THE CAPRICORN GROUP. 31 ( J 



soundings runs about three miles outside this reef 

 and island. Twenty miles N.W. of Lady Elliot's 

 Island is the First Bunkers Island, which is about 

 five miles within the edge of the bank. From this 

 a chain of islands and reefs runs to the northward, 

 parallel to the edge of the bank ; singly at first, but 

 in a double or triple row as we proceed. This group 

 of reefs and islets is called the Capricorn Group, 

 and extends from 23° 55' to 23° 10'. It consists of 

 twenty large reefs, ten of which have each a small 

 islet upon them. All the islets, except One Tree 

 Island, are near the leeward edge of the reef. The 

 islets are of an oval or circular form, and their 

 longest diameters often run in the same direction 

 with the longest diameter of the reefs. This is most 

 usually nearly east and west ; the reefs, as also the 

 islands, being often, but not invariably, longer in that 

 direction than from north to south, in the proportion 

 of five to two. The islands are composed of a base 

 of coral conglomerate, partially covered with loose 

 sand. The reefs have sometimes a shallow lagoon 

 in the centre ; the islands, also, often consist of a 

 ring- formed bank of sand, with a flat hollow in the 

 centre. There is never more than one islet on each 

 reef, and that is wholly on one side of the lagoon, 

 and very small, compared with the reef. From the 

 main land to the easternmost islands, the depth 

 increases from ten to twenty and thirty fathoms, the 

 most usual depth being twenty fathoms. Outside 

 the islands the bank gradually deepens for about 



