BY B, SAWYER AND E. C, ANDREWS. 99 



One, however, only was seen by us, the others being difficult of 

 approach. The occurrence was similar to the caves of Thithia. 



6. Vatu Leile. — This island contains caverns on its west coast, 

 partly submarine in habit. They occur at the base of large cliffs, 

 and are of very irregular shape, having the form of large 

 chambers communicating with the sea (lagoon) by means of sub- 

 marine conduits. They are approachable from the land side by 

 openings in the limestone shell encasing them. The cave waters 

 contain multitudes of speckled scarlet prawns of large size. This 

 is a unique occurrence. 



Numerous caves are reported to exist in the raised limestone 

 of Katavanga, Naitamba, Gamia, Tuvutha, Vanua Vatu, the 

 Yangasa and Yasawa clusters. These are said to be similar in 

 character to those of Mango or Thithia. 



D. —The Crevasses in the Submarine Reef-platforms. 



Some of the platforms fringing the various islands of the Lau 

 Group are marvellously cut up by networks of channels. On 

 passing over them at high tide in a small boat the general flat of 

 the reef is seen to be broken repeatedly by chasms and lenticu- 

 larly shaped chambers. 



At Vatu Vara one of these cracks has perpendicular walls, is 

 about 20 feet across, and is at least 200 feet deep. This great 

 depth was not continued throughout the reef to the sea, but 

 shallows away to nothing at the reef edge. 



At a depth it appeared to open out into chamber form.-'' 



At Kambara the whole reef flat is broken up by a series of 

 deep cracks. 



The walls of these crevasses are composed of luxuriant growths 

 of Madrepores, Porites, Pocillopora, etc. 



Mango furnishes similar sights, though on a much smaller scale. 



* It is quite easy to see objects at a depth of 100-120 feet in these clear 

 seas, and this too without the aid of water glasses. 



