INDIAN OCEAN. 
247 
informed, any reef. — Ceylon : a space of about 80 miles 
in length on the south-western and southern shores of these 
islands has been described by Mr. Twynam (Naut. Mag. 
1836, pp. 365 and 518) ; and parts appear to be regularly 
fringed by coral-reefs, which extend from a quarter to half 
a mile from the shore. These reefs are in places breached, 
and afford safe anchorage for the small trading craft. Out- 
side, the sea gradually deepens ; there is 40 fathoms about 
six miles off shore : I have coloured these reefs red. In the 
published charts of Ceylon, reefs also appear to fringe 
several parts of the south-eastern shores, coloured red. — At 
Venloos Bay the shore is likewise fringed. North of 
Trincomalee there are also reefs of the same character. 
The sea off the northern part of Ceylon is exceedingly 
shallow ; and therefore I have not coloured the reefs which 
partially fringe portions of the shores, and the adjoining 
islets, as well as the Indian promontory of Madura. 
Chagos, Maldiva, and Laccadive Archipelagoes. 1 — - 
These three great groups of atolls and atoll-formed banks, 
have been often referred to in this volume, and are now 
well known from the admirable surveys of Captain Moresby 
and Lieut. Powell. Their published charts are worthy of 
the most attentive examination. In the Laccadive group, 
the atoll-like structure is less evident than in the Maldivas; 
nevertheless the islands are all low, not exceeding the usual 
height of coral formations (see Lieut. Wood’s account, 
Geograph. Journ. vol. vi. p. 29), and most of the reefs are 
circular ; within several of them, as I am informed by 
Captain Moresby, there is deepisli water ; these, therefore, 
have been coloured blue. Directly north of the Laccadives, 
and almost forming part of the same group, there is along, 
narrow, slightly-curved bank, rising out of the depths of 
the ocean, composed of sand shells and decayed coral, with 
from 23 to 30 fathoms on it. I have no doubt that it has 
1 [See Appendix II.] 
