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 wavyes.? 
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. 
Vanua 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 now lies quitainland, 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, l. c., Plates 62, 65. 
