4 
C. F. Oldliam— Topography of the Arabian Sea. [No. 1, 
slopes 19 degrees each side : Kiltan has a slope of 23 degrees on the 
west side and 27 to 10 degrees on the east: Cliitlac has the steepest 
slope on the east side, namely, 27 to 10 degrees, and 13 degrees on the 
west. 
The sections of Kavaratti and Agatti are very similar, they have both 
a slope of 13 degrees on their west sides, and a more gradual declivity on 
the east sides. 
In Peremul Par and Betra Par, which are lagoon reefs, the slopes vary 
from 14 to 16 degrees in the former, and 10 to 20 degrees in the latter. 
From the above it will be seen that the narrowest atolls, viz., 
Kardamat-, Kiltan, and Ohitlac have the steepest slopes. 
The under-water slopes beyond the two-hundred-fathom line would 
appear to depend principally on the shape of the peak on which the 
atolls are situated. 
ii. The Physical Features of some of the Laccadive Islands, with 
Suggestions as to their Mode of Formation. 
The Laccadives (see Plate I), a group of coral atolls and reefs, 
lying from one hundred and twenty to two hundred miles from the 
West Coast of Hindustan, extend from Latitude 10°. N. to 14° N., and 
Longitude 71° 30' E to 74° E. 
This area contains four submerged coral reefs, six coral reefs with 
sand cays, or small uninhabited islets, and eight inhabited atolls. Five 
of the atolls and three of the reefs were examined during the visits of 
the “ Investigator ” in October and November 1892-93-94; and are de¬ 
scribed in the following notes :— 
Kiltan Island is two miles long N. N.-W., and S. S.-E., and 
a quarter of a mile broad, having a shallow lagoon on its side. The 
highest part of the island, which is about 25 feet above high water¬ 
mark, lies on the eastern side: from here there is a general slope down¬ 
wards to the lagoon, its north and south extremes curving slightly to 
the westward. In places, ridges of coral and coral-sand stretch along 
in the direction of its length, breaking the general slope lagoonwards. 
The island is formed of coral sand, coral sand rock, and broken 
fragments of coral reef rock, overlying a hard conglomerate composed 
of fragments of reef corals. The coral-sand rock may be seen exposed 
on the lagoon beach of most of the Laccadive islands ; it is of a friable 
nature, but its surface becomes very hard when exposed to the air. 
Most cf the houses are built of blocks of this stone, which are cemented 
together with chunam. Good water is obtained by sinking wells until 
the conglomerate reef rock is reached. 
