466 Mr Gardiner, The Coral Reefs of [Mar. 7, 



stone running straight into the volcanic rock, and being covered 

 by it in many places. In fact it would seem as if Koro Mbasanga 

 had been formed subsequent to the elevation of the limestone in 

 precisely the same way as the volcanic hill at Kambara. To the 

 west the island is all limestone, much cut into by creeks and 

 broken up into isolated hills, forming an irregular range in the 

 centre, with peaks and buttresses on either side, ending in cliffs 

 seawards with heights up to 600 feet. To the south the land is 

 undulating, having down its centre a ridge, steep but not pre- 

 cipitous ; to the east is an extensive sand flat by the shore. This 

 volcanic rock is a friable and very crystalline conglomerate, break- 

 ing down into a red coloured earth. About a mile from the south 

 end limestone again recurs ; it is here exceedingly crystalline and 

 much coloured by oxide of iron. At the juncture of the two rocks 

 are some hot springs, in one of which the water is nearly boiling. 

 Here again the limestone appears to have been formed before the 

 eruption of the volcanic rock. The cliffs, however, are not especi- 

 ally precipitous, nor is the amount of water action so great as 

 to lead to the conclusion that so much time had elapsed between 

 the elevation of the limestone and the eruption of the volcanic 

 rock as at Kambara. 



The barrier reef of the whole Exploring Group (Fig. 8) is about 

 80 miles round, lying far distant to the east, but to some extent 

 fringing Munia, Susui and Malatta. Within it round Vanua 

 Mbalavu is a fringing reef, small and inconspicuous off the lime- 

 stone part, projecting indeed little beyond the distance to which 

 this rock overhangs. The general depth of the lagoon is about 

 35 fathoms, with a pool in the centre about 75 fathoms deep; shoals 

 and patches abound in the shallower parts. The passages for such 

 a large lagoon are exceedingly few and small, but all have depths of 

 over 10 fathoms, and around the eastern one the 100 fathom line 

 runs for three miles into the lagoon; the other passages are one to 

 the south, one north-west, and two north, near the island of Sovu. 



Lakemba has flat limestone hills, rising abruptly to a height of 

 60 — 70 feet on the west coast, the foundation being the volcanic 

 conglomerate, which forms the rest of the island. I was informed 

 by the Rev. C. Heighway, resident missionary, that these are 

 frequent round the whole island, and that inland there is generally 

 a small flat at their base; they should then represent an upheaved 

 barrier reef. Inside these the island trends gradually upwards to 

 two peaks in the centre about 700 feet high ; there are good 

 springs of water and deep water-courses. The reef is fringing off 

 the west side, but a distant barrier off the east. 



One to the extreme south, Capt. Wilson stated, has some of the 

 islets coral and some volcanic. He considered the three larger 

 islands in the centre to be the remains of an old crater. 



