CORAL REEFS OF THE INDIAN OCEAN. 19 



Salomon atoll to the east of the last is oval, 5 miles long by 3 broad, with eleven islands 

 on the rim, which is awash everywhere save for a single passage to the north, which itself 

 has a shoal of 1 / in the centre ; the lagoon averages 12 /. deep, greatest sounding 17 /. 

 Blenheim reef to the E.N.E. of the last, 6 miles long by 2 broad, would closely resemble 

 Diego Garcia, if the latter instead of land had only a reef, swept by the tides ; its open- 

 ing, however, lies to the south-west, and its lagoon has only 10 /. of water. Finally, 

 Speaker's Bank to the north of the last two is an irregular oval reef, 24 miles long by 

 13 broad ; depths of 5 to 7 / are recorded right round its circumferential reef with 24 /. in 

 the central basin. 



4. Maldive Section. 



As my remarks on the Maldives are mainly based on my own observations and soundings 

 I shall defer them, together with those I may have to offer on the Laccadives, to a 

 separate chapter. The most southern atoll of the Maldive group, Addu, lies due north of 

 the Chagos Archipelago at a distance of 240 miles, and the latter group might well be 

 considered to be a continuation of the Laccadive-Maldive line. There is, however, one 

 sounding of 2500 f. so close to the centre of the channel between, that it is practically 

 certain that there is no bank at about 1000 /., connecting the Chagos, as assumed by 

 Mr Bourne. Since to the north the Laccadive banks very closely approach the Indian 

 coast, it is important to note that the 1000 /. line has been traced everywhere between. 



The Indian Peninsula has practically no reefs of any sort ; its southern part towards 

 Ceylon partakes of the same formation as the north portion of that island. The latter has 

 locally fringing reefs, mostly in bays along the south and north coasts ; above these to the 

 south a loose rock, composed mainly of fragments of coral, often forms broad flats, 3 to 4 feet 

 above high tide, now being rapidly washed away wherever they impinge on the beach '. 

 Near Dambula in the centre of the island I saw limestone hills, at least 700 feet high, 

 which from their general contour I should judge to have been of reef-formation ; the rock 

 is now completely crystallised, all trace of organic structure being lost. The Jaffna 

 Peninsula, the outlying islands and the northern part of Ceylon are all formed of raised 

 coralline rock, which still retains most of its organic structure ; the elevation, as I saw it, 

 did not appear to me to have been more than 40 feet, if as much. A former land con- 

 nection with India was clearly indicated, of which a reef, known as Adam's Bridge, between 

 the islands of Manar and Ramesvaram, is the remains-. 



■ These can be seen in numerous places between Matale Government Museum, Bulletin 3, 1895 ; also Report Brit. 

 and Weligama. Ass., p. 400, 1900. 



- See " Ramesvaram Island," by Edgar Thurston, Madras 



