, 
with coral reefs and shoals (here also mostly, but not by any 
means universally dead) rising to within from 3 to 6 feet of 
high water level, that I found it no easy task to steer the steam 
launch amongst them at half tide. Of course, except where these 
reefs and shoals occur, the bottom is all fine white coral sand, and 
the water exhibits that peculiar and lovely aqua-marine tint 
already alluded to, a colour that ‘never was on sea or land” 
save only in gems and in these coral atolls. 
The island itself is not composed of mere blocks of water- 
worn coral piled up by wind and waves, but of a compact in- 
durated lime-stone, undoubtedly the finely triturated debris of the 
reef cemented together by continual wetting, partial dissolution 
and re-deposit. It contains a larger proportion of organic 
matter,* however, I think, than is usual in the case of such air 
formations. 
When it was formed the reef can hardly have been in its 
present condition. I could nowhere detect the usual beach 
slope—on the contrary there was in some places a distinct dip 
towards the interior of the island. 
* The following is the report of the Geological Survey Department, to which I 
submitted specimens :— 
‘ Betra-Par, Laccadives. 
This peculiar rock is almost entirely a pure carbonate of lime, with only a trace 
of carbonate of magnesia, but it contains 2°33 of organic matter. 
The composition of the mass is, Carbonate of Lime, and a trace a Carbonate of 
Magnesia 5 aes nee 2c 96.80 
Oxides of iron and ‘alumina cy ae se see 0:70 
Insoluble cae are ie aS 5 0:17 
Organic matter... uae a es ice 2°33 
Z 100°00,” 
qa $8 
