ANDREWS: LIMESTONES OF THE FIJI ISLANDS. 15 
The Volcanic Islands. — These include islands like Kandavu, Taviuni, 
Ngau, Nairai, Mbengha, Totoya, and Moala. Some of the islands, like 
Munia and Ovalau, are formed mainly of andesitic agglomerates (Plate 
6) laid down rapidly in thick strata. In these beds occur layers of vol- 
eanic ash, finely comminuted, and filled with beautiful augite crystals. 
Generally this agglomerate consists of angular blocks so firmly welded 
in places as to render the junction of individual blocks almost indistin- 
guishable. On Vanua Mbalavu layers of volcanic conglomerate occur 
with rounded pieces, and this as much as 500 feet above the sea. Again, 
asat Taviuni, on a large scale, and more or less on almost every island in 
the group, streams of lava occur, the so-called “ vata loa”’ of the natives. 
On islands like Taviuni, Mango, Thithia, and Vanua Mbalavu, this 
vesicular Java appears so distinct as to seem but the product of yester- 
day (Plate 8). The basalt appears to have followed the andesite out- 
bursts. Basaltic and andesitic rocks are seen everywhere on Taviuni 
and Mango. Taviuni contains numerous craters, one being nearly 3000 
feet above the sea level, with its rim fully 4000 feet above the sea. 
The Limestone Islands.'— These are very few in number and are small. 
Vatu Vara, Wangava, Wailangilala, Katavanga, and Namuka are the 
only ones I know to be wholly limestone. Fulanga, Karoni, and Aiwa 
I believe may be (in the Lau division) added to this list. The Yasawas 
are limestone, 800 feet high. With the exception of Fulanga, each 
- of the above named is extremely small. They consist of compact lime- 
stones, very flinty in composition, and emitting showers of sparks when 
struck with a large hammer. 
The Limestone and Volcanic [slands.2 — These constitute a numerous 
and important group. Besides the two main islands, it comprises Mango, 
Vanua Mbalavu, Tuvuthaé, Naiau, Lakemba, Kambara, Thithia, and 
Naitamba. These islands were, originally and generally considered, 
lands possessing and presenting as many as six or seven terraces or indi- 
cations of elevation and subsequent reef extension. Subsequently came 
the upheaval which produced the volcanic agglomerates and lava masses. 
These burst through and destroyed a great part of the cliff slopes, and 
more or less filled the old inland lagoon areas. Such has been the case 
particularly with Mango, Thithia, Lakemba, and Vanua Mbalavu. At the 
latter island the force was so immense as to leave only the north and 
south extremities intact, carrying the middle reef formations as high as 
500 and 700 feet above high-water mark, leaving but a miserable meta- 
1 See A. Agassiz, /. c., p. 43. 
2 See A. Agassiz, /. c., p. 88. 
