ANDREWS: LIMESTONES OF THE FIJI ISLANDS. 21 



bases have been indented by the earlier sea at a former period. The whole 

 locality has the aspect of a mangrove swamp left dry by the receding 

 tide, and on a first visit to the place it is hard to disabuse oneself of the 

 idea that here is a modern tide-affected area. Mr. J. N. Lennox, part 

 owner of Thithia, assures me that there is no knowledge of the sea enter- 

 ing that gap. 



The undercutting of cliff bases by sea-erosion is generally confined to 

 limestone areas. At Thithia we have an instance where a volcanic agglom- 

 erate has undergone a similar carving by the action of waves. 1 



As with Mango, huge caverns occur, showing a great development of 

 stalagmite and secondary calcareous incrustations covering the walls. 

 The internal structure (15 yards in) reveals a rock similar in composi- 

 tion to the material of the general cliff face, containing very few corals, 

 and is in hand specimens non-fossiliferous, as is the rule in the raised 

 limestones of Fiji. 



Vanita Mbalavu (Plate 22). — This is literally "the long land." It 

 is a distorted S shape. The belly and middle curves are composed of 

 andesitic lava, andesite agglomerates, andesite basalts, and " talasinga," 

 or burnt earth of the natives. This "talasinga" is a recognizable 

 feature in almost any Fijian landscape. It is a soil arising from volcanic 

 rock decomposition, and is of such a bright red that at times it is used 

 as a pigment. The terminal points of the S consist of high bluffs of 

 elevated limestone, reaching in the north, at Ngillangillah and Mba 

 Vatu, a height of 500, and at the south a height of over 400 feet, at 

 Malatta and Susui islands. The length of the main island is 15 miles, 

 and disposed along the curving backbone of the island are the points of 

 eruption which have so altered the former topography. At the south of 

 the island the volcanic rock has tilted the limestone rocks. 



Vanua Mbalavu, with its associated islands and islets, lies in a barrier 

 reef of pronouuced type (Plate 22). A small patch of the lagoon 

 separates the reef from the mainland to the west, while to the east it 

 retreats for many miles from the land. 



Naitamba (Plates 23, 24) lies 20 miles north of Vanua Mbalavu. It 

 resembles Mango and Thithia in most particulars, but differs as to the 

 extent of the volcanism. The northern extension of the old limestone 

 ring uow lies quite inland, owing to andesite extension at the base of the 

 cliffs. To the south the cliffs have been fractured and lifted to a height 

 of 600 feet above sea-level. 



1 See A. Agassiz, I. c, Plates 62, 63. 



